Ashish Patil

<p>
 First image I took using my Foldscope. Impressed with the details I could see!
</p>
<figure class="wp-block-image">
 <img alt="IMG_20191111_091211572" class="wp-image-185399 gcloudimg" data-attachment-id="185399" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"800","shutter_speed":"0.0588","title":"","orientation":"1"}' data-image-title="IMG_20191111_091211572" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185398/IMG_20191111_091211572.jpg"/>
 <figcaption>
  Image of an onion peel
 </figcaption>
</figure>


Onion Peel

<figure class="wp-block-image">
 <img alt="IMG_20191113_002141187" class="wp-image-185405 gcloudimg" data-attachment-id="185405" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.04","title":"","orientation":"1"}' data-image-title="IMG_20191113_002141187" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185404/IMG_20191113_002141187.jpg"/>
</figure>
<p>
 Closeup of a filament of a Gardenia flower.
</p>


Gardenia Flower Filament

<figure class="wp-block-image">
 <img alt="IMG_20191113_010534793" class="wp-image-185409 gcloudimg" data-attachment-id="185409" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.0588","title":"","orientation":"1"}' data-image-title="IMG_20191113_010534793" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185408/IMG_20191113_010534793.jpg"/>
 <figcaption>
  Closeup of inner layer of sepal.
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191113_002512830" class="wp-image-185410 gcloudimg" data-attachment-id="185410" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.05","title":"","orientation":"1"}' data-image-title="IMG_20191113_002512830" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185408/IMG_20191113_002512830.jpg"/>
 <figcaption>
  Anther
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191113_012005281" class="wp-image-185411 gcloudimg" data-attachment-id="185411" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"1573608005","copyright":"","focal_length":"4.28","iso":"640","shutter_speed":"0.058823529411765","title":"","orientation":"0"}' data-image-title="IMG_20191113_012005281" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185408/IMG_20191113_012005281.jpg"/>
 <figcaption>
  This flower was used for the study
 </figcaption>
</figure>


Parts of a flower

<figure class="wp-block-image">
 <img alt="IMG_20191116_004446255" class="wp-image-185441 gcloudimg" data-attachment-id="185441" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"400","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_004446255" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185440/IMG_20191116_004446255.jpg"/>
 <figcaption>
  Closeup of anther
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191116_003740109" class="wp-image-185442 gcloudimg" data-attachment-id="185442" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"320","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_003740109" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185440/IMG_20191116_003740109.jpg"/>
 <figcaption>
  Closeup of anther.
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191116_004756902" class="wp-image-185443 gcloudimg" data-attachment-id="185443" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_004756902" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185440/IMG_20191116_004756902.jpg"/>
 <figcaption>
  Connection of anther and filament
 </figcaption>
</figure>


Rose Flower

<figure class="wp-block-image">
 <img alt="IMG_20191116_002925900" class="wp-image-185447 gcloudimg" data-attachment-id="185447" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"1000","shutter_speed":"0.0588","title":"","orientation":"1"}' data-image-title="IMG_20191116_002925900" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185446/IMG_20191116_002925900.jpg"/>
 <figcaption>
  Closeup of underside of a leaf.
 </figcaption>
</figure>


Leaf seen using Foldscope

<figure class="wp-block-image">
 <img alt="IMG_20191111_232115384" class="wp-image-185451 gcloudimg" data-attachment-id="185451" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"1573514475","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.03030303030303","title":"","orientation":"0"}' data-image-title="IMG_20191111_232115384" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185450/IMG_20191111_232115384.jpg"/>
 <figcaption>
  Salt grains seen using a Foldscope
 </figcaption>
</figure>
<p>
</p>


Table salt

<figure class="wp-block-image">
 <img alt="IMG_20191116_013114046" class="wp-image-185455 gcloudimg" data-attachment-id="185455" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"160","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_013114046" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185454/IMG_20191116_013114046.jpg"/>
 <figcaption>
  Stigma of a rose flower showing ‘en abancio’ shape.
  <br/>
  <br/>
  <br/>
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191116_012938280" class="wp-image-185456 gcloudimg" data-attachment-id="185456" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"160","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_012938280" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185454/IMG_20191116_012938280.jpg"/>
 <figcaption>
  Trichomes attached to the style of the flower. Thanks @TeamFoldscope for helping me figure out.
  <br/>
  <br/>
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_a6fzvb" class="wp-image-185457 gcloudimg" data-attachment-id="185457" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"200","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_a6fzvb" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185454/IMG_a6fzvb.jpg"/>
 <figcaption>
  More Trichomes
 </figcaption>
</figure>


Style and Stigma of a rose flower

<p>
 Images of a fern rizome (from a prepared slide that I purchased along with Foldscope).
</p>
<p>
 <em>
  Please don’t hesitate to correct the image captions in case I got them wrong !
 </em>
</p>
<p>
</p>
<figure class="wp-block-image">
 <img alt="IMG_20191116_231812368" class="wp-image-185578 gcloudimg" data-attachment-id="185578" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"640","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_231812368" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185577/IMG_20191116_231812368.jpg"/>
 <figcaption>
  I think the center portion is the Pith, surrounded by Xylem, Phloem and cortex
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191116_231509790" class="wp-image-185579 gcloudimg" data-attachment-id="185579" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"500","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_231509790" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185577/IMG_20191116_231509790.jpg"/>
 <figcaption>
  Closeup of cortex
  <br/>
  <br/>
  <br/>
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191116_232027814" class="wp-image-185580 gcloudimg" data-attachment-id="185580" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"400","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191116_232027814" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185577/IMG_20191116_232027814.jpg"/>
 <figcaption>
  Phloem and cortex closeup
 </figcaption>
</figure>
<h1>
</h1>


Fern Rizome

<p>
 Slide was made using cellotape and paper slide. I cut part of anther and placed it on piece of cellotape. Then placed another piece on top of it and removed it. Then used one of the tapes that just had a layer of pollen grains for observation. Found this technique very effective and convinient.
</p>
<figure class="wp-block-image">
 <img alt="IMG_20191117_231627163_20191119124218095" class="wp-image-185673 gcloudimg" data-attachment-id="185673" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"400","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191117_231627163_20191119124218095" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185672/IMG_20191117_231627163_20191119124218095.jpg"/>
 <figcaption>
  Oval structures with reticulate surface can be observed
 </figcaption>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191117_231249866_20191119124124989" class="wp-image-185674 gcloudimg" data-attachment-id="185674" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"400","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191117_231249866_20191119124124989" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185672/IMG_20191117_231249866_20191119124124989.jpg"/>
</figure>
<figure class="wp-block-image">
 <img alt="IMG_20191117_231627163" class="wp-image-185675 gcloudimg" data-attachment-id="185675" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"Moto G (5) Plus","caption":"","created_timestamp":"0","copyright":"","focal_length":"4.28","iso":"400","shutter_speed":"0.0303","title":"","orientation":"1"}' data-image-title="IMG_20191117_231627163" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_185672/IMG_20191117_231627163.jpg"/>
</figure>
<p>
</p>
<p>
</p>


Pollen from a Spider Lily flower

<figure class="wp-block-image">
 <img alt="insect1" class="wp-image-188533 gcloudimg" data-attachment-id="188533" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="insect1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/insect1.jpg"/>
 <figcaption>
  Insect imaged using the ‘anti-squish’ slide.
 </figcaption>
</figure>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/DAWPD_n-0LU?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  The slide allows insect to be observed while it is in motion !
 </figcaption>
</figure>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/orec-W3nMK0?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  If you see this video in 720p , you might be able to see some heartbeat like thing happening inside the belly of this insect !
 </figcaption>
</figure>
<h3 id="Introduction">
 Introduction
</h3>
<p>
 Ever since I got my hands on a
 <a href="https://www.foldscope.com/" rel="noreferrer noopener" target="_blank">
  Foldscope
 </a>
 , I have been pretty much
 <a alt="patilsaheb" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/patilsaheb" rel="noreferrer noopener" target="_blank">
  obsessed with it
 </a>
 . I have used the Foldscope to see and discover many interesting things. One fun activity, I am sure every Foldscope user must have tried, is observing insects using a Foldscope.
</p>
<p>
 If you have ever tried observing insects you might have realized that, there is a tendency of insects getting ‘squished’ due the magnets and foccusing mechanism of the Foldscope. I wanted to find a way to capture live and moving insects using Foldscope. The below write-up discusses in-detail a method of creating a ‘anti-squish’ slide for foldscope and observing insects using it.
</p>
<h3 id="Items-needed">
 Items needed
</h3>
<figure class="wp-block-image">
 <img alt="slide1" class="wp-image-188538 gcloudimg" data-attachment-id="188538" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"1"}' data-image-title="slide1" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/slide1-1.jpg"/>
</figure>
<ul>
 <li>
  Transparent nail polish (or some sort of transparent super glue).
 </li>
 <li>
  Glass slide
 </li>
 <li>
  Coverslip
 </li>
 <li>
  Plastic thread (something similar to one used for attaching price tags to apparels in malls and super markets).
 </li>
 <li>
  Bits of white paper
 </li>
 <li>
  Some patience !!
 </li>
</ul>
<h3 id="Creating-the-‘anti-squish’-slide">
 Creating the ‘anti-squish’ slide
</h3>
<p>
 Actually the idea is very simple. We want to glue the thread between the coverslip and the slide, along the borders , such that a cavity or air-gap is created between the slide and coverslip.
</p>
<p>
 For my experiment, I used a rectangular coverslip because it is easiler to bend the thread along the edges of coverslip and gule it.
</p>
<blockquote class="wp-block-quote">
 <p>
  Only glue on three sides of the coverslip. We will leave one side open as that will allow us to push small insects in the ‘glass-box’ we created.
 </p>
</blockquote>
<p>
 I used transparent nail-polish as a glue, but using a commercial transparent super-glue should work much better in my opinion.
</p>
<figure class="wp-block-image">
 <img alt="slide2" class="wp-image-188539 gcloudimg" data-attachment-id="188539" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"1"}' data-image-title="slide2" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/slide2.jpg"/>
</figure>
<figure class="wp-block-image">
 <img alt="slide3" class="wp-image-188540 gcloudimg" data-attachment-id="188540" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"1"}' data-image-title="slide3" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/slide3.jpg"/>
</figure>
<p>
 It must be noted that the air-gap needs to be very small, which means the plastic thread used to create the gap should be  thin. This results in a limitation that only very small insects (smaller than ants) can be viewed. You may be tempted to use a much thicker thread to create more head-room, but I should caution you that you may struggle with focusing.
</p>
<p>
 However, if you are able to design something that allows larger insects like ants to be observed please let us know !!
</p>
<h3 id="Observing-insects-using-this-slide">
 Observing insects using this slide
</h3>
<figure class="wp-block-image">
 <img alt="slide4" class="wp-image-188541 gcloudimg" data-attachment-id="188541" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"1"}' data-image-title="slide4" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_188531/slide4.jpg"/>
</figure>
<p>
 Ok, this is the fun part. This is what I typically do:
</p>
<ul>
 <li>
  Use a pointed object like needle or toothpick to transfer the insect or larvae on the glass slide first (near the open end).
 </li>
 <li>
  Now use a long strip of paper and gently push the specimen inside the cavity we created. Be gentle and try not to harm the insect in process.
 </li>
 <li>
  Push the specimen all the way inside towards the sealed walls. Since we have left one side of our glass-box open, there is a tendency of the coverslip bending near the open slide and ‘squishing’ the specimen, when we try to focus using our focusing mechanism of Foldscope.
 </li>
 <li>
  I have also tried to insert very tiny bits of papers inside the slide surrounding the specimen. It serves two purposes:
  <ul>
   <li>
    It puts limitations on movement of the insect. Also provides required support to the insect to re-orient itself and possibly expose different organs as it tries to moves through the bits of papers.
   </li>
   <li>
    It allows for scattering of light. This is very important for us to be able to see all sides of the insects
   </li>
  </ul>
 </li>
 <li>
  Use a strong LED light source for illuminating the specimen.
 </li>
</ul>
<h3 id="Doing-more">
 Doing more
</h3>
<p>
 Though the primary intention of this technique was to observe insects, there are many cool things you can try to observe using this technique, like :
</p>
<ul>
 <li>
  You can culture things like fungi and moss inside the slide and monitor their growth.
 </li>
 <li>
  You can try to observe various stages of an insect’s life-cycle (eggs –&gt; larvae –&gt; insect).
 </li>
 <li>
  Observe how insects feed. How they interact with each other.
 </li>
 <li>
  Germinating seeds can be observed. It would be fun to see cotyledons, roots and shoots !!
 </li>
</ul>
<h3 id="Finally">
 Finally
</h3>
<p>
 Hope you found my experiment intresting. If you decide to make this type of slide, please do share your findings with me and the Foldscope community.
</p>


Creating &#8216;anti-squish&#8217; slides for observing insects using Foldscope

<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/SDsHBp8nBEQ?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  <br/>
  There are three types of organisms one can see in above video, the round one, the long one and couple of amoeba
 </figcaption>
</figure>
<p>
 Last year, I was introduced to a wonderful scientific instrument called the ‘Foldscope’. I have spent hours observing things with it. One of my favorite past times is to observe ciliates using the Foldscope. Ciliates are very simple single cell organisms which are easy to find and come in numerous shapes and sizes. Most ciliates move very fast, and you need some skill with a microscope to follow them on the slide. This inspired me to write some code that could detect moving objects in a video and draw rectangles around them. Amazingly, I believe I was able to do a decent job with under 60 lines of python code (
 <a alt="motiondetection" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_192767/motiondetection">
  https://github.com/code2k13/motiondetection
 </a>
 )
</p>
<p>
 In this post I will discuss concepts which I used for detecting moving objects and how the work together to come up with the end results.
</p>
<h3>
 <strong>
  Reading videos with Python and OpenCV
 </strong>
</h3>
<p>
 The first thing we need to be able to do is load frames one by one from a video. OpenCV makes this task very easy. OpenCV has a very convenient function called ‘
 <em>
  cv2.VideoCapture
 </em>
 ’ which returns an object that can be used to find out information about the video (like width, height, frame rate). The same object allows us to read a single frame from the video by calling ‘
 <em>
  read()
 </em>
 ’ method on it. The ‘
 <em>
  read()
 </em>
 ’ method returns two values, a boolean indicating success of the operation and the frame as an image.
</p>
<pre class="wp-block-code python"><code>cap = cv2.VideoCapture("video_input.mp4") 
if cap.isOpened(): 
    width  = cap.get(3) # float
    height = cap.get(4) # float
    fps = cap.get(cv2.CAP_PROP_FPS)</code></pre>
<p>
 The full video can be read frame by frame using following code:
 <br/>
</p>
<pre class="wp-block-code"><code>success = True
while success:
    success,frame = cap.read() 
    if not success:
        break
    #do something with the frame</code></pre>
<h3>
 <strong>
  Writing videos using OpenCV
 </strong>
</h3>
<p>
 Writing videos with OpenCV is also very easy. Similar to ‘
 <em>
  VideoCapture
 </em>
 ’ function, the  ‘
 <em>
  VideoWriter
 </em>
 ’ function can be used to write video , frame by frame. This function expects path of output video, codec information, frames per second, width and height of output video as parameters.
</p>
<pre class="wp-block-code"><code>fourcc = cv2.VideoWriter_fourcc('m','p','4','v')
out = cv2.VideoWriter('video_output.mp4',fourcc , int(fps), (int(width),int(height)))</code></pre>
<p>
 Writing a frame to the video is as easy as calling:
</p>
<pre class="wp-block-code"><code>out.write(image_obj)</code></pre>
<h3>
 <strong>
  Finding frame difference
 </strong>
</h3>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/PdOXJt3mMD0?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  <br/>
  The above video was generated out of frame diffs from the original video
 </figcaption>
</figure>
<p>
 Images are represented as matrices in the memory. OpenCV has a function called ‘
 <em>
  cv2.absdiff()
 </em>
 ’ which can be used to calculated absolute difference of two images. This is the basis of our motion detection. We are relying on the fact that when something in the video moves ‘
 <em>
  absdiff ‘
 </em>
 will be non zero for those pixels. However if something is stationary and has not moved in two consequent frames, the
 <em>
  absdiff
 </em>
 will be zero. So, as we read the video frame by frame, we compare current frame with older frame and calculate
 <em>
  absdiff
 </em>
 matrix.
 <br/>
</p>
<p>
 Sounds easy , right ? But there are some problems with this approach. Firstly, cameras and software produce artifacts when they capture and encode videos. Such artifacts give us non-zero diff even when the object is stationary .  Uneven lighting and focusing can also cause non-zero diffs for stationary portions of videos.
 <br/>
</p>
<p>
 After experimenting with some approaches, I found out that thresholding the diff image using mean values works very well to eliminate such ‘noise’
 <br/>
</p>
<pre class="wp-block-code"><code>frame_diff[frame_diff &lt; frame_diff[np.nonzero(frame_diff)].mean()] = 0
frame_diff[frame_diff &gt; frame_diff[np.nonzero(frame_diff)].mean()]</code></pre>
<h3>
 <strong>
  Using edge detection to improve accuracy
 </strong>
</h3>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/gkm9Ch0u-XU?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  <br/>
  Edge detection using ‘Sobel’ filter performed on the frame diff video
 </figcaption>
</figure>
<p>
 As microorganisms move, they push matter around them, which gives positive pixels after diff-ing. But we want to differentiate micro-organisms from other things. Also focusing plays an important part here. Generally a lot of  out of focus moving objects will also give positive frame differences. Mostly these are blurred objects which we simply want to ignore. This is where edge detection comes into play, to find edges and borders in the image. This can be easily achieved by using
 <em>
  ‘Sobel
 </em>
 ‘ filter from scikitlearn package.
</p>
<pre class="wp-block-code"><code>from skimage import filters
output = filters.sobel(frame_diff)</code></pre>
<h3>
 Using contour detection to detect objects
</h3>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/WvaO9ieQTyM?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  <br/>
  Video generated after performing contour detection on the Sobel filter output
 </figcaption>
</figure>
<p>
</p>
<p>
 Most protozoans like ciliates will not always show a clear border (because they are mostly transparent). So when we use edge detection to detect shapes/outlines of moving objects, we get broken edges. In my experience contour detection works very well to group such broken edges and generate a more continuous border.
</p>
<pre class="wp-block-code"><code>contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)</code></pre>
<p>
 OpenCV has built-in functions to find contours. The best part is, the function is able to find nested contour structures and return a hierarchy. The ‘
 <em>
  cv2.findCountours
 </em>
 ‘ function returns a hierarchy of contours. We only consider top level contours (who don’t have a parent). If, for  a contour ‘
 <em>
  idx
 </em>
 ‘ ,  ‘
 <em>
  hierarchy[0][idx][3]
 </em>
 ‘ returns -1, it means that it is a top level contour and it does not have any parent. Everything else we ignore.
</p>
<h3>
 <strong>
  Drawing bounding boxes around objects
 </strong>
</h3>
<figure class="wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio">
 <div class="wp-block-embed__wrapper">
  <div class="jetpack-video-wrapper">
   <span class="embed-youtube" style="text-align:center; display: block;">
    <iframe allowfullscreen="true" class="youtube-player" height="563" src="https://www.youtube.com/embed/Vcz49aZtVZQ?version=3&amp;rel=1&amp;fs=1&amp;autohide=2&amp;showsearch=0&amp;showinfo=1&amp;iv_load_policy=1&amp;wmode=transparent" style="border:0;" type="text/html" width="1000">
    </iframe>
   </span>
  </div>
 </div>
 <figcaption>
  <br/>
  Video showing bounding boxes drawn over contours
 </figcaption>
</figure>
<p>
 Creating boxes around contours can require a bit of math. Luckily OpenCV has a convenient function ‘
 <em>
  cv2.boundingRect
 </em>
 ‘ which returns center coordinates, width and height of bounding rectangle around a given contour. Once we have that, a rectangle on our frame can simply be drawn using
 <em>
  cv2.rectangle
 </em>
 function. We can pass the color and border-width when drawing the rectangle to this function.
</p>
<pre class="wp-block-code"><code>if hierarchy[0][idx][3]== -1 :
    x,y,w,h = cv2.boundingRect(contour)
    if (w*h &lt;= (q)**2):
        continue
    image = cv2.rectangle(image, (x,y),(x+w,y+h), color, 1)
</code></pre>
<h3>
 <strong>
  The concept of ‘q’
 </strong>
</h3>
<p>
 Like I explained earlier, videos taken using a microscope can be messy. There can be a lot going on. We may be only interested in detecting objects of a certain size. This is where I have introduced a parameter called ‘q’. This parameter was used for altering settings for various filters I experimented with. Currently this is only used to filter out bounding rects which are smaller than q^2 in area. You should experiment with different values of ‘q’ , depending on the resolution of your video and size of objects you are interested in.
</p>
<h3>
 <strong>
  Things to improve
 </strong>
</h3>
<p>
 I want to make this approach fast enough so that it can run in real time. Also it would be nice if I can get this ported to a mobile phone. I also plan to experiment with ML based segmentation techniques for better detection.
</p>
<h3>
 Full code
</h3>
<p>
 The full code , along with sample video is available on GitHub:
</p>
<p>
 <a alt="motiondetection" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_192767/motiondetection">
  https://github.com/code2k13/motiondetection
 </a>
 <br/>
</p>


Motion detection in Foldscope videos using Python and OpenCV

<blockquote class="wp-block-quote">
 <p>
  👏This work was possible due to lot of support and guidance from Karthick Balasubramanian of the
  <a href="https://sites.google.com/view/d3lab/">
   D3 LaB
  </a>
  . He is a expert on diatoms and has provided valuable advice for carrying these experiments
 </p>
</blockquote>
<blockquote class="wp-block-quote is-style-default">
 <p>
  📌
  <strong>
   Safety Considerations
  </strong>
 </p>
 <p>
  Even though the experiments mentioned in the below article use household chemicals like laundry bleach and adhesives, these can be harmful if used inappropriately. Please read all safety considerations marked by ‘⚠️’ at important places in the article. Proceed with the experiments ONLY IF YOU UNDERSTAND ALL THE SAFETY CONSIDERATIONS. Adult supervision is recommended.
 </p>
</blockquote>
<figure class="wp-block-image">
 <img alt="diatoms_collage" class="wp-image-207008 gcloudimg" data-attachment-id="207008" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="diatoms_collage" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/diatoms_collage.png"/>
 <figcaption>
  Diatoms from a single slide, collected and observed using the method described in this article. The sample was not known to contain diatoms it was collected for studying algae.
 </figcaption>
</figure>
<p>
 Diatoms are some of the most interesting things you can see under a foldscope.  They  generate about 20-50% oxygen on earth every year.
 <br/>
 They are also known as  “jewels of the sea” and “living opals”. It is believed that there are around 200000 species of diatoms. Identification of diatoms can be done by observing the shape and marks on their ‘frustules’.
 <br/>
 A frustule is the siliceous part of a diatom cell wall. Under a microscope they look like different shaped glass beads with various engravings on them.
</p>
<p>
 To observe these frustules, we have to ‘clean’ the diatoms. We need to remove pigments and matter inside the diatom cell, so that we observe these ‘frustules’ under a microscope and identify the species of diatoms. There are well established laboratory methods for doing this. These involve use of hazardous chemicals , acids and heat. These methods are not suitable for use in a school or at home. This article explains a simpler and much safer method for cleaning and mounting diatoms.
</p>
<h2>
 What you will need
</h2>
<p>
 You will need the following items:
</p>
<ul>
 <li>
  Centrifuge Tubes (easily available online)
 </li>
 <li>
  Pipettes (easily available online)
 </li>
 <li>
  Fevi kwik (transparent general purpose instant adhesive)
 </li>
 <li>
  Vanish (or similar laundry bleach/detergent additive)
 </li>
 <li>
  Piece of strong thread
 </li>
 <li>
  Glass slides and coverslips
 </li>
 <li>
  Water sample containing diatoms
 </li>
 <li>
  Patience
 </li>
</ul>
<figure class="wp-block-image">
 <img alt="IMG_20220210_080840863" class="wp-image-207009 gcloudimg" data-attachment-id="207009" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644480521","copyright":"","focal_length":"4.74","iso":"330","shutter_speed":"0.03030303030303","title":"","orientation":"1"}' data-image-title="IMG_20220210_080840863" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/IMG_20220210_080840863.jpg"/>
</figure>
<h2>
 Collecting Diatoms
</h2>
<p>
 Diatoms are present in abundance in most saltwater and freshwater bodies. For the purpose of this experiment I collected a small sample of water from an artificial pond . The pond was filled with algae, and I wasn’t aware if it had any diatoms in it. You can try collecting water from different places and check it for diatoms.  You can also follow instructions mentioned in this YouTube video:
 <a alt="watch" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/watch">
  Diatoms. Part 1: Introduction and collection of diatoms – YouTube
 </a>
</p>
<p>
 <br/>
</p>
<h2>
 Cleaning Diatoms
</h2>
<p>
 This is the most important and time consuming part of the process. Cleaning helps remove matter inside the diatom cell and separate diatoms from other debris. Labs use acids and other chemicals for this process. We will use a laundry bleach (Vanish brand available in India) to do the same. This particular item is sold as a detergent additive and claims to have 10x more oxidizing power compared to a normal detergent (just what we want !).
</p>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️ Adult supervision is recommended. Be very careful when working with bleach of any kind. Wear gloves if you are not sure how strong the bleach is. Avoid spilling bleach on your skin and other body parts.  Read information on the packet/box before using. Consult an expert if you are unsure.
</p>
<p>
 Here are the steps for cleaning the diatoms:
</p>
<p>
 <strong>
  STEP 1
 </strong>
 <br/>
 Take about 30ml of water and mix 1/4 teaspoon of the detergent additive (Vanish) in it, in an
 <strong>
  OPEN container
 </strong>
 . Make sure it is fully dissolved. The quantity of water and amount of bleach would depend on the strength of your bleach.
</p>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️ DO NOT keep this solution in a closed or airtight container, because gases can build up pressure inside the container.
</p>
<figure class="wp-block-image">
 <img alt="ezgif-5-3c0770a1b3" class="wp-image-207063 gcloudimg" data-attachment-id="207063" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="ezgif-5-3c0770a1b3" data-recalc-dims="1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/ezgif-5-3c0770a1b3-1.gif"/>
 <figcaption>
  Oxidation of the sample causes generation of bubbles and release of gas. Keep the tube open.
 </figcaption>
</figure>
<p>
 <strong>
  STEP 2
 </strong>
 <br/>
 Take a few drops of water from the sample you have collected using a pipette in a centrifuge tube. Try to take few drops from the bottom of the sample. It is fine if there is some algae and debris in it.
</p>
<p>
 <strong>
  STEP 3
 </strong>
 <br/>
 Add 10 – 15 drops of the bleach solution we created in STEP 1 and let the solution settle for some time, say 60 minutes.
</p>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️ DO NOT close the cap on this centrifuge tube. You should see air bubbles inside the tube as the sample gets oxidised.
</p>
<p>
 <strong>
  STEP 4
 </strong>
 <br/>
 Once there are no more air bubbles or their generation has slowed down considerably, we need to centrifuge the mixture. Before that we should remove all the excess liquid very carefully from the tube using a pipette. Just leave behind the settled in debris at the bottom and only a 0.5 cm deep layer of water on top of it. Once we have gotten rid of most of the bleach, we should fill half of the tube with clean water.
</p>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️  Excess gas buildup in closed tube can be dangerous. We are getting rid of most of the bleach before centrifuging the mixture. This should ensure that gas build up during the centrifugation process is minimal and mitigates any risk.
</p>
<p>
 <strong>
  STEP 5
 </strong>
 <br/>
 Screw in the cap on the centrifuge tube. Tie a 30-40 cm long thread tightly just below the cap as shown in the below figure.
</p>
<figure class="wp-block-image">
 <img alt="IMG_20220208_100117432" class="wp-image-207010 gcloudimg" data-attachment-id="207010" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644314478","copyright":"","focal_length":"4.74","iso":"193","shutter_speed":"0.02","title":"","orientation":"1"}' data-image-title="IMG_20220208_100117432" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/IMG_20220208_100117432.jpg"/>
 <figcaption>
  DIY centrifuge !!
 </figcaption>
</figure>
<p>
 <strong>
  STEP 6
 </strong>
 <br/>
 Hold one end of the thread in your hand and start moving the tube in circles in a horizontal plane as shown in below the figure for a minute.
</p>
<figure class="wp-block-image">
 <img alt="centriguge" class="wp-image-207020 gcloudimg" data-attachment-id="207020" data-comments-opened="1" data-image-meta='{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}' data-image-title="centriguge" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/centriguge-1.png"/>
 <figcaption>
  DIY Centrifuge
 </figcaption>
</figure>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️ Make sure the thread is strong and tightly tied around the base of the centrifuge cap. Also ensure that you do this in open space to avoid hurting anyone or hitting anything.
</p>
<p>
 <strong>
  STEP 7
 </strong>
 <br/>
 Remove the cap of the centrifuge tube carefully and put it back on after a few seconds to let any gases escape. Keep it standing still on its pointed end for about 10 minutes by  resting it vertically against a wall. You should see matter settling down  at the bottom of the tube.
</p>
<p>
 <strong>
  STEP 8
 </strong>
 <br/>
 At this stage  remove the cap of the centrifuge tube again and very carefully remove excess water using a pipette while leaving the matter at the base of the tube intact. I generally keep a thin layer of water (0.5 cm) above the settled debris. Now fill the tube carefully with clean water so that it is half full. Repeat steps 6,7 and 8 two more times to wash out any bleach or soap remaining inside the tube.
</p>
<p>
 <strong>
  STEP 9
 </strong>
 <br/>
 Remove all excess water , keeping a thin layer of water (say 0.5 cm) above the settled down matter. Keep the tube in a vertical position all the time, do not invert the tube.
</p>
<p>
 Congratulations !! You have cleaned your first batch of diatoms. It is now time to mount them on a slide.
</p>
<h2>
 Creating the slide
</h2>
<p>
 Once the mixture in the tube has settled down, it is time to create a slide. You can create a slide from this sample without using any mounting medium.  But I would highly recommend using a mounting medium for two reasons:
</p>
<ol>
 <li>
  In the Foldscope, slides are held vertically when viewing.
 </li>
 <li>
  The coverslip and slide are pressed hard together by two magnets on both sides. This can put a lot of pressure on cover slip, especially during focusing. Diatom frustules are fragile and may break.
 </li>
</ol>
<p>
 There are many high refractive index mounting mediums which are used for diatoms like Naphrax, Zrax, Pleurax and Hyrax , which may be hard to find (depending on where you live) and expensive. Also heating is involved when using them and toxic fumes are released on heating them. I tried to use Pleurax and heated the slide using a  candle. The medium did not harden and my slide was sticky and a total mess to work with. This is why I recommend using ‘Fevi kwick’ or any of those general purpose transparent  liquid instant adhesives (these go by different brand names). These are cheap and readily available. But there is one problem, they harden very fast, in a matter of a couple of seconds. You have to be very precise with your slide placement in the first attempt itself. You won’t be able to adjust the slide after it makes contact with the adhesive.
</p>
<p class="has-text-color has-background has-vivid-red-color has-very-light-gray-background-color">
 ⚠️ Please read information on the adhesive packet about safety and usage.  Wear gloves if required. These things are super sticky and are not easily removable if they come in contact with your skin or fingers.
</p>
<p>
 To mount the diatom specimen follow these steps:
</p>
<p>
 <strong>
  STEP 1
 </strong>
 <br/>
 Using a pipette, take only a couple of drops of water from the very end of centrifuge tube containing the cleaned diatoms. This can be tricky. If you take in more water , hold the pipette still in a vertical position for a  couple of minutes.
</p>
<p>
 <strong>
  STEP 2
 </strong>
 <br/>
 Now carefully place a drop of this water from the pipette onto the centre of an empty glass slide. Spread the drop slightly using the same pipette so as to cover area equal to that of a cover slip.
</p>
<p>
 <strong>
  STEP 3
 </strong>
 <br/>
 Let the slide dry. This can take a  few minutes. You should see white powdery residue on the slide. This residue contains our diatoms.
</p>
<p class="has-background has-light-green-cyan-background-color">
 ✔️ If you don’t want to work with adhesives , you can skip steps 4,5 and 6. Instead just place a cover slip on the white powdery portion, secure the sides with transparent tape and move to step 7.
</p>
<p>
 <strong>
  STEP 4
 </strong>
 <br/>
 Now very carefully place a drop of adhesive on top of the powdery spot on the slide.
</p>
<p>
 <strong>
  STEP 5
 </strong>
 <br/>
 Hold the coverslip using tongs (recommended) or your fingernails (wearing gloves recommended) and place it on the adhesive drop. Immediately the tap center of the coverslip gently using a blunt object.
</p>
<p>
 <strong>
  STEP 6
 </strong>
 <br/>
 The coverslip will stick to the slide within a couple of seconds. If you made a mistake you will have to start over with new a slide and coverslip. (Always save some sample for such scenarios).
</p>
<p>
 <strong>
  STEP 7
 </strong>
 <br/>
 Congratulations !! You have created a slide out of your diatom sample.
</p>
<figure class="wp-block-image">
 <img alt="IMG_20220209_201619208" class="wp-image-207018 gcloudimg" data-attachment-id="207018" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644437779","copyright":"","focal_length":"4.74","iso":"4399","shutter_speed":"0.1","title":"","orientation":"1"}' data-image-title="IMG_20220209_201619208" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/IMG_20220209_201619208.jpg"/>
 <figcaption>
  Permanent slide using transparent instant adhesive.
 </figcaption>
</figure>
<h2>
 Viewing the Slide and Taking Pictures
</h2>
<p>
 If you plan to take pictures of these diatoms, make sure you have the  LED Magnifier attachment  for Foldscope.
 <br/>
 <a alt="led-mangifier-kit" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/led-mangifier-kit">
  LED Magnifier Kit – (Contains 20 LED/Magnifier Lights. This does not i – Foldscope Instruments, Inc. (teamfoldscope.myshopify.com)
 </a>
</p>
<p>
 Proper lighting and focus is very important for capturing the details of diatoms. From my personal experience I have found some mobile phone cameras are better at focusing when used with Foldscope compared to others. Take lots of pictures and upload the best ones here on microcosmos.  Below are some more images taken from a single slide created using the technique explained in this article.
</p>
<figure class="wp-block-image">
 <img alt="IMG_20220209_175534994_2" class="wp-image-207032 gcloudimg" data-attachment-id="207032" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644429335","copyright":"","focal_length":"4.74","iso":"380","shutter_speed":"0.03030303030303","title":"","orientation":"1"}' data-image-title="IMG_20220209_175534994_2" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/IMG_20220209_175534994_2.jpg"/>
</figure>
<figure class="wp-block-image">
 <img alt="wp_foldscope3" class="wp-image-207033 gcloudimg" data-attachment-id="207033" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644431604","copyright":"","focal_length":"4.74","iso":"422","shutter_speed":"0.03030303030303","title":"","orientation":"1"}' data-image-title="wp_foldscope3" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/wp_foldscope3.jpg"/>
</figure>
<figure class="wp-block-image">
 <img alt="wp_foldscope2" class="wp-image-207034 gcloudimg" data-attachment-id="207034" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644530912","copyright":"","focal_length":"4.74","iso":"386","shutter_speed":"0.03030303030303","title":"","orientation":"1"}' data-image-title="wp_foldscope2" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/wp_foldscope2.jpg"/>
</figure>
<figure class="wp-block-image">
 <img alt="wp_foldscope1" class="wp-image-207035 gcloudimg" data-attachment-id="207035" data-comments-opened="1" data-image-meta='{"aperture":"1.7","credit":"","camera":"moto g(40) fusion","caption":"","created_timestamp":"1644530465","copyright":"","focal_length":"4.74","iso":"389","shutter_speed":"0.03030303030303","title":"","orientation":"1"}' data-image-title="wp_foldscope1" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/wp_foldscope1.jpg"/>
</figure>
<p>
 Hope this information was useful to you all. Please share your comments and suggestions. Happy diatom hunting !!
</p>
<h2>
 References
</h2>
<p>
 <a alt="watch" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/watch">
  Diatoms. Part 1: Introduction and collection of diatoms – YouTube
 </a>
</p>
<p>
 <a alt="watch" class="gcloudimg" href="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_207003/watch">
  Diatoms. Part 2: Preparation of permanent slide) – YouTube
 </a>
</p>
<p>
 <a href="http://microcosmos.foldscope.com/?p=20005">
  Microjewels. – Microcosmos (foldscope.com)
 </a>
</p>


Ashish Patil

Earth

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