Micro-cam or Web-croscope

Here you can discuss DIY adaptations to the microscope.
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Joel_U
Posts: 8
Joined: Wed Feb 10, 2021 2:25 pm

Micro-cam or Web-croscope

#1 Post by Joel_U » Mon Feb 22, 2021 7:51 am

Hello,
As Hobby Brewers, we use an old microscope to check our yeast. It works well but the brewery is not "microscope friendly" because of the moisture, dust, vibrations. Something simple, robuste and cheap could be a good solution. On the web I found this :
https://hackteria.org/wiki/DIY_microscopy
A webcam, just reverse the lens, 3 threaded rods, 3 springs, 3 screws, 2 pieces of wood and you get this :
Cam-croscope201.jpg
Cam-croscope201.jpg (25.76 KiB) Viewed 194 times
You add a lamp, a Neubauer cell, a drop of yeast suspension and you get this :
comptage_levures_webcam.jpg
comptage_levures_webcam.jpg (38.77 KiB) Viewed 194 times
We can easily count the yeast even if the light is far from perfect.
Counting is the first step but we also need to test the viability adding some methylene blue. Dead cells turn blue and the alive one stay translucent.
Probleme : I can only get pictures in gray levels, no colour. I changed the light, dimm, add a kind of diaphragme, check that the webcam is not a black and white. Whenn I put the lens the right way on the cam I get some colour meaning that the driver I use is ok.
Any idea how to get some colour ? Why I loose the colours just reversing the lens ?
I could go that way :
https://www.osapublishing.org/boe/fullt ... &id=429869
Using a webcam with a real microscope objective and an additional lens... But it is much more expensive than just reversing a lens.
Joël UGHETTO

Placozoa
Posts: 34
Joined: Tue Jan 05, 2021 10:41 am

Re: Micro-cam or Web-croscope

#2 Post by Placozoa » Mon Feb 22, 2021 8:26 am

My guess would be that you are shining the light through the colored (grey) plastic causing it to act as a filter. Did you try adding an additional top light? Maybe a little flashlight or something above shining down?

MichaelG.
Posts: 2615
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: Micro-cam or Web-croscope

#3 Post by MichaelG. » Mon Feb 22, 2021 8:41 am

.

I can’t guarantee it, Joel ... but

I think you would get much better results by adding a reversed lens to the the front of the existing lens.
This has been demonstrated very successfully [using iPhone] in the literature
... if I can find the link, I will post it here.

The loss of colour is probably because light is now reaching the sensor at the wrong angle.

Great project !

MichaelG.
.
.
Edit: __ Found it quicker than I expected
https://journals.plos.org/plosone/artic ... ne.0095330
Last edited by MichaelG. on Mon Feb 22, 2021 8:46 am, edited 1 time in total.
Too many 'projects'

MicroBob
Posts: 2518
Joined: Sun Dec 25, 2016 9:11 am
Location: Northern Germany

Re: Micro-cam or Web-croscope

#4 Post by MicroBob » Mon Feb 22, 2021 8:45 am

Hi Joël,
interesting setup!
The colours depend on the illumination beam. Then using weak objectives and removes the condenser from a normal biological microscope to illuminate the full image the colours become quite subdued while sharpness is still good. So you might need a better illumination with a focussed beam. This could be had when using a condenser lens e.g. a fat plano-convex lens. The light source musn't be point-like but an evenly lit surface of e.g. 40mm diameter. This could be an LED panel with a diffuser on top. The "objective" of the camera might also contribute. By not being achromatic it might lead to washed out colours. Perhaps you can use an objective from an old analog pocket camera or film camera?

Bob

Scarodactyl
Posts: 1220
Joined: Sat Mar 03, 2018 9:09 pm

Re: Micro-cam or Web-croscope

#5 Post by Scarodactyl » Mon Feb 22, 2021 8:42 pm

If you're getting no color at all I'd guess you hsve a hardware failure, either a bad cable or something inside the camera.

hans
Posts: 697
Joined: Thu May 28, 2020 11:10 pm
Location: Southern California

Re: Micro-cam or Web-croscope

#6 Post by hans » Tue Feb 23, 2021 4:45 am

Joel_U wrote:
Mon Feb 22, 2021 7:51 am
...check that the webcam is not a black and white. Whenn I put the lens the right way on the cam I get some colour meaning that the driver I use is ok.
Strange, ImageMagick indicates the image is greyscale:

Code: Select all

hans@uganik ~/Downloads identify -verbose comptage_levures_webcam.jpg 
Image:
  Filename: comptage_levures_webcam.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 640x480+0+0
  Units: Undefined
  Colorspace: sRGB
  Type: Grayscale
...
  Colors: 209
  Histogram:
    1: (36,36,36) #242424 grey14
    1: (44,44,44) #2C2C2C srgb(44,44,44)
    1: (45,45,45) #2D2D2D srgb(45,45,45)
    1: (48,48,48) #303030 grey19
    1: (50,50,50) #323232 srgb(50,50,50)
    2: (51,51,51) #333333 grey20
    1: (52,52,52) #343434 srgb(52,52,52)
    1: (53,53,53) #353535 srgb(53,53,53)
    2: (54,54,54) #363636 grey21
    4: (56,56,56) #383838 grey22
    1: (57,57,57) #393939 srgb(57,57,57)
What camera is it, exactly? Seems unlikely, but is there any possible way the camera could sense that the lens is removed, affecting the behavior of the software?

Joel_U
Posts: 8
Joined: Wed Feb 10, 2021 2:25 pm

Re: Micro-cam or Web-croscope

#7 Post by Joel_U » Tue Feb 23, 2021 7:30 am

Thank you for all those comments.
This was an old project 2019, I haven't got the cam anymore BUT, I will soon scavenge/slaughter a new one :twisted:
To do : add a light condenser and an iris diaphragme.
Check the positionning of the reverse objective which has to be as perpendicular to the sensor as possible (I hope you understand what I mean).
Use a real microscope objective instead of the cam reversed one.
Come back and give you a full account of my actions.
Joël UGHETTO

MichaelG.
Posts: 2615
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: Micro-cam or Web-croscope

#8 Post by MichaelG. » Tue Feb 23, 2021 10:48 pm

MichaelG. wrote:
Mon Feb 22, 2021 8:41 am
.

I can’t guarantee it, Joel ... but

I think you would get much better results by adding a reversed lens to the the front of the existing lens.

[ etc. ]
.

I’m glad I didn’t offer that guarantee !!

Although the idea demonstrably works with the iPhone lens, my quick & dirty attempt [today] with a cheap little webcam was a miserable failure. ... I suspect that the ‘beauty ring’ on the front of each lens means the front elements are too far apart.

[ further butchery is required; I will report back if I have any success ]

MichaelG.
Too many 'projects'

Joel_U
Posts: 8
Joined: Wed Feb 10, 2021 2:25 pm

Re: Micro-cam or Web-croscope

#9 Post by Joel_U » Wed Feb 24, 2021 7:20 am

Thank you very much for this report Michael.
Last year I tried the Smartphone + reverse smartphone lens proposed in the publication. I have not been able to obtain any good result. I probably failed positioning correctly the 2 lenses + the sample + a good illumination at the same time.
Obtaining the first picture (Neubauer cell and Yeast) was really easy and I could reproduce it. In the publication, they show well stained cheek cells. We would like to see yeast... Very different stuff (size, color, contrast) :oops:
Feel free to report your attemps in this post. Negative results are as important as positive one ... And in my case much more numerous.
Joël

MichaelG.
Posts: 2615
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: Micro-cam or Web-croscope

#10 Post by MichaelG. » Wed Feb 24, 2021 9:38 am

.

Here’s a useful description of what Joel is doing:
https://www.whitelabs.com/beer/cell-cou ... ty-testing

MichaelG.
.

P.S. this is an interesting model of Yeast: https://youtu.be/OWiZU_DZzAU
Too many 'projects'

MichaelG.
Posts: 2615
Joined: Mon Apr 10, 2017 8:24 am
Location: NorthWest England

Re: Micro-cam or Web-croscope

#11 Post by MichaelG. » Wed Feb 24, 2021 11:20 pm

This is a VERY crude first step ... but I think it's one in the right direction

I removed the 'beauty rings' from two lenses [one for the webcam, and a spare] ...
This enabled them to be mounted face-to-face; closer together than before, but obviously still not close enough.

The lens on the camera is screwed fully home, so is maybe focussed on infinity
... and the supplementary lens then converts it into a 1:1 'macro' lens.

Hopefully, if I can trim the 'hoods' and get the front elements closer together; the vignetting will be dramatically reduced

Meanwhile: Here's an image of my iPad screen [264 pixels per inch = approx 96 micron pitch]
.
Crude 640x480 webcam experiment
Crude 640x480 webcam experiment
Photo on 24-02-2021 at 22.40.jpg (55.75 KiB) Viewed 19 times
.
... and, for comparison, a link to a much better one:
https://www.anandtech.com/show/5689/the ... analysis/2
[click the third image for a full picture, with scale-bar]

We're not there yet ... but watch this space

MichaelG.
.

Edit: corrected the micron pitch value
Too many 'projects'

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