Public Lab Research note


Infrared Insect Microscopy

by MaggPi | June 21, 2018 05:11 | 387 views | 7 comments | #16540 | 387 views | 7 comments | #16540 21 Jun 05:11

Read more: publiclab.org/n/16540


Summary:This research note shows microscopic images/ videos of three insects observed with white and IR (850nm/940nm) LED light. The images show that viewing insect internal features is possible.

Introduction: This note demonstrates that DIY microscope kits such as https://www.kickstarter.com/projects/publiclab/the-community-microscope-kit , can be modified with a Raspberry Pi NoIR camera and IR LEDs to obtain infrared images. One reason to adapt microscopes for IR imaging is that many insect parts are transparent when viewed with infrared light. Insect infrared observations have been done since 2005 using a variety of IR photomicroscopy techniques ( http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artoct05/dwd50ir.html ). Adapting microscopes with a Raspberry PI NoIR camera/ IR LEDs extends the range of these techniques by permitting high definition video, real time image processing and multispectral imaging.

Procedure: Microscope modifications: -The general approach is to combine a Raspberry Pi NoIR camera with a microscope objective. One possible method is to use a camera holder such as: https://publiclab.org/notes/partsandcrafts/11-26-2017/building-a-raspberry-pi-microscope

-Lighting modifications:Push button switches were used to toggle between different wavelengths. Two LEDS were used for IR viewing.

-Two 850nm LEDs connected to push button switch
-Two 940 nm LEDs connected to push button switch
-One white LED  connected to push button switch

-Video Processing-Since IR images have a washed out effect, video was adjusted for high contrast (80 picamera settings). This adjustment makes a noticeable difference in being able to detect internal features. Video was captured and displayed (on youtube) in h264 format.

-Bug collection - Sticky paper on top of light (sticky side up) placed outdoors at night. Typically is takes less then 20 minutes to collect bug samples. Paper (with bug) is then cut for mounting on microscope stage.

Insect Infrared Microscope Examples:


Slide1.JPG

-Bug 1a video (center) shows circulation/pumping action/850 nm view https://youtu.be/4D7N47cHwHA

-Bug 1b video (head) shows head internal features /850nm view https://youtu.be/F-Pif_V5uEE


Slide2.JPG

-Bug 2 video (center) shows circulation/pumping action/850nm and 940nm views https://youtu.be/keh14V4n7Vg


Slide3.JPG

-Bug 3 video (head) shows pumping action/850nm and 940nm views https://youtu.be/WOMTCmb2dVw


@warren, @icarito, @amirberAgain

Related posts:

https://publiclab.org/notes/MaggPi/06-05-2018/usb-webcam-vs-raspberry-pi-v2-field-of-view-fov-comparison-community-microscope-initial-evaluation-2

https://youtu.be/I99p_4ypk_c


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7 Comments

This is so cool!!!!

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😀

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Wow, this is amazing! I was wondering what this might look like... I'm excited to try to replicate this one!

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This is interesting, did you try to re-focus for the NIR LEDs? It's very likely that the lens wasn't designed for these wavelengths and re-focusing would let you capture images as sharp with those LEDs as well. Also, IDK about those insects specifically, but using a <400 nm LED could show some fluorescence.

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Great idea @amirberagain. @maggpi if you have a chance to record video of a live insect's face that would be so cool... 🐜

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Hello MaggPi,

Hopefully you or someone else can help. Is the purpose of two LEDs to have one for transmission(below sample) and another for reflection(above sample)? I was thinking of using these 5mm LED from LED supply (850nm & 940nm) on a credit card substrate with copper tape and button cell.

https://www.ledsupply.com/leds/5mm-led-infrared-850nm-50-degree-viewing-angle

Could you recommend resistor pot for dimmer control, or should I use their 20mA DynaOhm? I am wondering what's the best configuration to allow ease of exchange between wavelengths, as I was also considering using 365m, and 400nm wavelength LED (safety first).

Thanks for the feedback

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Hi, Your asking good questions…. @CD3000

-Is the purpose of two LEDs to have one for transmission (below sample) and another for reflection(above sample)? --Both the 850nm and 940 LEDs were used in the reflection mode. Two different LED wavelengths were used primarily to see which would produce ‘better pictures’ or provide greater contrast. Bug 2 and 3 pictures posted above show that that the different wavelengths highlight different insect features. --Suppose you could also work in transmission mode as well. Depends on how thick the insect is?

-I was thinking of using these 5mm LED from LED supply (850nm & 940nm) on a credit card substrate with copper tape and button cell. https://www.ledsupply.com/leds/5mm-led-infrared-850nm-50-degree-viewing-angle --LED model should work fine but have no experience with credit card substrate. My set up was: LED, wires, resistor, on/off switch connected to 9V battery. One issue is how to adjust LED for best picture. This typically means some type of holder to vary angle/distance to image.

-Could you recommend resistor pot for dimmer control, or should I use their 20mA DynaOhm? --I assume it should work but all my LEDs used fixed resistance. At the time, I always wanted max power to see if the IR light could make it through different layers of the insect.

-I am wondering what's the best configuration to allow ease of exchange between wavelengths, --One set up I used involved the Raspberry PI to sequence the different LEDs as well as control the different camera settings. Check out other MaggPI Public Lab posts such https://publiclab.org/notes/MaggPi/03-15-2018/computer-vision-led-plant-measurement-system

-I am wondering what's the best configuration to allow ease of exchange between wavelengths, as I was also considering using 365m, and 400nm wavelength LED.

--LED multispectral imaging can be very rewarding but also demanding. As an example, see the picture below of a basil leaf illuminated by different wavelength LEDs and observed with a Raspberry Pi camera. Note that UV1 and UV2 images (while different than WHT light image) look the same even though illuminated with two different wavelength LEDs. Believe this is due to the way the Pi color camera/lens interprets/filters the UV light. You may want also want to check out the UV TAGs on the Public Lab site (but most seem focused on UV spectroscopy vs UV imaging). .

Multi_led_exposure.png.jpg

Top left is a computer vision enhanced image. Top right is white light image. Images below are for ultraviolet (uv1)(375-385nm), ultraviolet (uv2) (385-395nm), blue(blu), green (grn), red and infrared (ir)(850nm) LEDs. Remaining images are processed images that highlight color contrast.

---Not exactly sure what your application is but if your working IR /UV insect imaging there are countless things to try out. Some high contrast options are non-colorless circulatory systems such as insects with yellow or green ‘blood’ and compound insect eyes with the well known UV sparkle effect, etc…

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