Custom Multispectral Fusion Monocular - Project Overview - Page 1
Forum section: electronics / general

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:21:30 pm
content: Hi everybody, I just wanted to give a bit of an update on my adventures and a teardown of the project I’ve been working on. I’m a just-graduated mechanical engineering student from Canada, and took this on as a way to learn more about thermal imaging, electronics, product design, night vision, and optics in general. The way these things go, you’re never really done… but I figured I finally have enough working to share here. Apologies for the word wall that follows.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:23:40 pm
content: I joined this forum about a year ago as a way to find more information about thermal cameras, and hopefully identify a mystery thermal core I had purchased from Ebay. This core turned out to be an ITC-1000, out of one of their older “hi-res” 240x240 firefighting cameras. However, there is a metallic rattling noise inside the vacuum chamber, and a likely mismatched calibration table in the control board, leading to high noise and a very bad image. Due to this, I resolved myself to buy a new camera – an ISG E380 helpfully torn-down by Fraser on this forum. Inside, a pristine ULIS nano-384 based core, perfect for my new project.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:27:43 pm
content: Initially, I tried to wire an FPV camera to a screen and make a “night vision” monocular. When this failed, I obviously decided to make things harder, and resolved myself to design a multispectral fusion system. The intent is to combine the advantages of thermal imaging and traditional night vision, so a user can see in the dark and see heat at the same time! After about a year, my latest prototype finally works.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:29:32 pm
content: Night Vision: Litton M891 Gen 3 MX10130-format non-inverting image intensifier tube (Green Phosphor, ~1300FOM?)Thermal Imaging: ULIS Nano 384, ISG control board (50Hz, 384x288)Both sourced from Ebay, total cost, ~$2000CAD

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:33:02 pm
content: There are two separate input optical paths – LWIR and VIS/NIR. These separate objective lenses are placed above one another, as close as possible, to minimize parallax between the images produced. Inside the device, the night vision tube greatly amplifies visible and near-infrared light, and shines this into a system of mirrors and lenses. These optics invert the image (because the image from the objective lens is upside-down and backwards), expand the image (to make it 1:1 scale to the human eye for the objective lens’s field of view) Meanwhile, the NTSC video from the thermal core is fed to a 640x480 0.33” Kopin microdisplay.A dichroic mirror is used to optically combine the two images – the green light from the intensifier tube bounces off the mirror, having a cut-off wavelength of around 600nm. The orange/red portion of white light from the microdisplay passes through the mirror, joining the green light through the rest of the optical pathway to the eye. In this way, when the uses looks through the single eyepiece lens, they are simultaneously viewing two physically separate focal planes.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:36:24 pm
content: Designing this took a very long time, and many, many prototypes - but it was an enormous learning experience and source of personal growth. This project actually just got me a dream job - so don't let anybody tell you that personal projects arent useful. This has more than paid off the >$3000CAD total cost in knowledge, opportunities, and experiences. Also, CAD and 3D printers are very, very useful. I highly recommend learning to operate both.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:37:52 pm
content: This project has many, many, many issues, not limited to the following.-Alignment of the two images (very, very, very hard to do)-Image focus: Properly focusing on both focal planes so the eye sees them as one-1:1 image scale to the unaffected eye given a certain FOV objective lens-Optical aberrations (mostly spherical aberration) These are pretty bad and distracting.-Miniscule eyebox, very hard to look through the eyepiece properly-Weight! This is about 700g. Not fun for your neck, and is very far forward, giving a high moment arm-Dust-sealing, water-proofing. More of a challenge than you’d think, especially when moving parts like apertures and focus adjustment are involved

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:42:43 pm
content: Optical design is very hard. If anybody is trying a similar project, I highly recommend learning to use optical design software like ZeMax. I spent probably hundreds of hours at my desk, fiddling with lenses ripped out of old cameras, trying to find that perfect combination. This is a very inefficient and silly way to do things, and expectedly, led to poorly constructed optics. In the future, I plan on doing this properly.This hobby almost necessitates using non-standard parts with few/no datasheets, obscure technologies, and even legally restricted information. Information is GOLD. Talk to people, ask questions dive into old testing procedures, PHD papers, and declassified information. It takes a lot of work, but somewhere out there is the number, name, or image you need. And remember, this is thanks to the tireless, unpaid, and extremely generous of hobbyists like yourself and others on this forum. Be nice, thank people, and help out. (Interfacing with these obscure parts is always going to be a challenge and lead to possibly sub-standard designs. Obviously, if I had a million dollars and a team of engineers, I would build this device pretty differently. But, I don’t, so here we are.)

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:45:21 pm
content: I know this forum is on thermal imaging, but there is a significant crossover between thermal imaging and night vision technologies. If anybody here has the opportunity to play with night vision or finds an image intensifier, remember – it’s a magic telescope. Even the old stuff is well worth your time. Having had the chance to use high spec, filmless L3 binocular night vision (even in Canada!) it is an otherworldly, surreal, almost religious experience to be able to see when you cant find your hand in front of your face.

author: Abbott242
author_rank: Regular Contributor
timestamp: May 08, 2022, 09:48:16 pm
content: Anyways, after putting so many hundred of hours into this system, I wanted to share it. Hopefully others can stumble across this and find it interesting or even useful! Please - ask questions or give advice. The best part of this forum is the communication. Thanks!

author: Arios Claudius Weion
author_rank: Newbie
timestamp: May 08, 2022, 11:29:40 pm
content: Excellent design,3years ago I tired the same thing. Look at my product, actually it is a modular design. Get the fusion ones when you combine them together or you will get one independent thermal imager and one informational NVG (JUST LIKE MINIE-D).Well I tested with Pi 0.

author: Arios Claudius Weion
author_rank: Newbie
timestamp: May 08, 2022, 11:40:01 pm
content: A quit classical design,its time to finish it.

author: Hydron
author_rank: Super Contributor
timestamp: May 09, 2022, 12:59:24 pm
content: Wow, impressive effort put into the build.I've seen this done in a slightly different way before - using clever optics to project a low intensity overlay image into the front of a standard monocular night-vision sight:https://www.thermoteknix.com/products/defence-security/clipir-xd(watch the video for example images).Worked pretty well in the demo that I saw, though I sadly didn't get the chance to try it in a real dark environment. No separation of thermal/intensified images by colour though (but possibly less eye strain due to only needing to focus on the single green wavelength).

author: Lambda
author_rank: Regular Contributor
timestamp: May 09, 2022, 01:09:25 pm
content: Hi.Abbot242, it is a great disclosure you offer to us!Definitively a nice example of good engineering process in the DIY and hobby world! This thread should be IMHO pinned up in the forum... An optronic experimentation in its most genuine meaning!I am also interested, as some of us at least, in this multispectral world. I tried by the past some very modest and crude experiments by using a sensitive CMOS camera and a thermal core, delivering respectively their video stream that i overlayed by using a simple freeware for superimposing two active windows on the screen of my computer. So the idea was just based on a small software trick.https://www.eevblog.com/forum/thermal-imaging/attempt-for-a-multi-apectral-night-vision-system/msg3596635/#msg3596635your design is definitively neat, and i would like to use, mutatis mutandis, with your permission, some of your ideas for later for sure.Again, thank you for sharing that with us here!Regards.Stéphane

author: Abbott242
author_rank: Regular Contributor
timestamp: May 09, 2022, 02:03:28 pm
content: Arios: Glad to hear I'm not the only one! That's a good looking design, modular is a great idea. What display is that you're using there btw, that looks very intriguing. I'd love to get my hands on one. Best of luck to your work, the overlay looks great!Hydron: Thanks, took me way too long lol. Yes, the front-projection systems are becoming more common, and definitely have their advantages. very good idea, but if it's too bright, it can damage the night vision. Never thought about the eye strain idea, I'll have to look into that, but the idea is that different colour just help you separate what is what.Lambda: Yes, I saw your work there! Very good results. Your pairing of a thermal core with a telescope is very inspiring too, I've been wondering about building a LWIR telescope and the results look pretty good! Feel free to use my ideas- I just made this version to learn and share. I might commercialize it later, but there would be significant design modifications.

author: Arios Claudius Weion
author_rank: Newbie
timestamp: May 09, 2022, 02:39:02 pm
content: Well that one made by EPSON,800*600 LCD,with VGA/A V input slot and paramter panel.Maybe you can upgrade it with much more powerful thermal module,I just got ULIS 384 17U sensor

author: Arios Claudius Weion
author_rank: Newbie
timestamp: May 09, 2022, 03:15:37 pm
content: Well，that`s the so called clip on thermal imager (COTI), according to the field test, OLED display pannel is recommended，Clip IR seems to take FLCOS display which is soooooo bright，like a beam saber，well，LED，will project a ”circle“ on FovCheck the attachment for one of my failed attempt.