Stereo LWIR sensors - Page 1
Forum section: electronics / projects

author: bfree
author_rank: Newbie
timestamp: January 17, 2023, 04:08:49 am
content: I'd like to prototype a stereo (2) long wave IR (thermal) sensor.There's a number of arduino/raspberryPi kits for stereo RGB cameras, and even short-wave (near-IR) cameras... but these seem to use data standards (USB-C/UVC, MIPI/CSI-2) that are different from those used in LWIR sensors (LVCMOS/BT.1120/LVDS).Anyone know of anyone who is doing this, has a kit for this, or has a shield/hat/lib that will work with one of these LWIR standards?My fallback is to use 2 USB-C/UVC cameras, but they tend to be low res, low framerate, and not sync'd.

author: berke
author_rank: Frequent Contributor
timestamp: January 22, 2023, 04:00:50 pm
content: What's your budget?You can get "industrial" USB3 vision (or GigE vision) cameras, these will normally have sync inputs/outputs on a separate connector and you can find some with good framerates (>150 Hz). The RPi might choke on the data stream though. Expect to pay $1 to $1.5k new for two cameras and basic lenses.Where do you find affordable LWIR sensors? The ones I know apparently cost $100 to $500k.

author: bfree
author_rank: Newbie
timestamp: January 23, 2023, 05:01:10 am
content: Hi Berke -I've been using a Xtherm T3Pro (UVC) - 384x288 25hz $849 to play with.I'd like to get something with higher res and faster framerates.The Infiray FT II384/640/1280 claims to do 640×512 @ 50hz and 1280×1024 @ 30hz (LVCMOS/BT.1120/LVDS interface) - no idea how much they cost in small quantities.The infiray LGC6122 claims 1280×1024 @ 30hz (LVCMOS/BT.1120/LVDS interface) - again no idea how much they cost in small quantities.I know how to talk to UVC; clueless about writing a driver for LVCMOS/BT.1120/LVDS. I don't want to dish out money for a high-end thermal sensor if I can't read it.Prefer using a microcontroller to get stereo depth via 2 thermal sensors, but may need to go with a CPU to handle the bandwidth.At the moment I'm testing/prototyping and don't mind paying extra for a decent thermal camera. 640×512 @ 50hz is about as low as I'm willing to go.

author: berke
author_rank: Frequent Contributor
timestamp: January 23, 2023, 09:33:04 am
content: Thanks for the info, I didn't know you could buy UVC thermal cameras with reasonable resolution.I don't know about BT.1120 but unfortunately LVCMOS or LVDS only specifies the electrical signaling (the lowest physical layer), and manufactureres typically expect that people will interface to their sensors using an FPGA and the sensor's custom protocol, and often you need an I2C or SPI channel for extra control.If you want to use a cheap RPi-like SBC your only two options are AFAIK GigE Vision and USB (UVC or USB Vision), and maybe MIPI CSI/CSI-2 if your SBC has it.If you can use an industrial PC you can buy a PC104/PCIe/etc. frame grabber card, that opens up interfaces such as CameraLink and CoaXpress.My personal advice is that if you're working on a machine vision idea that you think is worthwhile you should not waste time on camera interfacing, and instead invest a few thousand in whatever frame grabber/camera combination is readily available and works with the software you like, and focus on your concept/algorithm. Industrial cameras and cards can be resold without excessive loss. Interfaces come and go anyway.

author: bfree
author_rank: Newbie
timestamp: January 23, 2023, 04:56:03 pm
content: Hi Berke - can you recommend a company/vendor/supplier/model for "industrial" USB3 vision (or GigE vision) cameras, with good framerates (>150 Hz)?Thanks!

author: berke
author_rank: Frequent Contributor
timestamp: January 23, 2023, 05:25:36 pm
content: Sure,Since you're presumably in the US you can look into Teledyne (ex-FLIR, ex-PointGray). Their BlackFly series for example is pretty good. They have GigE and USB3 versions and many different sensors. You can use their SDK or aravis. They generally have an external so-called "GPIO" connector with pins for external trigger, sync output and auxiliary power in.Check their datasheets. The maximum quoted frame rate is normally for full frame and depends on the camera but also on the options such as bit depth and processing, and sometimes trigger mode (!). On mine if you reduce the ROI you can increase the frame rate. You can lose some frame rate if you do things such as binning.