[HN Gopher] Hacking the T2S+ Out of Fear: Get Lock-In Thermograp...
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Hacking the T2S+ Out of Fear: Get Lock-In Thermography for Free
Author : Luc
Score : 180 points
Date : 2024-10-28 12:49 UTC (5 days ago)
(HTM) web link (dmytroengineering.com)
(TXT) w3m dump (dmytroengineering.com)
| kragen wrote:
| This is fantastic! At a high level all he had to do for basic
| thermography was to flat-field the raw image with offsets
| acquired from the camera's shutter, without even having to derive
| per-pixel gains like you normally would, and mask out some bad
| pixels (and inpaint them for naive consumers that can't handle NA
| data). Then as a bonus he implemented lock-in thermography, which
| turns out to be just lock-in amplification applied to
| thermography by modulating a heat source over time.
|
| But the technical detail provided seems to be enough to make it
| easy for someone else to reproduce the whole setup. And provides
| ample evidence that you _should_ , because the provided drivers
| are evidently malware.
|
| Oh, and apparently you get a free FPGA with your thermographic
| sensor!
| gsliepen wrote:
| > At this point, I realized that I got the "V2" of the camera.
| This camera is regarded as worse than the "V1" mostly because the
| manufacturer removed the internal processing FPGA?
|
| That's actually better. In-camera processing will just reduce the
| amount of information you can get out of the sensor. For example,
| even if it does exactly the same flat-fielding as you do, the in-
| camera flat-fielded image has to be requantized to 8-bit format
| before sending to the computer, therefore losing precision.
|
| You can get even better accuracy by taking a dark or bias field
| (might be possible if you can set the exposure time to something
| very short, but this might not be possible with these
| thermographic cameras) and taking flatfields at different
| temperatures, so you can get per-pixel linearity curves. That's a
| lot of work though, and ideally each camera was indiviually
| calibrated by the producer, but I am guessing that is not done
| for these cheap cameras.
| daniel_reetz wrote:
| The article points out that the FPGA was not actually removed.
| However it is true in some circumstances having access to data
| earlier in the pipeline is useful. Microbolometer cameras like
| these have their own quirks.
| sangnoir wrote:
| > In-camera processing will just reduce the amount of
| information you can get out of the sensor
|
| More information is not necessarily better. For instance, if
| the FPGA does calibration and removes sensor noise, removing
| the preprocessing adds literal noise to the data, which is
| worse.
| mschuster91 wrote:
| > In order to practically implement this we first close the
| shutter.
|
| Fun fact, Sony does the same once in a while for dead-pixel
| detection and remapping on their mirrorless cameras [1].
|
| [1] https://news.ycombinator.com/item?id=38579634
| tiagod wrote:
| Been thinking of getting one of these but was worried about the
| proprietary app. I guess I have no reason now : )
| buran77 wrote:
| There are a few open projects to support a lot of these thermal
| cams like the more popular Topdon or InfiRay models.
| PyThermalCamera [0] or Thermal-Camera-Redux [1] are good ones,
| I got my thermal cam working on my Linux laptop just fine.
|
| [0] https://github.com/leswright1977/PyThermalCamera
|
| [1] https://github.com/92es/Thermal-Camera-Redux
| TeMPOraL wrote:
| Do you know of anything that can handle UNI-T cams,
| particularly something like UTi721M, which is a nice thermal
| cam that attaches to a smartphone via USB-C?
| buran77 wrote:
| Eevblog forum is the original source for most of the Github
| projects around these thermal cams. So that's a good place
| to start.
|
| https://www.eevblog.com/forum/thermal-imaging/new-
| software-f...
|
| https://github.com/Santi-hr/UNI-T-Thermal-Utilities
| pavel_lishin wrote:
| Unrelated to the article, but I love the "glow" effect on the
| code snippets. Any chance this exists as a plugin for VSCode, for
| when I want to re-live my teenager dreams of what working on
| computers looks like?
| sitkack wrote:
| It is just fuzzy from zooming up screenshots, a by product of
| the subpixel aliasing.
|
| If it doesn't, you could probably add a post processing filter
| to https://github.com/wez/wezterm or
| https://github.com/alacritty/alacritty
| _Microft wrote:
| GP is talking about the code sections and the "CRT effect"
| that was added via CSS. Press "Toggle glow" to make it
| obvious what effect that is.
| a1o wrote:
| I haven't like, checked the code, but I have seen this glow in
| websites that used a JS library called prism (or PrismJS).
| vermon wrote:
| Very cool! I thought maybe I'll take a crack at building a better
| iOS application for these things, but then I remembered that for
| the Lightning connector you needed to get the permission of the
| manufacturer if you wanted to interface with a device (tried that
| once with a Lightning Yubikey and luckily they didn't have any
| objections). Is this not an issue anymore with USBC iPhones?
| seany wrote:
| I built an interposer board to do this about 5 years ago (for a
| product that didn't go anywhere). Ended up using a beagle bone
| in USB gadget mode to expose an Ethernet adapter to the iPad I
| was using.
| InvaderFizz wrote:
| USB-C iPhones work with all kinds of USB-C hubs, devices,
| keyboards, mice, Ethernet adapters, etc out of the box.
|
| As far as I have seen, USB-C on iOS devices has no
| authentication restrictions for anything.
|
| The device in the article already has an iOS app, so while
| there may be a needed app entitlement, I don't think there are
| any showstoppers for making an iOS app for this particular
| thermal camera.
| knowitnone wrote:
| FLIR sucks. from personal experience. They sell crap that doesn't
| even work with your smartphone.
| immibis wrote:
| I heard the reason USA-made-and-designed thermal cameras suck
| is arms export regulations. They are considered military
| equipment unless they stick to certain limits. I guess China
| has no such rules, so the USA throws yet another manufacturing
| sector in the trash once again.
| wbl wrote:
| FLIR is owned by Raytheon. They are very much not in the
| trash and make very good imagers. You just can't buy them.
| stefan_ wrote:
| It's really just the framerate restriction to 9hz that the
| Chinese imagers don't suffer ftom
| heroprotagonist wrote:
| Looking at those permissions, I think whatever fear he decompiled
| this out of was justified.
|
| I guess that's one way to implement industrial espionage.
|
| Build telemetry and malware, or code that can become malware with
| a little tweaking or remote checks, into a component that's
| likely to be used by technologists in whatever sector you're
| interested in.
|
| Make it a bit better and a lot cheaper than all the alternatives.
| Get on their phone with lots of permissions, and use the
| telemetry. Once you know who they are you can decide on more
| targeted actions to turn them into a vector against their
| employer or whoever, or just watch what you can to collect
| information.
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(page generated 2024-11-02 23:00 UTC)