Infrared Solutions IR Snapshot teardown

[beenai2018]

Acquired this IR snapshot recently,and boy was the posted photo deceptive .. lol  .Cant complain for the price of free !!

Had no  other accessories other than the camera and the PCMCIA card (16 MB !!)

Hooked up to the power supply and was only getting stripes on the screen .. Was  kinda sad until I realized the lens cap was still on ...  Its easy enough to spot with an SLR , but totally ambigous with the IR cam which still makes stripes on the screen .

Took the cap off and beautiful images!! at a glorious 120 * 120 !! . Seems to work well enough but slow  like a flatbed paper scanner.

So ,lets disassemble this.



Heads up , this thing weighs 4 pounds without the battery.

[beenai2018]

Splitting the shell

[beenai2018]

Rear of Main board and Sensor Assembly

[beenai2018]

Here is where I'm kinda stuck .

The sensor and the Stepper Motor seem to be attached firmly. I see a grub screw on the sensor end .The Stepper seems to be linear actuation and not rotary.

Im wary of trying to pull them apart for messing up alignment . The grub screw is at an angle and I dont have the correct allen . The screwdriver bits seem to slip

(There were a bunch of  micro allen screws on the exterior case that I ground out to make them slotted screw to remove , but dont want to do that on delicate stuff) .

If anyone has taken these apart and have some hints it might help me .Hope the pictures are useful.

[Fraser]

Thankyou for the pictures 

I own one of these cameras and found the patent document for it. This camera is an early attempt at creating a more affordable thermal camera that did not need an expensive mechanical cooler, liquid nitrogen or expensive scanning mechanism. The slow speed of image capture and limitation of only being useable to image static objects was considered an acceptable trade-off for the ability to capture thermal images at an affordable price. The unit was primarily intended for use in Industry for preventative maintenance and building survey work. In these roles, it was slow, but effective.

The image capture device is a Honeywell designed Thermo Electric linear detector array that is mounted on a motorised linear movement sledge that moves it across the image circle created by the lens. This way a whole image could be created with a linear pixel array. The image detector sledge design was inspired by the mechanism found in a floppy disk drive. Inside the sledge assembly there is not a great deal to see and disassembly  does carry risk if you want the camera to still work.

I think I have the software for viewing the images from this camera but you will need Windows 98 or XP to use it.

Fraser

[Fraser]

Some information on these cameras from my Archive. They were sold under different names and brands with slight differences in the case mounted keypad. Inframetrics sold the camera as the "Thermasnap 525".

[Fraser]

A web page capture detailing the Honeywell TE sensor array technology

[beenai2018]

@Fraser

Thanks for the information .I had seen quite a few of your informative posts and take-aparts from other cameras, when I picked this up originally.

I don't mind the slowness of the camera at all .In fact it gives a "Predator " movie vibe when it's working .    A full scan takes a about 2 seconds and the thing is ,  thermal conduction speeds are not very fast anyway ..

In one of the comments you mentioned attaching the scanning sensor to a modern micro . That set off my interest in opening this up .


One question I did have is .. in optical photography , DOf is a big deal ...  What are the analogues  in thermal ? ie if the lens is not focused on the heat ( plane of focus)  ,what is the sensor measuring ? ie what is the objective definition of heat blur ?

[Fraser]

Hi,

Sorry I do not recall mentioning attaching the scanning sensor to a modern microbolometer as what would that actually achieve ?

Regarding your question on thermal DoF. I am not certain what you mean. The thermal camera behaved the same way as a visible light camera in terms of the lens and sensor array, just at different wavelengths of energy and resolution. DoF exists in thermal cameras and targets falling outside the DoF are blurred and due to the low resolution detail is lost. I am not sure whether Artistic Bokeh is a thing in thermal imaging as I am not into the artistic imaging scene. Uncooled Thermal cameras do tend to have a large aperture and small F number. F1.0 is common.

Fraser

[beenai2018]

Firstly the patent was interesting reading  .It references a 96 array ,but the devices is a 120* 120 . Also the ADC is 16 bits.  There is also a lot of software calibration related statements in there.

I apologize  if I misquoted you , but I was referring to  attaching the scanning type sensor to a modern micro-controller/ADC . Unless the sensor itself limits the frame rate  , better processing might make it faster .

The Dof  is clear now if analogous to light . I thought the "blur" might have different physical properties to  it ,since light is captured as an optical reflection ,but heat moves via medium . This is all over my head now,lol .

[Fraser]

The speed of the scan may have been chosen to match the response time of the Thermoelectric pixels. They are basically thin film thermocouples. The camera uses an Intel 80386 processor that should be more than capable of processing 120 pixel outputs very quickly.

In terms of thermal domain imaging, we are still dealing with photons, just as with visible light. The target under observation does display thermal conduction, convection and radiation characteristics when imaged. The camera side of things just interprets the photon energy that hits the pixels on its imaging array. A thermal camera is a radiant photon energy imaging device that may have radiant energy to temperature unit conversion curves applied for temperature measurement. It is important that the thermal domain energy is correctly focussed on the pixel array in order to achieve best image sharpness with the very limited number of pixels available. In thermography where accurate temperature measurements may be important, correct focus is needed to provide best energy transfer to the pixels for accurate measurements of the radiant energy. A blurred image will spread the available radiant energy over more pixels, potentially at a lower energy level per pixel.

In general, treat a thermal camera the same way that you would a visible light camera. It is a “Camera” and uses its optics to focus the incoming scene photons onto an array of photon energy responsive pixels. Changing lens aperture affects the amount of photon energy arriving at the FPA pixels and good focus ensures that the thermal scene illuminates the pixels most efficiently for image sharpness and least image blur. Deliberate de-focussing of a thermal camera would be an unusual technique in normal use as the user usually wants the best possible image clarity in order to interpret the thermal scene being presented to them by the camera.

Fraser