Electrophysics Micronviewer 7290A heat imaging test and inherent display lag

[_Wim_]

 Just discovered (removed the company label that covered the device type) my device was not a DFG/USB2PRO but an older DFG/USB2-It. It looks identical, but it is much older (window XP latest support)

https://www.viewrun.co.kr/files/Brochure.pdf

It is based on a tv master tm5600 chipset

[_Wim_]

The same chipset is also used in other devices:
https://www.linuxtv.org/wiki/index.php/Trident_TM6000

[DaJMasta]

Finished my oscillator replacement of the Electrophysics 7290 (non-A) posted earlier, and while this video doesn't show a heat source, I've adjusted the target voltage and image parameters a bit so it's better than the first showing.  I could still turn the target voltage higher, but it didn't make a big difference, so in the interest of prolonging tube life, I left it at a middling voltage.  Worth mentioning that on the 7290, the potentiometer for the target voltage is marked "Volt" only, and is behind the metal flange from the front panel, so you have to remove it to adjust it.



You can see different stuff showing with the differing light sources and the RG1000 filter here, but interestingly, the image lag is different in different bands.  In the SWIR band there is a reasonable amount of delay/ghosting (still better than my initial testing), but when I take the filter off and switch light sources, it is noticeably faster response.

[Ultrapurple]

Thanks DaJMasta - very interesting.

I suspect the faster response when you remove the filter may be down to the simple fact that there's more light reaching the sensor. My memory of vidicons is pretty sketchy but I do remember that a camera that gave a perfect, essentially lag-free image in good light would become more and more laggy and low-contrast as the light level reduced. Much of the time this was compensated for (to a certain extent) by opening the lens aperture in dimmer conditions but of course there came a point that it was as open as it could get.

I used some Sony HVC3000P Trinicon-based colour cameras back in the early 1980s when they were new. They were fine in daylight but awful indoors of an evening. Trinicons were basically just a vidicon with a colour stripe filter over the faceplate, so suffered from all the good and bad features of the vidicon - except that, thanks to the attenuating effect of the filter, they were noticeably less sensitive than vidicons of the same vintage.

I still have some HVC3000P and probably an even older HVC2000P somewhere, still in their rather nice flight cases. Apart from the fact that the microphone windshield foam had deteriorated, the last time I looked at one it still appeared to be in quite good nick. I may even try firing one up one day, just for old time's sake.

[DaJMasta]

That certainly could be - the SWIR source was actually pretty bright, so I put it a bit across the room for a more even, less washed out image (though I think the black level needs to be brought down), but what I'm thinking may be the case now is that the decay of the image on the tube is logarithmic.  If it's very intense, the time it takes to get to half brightness is short, but if it's dimmer, the time it takes to get to half brightness is shorter, so as you say, brighter lighting would look faster.  Maybe I'll try a bit more experimentation - I remember that I've got a 1550nm fiber test laser that may be bright enough to show for sure what the SWIR response time is like.

[Fraser]

The difference in lag with bright and darker scenes could possibly be related to the cameras AGC and increased sensitivity to the latent image when viewing a darker scene. In a lower gain mode, viewing a brighter scene, the lag may still be present but the low level latent image not as easily seen. The lag is a product of the tubes physics and the latent image ‘erased’ by dissipation of the charge on the target. Bright or dark scenes should not effect lag duration as that infers a change in the charge dissipation characteristics which would involve physical changes in the target material or beam current. My 7290A has both manual and automatic gain settings and testing for lag changes due to scene illumination should really be done with a fixed high sensitivity gain setting to highlight the low level latent image on the target as it is slowly erased. High gain might cause a poor, over bright, image in a bright scene but it is the low level lag you want to see when the scene is blanked by a barrier, as I used in my test.

Fraser

[DaJMasta]

Not 7290(A) related, but heat imaging on non LWIR cameras related.... soldering irons can show up on NIR cameras!

About 415C was the setting, taken with an ARTCAM-500MI-NIR, which should be sensitive to 1150nm or 1200nm

[Fraser]

Dajmasta,

Thanks for the pictures. These would appear to show just how much further into the SWIR band the Micronviewer can see compared to a silicon based detector. Nice to have that comparison 

Fraser

[_Wim_]

....taken with an ARTCAM-500MI-NIR, which should be sensitive to 1150nm or 1200nm

I always wondered how these performed. Thanks for posting!

[DaJMasta]

If you mean the camera specifically, while the image quality is great, the framerate is low and the older camera shows it in the driver support.  Under windows 10, only the DirectX driver installs, which is fine, but which doesn't allow for any frame size or bit depth adjustment.  Under XP the "standard" driver installs and you can get the lower resolutions, binning options, etc., but the framerate tops out at 10fps or so with any resolution because it's only USB2.

Of course other NIR enhanced mono cameras should perform in this one's ballpark, since this uses a standard sensor (and I used a midwest optical LP715 to cut out the visible band).  I will be trying out a new sensor, an IMX462 for NIR performance which is quite promising with the unusual trait of it actually being a standard color camera - it's just the back illumination, deep wells, and color filters used which are transparent to NIR that together may actually give it better NIR sensitivity than a standard NIR enhanced mono sensor.  We'll see!

[_Wim_]

If you mean the camera specifically, while the image quality is great, the framerate is low and the older camera shows it in the driver support. 

I somehow did not get a notification about your post, so a bit of a late reply...

I did not mean this camera specifically, but more in general cmos-based camera's promoted for their NIR range. I always wondered if these are actually any different from standard black & white industrial cmos camera's which also typically have some extended sensitivity. I will try to run a test with an uEye UI-5240CP-M-GL with a long pass filter attached to see if it also can detect a soldering iron at 415C.

[DaJMasta]

Some image tweaks to the 7290, and I gathered up the 4 USB capture devices and pitted them against my newest PCIe device, a Viewcast Osprey 450e.  Some big differences in default image quality settings and some odd artifacting on some devices, but they are all serviceable.  The Osprey takes the image quality crown and has the most accurate default settings as well as the most comprehensive driver options and software.  The three UVC devices ("UVC", Easycap, UCEC) are the most broadly compatible because of the UVC implementation that basically every software can read from.

[_Wim_]

I am still quite surprised how big the difference is between the different capture devices. Excellent comparison!

[DaJMasta]

Thanks, was surprisingly quick to do with the computer setup so glad it's useful.  I was surprised too, especially thinking initially that the easycap and UVC dongles were just the same in a different housing, but I think a lot of the difference comes down to color/contrast profile settings.  Some of it is also probably noise, distortion, or lack of bits at the ADC, but I think with some post processing and resizing they would look less starkly different.

[_Wim_]

I will try to run a test with an uEye UI-5240CP-M-GL with a long pass filter attached to see if it also can detect a soldering iron at 415C.

Today I finally did the test. Camera was running at 5 frames per second (200ms exposure). From +-350°C some IR was visible. A 950nm long pass filter was installed.