Frame color is too bright using GetThermal on raspberry pi

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Apr 23, 2024, 9:10:22 PMApr 23
to Flir Lepton
I've installed GetThermal from the source and the below image is the result. I'm using Lepton 3.5 with Pure Thermal 2 on raspberry pi 5 and the same issue happens while using uvc-radiometry.py example code. Anyone who faced same issue? 

Screenshot_20240424_100559.png

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May 3, 2024, 3:55:19 AMMay 3
to Flir Lepton
I found that the min value on rpi is too low(3728.0) while on pc is 29552.0. Anyone knows why this happen? I'm using included libuvc and i didn't change anything...

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May 3, 2024, 3:59:37 AMMay 3
to Flir Lepton
Max value of both pi and pc is ok tho

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May 7, 2024, 12:10:31 AMMay 7
to Flir Lepton
Still don't get it why this happens but is there any chance that low voltage causes this issue? I'm using macbook pro power supply and it seems it can't supply enough power for pi.
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Nav

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May 19, 2024, 8:23:02 AMMay 19
to Flir Lepton
It seems the issue is with the RPi 5 only. It works well on a  RPi 4. I guess  there is some issue with the USB connection on the new RPi 5 that is managed by a different chip.

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May 19, 2024, 12:02:58 PMMay 19
to Flir Lepton

Thank you for your response. I should ask to my boss if i can test it on pi 4.

Nav

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May 23, 2024, 9:23:05 AMMay 23
to Flir Lepton
I am not sure but try to connect the Purethermal ground to RPi 5 ground if there are some noise in data.

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May 29, 2024, 10:25:38 PMMay 29
to Flir Lepton
Finally figured out the reason why this happens! There is small noises on the frame which contain 0 value so this is the reason why the minimum range of temperature is too low like -273.15. My workaround is simple just replacing that 0 values to normal value. For instance i'm targeting the minimum temperature is 20 so replacing 0 to 29315. You can use this formula to convert Celsius to Kelvin `val` * 100 + 27315.

I'm attaching the complete workaround here. Hope it would help someone. I'm still don't know how that noises created.

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