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3dtof / voxelsdk

VoxelSDK - an SDK supporting TI's 3D Time of Flight cameras
BSD 3-Clause "New" or "Revised" License
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HDR setting on OPT8320 with SFH4250 LED Illum #80

Open SankethR opened 8 years ago

SankethR commented 8 years ago

I wish to enable HDR on the device after some preliminary tests with targets of different reflectivity values showed that the camera is not able to discern values due to integration times being too high. Here are some samples: Target: 7% remission at 850 nm Number of frames: 1000 frames Distance from camera to target: 500 mm Imager Settings: mod_freq1 - 24.75 MHz; intg_time - 88% ; illum_power_percentage - 100%

close_range_7 target_over-estimation

To do some additional tests with HDR enabled, I followed the procedure in the Manual OPT8320 SBAS748 - December 2015, but I am getting an error when I try to configure by VoxelCLI.exe. Here is the screenshot.

hdr_procedure_voxelcli

I set the ALT_FREQ_SEL = 7 because I do not wish to extend the unambiguous range and want to use the same frequency as earlier. (In the screenshot I changed the unambiguous_range to 5 m) The pix_cnt_max value is unchanged and set to 50000 as earlier. I don't know how to change this when ALT_FRAME_EN = 1, the manual has not elaborated on this aspect.

My questions are: 1) How can I improve short range performance of the camera? I can think of implementing HDR, increasing the number of sub-frames to prevent saturation of pixels. Any more?

2) I have read in the manual that the phase of saturated pixels is set to 0, while the Amplitude data remains unchanged. Going on those lines, shouldn't the distance in the pixels be 0 if the pixels are saturated? Instead, I notice an over-estimation of distances and huge deviations in the measured distances. Is this more of a calibration issue then? (I haven't done any calibration on the device so far)

3) What could the be the cause for the inability to set HDR on the device?

Thanks and best regards, Sanketh

SankethR commented 8 years ago

I got some clarity on question 1) after reading an earlier post on Phase_corr1 by @Yorkland, I did some trials to check the Phase Offset and it was way off. Will do some additional tests with the corrected values. But I would still appreciate your feedback on improving short range Performance of the camera and setting HDR on the OPT8320.

SankethR commented 8 years ago

I still get errors trying to Setup HDR on the device. Any thoughts on what I am doing wrong?