OPT8241-CDK-EVM: the opt8241 depth data distribution like circle?

None_feiyu

Expert 1320 points

Part Number: OPT8241-CDK-EVM

Dear Larry&Anand，

I have used a different color represent depth data. just like the below figure.

It's very interesting the depth distribution like circle. this phenomenon affected the RGB-D rectification

Can you give me advise about this.

thanks&regards

over 8 years ago

0 None_feiyu over 8 years ago

Expert 1320 points

Hi Larry & Anand,

Can your give me advice about this question?

thanks&regards

None

0 Moetaz Abbas over 8 years ago in reply to None_feiyu

Prodigy 160 points

From what I see, it can be explained by turning off calibration and having a white board in front of the camera at a big distance. I am assuming you are using a color coding for the depth, is that true?

0 Anand Gadiyar over 8 years ago

TI__Genius 15005 points

Hi None,

If you are plotting the raw phase data or the depth data from the SDK, this represents the radial distance. Therefore the image you get for a properly calibrated camera will look like concentric circles - this is expected behavior.

If the lens parameters are known, the SDK can also provide point cloud data. The Z values from the point cloud should give you a flat surface when plotted.

0 Larry Li over 8 years ago in reply to None_feiyu

TI__Expert 3495 points

Your color values are repeating, that tells me your value-to-color mapping is aliasing, most likely caused by not matching the full range of values to full range of colors. Please double check.

0 None_feiyu over 8 years ago in reply to Anand Gadiyar

Expert 1320 points

Dear Anand,

I don't understand why this is expected behavior? I think it should be Linear gradient color?

hopes you give me more advise.

Thanks&Regrads

None

0 None_feiyu over 8 years ago in reply to Larry Li

Expert 1320 points

Dear Larry，

Thanks for you information.

What I'm concerned about is the color map like Concentric circles，just like below figure.

0 Larry Li over 8 years ago in reply to None_feiyu

TI__Expert 3495 points

Anand's answer is on mark. The depth map measures the distance from the pixel the point in the scene it images. In the case of a flat wall, the center pixel distance will be the shortest, and increasing for pixels further away from the center. The reason for the repeating color is likely a bug in your depth-to-color mapping--which can happens when input range is not correctly mapped to the color range.

0 Larry Li over 8 years ago in reply to Larry Li

TI__Expert 3495 points

Also please make sure your image is not saturating (too strong of reflection).

0 Larry Li over 8 years ago in reply to Larry Li

TI__Expert 3495 points

None_feiyu,

Is this issue resolved? I think someone from your end was supposed send us some raw data VXL file with the above issue to review.

-Larry

0 None_feiyu over 8 years ago in reply to Larry Li

Expert 1320 points

Dear Larry,

Sorry for the delay reply. the email sent for you is from me.

We have understand why the depth data look like concentric circles,but this issue affected the RGB-D rectification

Now this issue is suspend,we have no idea about this issue. because in the RGBD Piond cloud it look like ok.

if want to solve this issue fully,it mybe need two RGB sensor for the RGBD rectification.

thanks & regards.

None.

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OPT8241-CDK-EVM: the opt8241 depth data distribution like circle?