AM62A7: Water ripples appear in the YUV image

Hi Peng,

Could you please share the sensor companding knee points and the ISP configuration in xml files when this issue happens?

Hi Gang

This is the relevant file.

8360.case.zip

Hi Gang

I have converted the value of the register into a compression curve.

0601.case.zip

Hi Gang

Have you reproduced the water ripple?

Hi peng,

Sorry about the delay.

I am not able to completely reproduce the issue using your xml files in 0601.case.zip without your GLBCE settings.
This is what I get after adjusting image brightness with asym=10 for GLBCE settings and additional digital gain.
/cfs-file/__key/communityserver-discussions-components-files/791/o_5F00_1920x1080_5F00_nv12.yuv

It looks like a problem concerning tone mapping (GLBCE), noise filtering, and sharpening.
I checked your decompanding settings and they look OK and should not cause any contours.
Noise filtering gives smooth output after removing noise and then tone mapping and conversion to yuv may cause quantization error that looks like contours on smooth and neutral image areas.

You may adjust your tone mapping and noise filtering (maybe slightly weaker) a little more to reduce the contours.

Hi Gang 

My image was saved after passing GLBCE. So water ripples are not caused by glbce.

So can I assume that this phenomenon is quantization error caused by image compression.

Hi peng,

I suppose you mean GLBCE is by passed.

GLBCE alone won't cause the contours.
It is a combination of noise filtering, tone mapping (global and/or local) and quantization in conversion to YUV.

This kind of gray field gives a smooth gradient output image after noise filtering and it is contrast enhanced by global/local tone mapping.
Then, small quantization error becomes visible because of the nature of the gray field.