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waveform80 / picamera

A pure Python interface to the Raspberry Pi camera module
https://picamera.readthedocs.io/
BSD 3-Clause "New" or "Revised" License
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Bayer de-noise algorithm cannot be disabled #565

Open karpawich opened 5 years ago

karpawich commented 5 years ago

The "Hardware" section of the PiCamera documentation describes "several post-processing steps on the frame data" by the GPU's image signal processor:

Bayer de-noise: This is a noise reduction algorithm run on the frame data while it is still in Bayer format.

...

YUV de-noise: Another noise reduction algorithm, this time with the frame in YUV420 format. See image_denoise and video_denoise.

As explained, the PiCamera Python interface allows the developer to disable the YUV de-noise operation via image_denoise and video_denoise. However, the Bayer de-noise operation appears to be a separate operation that cannot be controlled via those two settings.

Since I am testing the PiCamera v2.1 module as an entropy source, I need to maximize image static to maximize image entropy. Given that the YUV de-noise and Bayer de-noise operations are both performed by the ISP, can the Bayer operation also be disabled via the PiCamera Python interface?

6by9 commented 5 years ago

You need to add 

'bayer-denoise': 1<<10,

to https://github.com/waveform80/picamera/blob/master/picamera/camera.py#L334, and then set isp_blocks with 'bayer-denoise'.

Notes as per https://www.raspberrypi.org/forums/viewtopic.php?f=43&t=175711 - don't complain if these settings mess up the capture pipeline.

karpawich commented 5 years ago

@6by9 I've submitted a Pull Request with the simple change you suggested above. Should this Issue be closed, or left open until the change can be done without modifying the source directly?