Hello again all !
Just some follow up from the previous messages.
I can confirm that the stl generated file for the Arducam mount fits perfectly (I said the Arducam was a B0196, it is actually a B0292, only difference is the auto-focus). I also redesigned the electronic_drawer, as I only need three sockets : the camera cable, Arduino Nano connection and the external supply for the motors. I did it on Solidworks, as I do not know Openscad nearly well enough, tell me if it is still of interest that I publish it here.
For the calibration, it is pretty restricted, the ONLY two parameters that communicates with the ISP directly are the exposure and gamma. Note that both of those are integers (from 0 to -11 for the exposure) which means they are just knobs on a black box. From there, I made an auto-calibration which finds the best exposure for a specified brightness, and the white balance for a relative equality between color intensity across the image. The other parameters can be changed manually (contrast, gain, etc).
Here is my microscope :
And my problem is a color gradient across the image, with purple/pink on the edge and green in the centre, see the image hereunder. From Color dots in the image - #5 by MetallicaSPA , I reckon it looks like this post, but I do not have access to flat field correction, is that what the problem might be ? Any idea how I could resolve that ? Disregard the shading on the image, it seems like dust has compromised the sensor.
Best regards