Support crop image on sensor, grayscale, and auto exposure level

[jasaw]

Features:

1. Camera takes 1600x1200 resolution cropped to 640x480, or 800x600 cropped to 640x480 (or 320x240 depends on config). Only tested extensively on OV2640 camera.
2. Grayscale mode works with brightness/contrast/saturation control.
3. Adjustable auto exposure level, which is very important for certain lighting conditions.
4. Option to choose "Auto Exposure Control 2" algorithm for auto exposure. This might fix some under-exposed or over-exposed issues.
5. Negative photo effect might work better with existing digit models.

All these features are done by the camera itself, so no impact on memory usage or performance of the ESP32.

Discussion here: #2733

This is my test setup where the camera is taking 1600x1200 and cropping 640x480 out of it.

[caco3]

Thank you for your contribution!

Can you please do the following:

• Rebase to latest rolling
• Add the defaults of each parameter to the sd-card/config/config.ini
• For each new parameter, add a parameter description in param-docs/parameter-pages. Check the https://github.com/jomjol/AI-on-the-edge-device/tree/rolling/param-docs#readme. I can help you if needed. Those pages will be used for the tooltips on the config page as well as for the online documentation.
• I think it would be good to also add the parameters to the config page. I can help you if needed.

[jasaw]

@caco3 I've done these:

• rebase to latest rolling
• add defaults to sd-card/config/config.ini
• add parameter description to documentaion in param-docs/parameter-pages.
• add parameters to config page. I haven't quite figured out what those suffix in <tr id> mean, like _ex10, or _ex8, or ex3.

If you can help me with those parameters in the config html page, that would be greatly appreciated.

[caco3]

Dear @jasaw

Thank you for your contribution, especially the detailed parameter documentation! I will add the parameters to the config page, but it will take me a moment as live is quite busy atm.

[caco3]

I merged it to jomjol:feature/crop_image so I can edit the files of it