How to detect average pixel intensity from live camera preview?

Question

I am building a scanner app, and trying to determine the \"preview quality\" from the preview callback of the camera. I want to customize the camera\'s AUTO_FLASH_MODE

Answer 1

Either find out how to access pixel values of your image and calculate the average intensity yourself or use any image processing library to do so.

Dark pixels have low values, bright pixels have high values. You want to calculate the average of all red, green and blue values divided by three times your pixel count. Define a threshold for when to turn on the flash, but keep in mind that you have to get a new exposure time then. Prefer flash over exposure time increase as long exposure times yield higher image noise.