Image processing and Camera ISO

Question

I am interested changing the ISO values of my Android Phone Camera. I have looked through the developer pages but nothing was satisfactory. I also found out about OpenCV. But i am unable to understand what does it mean mathematically to change the iso of a an array of pixel intensity values? Maybe if i understood that i could try working on changing the iso of the image from a camera.

Answer 1

ISO is a reference back to film photography, where a high ISO number means that the film is more sensitive to light. A 400-speed film requires half as much light as a 200-speed film to produce the same image.

On a digital camera, ISO is electronic gain applied to the analog signal from the image sensor before it is digitized. Adding gain makes the system more sensitive, but it also amplifies noise - the same tradeoff you get with film.

So changing the ISO of an image is nonsense. You can only change the ISO of a camera, and you do it before taking the picture.

Answer 2

The closest solution for your problem is using an Android camera parameter called exposure compensation - if your particular Android supports it.

Check this similar post Android Camera API ISO Setting?