Question

I have a stupid question:

I have a black circle on white background, something like:

I have a code in Matlab that gets an image with a black circle and returns the number of pixels in the circle.

will I get the same number of pixels in a camera of 5 mega pixel and a camera of 8 mega pixel?

Answer 1

The short answer is: Under most circumstances, No. 8MP should have more pixels than 5MP, However…

That depends on many factors related to the camera and the images that you take:

1. Focal length of the cameras, and other optics parameters. Consider a fish-eye lens to understand my point.
2. Distance of the circle from the camera. Obviously, closer objects appear larger.
3. What the camera does with the pixels from the sensor. For example, 5MP cameras that works in a down-scaled regime, outputting 3MP instead.