How many pixels in the sensor are required?

In order to accurately measure particle size in a digital image the number of pixels in the sensor must be twice the size (or frequency) of the particles to be measured. Too few pixels results in undersampling and aliasing in the image (the ‘jaggies’). Too many will cause oversampling and a degradation of the image since enough information is simply not present in the image. It is important to have the right number of pixels in the sensor to avoid these problems.