8.1 The Numbers Game

The next link in the imaging chain is the point where the camera's sensor turns an image into an array of numbers, typically between 0 and 255. The sensor divides the image into picture elements, or pixels, and assigns a number to represent the brightness of the image at each pixel. (A color camera creates three arrays of numbers, corresponding to the brightness of the red, green, and blue pixels.) Mathematicians love this, because they can now play with the numbers using various equations to alter the look of an image, or to extract information from the image data. An image can be processed using various mathematical formulas to change the numbers in an attempt to improve the way the image looks. Of course, beauty is in the eye of the beholder, so people do not necessarily agree on the exact process that results in the best image, but that is the subject of the next chapter!