This bachelor's thesis describes the designing of algorithms for detection, processing and conversion of desired objects from input color images to grayscale or black and white domain. The input images are divided into two groups, where the first group consists of sudoku images and other brain puzzles. The second group contains images of paper documents. The thesis analyses imperfections of input images and their effect on the building and functionality of each of the programs. Subsequently, it looks for solutions of a reliable detection of desired objects and correction of their geometric distortions. For a better readability and toner saving when printing the output images respectively, the thesis gives answers as to how to erase unwanted...