what is pixel raster
In computer graphics, a raster graphics image is a dot matrix data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium. Raster images are stored in image files with varying formats.t originates from the raster scan of cathode ray tube (CRT) video monitors, which paint the image line by line by magnetically steering a focused electron beam. By association, it came also to refer to a rectangular grid of pixels. The word rastrum is now used to refer to a device for drawing musical staff lines.