Indexed Color Image
Enables obtaining up to 256 fixed colors defined in advance in a palette. It uses only a single layer.
Encoded in 8 bits per pixel (bpp): 28 = 256 possibilities
Each pixel can have up to 256 possible fixed colors
As we can observe in Figure 9., with 256 colors, some gradients in this image may appear dithered, and the quality is close to a photo, but there is room for improvement.
We can observe that the most natural way to represent a color image is to use three matrices. However, for large images, this leads to significant memory usage
We will demonstrate more precisely the principle of this representation as indicated in Figure 9 .
Indeed, these colors are stored in a color table (colormap), which is an nx3 matrix (where n is the number of colors). The image is then a matrix containing integers ranging from 1 to n, with each integer serving as an index relative to the color table.
Example: The element shown in Figure 10 contains the integer 18, which refers or points to the 18th row of the color table to determine the color of the corresponding pixel.
