3. Let be an image with 1111 pixels. In the center of the image is a square of 55 pixels. The gray level of the background is 100 and the gray level of the square is 0 . a) represent the image as an indexed one (aka write the matrix that represents the image) (1point) b) Compute the result of a linear filter with the kernel below (the origin is the middle pixel). Explain your result. What is this filter useful for? (2 points) c) Compute the result of a median filter with 33 centered neighbourhood (2points) d) Compute the result of the magnitude of edges given by the compass operator for this image. Take into account that the image is not noisy. Explain your result. (5 points)