The + sign in the figure is shown using 9 pixels in a 3 × 3 grid. The color levels are given to the right of the figure. Each color is represented by a specific number: 0, 1, 2, or 3. Use this information to solve Exercises 51–52.

a. Find a matrix that represents a digital photograph of the + sign.

b. Adjust the contrast by changing the black to dark gray and the light gray to white. Use matrix addition to accomplish this.

c. Adjust the contrast by changing the black to light gray and the light gray to dark gray. Use matrix addition to accomplish this.

+ White Light gray Dark gray 0 1 2 Black 3