# 2014F001/User talk:areeba14/homework 8

### From CDS 130

## Contents |

# 1. Image manipulation

- Create a
`10x10`

matrix that contains any number from 1 through 10 at least once. The numbers may be in any order. Create the matrix using a double for loop. - Create a colormap matrix such that each number is mapped to a unique color.
- Use the
`image`

command to plot your image. - Use the
`colorbar`

command to show a colorbar. - Describe (in words) how you could change the colormap matrix to achieve the same result.

for i = 1:10

for n = 1:10

A(i, n) = randi(10);

end

end

>> A

A =

8 4 6 2 7 3 7 7 8 5 1 3 10 2 9 6 10 1 5 2 10 1 8 9 9 1 4 3 9 5 10 2 3 2 2 9 6 6 2 9 7 4 6 5 1 3 2 2 3 5 1 10 10 5 5 4 10 4 2 8 4 3 5 1 2 10 10 6 1 3 4 9 1 1 2 7 8 7 5 6 3 8 2 7 2 4 7 8 1 10 8 5 5 5 4 6 6 9 8 7

>> mycolormap = [0 0 0; 0 0 1; 0 1 0; 0 1 1; 1 1 0; 1 1 1; 0.5 0.5 0.5; 1 0 1; 0.5 1 0; 0.5 0.5 0];

>> colormap(mycolormap)

>> imagesc(A)

>> colorbar

%I could change the order in the colormap matrix and switching the numbers to achieve the same results

# 2. Using ` fill `

or ` image `

Write a MATLAB code that draws 8-by-8 checkerboard with red and black tiles.

M = [0 1 0 1 0 1 0 1; 1 0 1 0 1 0 1 0];

M = [M; M];

M = [M; M];

mycolormap = [1 0 0; 0 0 0];

colormap(mycolormap)

imagesc(M)

# 3. Color map and images

Write a Matlab script to create an image as follows: ( Note: you need to provide seven colors and the correct orientation of the strips.)

mycolormap = [1 0 0; 0 0 1; 1 0 1; 0 0 0; 1 1 1; 0.5 0.5 0.5; 1 1 0]

M = [1, 2, 3, 4, 5, 6, 7]

image (M);

colormap (mcolormap) ;

axis square;

axis off;

# 4. Create images

Run the following Matlab code.

clear; i=0:2*pi/1000:2*pi; x=sin(i); y=cos(i); fill (x,y, 'r', 'EdgeColor', 'r'); hold on fill (x*0.98, y*0.98, 'b', 'EdgeColor', 'b'); hold off axis equal off shg

Understand the meaning of this code. Now, make use of this script and write a MATLAB code to generate the Target logo.

MATLAB code:

clear;

i=0:2*pi/1000:2*pi;

x=sin(i);

y=cos(i);

fill (x,y, 'r', 'EdgeColor', 'r');

hold on

fill (x*0.75, y*0.75, 'r', 'EdgeColor', 'r');

hold on

fill (x*0.50, y*0.50, 'w', 'EdgeColor', 'w');

fill (x*0.20, y*0.20, 'r', 'EdgeColor', 'r');

axis equal off

shg

# 5. Plots

(a) Plot the following equations, first by choosing points within the range as a vector, computing the associated y values, and finally by building a proper plot using MATLAB statements.

0 < *x* < 4π,

Plot:

MATLAB code:

x = linspace (0, 4*pi, 100);

y =(sin(x.^4)/16)-(cos(x.^3)/8)+(sin(x.^2)/4)-(cos(x)/2);

plot(x,y)

# 6. making polygon shapes

Write a Matlab script to create an image as follows:

x = [0, 0, 0 ];

y = [0, 1, 1, 0 ];

z =[1, 1, 0, 0 ];

fill (x, y, z)