Question

1. Reflection Write a program in Python or Matlab to perform reflection of an image about its y-axis. Apply your program to an image of your choice to demonstrate the reflection. Do not use transpose library.

Answer 1

A colored image consists of 3-D matrix values where each plane is for each color channel of RGB colors.

To reflect an image about y-axis, we need to start with the bottom row and end with the first row for all the 3 colors. For example take a binary colored image ( 1 plane => 2-D matrix) as

1 2 3 4

5 6 7 8

9 10 11 12

To reflect it about y-axis, we write this as

9 10 11 12

5 6 7 8

1 2 3 4

We can do this in MATLAB, by starting with the bottom row (denoted by end) and decreasing this by -1 at each iteration till 1.

the end:-1:1 is the code for the same in MATLAB.

Program:

img = imread('example.jpg'); % read image

subplot(2,1,1); % subplot 1

imshow(img); % display image

title('Original Image');

y_img = img(end:-1:1, :, :); % reflected image, starting with last row and end with the first row, y remains same

subplot(2,1,2); % subplot 2

imshow(y_img); % display the reflected image

title('Image reflected about y-axis');