Log Transformation in Image Processing with Example

Log Transformation in Image Processing with Example. Here log transformation graph and matlab code with input and output image.

1. Log Transformation Presented by: Group no: 08 Roll: 160129 , 160134 Session: 2016-17 Department of Computer Science and Engineering Jashore University of Science and Technology

2. Objectives What is log transformation? Properties of log transformation; Log transformation graph; Coding technique; Input and output; Log transformation applications; References.

3. What is Log Transformation? Log transformation means replacing each pixel value with its logarithm value. The log transformations can be defined by this formula s = c log(r + 1 ) Where s and r are the pixel values of the output and the input image and c is a constant. The value 1 is added to each of the pixel value of the input image because if there is a pixel intensity of 0 in the image, then log (0) is equal to infinity. So 1 is added, to make the minimum value at least 1.

4. Properties of log transformations For lower amplitudes of input image the range of gray levels is expanded For higher amplitudes of input image the range of gray levels is compressed

5. Log Transformation Graph Figure: Log Transformation Graph

6. Coding Technique a1 = imread ( 'image.jpg' ); a = double(a1)/255; c = 2; f = c*log(1 + (a)); subplot(1,2,1), imshow (a1),title( 'Original Image' ); subplot(1,2,2), imshow ((f)),title( 'Log Transformation Image' );

7. Input and Output Figure: Log Transformation Graph

8. Log Transformation Applications Expands the dark pixels in the image while compressing the brighter pixels. Compresses the dynamic display.

9. References https://www.tutorialspoint.com/dip/gray_level_transformations.htm # https://theailearner.com/2019/01/01/log-transformation /

10. T H A N K Y O U