Log Transformation in Image Processing with Example
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The document discusses log transformation in image processing, which involves replacing pixel values with their logarithmic equivalents to enhance image details. It defines the transformation formula, explains its properties, presents a coding technique, and illustrates the applications of log transformation in image analysis. References are provided for further reading and the document concludes with a thank you note.
Log Transformation in Image Processing with Example
- 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.
- 10. THANK YOU