Matlab:Image enhancement techniques<br />
Filtering<br />Filtering is a technique for modifying or enhancing an image. Image processing operations implemented with ...
Filtering an Image with Predefined Filter Types<br />The ‘fspecial’ function produces several kinds of predefined filters....
h = fspecial('unsharp');
 I2 = imfilter(I,h);
imshow(I), title('Original Image')
 figure,  imshow(I2), title('Filtered Image')</li></li></ul><li>Filtering an Image with Predefined Filter Types<br />
Filtering an Image with Predefined Filter Types<br /><ul><li>Predefined filters provided by ‘fspecial’
average’ 	Averaging filter
'disk’ 		Circular averaging filter (pillbox)
'gaussian’	Gaussian lowpass filter
'laplacian’	Approximates the two-dimensional Laplacian operator
Upcoming SlideShare
Loading in...5
×

Matlab Image Enhancement Techniques

16,476

Published on

Matlab Image Enhancement Techniques

Published in: Technology, Business
0 Comments
9 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
16,476
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
0
Comments
0
Likes
9
Embeds 0
No embeds

No notes for slide

Matlab Image Enhancement Techniques

  1. 1. Matlab:Image enhancement techniques<br />
  2. 2. Filtering<br />Filtering is a technique for modifying or enhancing an image. Image processing operations implemented with filtering include smoothing, sharpening, and edge enhancement.<br />
  3. 3. Filtering an Image with Predefined Filter Types<br />The ‘fspecial’ function produces several kinds of predefined filters. After creating a filter with ‘fspecial’, we can apply it directly to our image data using ‘imfilter’.<br /><ul><li>I = imread('moon.tif');
  4. 4. h = fspecial('unsharp');
  5. 5. I2 = imfilter(I,h);
  6. 6. imshow(I), title('Original Image')
  7. 7. figure, imshow(I2), title('Filtered Image')</li></li></ul><li>Filtering an Image with Predefined Filter Types<br />
  8. 8. Filtering an Image with Predefined Filter Types<br /><ul><li>Predefined filters provided by ‘fspecial’
  9. 9. average’ Averaging filter
  10. 10. 'disk’ Circular averaging filter (pillbox)
  11. 11. 'gaussian’ Gaussian lowpass filter
  12. 12. 'laplacian’ Approximates the two-dimensional Laplacian operator
  13. 13. 'log’Laplacian of Gaussian filter
  14. 14. 'motion’ Approximates the linear motion of a camera
  15. 15. 'prewitt’ Prewitt horizontal edge-emphasizing filter
  16. 16. 'sobel’Sobel horizontal edge-emphasizing filter
  17. 17. 'unsharp’Unsharp contrast enhancement filter</li></li></ul><li>Image Enhancement<br />Image Enhancement Tools<br />adapthisteqContrast-limited adaptive histogram equalization (CLAHE)<br />decorrstretchApplydecorrelation stretch to multichannel image<br />histeqEnhance contrast using histogram equalizationi<br />madjustAdjust image intensity values or colormap<br />imnoiseAdd noise to image<br />
  18. 18. Image Enhancement<br />Image Enhancement Tools<br />intlutConvert integer values using lookup table<br />medfilt22-D median filtering<br />ordfilt22-D order-statistic filtering<br />stretchlimFind limits to contrast stretch image<br />wiener22-D adaptive noise-removal filtering<br />
  19. 19. Image Enhancement<br />Image Restoration (Deblurring)<br />DeconvblindDeblur image using blind deconvolution<br />DeconvlucyDeblur image using Lucy-Richardson method<br />DeconvregDeblur image using regularized filter<br />DeconvwnrDeblur image using Wiener filter<br />Edgetaper Taper discontinuities along image edges<br />Otf2psf Convert optical transfer function to point-spread function<br />Psf2otf Convert point-spread function to optical transfer function<br />
  20. 20. Image Enhancement<br />Dilation- and Erosion-Based Functions<br />Bwhitmiss Logical AND of an image, eroded with one structuring element, and the image&apos;s complement, eroded with a second structuring element.<br />Imbothat Subtracts the original image from a morphologically closed version of the image. Can be used to find intensity troughs in an image.<br />
  21. 21. Image Enhancement<br />Dilation- and Erosion-Based Functions<br />Imclose Dilates an image and then erodes the dilated image using the same structuring element for both operations.<br />Imopen Erodes an image and then dilates the eroded image using the same structuring element for both operations.<br />Imtophat Subtracts a morphologically opened image from the original image. Can be used to enhance contrast in an image.<br />point-spread function to optical transfer function<br />
  22. 22. Dithering<br />Dithering changes the colors of pixels in a neighborhood so that the average color in each neighborhood approximates the original RGB color.<br />

×