Matlab Image Enhancement Techniques

1. Matlab:Image enhancement techniques

2. Filtering Filtering is a technique for modifying or enhancing an image. Image processing operations implemented with filtering include smoothing, sharpening, and edge enhancement.

4. h = fspecial('unsharp');

5. I2 = imfilter(I,h);

6. imshow(I), title('Original Image')

9. average’ Averaging filter

10. 'disk’ Circular averaging filter (pillbox)

11. 'gaussian’ Gaussian lowpass filter

12. 'laplacian’ Approximates the two-dimensional Laplacian operator

13. 'log’Laplacian of Gaussian filter

14. 'motion’ Approximates the linear motion of a camera

15. 'prewitt’ Prewitt horizontal edge-emphasizing filter

16. 'sobel’Sobel horizontal edge-emphasizing filter

18. Image Enhancement Image Enhancement Tools intlutConvert integer values using lookup table medfilt22-D median filtering ordfilt22-D order-statistic filtering stretchlimFind limits to contrast stretch image wiener22-D adaptive noise-removal filtering

19. Image Enhancement Image Restoration (Deblurring) DeconvblindDeblur image using blind deconvolution DeconvlucyDeblur image using Lucy-Richardson method DeconvregDeblur image using regularized filter DeconvwnrDeblur image using Wiener filter Edgetaper Taper discontinuities along image edges Otf2psf Convert optical transfer function to point-spread function Psf2otf Convert point-spread function to optical transfer function

20. Image Enhancement Dilation- and Erosion-Based Functions Bwhitmiss Logical AND of an image, eroded with one structuring element, and the image's complement, eroded with a second structuring element. Imbothat Subtracts the original image from a morphologically closed version of the image. Can be used to find intensity troughs in an image.

21. Image Enhancement Dilation- and Erosion-Based Functions Imclose Dilates an image and then erodes the dilated image using the same structuring element for both operations. Imopen Erodes an image and then dilates the eroded image using the same structuring element for both operations. Imtophat Subtracts a morphologically opened image from the original image. Can be used to enhance contrast in an image. point-spread function to optical transfer function

22. Dithering Dithering changes the colors of pixels in a neighborhood so that the average color in each neighborhood approximates the original RGB color.