![Spatial Domain transformation
8/30/2023 4
( , ) [ ( , )])
( , ) :input image
( , ) :output image
:an operator on defined over
a neighborhood of point ( , )
g x y T f x y
f x y
g x y
T f
x y
](https://image.slidesharecdn.com/imageenhancementinspatialdomain-230830114215-1c72f710/85/Image-enhancement-in-spatial-domain-ppt-4-320.jpg)
Image enhancement in spatial domain.ppt
- 1. Image Enhancement in Spatial Domain by P. S. Patil
- 2. Image enhancement Image Enhancement process Image enhancement schemes: Spatial domain enhancement methods Frequency domain enhancement methods Point operations Vs neighborhood operations Histogram methods
- 3. Introduction • The image enhancement is the process of making image under consideration suitable for a specific application • different methods of image enhancement:
- 4. Spatial Domain transformation 8/30/2023 4 ( , ) [ ( , )]) ( , ) :input image ( , ) :output image :an operator on defined over a neighborhood of point ( , ) g x y T f x y f x y g x y T f x y
- 5. Spatial domain enhancement methods Spatial domain techniques are performed in the image plane It is based on modifying the pixels in an image directly. Types 1) Point operations. 2) Spatial operations.
- 6. Frequency Domain Enhancement • In this method image is transformed into frequency domain and transformed coefficients are manipulated. Weeks 1 & 2 6
- 8. contrast stretching • The idea behind contrast stretching is to increase the dynamic range of the gray levels in the image • Mathematical modeling : -For α<1 ,a=L/3 -For β>1 ,b=2/3L
- 9. Thresholding: - Thresholding is an extreme contrast stretching which results into binary image
- 10. Digital negative • Negative image can be obtained by, • S= T(r)= L-r-1 Image negatives 1 s L r
- 11. Gray level slicing • Certain areas from the image under consideration can by highlighted using this transformation.
- 12. Log Transformations for image enhancement 8/30/2023 12 Log Transformations log(1 ) s c r
- 13. The histogram 13 The histogram of an image shows us the distribution of grey levels in the image
- 14. Image enhancement by histogram Processing Histogram Equalization Histogram specification 8/30/2023 14
- 15. Histogram Equalization • Histogram equalization is a method in image processing of contrast adjustment using the image's histogram. • This method usually increases the global contrast of many images, especially when the usable data of the image is represented by close contrast values. • Through this adjustment, the intensities can be better distributed on the histogram. • This allows for areas of lower local contrast to gain a higher contrast. • Histogram equalization accomplishes this by effectively spreading out the most frequent intensity values. Weeks 1 & 2 15
- 16. Weeks 1 & 2 16
- 17. Weeks 1 & 2 17
- 18. Neighbourhood Operations Neighbourhood operations simply operate on a larger neighbourhood of pixels than point operations Neighbourhoods are mostly a rectangle around a central pixel Any size rectangle and any shape filter are possible Origin x y Image f (x, y) (x, y) Neighbourhood
- 19. Thank you Weeks 1 & 2 19