digitalimageprocessing
Digital Image Processing
IIT Delhi, 1997-2002
Blurring and Median Filtering
Original Image
Average Mask(3x3)
Median Filter(3x3)
Average Mask(7x7)
Median Filter(7x7)
Highpass and Highboost Filtering
Original Image & High Pass(3x3)
High Boost(3x3,a=1.1),High Boost(3x3,a=1.3) & High Boost(3x3,a=1.5)
Image Averaging
Noised Images
Average Image
Constrast Stretching
The following are some experimental results. Histograms are shown whereever relevant. Click on the histograms to see in more detail.
Original Image
After contrast stretch
(r1,s1,r2,s2) = (0,0,0.3,0.8)
(r1,s1,r2,s2) = (0,0,0.4,0.8)
Histogram Equalization
After global histogram equalization
After local histogram equalization(mask:21x21)
After local histogram equalization(mask:51x51)
Click on the images below for more experimental results.
Half Toning and Dithering
Original Image and image after dithering with a mask of size 2x2
Image and halftoned copies of the same. Mask sizes 2x2 and 3x3 respectively
The same image after dithering, the dithering levels being 2, 4 and 16.
Fourier Transform
Image,it's fourier transform & Inverse of the fourier transform
Fourier Transform(centered)
Fourier Transform: 3D plot
Fourier Transform: x=Max_x/2
Time taken to compute fourier transform (fft) : 'N' Vs Processor time(clock cycles)
LowPass Filters (Frequency Domain)
Filter
Ideal
(faulty !)
Ideal
butterworth
n=2
butterworth
n=5
butterworth
n=25
D0=25
D0=50
Effect of spatial smoothing filters on fourier transform
Original
After Nhbd. Averaging(3x3)
After Nhbd. Averaging(11x11)
HighPass Filters (Frequency Domain)
Filter
Ideal
butterworth
n=2
butterworth
n=5
D0=25
D0=50
Effect of spatial sharpening filters on fourier transform
Original
After HighPass Filtering(3x3)
After HighPass filtering(11x11)