Digital Image Processing By Asst Prof Juthawut Chantharamalee
Digital Image Processing By Asst. Prof. Juthawut Chantharamalee Chapter 3 Gray-Level Intensity Computer Science at Suan Dusit University Thailand Transformations and Histogram
PART 1 Chapter 3 Gray-Level Intensity Computer Science at Suan Dusit University Thailand Transformations
Chapter 3 Intensity Transformation and Spatial Filtering Spatial Domain image plane ( x-y plane) ��������� pixel ������
Chapter 3 Intensity Transformation and Spatial Filtering ������ Spatial Domain ������������ g(x, y) = T[f(x, y)] ������ f(x, y) ��� input image g(x, y) ��� output image T �������� f ���� (x, y)
Chapter 3 Intensity Transformation and Spatial Filtering Basic implementation on a single image (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering ���� ��� f(x, y) ���� (100, 150( ����� T ��� “computethe average intensity of the 3 x 3 neighborhood” g(x, y) = (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image (20+55+62+34+70+77+67+72+ Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Gray-Level Transformation • Pixels ������ (x, y) ������ 1 x 1 ���������� ��� • ������� ��� s = g(x, y) ��� r = f(x, y) • ����������� s = T(r) ���� “intensity (gray-level ���� mapping) transformation function”
Chapter 3 Intensity Transformation and Spatial Filtering ���� intensity transformation function a) Contrast stretching function b) Thresholding function (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Basic intensity transformation functions • Linear (negative and identity transformation) • Logarithmic (log and inverse-log transformation) • Power-Law (nth power and nth root transformation)
Chapter 3 Intensity Transformation and Spatial Filtering (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Image Negatives • ����� gray level ����� [0, L-1] �� ����� Negative transformation ������� s=L-1 -r
Chapter 3 Intensity Transformation and Spatial Filtering ���� image 8 bits ���� 2 x 2 ������ (0, 0) s = L – 1 negative transformation = 256 – 1 – 0 = 255 ��� (0, 1) s = L – 1 = 256 – 10 = 245 ��� (1, 0) s = L – 1 = 256 – 1 – 200 = 55 ��� (1, 1) s = L – 1 = 256 – 1 – 255 = 0
Chapter 3 Intensity Transformation and Spatial Filtering Part 1 ���� ��� image negatives negative ��� � ��������� ���� �� ��� (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image ����� Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Log Transformation • ����� gray level ����� [0, L-1] ������� log transformation ������� s = c * log (1 + r) c ������� r >= 0
Chapter 3 Intensity Transformation and Spatial Filtering ��������� pixel ������� 106 ����� c = 1 �� ��� s = c * log (1 + r) = 1 * log (1 + 610) =6 �������������
Chapter 3 Intensity Transformation and Spatial Filtering ������ Log Transformations ��� log transformation �� �� �� �c = 1 Fourier Spectrum ���� �� 0 ��� 6. 2 ����� � 0 ������ ����� 8 ��� 1. 5 x 106
Chapter 3 Intensity Transformation and Spatial Filtering Power-Law (Gamma) Transformations • ����� gray level ����� [0, L-1] ������� power-law transformation��� ���� s = c*cy c ��� y �������
Chapter 3 Intensity Transformation and Spatial Filtering (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering ���� MRI image � ������� � ��� 0. 4 (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition. ��� �� ���
Chapter 3 Intensity Transformation and Spatial Filtering �������� � ��� 3 (Figure from Rafael C. � Gonzalez and Richard E. Wood, Digital Image ��� 4 Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Piecewise-Linear Transformation Functions • ������������ • �� ������ • ��������� contrast stretching, intensity slicing, bit-plane slicing
Chapter 3 Intensity Transformation and Spatial Filtering ���� Contrast Stretching ����������� 700 ���� ��� electron microscope (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Figure 3. 10 (a) ���� ��� � ������ � ��� contrast stretching � ��(r 1, s 1) �� �(r 2, s 2) �� �� ��� ���transformation function �� �� �r 1 = s 1 �� �r 2 = s 2 ������ linear function ��� � � �� ����� ���� �� �r 1 = r 1. s 1 = L-1 ������ threshold function ��� � �����
Chapter 3 Intensity Transformation and Spatial Filtering ���� Gray-level slicing (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering Part 1 ������� highlight (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image ������������ Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering ���� �� ���� �bit plane, ������ ��� �� ������ � ��� 194 ��� � � �� � 11000010 ��� � � ����� � ����� (Figure from Rafael�� C. Gonzalez and Richard Digital Image ���E. Wood, � �bit plane Processing, 3 rd Edition.
Chapter 3 Intensity Transformation and Spatial Filtering �������������� (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
PART 2 Chapter 3 Histogram Computer Science at Suan Dusit University Thailand
Chapter 3 Histogram ���� image A ����� gray level ���� 80 80 80 200 200 80 80 80 200 200 80 80 80 200 200 150 150 80 80 80 80 80
Chapter 3 Histogram ��� image A
Chapter 3 Histogram ���� Histogram ��� Dark image ������ gray level ������� ����� ��� Bright image ��� gray level ������� ��������� (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Histogram ��� Low-contrast image ������ gray level������ � ����� � image ��� High-contrast ��� gray level����������� (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Histogram (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Histogram rk ����� • ������������ pr ( rk) n=k / n � �����k = 02, , 1…, , L – 1 Histogram Equalization
Chapter 3 Histogram ���� Histogram Equalization ����� image 3 bit (L = 8) ����� 64 x 64 pixels �� ��������� Table 3. 1 ����������� [0, L-1] = [0, 7]
Chapter 3 Histogram (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
Chapter 3 Histogram
Chapter 3 Histogram r 4 = 0 ��� s 0 = 1 r 3 ��� r 4 ��� map ����� 6(Figure ������� ��� �� (656+329) = and 985 pixels ���� Digital Image from Rafael C. Gonzalez Richard E. Wood, Processing, 3 rd Edition.
Chapter 3 Histogram (Figure from Rafael C. Gonzalez and Richard E. Wood, Digital Image Processing, 3 rd Edition.
The Chapter End 3 Gray-Level Intensity
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