Elements of Biomedical Image ProcessingBMI 731 Winter 2005

Kun HuangDepartment of Biomedical Informatics

Ohio State University

- Introduction to imaging processing- Mathematical background

- Convolution and Fourier transform- Filtering

- Image enhancement- Noise removal- Color correction and color space transform

- Feature extraction- Edge, point, line (Hugh transform)

- 3-D reconstruction - Radon transform

- Image Processing : what should be done?- Image restoration and enhancement- Feature extraction- Pattern recognition

- Mathematical Background- Convolution

- 2-D convolution

17 241 8 15

23 57 14 16

4 613 20 22

10 12 19 21 3

11 18 25 2 9

2 9 4

7 5 3

6 1 8

1x2+8x9+15x4+7x7+14x5+16x3+13x6+20x1+22x8=575

- Mathematical Background- Fourier transform (FT)

- Mathematics

- 2-D FT

- Mathematical Background- Fourier transform (FT)

- Fast FT (FFT)

- Mathematical Background- Convolution and Fourier transform (FT)

- Mathematical Background- Filtering

- High-pass filter, low-pass filter, band pass filter

- Gradient filters

1 1 -1 -1

1 1 -1 -1

1 1 -1 -1

1 1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

1 1 1 1

1 1 1 1

- Mathematical Background- Filtering

- Wiener filter and deblurring

- Image Enhancement- Denoise

- Averaging

- Median filter

1/9 1/9 1/9

1/9 1/9 1/9

1/9 1/9 1/9

20 5 43

78 3 22

115 189 200

43

- Image Enhancement- Denoise/restoration

From Gonzalez, Woods, and Eddins

- Image Enhancement- Color and intensity adjustment

- Histogram equalization

- Image Enhancement- Color space transform

RGB -> HSV, HSL, YCbCr, …

R = 64G = 31B = 62

R = 125G = 80B = 147

H = 199S = 117V = 147

H = 214S = 132V = 64

- Feature Extraction- Region detection – morphology manipulation

- Dilate and Erode

- Open- Erode dilate - Small objects are removed

- Close- Dilate Erode - Holes are closed

- Skeleton and perimeter

- Feature Extraction- Edge detection

- Gradients

- Canny edge detector- Gaussian smoothing- Gradients- Two thresholds- Thinning

1 1 -1 -1

1 1 -1 -1

1 1 -1 -1

1 1 -1 -1

-1 -1 -1 -1

-1 -1 -1 -1

1 1 1 1

1 1 1 1

- Feature Extraction- Point detection

- Harris detector

x

- Feature Extraction- Radon transform

- Straight line detection- Hugh transform

y

y

- Feature Extraction- Straight line detection

- Hugh transform

From Gonzalez, Woods, and Eddins

- 2-D/3-D reconstruction- Radon/inverse radon transforms and

backprojection

- Reference- Digital Image Processing using Matlab

By R.C.Gonzalez, R.E.Woods, and S.L.EddinsPublished by Printice-Hall, 2004