Introduction to Digital Image Processing March 4, 2003 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring03/cc/

Module Overview Lecture 1 Lecture 2 Digital Image Fundamentals Digital Image Enhancement Digital Image Segmentation Digital Image Compression

Digital Image Fundamentals Lecture 1 Digital Image Fundamentals

Monochromatic Digital Image y x Gray Level f(x,y)

R+G+B R G B R+G+B R G B R+G+B R G B R+G+B R G B R+G+B R G B R+G+B R G B

Sampling & Quantization demos/demo1sampling_and_quantization/demo_sampling.m Quantization demos/demo1sampling_and_quantization/demo_quant.m Digital Image Processing Course Nos. 0909-452-01 (Senior Elective) and 0909-552-01 (Graduate) Fall 2003 Previous Offering: http://engineering.rowan.edu/~shreek/fall01/dip/

Fundamental Steps* Knowledge Base Preprocessing (Enhancement & Restoration) Representation & Description Segmentation Problem Domain Knowledge Base Image Acquisition Recognition & Interpretation Result *Rafael C. Gonzalez and Richard E. Woods, Digital Image Processing, Addison-Wesley, 1992

Digital Image Enhancement

Point Processing (Intensity Transformation) s(x,y) = T{ r(x,y)} Transformed Gray Level Original Gray Level Transformation Function >>imadjdemo >>imadjust

Point Processing Pixel Operations Point processing Histogram equalization Connectivity individual pixels all pixels neighboring pixels

Point Processing >>imadjdemo >>imadjust g L-1 s2 s s s1 r L-1 L-1 s2 s g s s1 r r r1 r2 L-1 >>imadjdemo >>imadjust

Image Histogram >>imadjdemo >>imhist

Histogram Equalization (Balancing) >>imadjdemo >>histeq

Fundamental Steps* Knowledge Base Preprocessing (Enhancement & Restoration) Representation & Description Segmentation Problem Domain Knowledge Base Image Acquisition Recognition & Interpretation Result *Rafael C. Gonzalez and Richard E. Woods, Digital Image Processing, Addison-Wesley, 1992

Digital Image Segmentation

Spatial Filtering (Masking) Portion of a digital image Mask z1 z2 z3 z4 z5 z6 z7 z8 z9 w1 w2 w3 w4 w5 w6 w7 w8 w9 Replace with R = w1z1 + w2z2 + ….. +w9z9

Edge Detection Sobel Masks -1 -2 1 2 -1 1 -2 2 >>edgedemo 1 2 -1 1 -2 2 >>edgedemo >>edge demos/demo2spatial_filtering/edgegradientdemo.m

Fundamental Steps* Knowledge Base Preprocessing (Enhancement & Restoration) Representation & Description Segmentation Problem Domain Knowledge Base Image Acquisition Recognition & Interpretation Result *Rafael C. Gonzalez and Richard E. Woods, Digital Image Processing, Addison-Wesley, 1992

Digital Image Compression

Discrete Cosine Transform Information Concentration Data Compaction Feature Extraction Discrete Cosine Transform >>dctdemo

JPEG Compression Standard Compute DCT F(u,v) Level Shift Reorder to form 1-D Sequence f(x,y) Normalize Compute DC Coefficient Compute AC Coefficients http://www.jpeg.org/

Summary Digital Image Processing Course Nos. 0909-452-01 (Senior Elective) and 0909-552-01 (Graduate) Fall 2003 Previous Offering: http://engineering.rowan.edu/~shreek/fall01/dip/