Color Image Processing

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Color Image Processing Image Processing CSE 166 Lecture 9 Reading • Digital Image Processing, 4th edition – Chapter 7: Color Image Processing CSE 166, Fall 2017 2 Electromagnetic spectrum CSE 166, Fall 2017 3 Separating visible light CSE 166, Fall 2017 4 Human eye cones CSE 166, Fall 2017 5 Note that Mixing light green, cyan, and blue are not accurate colors in the Light book. More accurate colors below. Primary and secondary RED colors are swapped YELLOW GREEN Pigment CYAN BLUE MAGENTA CSE 166, Fall 2017 6 RGB color model RGB color cube RGB coordinates CSE 166, Fall 2017 7 XYZ color model and chromaticity coordinates Not actual colors locations; just gives an idea CSE 166, Fall 2017 8 Color gamuts Average person Computer monitor Printer CSE 166, Fall 2017 9 HSI color model: Relationship to RGB color model All colors with cyan hue RGB color cube rotated such that line joining black and white (intensity axis) is vertical CSE 166, Fall 2017 10 HSI color model RGB color cube rotated such that HSI intensity axis observer is on intensity axis, beyond white looking towards black RGB color cube Shape does not matter, only angle from red CSE 166, Fall 2017 11 HSI color model HS‐plane is orthogonal to intensity axis CSE 166, Fall 2017 12 Color models CMYK CMY RGB HSI CSE 166, Fall 2017 13 Intensity slicing Grayscale to 2 colors CSE 166, Fall 2017 14 Intensity slicing Grayscale to 2 colors CSE 166, Fall 2017 15 Intensity slicing Grayscale to 8 colors CSE 166, Fall 2017 16 Intensity slicing Colorbar Grayscale to 256 colors CSE 166, Fall 2017 17 Intensity to color transformations Grayscale RGB input image output image CSE 166, Fall 2017 18 Intensity to color transformations X‐ray grayscale input image Without With explosive explosive RGB output images Misses CSE 166, Fall 2017 explosive 19 Intensity to color transformations Multiple Single grayscale RGB input images output image CSE 166, Fall 2017 20 Intensity to color transformations Red (R) Green (G) Blue (B) Multiple satellite grayscale input images Near infrared (NIR) NIR,G,B as RGB R,NIR,B as RGB Output RGB images 21 Intensity to color transformations Multiple grayscale Single input images, RGB some outside of output image visible spectrum Physical and chemical processes likely to Close up affect sensor response CSE 166, Fall 2017 22 Full‐color image processing Spatial filtering: process each channel independently CSE 166, Fall 2017 23 Full‐color image processing Spatial filtering: image smoothing All RGB HSI intensity Difference channels channel only CSE 166, Fall 2017 24 Full‐color image processing Spatial filtering: image sharpening All RGB HSI intensity Difference channels channel only CSE 166, Fall 2017 25 Full‐color image processing Histogram equalization: do not process each channel independently 1. RGB to HSI 2. Histogram 4. HSI saturation equalize adjustment HSI intensity 3. HSI to RGB CSE 166, Fall 2017 26.

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CDOT Shaded Color and Grayscale Printing Reference File Management
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