Lecture 15 Figures from Gonzalez and Woods, Digital Image Processing, Second Edition, 2002. Geometric Transformation (1) Geometric Transformation (2) Chapter 5 Image Restoration Chapter 5 Image Restoration Geometric Transformation (3) Geometric Transformation (4) Tiepoints established by application dependent methods Physical artifacts (like metallic points) embedded on the sensor itself. Produces a known set of points (called reseau marks) on the image as acquired. An image distorted by some other process, e.g., display or image reconstruction can be geometrically corrected. Chapter 5 Image Restoration Chapter 5 Image Restoration Gray Level Interpolation Above technique can result in noninteger values of x and y Inferring gray levels can gray level interpolation Two techniques Nearest neighbor interpolation (zero order interpolation) Bilinear interpolation from four nearest points Chapter 5 Image Restoration Chapter 5 Image Restoration Chapter 5 Image Restoration Chapter 5 Image Restoration Color Image Processing Two general types discussed Full-color acquired with full color sensor such as a TV camera Psuedo-color Problem of assigning a color to a particular monochrome intensity or range of intensities Until recently almost all color processing was psuedo- color,but full color sensors and hardware are now available at reasonable prices Description of Light Source Chromatic light spans EM spectrum from 400 to 700 nm. Three qualities used to describe light source Radiance-total amount of energy from source (measured in watts) Luminance- energy an observer perceives from source (measured in lumens) Brightness- Embodies notion of intensity. Hard to measure. Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Colors ``Primary colorsred,green,blue ``Secondary colorsmagenta=red+blue; cyan=green+blue; yellow=red+green. In pigment a primary color subtracts or absorbs primary color of light and reflects or transmits other two Primary colors of pigment are megenta, cyan, and yellow. Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Color Models Red, Green, Blue (RGB) color monitors and a broad class of video cameras CMY (cyan, magenta, yellow) and CMYK (cyan, magenta, yellow, black) for color printing HIS (hue, saturation, intensity) corresponds with how humans describe and interpret color Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing Chapter 6 Color Image Processing