1. © 2002 by Yu Hen Hu 1 ECE533 Digital Image Processing Image Acquisition

2. © 2002 by Yu Hen Hu 2 ECE533 Digital Image Processing Electromagnetic Spectrum The wavelength required to “see” an object must be the same size or smaller than the object

3. © 2002 by Yu Hen Hu 3 ECE533 Digital Image Processing Image Sensors

4. © 2002 by Yu Hen Hu 4 ECE533 Digital Image Processing Sensor Strips

5. © 2002 by Yu Hen Hu 5 ECE533 Digital Image Processing Chapter 2: Digital Image Fundamentals

6. © 2002 by Yu Hen Hu 6 ECE533 Digital Image Processing Chapter 2: Digital Image Fundamentals

7. © 2002 by Yu Hen Hu 7 ECE533 Digital Image Processing Chapter 2: Digital Image Fundamentals

8. © 2002 by Yu Hen Hu 8 ECE533 Digital Image Processing Digital Image Representation l An image is a function defined on a 2D coordinate f(x,y). l The value of f(x,y) is the intensity. l 3 such functions can be defined for a color image, each represents one color component l A digital image can be represented as a matrix.

9. © 2002 by Yu Hen Hu 9 ECE533 Digital Image Processing Spatial and Gray Level Resolution l Spatial resolution: »# of samples per unit length or area »DPI: dots per inch specifies the size of an individual pixel »If pixel size is kept constant, the size of an image will affect spatial resolution l Gray level resolution: »Number of bits per pixel »Usually 8 bits »Color image has 3 image planes to yield 8 x 3 = 24 bits/pixel »Too few levels may cause false contour

10. © 2002 by Yu Hen Hu 10 ECE533 Digital Image Processing Same Pixel Size, different Sizes

11. © 2002 by Yu Hen Hu 11 ECE533 Digital Image Processing Same Size, Different Pixel Sizes

12. © 2002 by Yu Hen Hu 12 ECE533 Digital Image Processing Varying Gray Level Resolution

13. © 2002 by Yu Hen Hu 13 ECE533 Digital Image Processing Size, Quantization Levels and Details Isopreference curves

14. © 2002 by Yu Hen Hu 14 ECE533 Digital Image Processing Aliasing: Moiré Effect

15. © 2002 by Yu Hen Hu 15 ECE533 Digital Image Processing Zooming

16. © 2002 by Yu Hen Hu 16 ECE533 Digital Image Processing Zooming and Interpolation