Image Processing1 Image Acquisition Photo sensors –Photo diodes and photo diode array –Photo transistor Video camera

Image Processing2 Primitive camera structure Slotted board, rotating disc Photosensitive device Lens Illumination for object

Image Processing3 Vidicon

Image Processing4 Color Images involves the capture of 3 images simultaneously, r,g,b placing filters over the lens of the camera is unsatisfactory Use color stripes placed between lens and photo sensor

Image Processing5 Video Image Capture use a device call --frame grabber-- r g --> 8-bit video A/D --> color converter--> mem --> color converter -- >video DAC --> g b ADC = 6 million conversion/sec, 160 ns per conversion

Image Processing6 Real-time capture 25 frame/second minimum to avoid flickering Must be done electronically Example to grab image of 500x500 dot with 256 grey levels requires 6.25MB per sec. Require lots of resources

Image Processing7 Image Scanner Flat bed Hand-held for still images only mechanical accuracy can be a problem

Image Processing8 Charge-Coupled Device (CCD)

Image Processing9 Image Display Display monitors –CRT (Cathode-ray Tube) -based on R, G, B colors -Cannot display all colors that human can see -Black is not real black and white is not real white –LCD (Liquid Crystal Display) -Light weight -Low power consumption -Slow

Image Processing10 Image Display Printers (mention dithering and patterning) –Dot matrix printers –Laser printers –Inkjet printers (use CMYK color model) –Thermal wax transfer printers –Dye sublimation printers