image_intro2 - Image Compression and Video Compression #2...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Image Compression and Video Compression #2 Topics z Introduction to Image Compression z Transform Coding z Subband Coding, Filter Banks z Haar Wavelet Transform z SPIHT, EZW, JPEG 2000 z Motion Compensation z Wireless Video Compression #3 Standards z JPEG z Joint Photographic Expert Group z Still Image Compression Standard z JBIG z Bi-level Compression (Not used much) z JPEG-2000 z Wavelet Based z H.261, H.263 and H.264 z Interactive Video Standards. z MPEG-1, MPEG-2 z Moving Picture Expert Group z Video Compression Standards for CD ROMs, internet and television. z MPEG 4 z Low Bit Rate Video Compression z MPEG - 7 z (follow-on to MPEG-4) Content searchable video #4 Contents z Capture and represent digital images z Light and Color z Why can Images be Compressed? z Spatial Redundancy z Temporal Redundancy z Spectral Redundancy z Psycho-visual Redundancy z Distortion Measures Human Visual System #5 Image Formulation #6 Image Orientation z An image consists of a two-dimensional array of pixels. z Neighbors of a pixel (x-1,y-1) (x-1,y) (x-1,y+1) (x,y-1) (x,y) (x,y+1) (x+1,y-1) (x+1, y) (x1,y+1) #7 Number of Gray Levels z Decreasing gray level results in visual unpleasure and loss of detail. #8 Contents z Capture and represent digital images z Light and Color z Why can Images be Compressed? z Spatial Redundancy z Temporal Redundancy z Spectral Redundancy z Psycho-visual Redundancy z Distortion Measures Human Visual System #9 Light and Color z The wavelengths of electromagnetic radiation between roughly 370nm and 730nm account for light visible to the human visual system. z The curve is the spectrum of the solar radiation (the WHITE light) reaching the earths surface. z The white light is a mixture of all wavelengths. #10 Visible Light z Color is the visual perception to different wavelengths of visible light. z Different ranges give rise to different color response. Range* (in nm) Color 380 - 450 Violet 450 - 490 Blue 490 - 560 Green 560 - 590 Yellow 590 - 640 Orange 640 - 730 Red Ranges are approximate There is no sharp boundary * #11 Tri-chromatic Nature of Color z Almost any color can be described as the mixture of the basic color: R, G, B ( YES, theoretically there are some colors that cannot be encoded as a combination of three colors ). z This is the basis of the digital color techniques. Used in the digital camera, CRT/LCD monitor, projector, etc. z Directly due to the three photoreceptors on the retina (explained later). #12 Color Reproduction z Each pixel can be represented by a spectrum (left). On the monitor it is represented by the [RGB] value. Physical Energy Spectrum Wavelength (nm) Wavelength (nm) Retinal Response In RGB #13 Black and White Image z Only two colors (black or white) for each pixel on the screen....
View Full Document

Page1 / 61

image_intro2 - Image Compression and Video Compression #2...

This preview shows document pages 1 - 14. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online