Discrete Cosine Transform

Jul 13, 2014

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Discrete Cosine Transform. The forward equation, for image A, is. The inverse equation, for image B, is. Here . Discrete Cosine Transform. Basic idea of JPEG: Convert image to YIQ color space (luminance-hue-saturation model used for TV transmission)

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jpeg compression interface
tv transmission
color plane
entropy encoder dct quantizer
preset quantization values
quantizertable

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Discrete Cosine Transform

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Discrete Cosine Transform • The forward equation, for image A, is • The inverse equation, for image B, is • Here
Discrete Cosine Transform Basic idea of JPEG: • Convert image to YIQ color space (luminance-hue-saturation model used for TV transmission) • Each color plane is partitioned into 8x8 blocks • Apply DCT to each block • Values are quantized by dividing with preset quantization values (in a table) • Values are then rounded to nearest integer
JPEG Compression Interface COMPRESSED IMAGE 8 X 8 BLOCK ENTROPY ENCODER DCT QUANTIZER (0,0) QUANTIZERTABLE
Basis function of DCT

The Discrete Cosine Transform (DCT)

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