Q20Digital Image Processing
Question
What is image compression? Explain the JPEG image compression standard in detail with block diagrams.
Answer
Image compression and JPEG standard.
Image compression addresses the problem of reducing the amount of data required to represent a digital image by removing redundant data (coding, spatial, and psychovisual redundancies). The JPEG (Joint Photographic Experts Group) standard is a widely used lossy compression method for continuous-tone images.
The JPEG encoding process involves color space conversion (RGB to YCbCr), subsampling of chrominance channels, division of the image into 8x8 blocks, application of the Discrete Cosine Transform (DCT) to each block, quantization of the DCT coefficients, and finally entropy coding (like Huffman or Arithmetic coding). The quantization step introduces the loss of data but provides the most compression.