DCT-Based Image Compression Source Code

This MATLAB source code implements DCT-based image compression using a systematic approach. The algorithm begins by dividing the input image into non-overlapping 8x8 pixel blocks through block processing functions. Each block undergoes Discrete Cosine Transform (DCT) using MATLAB's dct2 function, which converts spatial domain pixel values into frequency domain coefficients. The implementation includes critical quantization steps using predefined quantization tables that reduce high-frequency components while preserving essential image information. The compression process strategically discards less important frequency components to achieve significant data reduction. For reconstruction, the code performs inverse DCT transformation using idct2 and reassembles the blocks into the complete image. The implementation demonstrates proper handling of quantization matrices, zigzag scanning for coefficient processing, and quality-factor adjustments for compression ratio control. This comprehensive solution effectively showcases how DCT transformation and quantization techniques can substantially reduce image data size while maintaining acceptable visual quality during decompression and reconstruction phases.