Subjective testing results for still picture compression algorithms for international standardization

During 1987 and 1988, a joint group of ISO and CCITT has worked to create a world standard for data compression of still-frame color continuous-tone images. During this period, the adaptive discrete cosine transform (ADCT) was selected for final refinement from 12 proposed algorithms. Because the standard is required to provide either lossless or lossy compression, subjective image quality testing procedures were used extensively in the selection process. Each algorithm compressed test pictures to predefined bit rates, and the quality of the resulting images was evaluated using a modification of the CCIR 500 television quality evaluation procedures. The authors describe the perceptual test procedures and results which led to selection of the ADCT