Visually Lossless Image Compression: From JPEG to BPG and Vice Versa

This letter presents an investigation into visually lossless JPEG and BPG compression through subjective assessments. The results of subjective tests have shown that the information about the boundary between visually lossless and visually lossy of one type of compression can be used to determine the boundary of another type of compression, and the transfer of information is two-way. This observation is confirmed on a large-scale crowdsourced publicly available KonJND-1k dataset with more than 1000 original images. The linear correlation between the objective scores that correspond to this boundary, obtained using knowledge from the newly created dataset and using predictions obtained from the KonJND-1k is greater than 97%. This opens up new possibilities in the development of visually lossless compression techniques.