Perceptual coding of stereo endoscopy video for minimally invasive surgery

In this paper, we propose a compression scheme that is tailored for stereo-laparoscope sequences. The interframe correlation is modeled by the deformation field obtained by elastic registration between two subsequent frames and exploited for prediction of the left sequence. The right sequence is lossy encoded by prediction from the corresponding left images. Wavelet-based coding is applied to both the deformation vector fields and residual images. The resulting system allows spatio temporal scalability, while providing lossless performance. The implementation of the wavelet transform by integer lifting ensures a low computational complexity, thus reducing the required run-time memory allocation and on line implementation. Extensive psychovisual tests were performed to validate that interpolation artifacts are less annoying than DCT ones. The system has proved to provide a clear advantage over the MPEG4 standard when operated at mid and low bitrates according to both objective and subjective image quality assessment.