A Two-Level Auto-Encoder for Distributed Stereo Coding

We propose a new technique for stereo image compression that is based on Distributed Source Coding (DSC). In our setting, two cameras transmit their image back to a processing unit. Naively doing so requires each camera to compress and transmit its image independently. However, the images are correlated because they observe the same scene, and our goal is to take advantage of this fact. In our solution, one camera, assume the left camera, sends its image to the processing unit, as before. The right camera, on the other hand, transmits its image conditioned on the left image, even though the two cameras do not communicate. The processing unit can then decode the right image, using the left image. The solution is based on a two level Auto-Encoder (AE). During training, the first level AE learns a standard single image compression code. The second level AE further compresses the code of the right image, conditioned on the code of the left image. During inference, the left camera uses the first level AE to transmit its image to the processing unit. The right camera, on the other hand, uses the encoders of both levels to transmit its code to the processing unit. The processing unit uses the top level decoder to recover the left image, and the decoders of both levels, as well as the recovered left image, to recover the right image. The system achieves state of the art results in image compression on several popular datasets.