Multiple Description Coding Based on Optimized Redundancy Removal for 3D Depth Map

Sen Han,Mengmeng Zhang,Huihui Bai

doi:10.3390/e18070245

Sen Han, Mengmeng Zhang + Show 1 more

Open Access

https://doi.org/10.3390/e18070245

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Abstract

Multiple description (MD) coding is a promising alternative for the robust transmission of information over error-prone channels. In 3D image technology, the depth map represents the distance between the camera and objects in the scene. Using the depth map combined with the existing multiview image, it can be efficient to synthesize images of any virtual viewpoint position, which can display more realistic 3D scenes. Differently from the conventional 2D texture image, the depth map contains a lot of spatial redundancy information, which is not necessary for view synthesis, but may result in the waste of compressed bits, especially when using MD coding for robust transmission. In this paper, we focus on the redundancy removal of MD coding based on the DCT (discrete cosine transform) domain. In view of the characteristics of DCT coefficients, at the encoder, a Lagrange optimization approach is designed to determine the amounts of high frequency coefficients in the DCT domain to be removed. It is noted considering the low computing complexity that the entropy is adopted to estimate the bit rate in the optimization. Furthermore, at the decoder, adaptive zero-padding is applied to reconstruct the depth map when some information is lost. The experimental results have shown that compared to the corresponding scheme, the proposed method demonstrates better rate central and side distortion performance.

Highlights

From the conventional 2D texture image, the depth map, as a special format of 3D image data, represents the distance information between a camera and the objects in the scene
Depth maps are often treated as gray-scale image sequences, which are similar to the luminance component of texture videos
This paper focuses on the comparison of the proposed optimized scheme against the conventional scheme

Summary

Introduction

From the conventional 2D texture image, the depth map, as a special format of 3D image data, represents the distance information between a camera and the objects in the scene. Many scholars applied the compressive sensing (CS) theory to the texture image and depth map coding. In [9], according to a spatially sparse signal, a new image/video coding approach is proposed, which combines the CS theory with the traditional discrete cosine transform (DCT)-based coding method to achieve better compression efficiency. The original video signal can be split into multiple bit streams (descriptions) using an MD encoder These MDs can be transmitted over multiple channels. MD video coding schemes were designed to achieve promising results [23,24] Another significant class of MDC is based on pre- and post-processing. In this paper, considering the special characteristics of depth information, an MDC scheme is proposed based on optimized redundancy removal for the 3D depth map.

Encoder

Decoder

Experimental

TheMap values of the sequence

Conclusions