Depth Coding Using a Boundary Reconstruction Filter for 3-D Video Systems

Kwan-Jung Oh, Anthony Vetro, Fellow, IEEE, Yo-Sung Ho, Senior Member, IEEECSVT, MARCH 2011

Outline

• Introduciotn• Analysis of Depth Coding• Depth Boundary Reconstruction Filter• Experimental Results

Introduction

• Depth coding must consider the rendering quality it is capable of producing at different rates.

• 2 main groups of depth coding technique : (depending on the relation with color video coding )

– Joint coding– Independent coding

Analysis of Depth Coding

Flat region : SKIP, Inter/Intra 16×16

Complex region : detail partitions

Flat regions need less rate and have less distortion

Analysis of Depth Coding

• Relationship between QP and distortion/rate Mean squared error

Average coding bits

Analysis of Depth Coding

• Even the complex region spends many coding bits, it incurs a large distortion and is sensitive to QP changes.

• Even small pixel changes in depth image have a notable effect on rendering quality.– Especially, the changes around the boundaries.

Depth Boundary Reconstruction Filter

• Consider 3 measures : 1) Occurrence frequency

2) Similarity

3) Closeness

8 8 8 8 8

8 0 7 7 8

0 8 9 7 8

2 8 8 8 8

8 7 7 8 8

Depth Boundary Reconstruction Filter

• Test various combinations of the 3 costs

• Cost function considering above measurement

Depth Boundary Reconstruction Filter

Depth Boundary Reconstruction Filterbefore

after

Advantage• Robust against outliers• Filtering does not create new

unrealistic pixel values

Depth Boundary Reconstruction Filter

• Some Gaussian noise still remains after filtering Apply 3×3 bilateral filter to eliminate the remaining errors.

• Use the proposed filter as an in-loop filter located right after the deblocking filter.

Depth Boundary Reconstruction Filter-- determination of filter parameters

• Assume that the window size and range sigma having the best depth quality would guarantee the best rendering quality.

• Find the best parameters by considering depth quality for each slice• Encode the information into the bitstream 6 bits/slice

Experimental Results• Depth Rate & Depth Quality • Method 1 : proposed method without bilateral filter

• Method 2 : proposed method with bilateral filter

Method 1 Method 2

Depth quality + 0.54 dB + 0.71 dB

Experimental Results

Experimental Results

• Depth Rate & Rendering Quality

Method 1 Method 2Rendering quality + 0.15 dB + 0.14 dB

JMVC 3.0 JMVC 3.0proposed proposed

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