Abstract—Traditional patch-based sparse representation modeling of natural images usually suffer from two problems. First, it has to solve a large-scale optimization problem with high computational complexity in dictionary learning. Second, each patch is considered independently in dictionary learning and sparse coding, which ignores the relationship among patches, resulting in inaccurate sparse coding coefficients. In this paper, instead of using patch as the basic unit of sparse representation, we exploit the concept of group as the basic unit of sparse representation, which is composed of nonlocal patches with similar structures, and establish a novel sparse representation modeling of natural images, called group-based sparse representation (GSR). The proposed GSR is able to sparsely represent natural images in the domain of group, which enforces the intrinsic local sparsity and nonlocal self-similarity of images simultaneously in a unified framework. Moreover, an effective self-adaptive dictionary learning method for each group with low complexity is designed, rather than dictionary learning from natural images. To make GSR tractable and robust, a split Bregman based technique is developed to solve the proposed GSR-driven L0 minimization problem for image restoration efficiently. Extensive experiments on image inpainting, image deblurring and image compressive sensing recovery manifest that the proposed GSR modeling outperforms many current state-of-the-art schemes in both PSNR and visual perception.
Paper:
Group-based Sparse Representation for Image Restoration
J. Zhang, D. Zhao, W. Gao
IEEE Transactions on Image Processing
[PDF] [Matlab Code]Instructions: click on the thumbnail image to see the corresponding results from various algorithms.
Input Ground Truth
|
Barbara in the case of Ratio=20% |
HSR (28.83 dB) SKR (21.92 dB) NLTV (23.46 dB) |
SAIST (29.68 dB) BPFA (25. 70 dB) Proposed (31.32 dB) |
---|
Input Ground Truth
|
Parrots in the case of Ratio=20% |
HSR (28.63 dB) SKR (28.79 dB) NLTV (27.58 dB) |
SAIST (29.41 dB) BPFA (27.63 dB) Proposed (29.83 dB) |
---|
Input Ground Truth
|
House in the case of Ratio=20% |
HSR (32.35 dB) SKR (30.40 dB) NLTV (31.19 dB) |
SAIST (35.73 dB) BPFA (30.89 dB) Proposed (35.61 dB) |
---|
Text Removal
Input Ground Truth
|
Barbara |
HSR (38.86 dB) SKR (30.81 dB) NLTV (32.60 dB) |
SAIST (39.00 dB) BPFA (34.28 dB) Proposed (40.86 dB) |
---|
Input Ground Truth
|
House |
HSR (38.65 dB) SKR (38.65 dB) NLTV (38.44 dB) |
SAIST (41.20 dB) BPFA (39.01 dB) Proposed (42.51 dB) |
---|
Input Ground Truth
|
Bike Uniform Kernel: 9x9 with sigma=0.5 |
TVMM (26.51 dB) L0_ABS (26.78 dB)
|
IDDBM3D (28.45 dB) NCSR (27.92 dB) Proposed (28.61 dB) |
---|
Input Ground Truth
|
Barbara Gaussian Kernel: fspecial('Gaussian', [7 7], 8) with sigma=0.5 |
TVMM (27.79 dB) L0_ABS (28.39 dB)
|
IDDBM3D (31.73 dB) NCSR (30.37 dB) Proposed (33.52 dB) |
---|
Input Ground Truth
|
Leaves Motion Kernel: fspecial('motion', 20, 45) with sigma=0.5 |
TVMM (30.60 dB) L0_ABS (29.44 dB)
|
IDDBM3D (34.40 dB) NCSR (34.23 dB) Proposed (34.54 dB) |
---|
Input Ground Truth
|
Barbara (256x256) Uniform Kernel: 9x9 with sigma=sqrt(2) |
TVMM (26.00 dB) L0_ABS (26.41 dB)
|
IDDBM3D (27.98 dB) NCSR (28.10 dB) Proposed (28.95 dB) |
---|
Input Ground Truth
|
House (256x256) Gaussian Kernel: fspecial('Gaussian', 25, 1.6) with sigma=sqrt(2) |
TVMM (33.01 dB) L0_ABS (33.07 dB)
|
IDDBM3D (34.08 dB) NCSR (33.63 dB) Proposed (34.45 dB) |
---|
Table 1: Six Typical Deblurring Experiments
All the six typical experiments achieved by GSR can be downloaded here: Download
Input Ground Truth |
Barbara (512x512) (Scenario 2 in Table 1) |
TVMM (ISNR=1.33 dB) NCSR (ISNR=3.64 dB) |
IDDBM3D (ISNR=3.96 dB) Proposed (ISNR=4.80 dB) |
---|
3. Image Compressive Sensing Recovery
Ground Truth |
Barbara (in the case of CS Ratio=0.2) |
DWT (23.96 dB) MH (31.09 dB) |
TV (23.79 dB) CoS (26.60 dB) Proposed (34.59 dB) |
---|
Ground Truth |
Vessels (in the case of CS Ratio=0.2) |
DWT (21.14 dB) MH (24.95 dB) |
TV (22.04 dB) CoS (26.71 dB) Proposed (31.58 dB) |
---|