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Context-Aware Image Compression.

Chan JC, Mahjoubfar A, Chen CL, Jalali B - PLoS ONE (2016)

Bottom Line: We describe a physics-based data compression method inspired by the photonic time stretch wherein information-rich portions of the data are dilated in a process that emulates the effect of group velocity dispersion on temporal signals.With this coding operation, the data can be downsampled at a lower rate than without it.We present rate-distortion analysis and show improvement in PSNR compared to compression via uniform downsampling.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California, United States of America.

ABSTRACT
We describe a physics-based data compression method inspired by the photonic time stretch wherein information-rich portions of the data are dilated in a process that emulates the effect of group velocity dispersion on temporal signals. With this coding operation, the data can be downsampled at a lower rate than without it. In contrast to previous implementation of the warped stretch compression, here the decoding can be performed without the need of phase recovery. We present rate-distortion analysis and show improvement in PSNR compared to compression via uniform downsampling.

No MeSH data available.


Related in: MedlinePlus

Comparison of compression performance with the colour portrait image.(A) The 8X uniformly downsampled image and (B) the 10.2X warp stretch-compressed image are shown with (C) the original image and (D-E) their respective reconstructions, while (F-H) are, in turn, their respective close-up portions. Further zoom-ins on the rims of the glasses are shown in (I-K), highlighting the failure of uniform downsampling to capture this sharp feature. The downsampling rate for the uniform case was adjusted such that the resultant file sizes for both warped and uniform compression become equal; however, since all three colour channels share the same warp kernel, the overhead burden is reduced by a third in this scenario. After reconstruction, the warped case (E,H,K) achieved a PSNR of 39.1 dB, which was 3.11 dB better than the uniform downsampling case (D,G,I).
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pone.0158201.g006: Comparison of compression performance with the colour portrait image.(A) The 8X uniformly downsampled image and (B) the 10.2X warp stretch-compressed image are shown with (C) the original image and (D-E) their respective reconstructions, while (F-H) are, in turn, their respective close-up portions. Further zoom-ins on the rims of the glasses are shown in (I-K), highlighting the failure of uniform downsampling to capture this sharp feature. The downsampling rate for the uniform case was adjusted such that the resultant file sizes for both warped and uniform compression become equal; however, since all three colour channels share the same warp kernel, the overhead burden is reduced by a third in this scenario. After reconstruction, the warped case (E,H,K) achieved a PSNR of 39.1 dB, which was 3.11 dB better than the uniform downsampling case (D,G,I).

Mentions: We also performed warped stretch compression on a 3-channel RGB colour portrait image. Fig 6 shows the comparison in compression performance between uniform downsampling and warped stretch compression at 8X and 10X compression, respectively. All three channels here are able to share the same warp kernel, which reduces the metadata overhead. The warp kernel was generated using only the blue channel as it was the most feature-dense. The reconstruction performance exceeds the uniform downsampling case by approximately 3 dB at 10X compression.


Context-Aware Image Compression.

Chan JC, Mahjoubfar A, Chen CL, Jalali B - PLoS ONE (2016)

Comparison of compression performance with the colour portrait image.(A) The 8X uniformly downsampled image and (B) the 10.2X warp stretch-compressed image are shown with (C) the original image and (D-E) their respective reconstructions, while (F-H) are, in turn, their respective close-up portions. Further zoom-ins on the rims of the glasses are shown in (I-K), highlighting the failure of uniform downsampling to capture this sharp feature. The downsampling rate for the uniform case was adjusted such that the resultant file sizes for both warped and uniform compression become equal; however, since all three colour channels share the same warp kernel, the overhead burden is reduced by a third in this scenario. After reconstruction, the warped case (E,H,K) achieved a PSNR of 39.1 dB, which was 3.11 dB better than the uniform downsampling case (D,G,I).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4930214&req=5

pone.0158201.g006: Comparison of compression performance with the colour portrait image.(A) The 8X uniformly downsampled image and (B) the 10.2X warp stretch-compressed image are shown with (C) the original image and (D-E) their respective reconstructions, while (F-H) are, in turn, their respective close-up portions. Further zoom-ins on the rims of the glasses are shown in (I-K), highlighting the failure of uniform downsampling to capture this sharp feature. The downsampling rate for the uniform case was adjusted such that the resultant file sizes for both warped and uniform compression become equal; however, since all three colour channels share the same warp kernel, the overhead burden is reduced by a third in this scenario. After reconstruction, the warped case (E,H,K) achieved a PSNR of 39.1 dB, which was 3.11 dB better than the uniform downsampling case (D,G,I).
Mentions: We also performed warped stretch compression on a 3-channel RGB colour portrait image. Fig 6 shows the comparison in compression performance between uniform downsampling and warped stretch compression at 8X and 10X compression, respectively. All three channels here are able to share the same warp kernel, which reduces the metadata overhead. The warp kernel was generated using only the blue channel as it was the most feature-dense. The reconstruction performance exceeds the uniform downsampling case by approximately 3 dB at 10X compression.

Bottom Line: We describe a physics-based data compression method inspired by the photonic time stretch wherein information-rich portions of the data are dilated in a process that emulates the effect of group velocity dispersion on temporal signals.With this coding operation, the data can be downsampled at a lower rate than without it.We present rate-distortion analysis and show improvement in PSNR compared to compression via uniform downsampling.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California, United States of America.

ABSTRACT
We describe a physics-based data compression method inspired by the photonic time stretch wherein information-rich portions of the data are dilated in a process that emulates the effect of group velocity dispersion on temporal signals. With this coding operation, the data can be downsampled at a lower rate than without it. In contrast to previous implementation of the warped stretch compression, here the decoding can be performed without the need of phase recovery. We present rate-distortion analysis and show improvement in PSNR compared to compression via uniform downsampling.

No MeSH data available.


Related in: MedlinePlus