Post-compression Rate-distortion Research Articles

High Throughput JPEG 2000 for Video Content Production and Delivery Over IP Networks

ITU-T Rec T.814 | IS 15444-15, known as High Throughput JPEG 2000, or simply HTJ2K, is Part-15 in the JPEG 2000 series of standards, published in 2019 by the ITU and ISO/IEC. JPEG 2000 Part-1 has long been used as a key component in the production, archival and distribution of video content, as the distribution format for Digital Cinema, and an Interoperable Master Format from which streaming video services are commonly derived. JPEG 2000 has one of the richest feature sets of any coding standard, including scalability, region-of-interest accessibility and non-iterative optimal rate control. HTJ2K addresses a long-standing limitation of the original JPEG 2000 family of standards: relatively low throughput on CPU and GPU platforms. HTJ2K introduces an alternative block coding algorithm that allows extremely high processing throughputs, while preserving all other aspects of the JPEG 2000 framework and offering truly reversible transcoding with the original block coded representation. This paper demonstrates the benefits that HTJ2K brings to video content production and delivery, including cloud-based processing workflows and low latency video content streaming over IP networks, considering CPU, GPU and FPGA-based platforms. For non-iterative optimal rate control, HTJ2K encoders with the highest throughputs and lowest hardware encoding footprints need a strategy for constraining the number of so-called HT-Sets that are generated ahead of the classic Post-Compression Rate-Distortion optimization (PCRD-opt) process. This paper describes such a strategy, known as CPLEX, that involves a second (virtual) rate-control process. The novel combination of this virtual (CPLEX) and actual (PCRD-opt) processes has many benefits, especially for hardware encoders, where memory size and memory bandwidth are key indicators of complexity.

Regional bit allocation with visual attention and distortion sensitivity

This paper proposes a regional rate allocation method for enhancing the perceived quality in image compression. Bit allocation to image regions should be performed by considering the viewer’s attention and distortion sensitivity maps in order to address subjective quality concerns. The paper first proposes an exponential model for the relation between the viewer’s fixation duration and perceived information. The human visual system is more sensitive to the distortion around edges than the distortion in complex textured regions. Therefore, a novel distortion sensitivity method is also proposed that distinguishes true edges from complex textures without using edge detectors or gradient magnitude thresholds. The estimates for the visual attention level and the distortion sensitivity level are jointly used to modify the distortion contribution of each codeblock for determining its quantization parameter. The experiments validate the improved perceptual quality of decoded images due to the integrated use of the visual distortion sensitivity and the visual attention level in bit allocation. Moreover, the proposed bit allocation method is experimentally shown to yield a substantially higher subjective evaluation score than the other well-known bit allocation methods based on post-compression rate-distortion optimization, saliency maps, foveation of fixations and foveated just-noticeable-difference maps.

An efficient rate control algorithm for JPEG2000 based on reverse order

The JPEG2000 image compression standard is the powerful encoder which can provide phenomenal rate-control performance. The post-compression rate-distortion (PCRD) algorithm in JPEG2000 is not efficient. It requires encoding all coding passes even though a large contribution of them will not be contained in the final code-stream. Tier-1 encoding in the JPEG2000 standard takes a significant amount of memory and coding time. In this work, a low-complexity rate distortion method for JPEG2000 is proposed. It is relied on a reverse order for the resolution levels and the coding passes. The proposed algorithm encodes only the coding passes contained in the final code-stream and it does not need any post compression rate control part. The computational complexity of proposed algorithm is negligible, making it suitable to compression and attaining a significant performance. Simulations results show that the proposed algorithm obtained the PSNR values are comparable with the optimal PCRD.

Pairwise KLT-Based Compression for Multispectral Images

This paper presents a pairwise KLT-based compression algorithm for multispectral images. Although the KLT has been widely employed for spectral decorrelation, its complexity is high if it is performed on the global multispectral images. To solve this problem, this paper presented a pairwise KLT for spectral decorrelation, where KLT is only performed on two bands every time. First, KLT is performed on the first two adjacent bands and two principle components are obtained. Secondly, one remainning band and the principal component (PC) with the larger eigenvalue is selected to perform a KLT on this new couple. This procedure is repeated until the last band is reached. Finally, the optimal truncation technique of post-compression rate-distortion optimization is employed for the rate allocation of all the PCs, followed by embedded block coding with optimized truncation to generate the final bit-stream. Experimental results show that the proposed algorithm outperforms the algorithm based on global KLT. Moreover, the pairwise KLT structure can significantly reduce the complexity compared with a global KLT.

A highly efficient rate control algorithm for JPEG2000 images

The JPEG2000 image compression standard is the newest still image compression standard for digital image consumer electronics, such as digital cameras. However, Tier-1 encoding in the JPEG2000 standard algorithm requires a significant amount of memory and code time. In this study, a highly efficient and low-complexity rate control algorithm for JPEG2000 is proposed to reduce the memory requirements and the computation time. A revisable threshold is developed and is used to select the passes of each code block during Tier-1 encoding. Only the selected passes are encoded during Tier-1 and Tier-2 encoding. This routine avoids the encoding of all code passes and improves the coding efficiency. The experimental results based on standard test images show that the proposed algorithm can reduce the Tier- 1 coding time by up to 86.36% and the working memory by up to 95.50% at a bit rate of 0.125 bpp in comparison to the post-compression rate distortion algorithm. The peak-signal-to-noise ratio across the images remains almost unchanged. The proposed algorithm can not only significantly improve the encoding efficiency but also maintain the image quality. Therefore, it can be applied to consumer imaging devices such as digital cameras, cameras in mobile phones and compact consumer cameras in the form of either embedded or processing software to reduce the memory and hardware requirements.

3D geometry-dependent texture map compression with a hybrid ROI coding

Differing from common 2D images, a texture map, since it is used to project onto a 3D model in 3D space, not only contains 2D texture information, but also implicitly associates certain 3D geometric information. Related to this, an effective 3D geometry-dependent texture map compression method with hybrid region of interest (ROI) coding is proposed in this paper. We regard the visually important area of the texture map as the ROI. To acquire the visually important areas of the texture map, we take into account information from both the 3D geometry and 2D texture maps, depicting the saliency of the textured model, distortion of the texture mapping, and boundary of the texture atlas. These visually important areas are expressed as a visual importance map. According to the particularity of the texture map, a hybrid ROI coding method that utilizes Max-Shift and an improved post compression rate distortion (PCRD) technique is presented, guided by this visual importance map. To find the exact wavelet coefficients pertaining to these ROIs before carrying out the hybrid ROI coding, this paper proposes a stochastic coefficient priority mask map computational method. Experimental results show that the visually important areas of the texture image have a better visual effect and that a good rendering result can be obtained from the texture mapping.

Prediction Truncation Algorithm Based on Regression Analysis for Embedded Block Coding

In order to solve the problems of execution complexity and time waste in compression process induced by Post Compression Rate Distortion(PCRD) Optimization in embedded block coding in JPEG2000, this paper proposes an effective method to promote coding efficiency-embedded block coding algorithm with prediction truncation based on regression analysis. This algorithm predicts the truncation points based on regression formula derived from linear regression analysis. It avoids scanning and encoding the bit planes that can be truncated, discards the time-consuming rate-distortion truncation processing, so that the algorithm is able to speed up the compression process. The experiment results show the algorithm obtains obvious promotion efficiency of coding speed. high compression ratio such as 0.125 or 0.0625, the majority of the coefficients which have been encoded in tier-2 stage are discarded through truncation. Obviously, a lot of running time is wasted in the coding of coefficient bits that will be truncated. This paper proposes the predict truncation algorithm based on regression analysis, while embedded coding it can predict plane scan code stream position of the truncated points, give up coding to the coefficients bits that will be discarded, and give up the rate distortion calculation and optimization truncation based on cycle search in Tier-2 coding, thus greatly improves the encoding speed.

Efficient rate control approach for JPEG2000 image coding

Abstract. JPEG2000, the new image coding standard, is more effi-cient when compared with the old JPEG standard. However, most ofthe computationsand memory usagein post-compressionrate distor-tion(PCRD)optimizationschemeinJPEG2000isredundant.Wepro-pose an efficient rate control approach for the JPEG2000 encoder. Inthis approach, optimal rate distortion (RD) slope threshold is selectedusing the minimum RD slope of lower level horizontally and verticallylow pass (LL 0 ) subband of the wavelet decomposed image. Also, thepasses of the code blocks of other subbands, whose RD slopes areless than the optimal RD slope, are skipped. The proposed approachreduces memory requirements and encoding time when comparedwith the existing rate control approaches for JPEG2000 standard,and also provides the same image quality as that of the PCRDapproach used in the JPEG2000 standard. © 2012 SPIE andIS&T. [DOI: 10.1117/1.JEI.21.3.033004] 1 IntroductionJPEG2000 is the new state-of-art image and video codingstandard. It has excellent coding performance and novel fea-tures such as superior low-bit rate compression performance,lossless and lossy compression, progressive transmission,region of interest coding, error resilience and randomcode stream access, and so on.

A Novel Error Resilient Scheme for Wavelet-based Image Coding Over Packet Networks

this paper presents a robust transmission strategy for wavelet based scalable bit stream over packet erasure channel. By taking the advantage of the bit plane coding and the multiple description coding, the proposed strategy adopts layered multiple description coding (LMDC) for the embedded wavelet coders to improve the error resistant capability of the important bit planes in the meaning of D(R) function. Then, the post-compression rate-distortion (PCRD) optimization process is used to improve the overall performance. At decoding, a simple error concealment technique is used to compensate the data loss. The proposed method is applied on Set Partitioning in Hierarchical Trees (SPIHT) coded image and the experimental results show graceful degradation for variable packet erasure rate.

Prediction Truncation Algorithm Based on Regression Analysis for Embedded Block Coding

In order to solve the problems of execution complexity and time waste in compression process induced by Post Compression Rate Distortion(PCRD) Optimization in embedded block coding in JPEG2000, this paper proposes an effective method to promote coding efficiency-embedded block coding algorithm with prediction truncation based on regression analysis. This algorithm predicts the truncation points based on regression formula derived from linear regression analysis. It avoids scanning and encoding the bit planes that can be truncated, discards the time-consuming rate-distortion truncation processing, so that the algorithm is able to speed up the compression process. The experiment results show the algorithm obtains obvious promotion efficiency of coding speed. high compression ratio such as 0.125 or 0.0625, the majority of the coefficients which have been encoded in tier-2 stage are discarded through truncation. Obviously, a lot of running time is wasted in the coding of coefficient bits that will be truncated. This paper proposes the predict truncation algorithm based on regression analysis, while embedded coding it can predict plane scan code stream position of the truncated points, give up coding to the coefficients bits that will be discarded, and give up the rate distortion calculation and optimization truncation based on cycle search in Tier-2 coding, thus greatly improves the encoding speed.

The Analysis and Detection of Double JPEG2000 Compression Based on Statistical Characterization of DWT Coefficients

Detection of double image compression is all the world to the analysis of tampered image and image steganalysis. In order to detect double JPEG2000 compression, through the comparison with JPEG double compression, we analysis the different statistical characterization of DWT coefficients’ frequency histogram under single and double compression because of post compression rate distortion optimization(PCRD-opt algorithm)in JPEG2000 codec. We find a new statistical characterization which is different form double JPEG compression. Under certain conditions, experimental results show that such features can be used to detect whether the JPEG2000 image is double compressed or not.

A Fast and Efficient Adaptive Threshold Rate Control Scheme for Remote Sensing Images

The JPEG2000 image compression standard is ideal for processing remote sensing images. However, its algorithm is complex and it requires large amounts of memory, making it difficult to adapt to the limited transmission and storage resources necessary for remote sensing images. In the present study, an improved rate control algorithm for remote sensing images is proposed. The required coded blocks are sorted downward according to their numbers of bit planes prior to entropy coding. An adaptive threshold computed from the combination of the minimum number of bit planes, along with the minimum rate-distortion slope and the compression ratio, is used to truncate passes of each code block during Tier-1 encoding. This routine avoids the encoding of all code passes and improves the coding efficiency. The simulation results show that the computational cost and working buffer memory size of the proposed algorithm reach only 18.13 and 7.81%, respectively, of the same parameters in the postcompression rate distortion algorithm, while the peak signal-to-noise ratio across the images remains almost the same. The proposed algorithm not only greatly reduces the code complexity and buffer requirements but also maintains the image quality.

An Adaptive Coding Pass Scanning Algorithm for Optimal Rate Control in Biomedical Images

High-efficiency, high-quality biomedical image compression is desirable especially for the telemedicine applications. This paper presents an adaptive coding pass scanning (ACPS) algorithm for optimal rate control. It can identify the significant portions of an image and discard insignificant ones as early as possible. As a result, waste of computational power and memory space can be avoided. We replace the benchmark algorithm known as postcompression rate distortion (PCRD) by ACPS. Experimental results show that ACPS is preferable to PCRD in terms of the rate distortion curve and computation time.

POST-COMPRESSION RATE-DISTORTION DEVELOPMENT FOR EMBEDDED BLOCK CODING WITH OPTIMAL TRUNCATION IN JPEG2000 IMAGERY

This paper presents a development of the post-compression rate-distortion optimization (PCRD-opt) algorithm in JPEG2000 used for optimal truncation (OT) rate control. The proposed treatment of PCRD-opt differs from the treatment given in the JPEG2000 standard and what is given in a number of publications. The proposed algorithm is implemented in a complete JPEG2000 compression engine as well as the algorithm published in the JPEG2000 standard. The proposed algorithm gives a substantial performance gain, outperforming the implementation given in the standard by 0.25–1 dB in PSNR on average, demonstrating an improvement from the method for PCRD-opt given in the standard. The proposed algorithm is also compared to the JPEG2000 reference implementation, JasPer, and the popular Kakadu JPEG2000 compressor. The proposed algorithm provides equivalent performance results to both JasPer and Kakadu, indicating that the proposed PCRD-opt treatment provides correct OT of JPEG2000 compressed imagery.

Proto-Object Based Rate Control for JPEG2000: An Approach to Content-Based Scalability

The JPEG2000 system provides scalability with respect to quality, resolution and color component in the transfer of images. However, scalability with respect to semantic content is still lacking. We propose a biologically plausible salient region based bit allocation mechanism within the JPEG2000 codec for the purpose of augmenting scalability with respect to semantic content. First, an input image is segmented into several salient proto-objects (a region that possibly contains a semantically meaningful physical object) and background regions (a region that contains no object of interest) by modeling visual focus of attention on salient proto-objects. Then, a novel rate control scheme distributes a target bit rate to each individual region according to its saliency, and constructs quality layers of proto-objects for the purpose of more precise truncation comparable to original quality layers in the standard. Empirical results show that the suggested approach adds to the JPEG2000 system scalability with respect to content as well as the functionality of selectively encoding, decoding, and manipulation of each individual proto-object in the image, with only some slightly trivial modifications to the JPEG2000 standard. Furthermore, the proposed rate control approach efficiently reduces the computational complexity and memory usage, as well as maintains the high quality of the image to a level comparable to the conventional post-compression rate distortion (PCRD) optimum truncation algorithm for JPEG2000.

Integer-based, post-compression rate-distortion optimization computation in JPEG2000 compression

An integer-based, post-compression rate-distortion optimization (PCRD-Opt) algorithm for JPEG2000 rate control is presented. The distortion estimation, described in the JPEG2000 standard, requires noninteger processing, and the overwhelming computational burden on JPEG2000 is the distortion calculation, which is calculated for every bit of the uncompressed image. An integer-based approach for distortion calculation is proposed. The proposed method reduces the computational requirements for PCRD-Opt within the Tier I encoder, as well as provides a more straightforward algorithm for embedded processing, requiring no distortion lookup tables (LUTs) for proper distortion computation. The proposed integer-based method improves upon the PCRD-Opt method described in the standard. Specifically, the proposed method reduces the Tier I processing time from a direct implementation of PCRD-Opt by approximately 39% on average and reduces the overall JPEG2000 processing by 34%. The proposed method reduces the Tier I processing time from an offline implementation of PDRD-Opt utilizing LUTs by approximately 21% on average, and reduces the overall JPEG2000 processing by 19%. The proposed integer-based distortion estimation provides a rate-distortion curve equivalent to both the direct and offline PCRD methods described in the standard.

Adaptive rate control for Motion JPEG2000

Rate and quality-constrained rate control is very effective for video applications, since it can maintain constant quality while eliminating local rate spikes. An adaptive rate control method based on image activity measures (ARCIAM) is proposed for Motion JPEG2000. The algorithm can efficiently adjust the compressed bit rates to meet the rate and quality constraints for different types of colour sequences. It predicts the rate-distortion (RD) slope thresholds for frames based on image activity measure (IAM) before entropy coding. Thus, the encoding of unnecessary coding passes can be avoided. Experimental results show that the proposed method can meet the quality and rate constraints, and can achieve quality performance comparable to post-compression rate distortion optimisation at the same bit rate. Under 3 bpp and 40 dB constraints, ARCIAM can reduce the total encoding time and tier-1 encoding time for sequences by more than 20 and 30%, respectively. Moreover, the memory requirement for buffering bit-streams and RD-slope information is reduced by more than 30% on average. Besides, the method can be incorporated into the line-based JPEG2000 encoding system easily, and has been implemented on Kakadu.

Robust Rate-Control for Wavelet-Based Image Coding via Conditional Probability Models

Real-time rate-control for wavelet image coding requires characterization of the rate required to code quantized wavelet data. An ideal robust solution can be used with any wavelet coder and any quantization scheme. A large number of wavelet quantization schemes (perceptual and otherwise) are based on scalar dead-zone quantization of wavelet coefficients. A key to performing rate-control is, thus, fast, accurate characterization of the relationship between rate and quantization step size, the R-Q curve. A solution is presented using two invocations of the coder that estimates the slope of each R-Q curve via probability modeling. The method is robust to choices of probability models, quantization schemes and wavelet coders. Because of extreme robustness to probability modeling, a fast approximation to spatially adaptive probability modeling can be used in the solution, as well. With respect to achieving a target rate, the proposed approach and associated fast approximation yield average percentage errors around 0.5% and 1.0% on images in the test set. By comparison, 2-coding-pass rho-domain modeling yields errors around 2.0%, and post-compression rate-distortion optimization yields average errors of around 1.0% at rates below 0.5 bits-per-pixel (bpp) that decrease down to about 0.5% at 1.0 bpp; both methods exhibit more competitive performance on the larger images. The proposed method and fast approximation approach are also similar in speed to the other state-of-the-art methods. In addition to possessing speed and accuracy, the proposed method does not require any training and can maintain precise control over wavelet step sizes, which adds flexibility to a wavelet-based image-coding system.

Precompression Quality-Control Algorithm for JPEG 2000

In this paper, a precompression quality-control algorithm is proposed. It can greatly reduce computational power of the embedded block coding (EBC) and memory requirement to buffer bit streams. By using the propagation property and the randomness property of the EBC algorithm, rate and distortion of coding passes is approximately predicted. Thus, the truncation points are chosen before actual coding by the entropy coder. Therefore, the computational power, which is measured with the number of contexts to be processed, is greatly reduced since most of the computations are skipped. The memory requirement, which is measured with the amount required to buffer bit streams, is also reduced since the skipped contexts do not generate bit streams. Experimental results show that the proposed algorithm reduces the computational power of the EBC by 80% on average at 0.8 bpp compared with the conventional postcompression rate-distortion optimization algorithm. Moreover, the memory requirement is also reduced by 90%. The average PSNR degrades only about 0.1-0.3 dB, on average.

Efficient Rate-Control System With Three Stages for JPEG2000 Image Coding

Although the conventional post-compression rate distortion (PCRD) optimum algorithm in JPEG2000 can provide excellent rate-distortion performance, it remains troublesome for VLSI design. It requires high-complexity computation and a large quantity of working memory. In this paper, a novel rate-control system for JPEG2000 image coding, which consists of three stages, is proposed to efficiently reduce the computational complexity and memory usage, as well as maintaining the high image comparable with PCRD. In the precoding stage, the rate allocation for the image tiles (RAIT) can allocate the bit rates for different image tiles based on their internal information; moreover, in order to make VLSI design easier, the image edge-detect algorithms and the prediction algorithms are used to evaluate the information of the image tiles. In the tier1 coding stage, according to the given bit rate, the rate allocation based on the rest rate distortion (RARRD) can adaptively truncate code stream based on the rest rate distortion of the current image tile and the rate-distortion (RD) slope of the current coding pass during the current code-block coding, and all of the truncated data need not be encoded and stored. In the post-coding stage, a new fast rate control with approximately optimum truncation (RCAOT) can get the approximately optimum truncation points through searching among the 256 quality layers once, which are divided based on the 8-b RD-slopes expressed by means of a logarithm. This system can not only maintain high image quality through RCAOT and RAIT but also save working memory and encoding time by means of RARRD and RCAOT. Experimental results show that, for the image which has distinct objects and background, the PSNR of the reconstructed images compressed by our rate-control system are much higher than those using PCRD; for other images, our system has the comparative effect as PCRD