- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Evaluation of the temperature pattern of a complex body from thermal imaging and 3D information: A method and its MATLAB implementation
摘要： The standard setting of a camera used in Infrared thermography (IRT) is based on the choice of the same values of emissivity and distance for all pixels of a thermal image even if the emissivity depends on the relative position of camera and observed surface. Often this is not a problem. However, the resulting temperature pattern could be inadequate if a body having a complex shape is observed from strongly constrained positions. In order to face this issue, a procedure aimed at providing a correct temperature pattern by using 3D information related to a point cloud is proposed together with its MATLAB implementation (COMAP3 toolbox). For each pixel of a thermal image, the relative position of camera and observed surface is estimated, leading to pixel-specific values of emissivity and distance. The temperature obtained in this way is also mapped onto the point cloud. The effectiveness of the procedure in recognizing areas characterized by peculiar thermal behavior is shown in the case of a historic cylindrical masonry bell tower (Caorle’s bell tower, Venice, Italy).
关键词： Damage recognition,3D thermography,In situ measurements,Thermal imaging,Radiometric JPEG image
更新于2025-09-23 15:23:52
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Lossless Information Hiding in Images || Lossless Information Hiding in JPEG- and JPEG2000-Compressed Images
摘要： This chapter focuses on the lossless information hiding in JPEG and JPEG2000 images. For JPEG images, seven typical methods including two schemes from the authors were introduced. For the first five schemes, we introduced the basic ideas, whereas for the schemes from the authors, we provided a detailed introduced detail with experimental results. In the first method of ours, our high-capacity reversible JPEG-to-JPEG data hiding scheme is introduced. Through lowering certain quantization table entries and lifting corresponding quantized DCT coefficients, space is made for embedding data. Using the proposed embedding strategy, our scheme can achieve high embedding capacity and keep the distortion introduced by embedding very low; meanwhile the original cover JPEG image can be restored after the secret data are extracted. Experiments results demonstrate that the proposed scheme maintains the image quality of a stego JPEG image when the embedding capacity is high. Besides, the file size after embedding with not too huge data is acceptable. Compared with Chang et al.’s method and Xuan et al.’s method, the proposed method is superior in terms of the image quality, hiding capacity, and file size. Our scheme is very practical for image files stored and transmitted in the JPEG format. In the second method of ours, a lossless data hiding scheme with file size preservation is proposed. Through analyzing the code space and the statistics of both used and unused VLCs, we find there is still potential free space in the JPEG bitstream that can be explored to hide data. The best of unused VLCs are made and mapped to the used VLCs in specific mapping manners. The proposed scheme embeds data into the VLC codes and whatever mapped VLCs are present are not changed, therefore the image content after data hiding is exactly the same as the original one. Experimental results demonstrate that the proposed scheme can reach better performance irrespective of whether file size preservation is required or not. For JPEG2000 images, we first introduced two schemes from the literature, and then introduce our scheme. In our scheme, high-frequency subbands of the cover image are divided into blocks. In each block, a new histogram shifting method is applied to the histogram of the block for embedding data. Every coefficient that is associated with the peak point embeds 2 bits of data. In addition, we shift the histogram to the left or right adaptively according to a direction sign. Experimental results show that the proposed scheme has high embedding capacity and good invisibility of hidden data.
关键词： steganography,histogram shifting,data hiding,quantization table,reversible watermarking,JPEG2000,Lossless information hiding,JPEG,VLC mapping,DCT coefficients
更新于2025-09-23 15:23:52
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[IEEE 2018 Eighth International Conference on Image Processing Theory, Tools and Applications (IPTA) - Xi'an, China (2018.11.7-2018.11.10)] 2018 Eighth International Conference on Image Processing Theory, Tools and Applications (IPTA) - Interval-valued JPEG decompression for artifact suppression
摘要： JPEG is the most used image compression algorithm but block wise DCT compression methods produce artifacts due to coefficient quantization. JPEG decompression can be seen as a reconstruction problem constrained by quantization. In this context, we propose to handle this problem by using interval-valued arithmetic. Our method allows to produce interval-valued image that includes the non-compressed original image. The produced convex set allows to apply constrained Total Variation (TV) reconstruction in order to reduce JPEG artifacts (blocking, grainy effects and high frequency noise). Experiments show visual improvement of JPEG decoding assessed by non-reference quality metric. In addition, the stopping criterion of the TV algorithm is given by this metric which provides evidence about JPEG decompression improvement.
关键词： JPEG artifact removing,image reconstruction,interval-valued arithmetic,image selection,JPEG decompression
更新于2025-09-23 15:22:29
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Edge based enhancement of retinal images using an efficient JPEG-compressed domain technique
摘要： With substantial usage of Imaging Technology in the medical field for the diagnosis and treatment of illnesses, a huge volume of medical images are being generated which provide a bigger challenge in terms of storage, transmission and processing. The high resolution medical images thus generated occupy large storage space, and hence they are subjected to compression to make them storage and transmission efficient. Though compression overcomes the issues of storage and transmission to some extent, but the problem of processing compressed images still remains as a challenge. This is because; the usual way of processing the compressed medical images is through the operations of decompression and recompression, which consume lots of computing resources. Therefore, it would be novel, if the compressed medical images are processed and analysed directly in the compressed formats without involving the expensive operations like decompression and recompression. In this direction, the current research paper demonstrates a novel technique of edge based enhancement of retinal images, which is a very critical operation from disease diagnosis perspective, directly in the JPEG compressed domain. The developed algorithm is validated with publicly available retinal datasets of DRIVE and DIARETDB1, and the performance reported is compared with the state-of-the-art techniques in the uncompressed (spatial) domain in terms of both quality of enhancement and computation time.
关键词： compressed domain,Edge enhancement,Discrete Cosine Transform (DCT),JPEG compressed domain,retinal images
更新于2025-09-23 15:22:29
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Frequency Reconfigurable Slot Antenna Backed by the Substrate Integrated Waveguide Cavity for 5G Applications
摘要： In this paper, a novel near-lossless color ?lter array (CFA) image compression algorithm based on JPEG-LS is proposed for VLSI implementation. It consists of a pixel restoration, a prediction, a run mode, and entropy coding modules. According to the information of the previous research, a context table and row memory consumed more than 81% hardware cost in a JPEG-LS encoder design. Hence, in this paper, a novel context-free and near-lossless image compression algorithm is presented. Since removing the context model causes decreasing of the compression performance, a novel prediction, run mode, and modi?ed Golomb–Rice coding techniques were used to improve the compression ef?ciency. The VLSI architecture of the proposed image compressor consists of a register bank, a pixel restoration module, a predictor, a run mode module, and an entropy encoder. A pipeline technique was used to improve the performance of this. It contains only 10.9k gate count, and the core area is 30 625 μm2, synthesized by using a 90-nm CMOS process. Compared with the previous JPEG-LS designs, this paper reduces the gate counts by 44.1% and 41.7%, respectively, for ?ve standard and eight endoscopy testing images in CFA format. It also improves the average PSNR values by 0.96 and 0.43 dB, respectively, for the same test images.
关键词： JPEG-LS,Color ?lter array,VLSI,context-free,wireless capsule endoscopy,Golomb-Rice coding,near-lossless,run mode
更新于2025-09-23 15:19:57
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Disparities selection controlled by the compensated image quality for a given bitrate
摘要： A stereoscopic image consists of two views rendering a depth sense. Indeed each eye is constrained to look at one view, and the small objects displacements across the two views are interpreted as an indication of depth. These displacements are exploited as speci?c inter-view redundancies from a compression viewpoint. The classical still compression scheme, called disparity-compensated compression scheme, compresses one view independently of the second view, and a block-based disparity map modeling the displacements is losslessly compressed. The difference between the original view and its disparity predicted view is then compressed and used by the decoder to compute the compensated view to improve the disparity predicted view. However, a proof of concept work has already shown that selecting disparities according to the compensated view, instead of the predicted view, yields increased rate-distortion performance. This paper derives from the JPEG-coder, a disparity-dependent analytic expression of the distortion induced by the compensated view. This expression is embedded into an algorithm with a reasonable numerical complexity approaching the performance obtained with the proof of concept work. The proposed algorithm, called fast disparity-compensated block matching algorithm, provides at the same bitrate an average performance increase as compared to the classical stereoscopic image coding schemes.
关键词： Stereoscopic image,Compression,Block matching algorithm,Disparity compensation,JPEG-distortion
更新于2025-09-23 15:19:57
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[IEEE 2019 27th Telecommunications Forum (TELFOR) - Belgrade, Serbia (2019.11.26-2019.11.27)] 2019 27th Telecommunications Forum (TELFOR) - Organic Semiconductors in Optical Communications
摘要： In this paper, a novel near-lossless color ?lter array (CFA) image compression algorithm based on JPEG-LS is proposed for VLSI implementation. It consists of a pixel restoration, a prediction, a run mode, and entropy coding modules. According to the information of the previous research, a context table and row memory consumed more than 81% hardware cost in a JPEG-LS encoder design. Hence, in this paper, a novel context-free and near-lossless image compression algorithm is presented. Since removing the context model causes decreasing of the compression performance, a novel prediction, run mode, and modi?ed Golomb–Rice coding techniques were used to improve the compression ef?ciency. The VLSI architecture of the proposed image compressor consists of a register bank, a pixel restoration module, a predictor, a run mode module, and an entropy encoder. A pipeline technique was used to improve the performance of this. It contains only 10.9k gate count, and the core area is 30 625 μm2, synthesized by using a 90-nm CMOS process. Compared with the previous JPEG-LS designs, this paper reduces the gate counts by 44.1% and 41.7%, respectively, for ?ve standard and eight endoscopy testing images in CFA format. It also improves the average PSNR values by 0.96 and 0.43 dB, respectively, for the same test images.
关键词： JPEG-LS,Color ?lter array,VLSI,context-free,wireless capsule endoscopy,Golomb-Rice coding,near-lossless,run mode
更新于2025-09-19 17:13:59
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[IEEE 2018 IEEE Advanced Accelerator Concepts Workshop (AAC) - Breckenridge, CO, USA (2018.8.12-2018.8.17)] 2018 IEEE Advanced Accelerator Concepts Workshop (AAC) - Compression of Terawatt Long-Wavelength Laser Pulses Through Backward Raman Amplification
摘要： JPEG is one of the widely used lossy compression methods. JPEG-compressed images usually suffer from compression artifacts including blocking and blurring, especially at low bit-rates. Soft decoding is an effective solution to improve the quality of compressed images without changing codec or introducing extra coding bits. Inspired by the excellent performance of the deep convolutional neural networks (CNNs) on both low-level and high-level computer vision problems, we develop a dual pixel-wavelet domain deep CNNs-based soft decoding network for JPEG-compressed images, namely DPW-SDNet. The pixel domain deep network takes the four downsampled versions of the compressed image to form a 4-channel input and outputs a pixel domain prediction, while the wavelet domain deep network uses the 1-level discrete wavelet transformation (DWT) coefficients to form a 4-channel input to produce a DWT domain prediction. The pixel domain and wavelet domain estimates are combined to generate the final soft decoded result. Experimental results demonstrate the superiority of the proposed DPW-SDNet over several state-of-the-art compression artifacts reduction algorithms.
关键词： JPEG,soft decoding,deep convolutional neural networks,compression artifacts,DPW-SDNet
更新于2025-09-11 14:15:04
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Robust median filtering detection based on the difference of frequency residuals
摘要： Recently, the detection of median filtering (MF), which is a popular nonlinear denoising manipulation, has attracted extensive attention from researchers. Several detectors with satisfying performance have been developed, while most of them need to train proper classifiers and their performance may be degraded under JPEG compression. In this paper, a training-free MF detector with single-dimensional feature is proposed based on the difference of frequency residuals, which can solve the detection issue of median filtering images under JPEG post-processing. It is designed relying on the fact that when an image is median filtered over and over again, the frequency residual obtained from continuous two images monotonically decreases. The difference between the frequency residuals obtained from the first MF and the second MF is pretty large in an unfiltered test image, while it is relatively small if the test image is a median filtered one. Thus, the unfiltered and the median filtered images are distinguishable. Furthermore, a novel strategy combining unsharp masking (USM) sharpening is implemented to suppress the effect of image content and find a universal threshold which is utilized to classify two types of images. Experimental results show that the proposed method outperforms some state-of-the-art methods at the condition of a low false alarm rate, especially when the test images are in low quality and low resolution.
关键词： Median filtering,JPEG compression,Digital image forensics,USM sharpening,False alarm rate
更新于2025-09-10 09:29:36
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Encryption-then-Compression Systems using Grayscale-based Image Encryption for JPEG Images
摘要： A block scrambling-based encryption scheme is presented to enhance the security of Encryption-then-Compression (EtC) systems with JPEG compression, which allow us to securely transmit images through an untrusted channel provider, such as social network service providers. The proposed scheme enables the use of a smaller block size and a larger number of blocks than the conventional scheme. Images encrypted using the proposed scheme include less color information due to the use of grayscale images even when the original image has three color channels. These features enhance security against various attacks such as jigsaw puzzle solver and brute-force attacks. In an experiment, the security against jigsaw puzzle solver attacks is evaluated. Encrypted images were uploaded to and then downloaded from Facebook and Twitter, and the results demonstrated that the proposed scheme is effective for EtC systems.
关键词： jigsaw puzzle,JPEG,image encryption,EtC system
更新于2025-09-09 09:28:46