294 results about "Jpeg compression" patented technology

This invention has as its object to provide an image processing apparatus and method which can efficiently compress an image while maintaining high image quality, and a storage medium for implementing the method. To accomplish this, an apparatus has a text area detector (101) for extracting a text area from multi-valued image data, and generating text area coordinate data (109) as position data of the text area, a binarization unit (102) for generating binary image data (108) by binarizing multi-valued image data of the text area, a color computation unit (103) for generating text color data (110) by computing a representative color of the text area, a text paint unit (104) for generating non-text multi-valued image data A by converting multi-valued image data of the text area using multi-valued image data of an area other than text, a reduction unit (105) for generating reduced non-text multi-valued image data by lowering the resolution of the non-text multi-valued image data, a JPEG compression unit (106) for compressing the non-text multi-valued image data by JPEG, and an MMR compression unit for compressing the binary image data of the text area by MMR.

The invention discloses a digital image compressing, encrypting and encoding combined method, and belongs to the technical field of image encrypting. The method is achieved on the basis of the JPEG compressing and encoding standard which is most widely applied at present, and the encrypting algorithm based on chaos is integrated with the encoding process; according to the characteristic that DC coefficients and AC coefficients are separately encoded on the basis of the JPEG standard, the DC coefficients and the AC coefficients of an image are separately encrypted; in order to give consideration to both security and compressing efficiency, all the DC coefficients and part of the AC coefficients are encrypted through the method, coefficients at the same positions in all DCT blocks are divided into different groups and are scrambled and diffused within the groups, and damage to differential encoding and run length encoding in the encrypting process is reduced as much as possible; scrambling and diffusing are achieved on the basis of logistic chaotic mapping and Chebyshev chaotic mapping respectively. The experiments prove that the method has high data compressing capacity while providing effective image data security protection.

A method and apparatus for communicating compressed video information includes storing video information compressed based on a first compression method, such as a method with a high compression ratio, and transcoding the compressed video information to produce corresponding recompressed video information that is based on a second compression method, with a lower compression ratio such as standard JPEG compression or other suitable compression. The method and apparatus, if desired, may include sending the recompressed video information for a destination apparatus which may then suitably decompress the video information using a standard decompression technique. For example, storing the compressed image in a high compressed format, for example, in a piecewise basis may be done online while the camera, for example, is in use so that the image is properly captured and then, transcoding the compressed image to a different level of compression while the camera is offline.

The invention discloses a digital image blind watermark adding method suitable for internet, which comprises the steps of: acquiring the original images of a watermark image and a watermark to be added, binarizing the watermark image, conducting Arnold scrambling, and then modifying part of intermediate frequency coefficient transformed by DCT, thus realizing the embedding of the watermark; the invention correspondingly discloses a digital image blind watermark extracting method which realizes watermark extraction by detecting the part of intermediate frequency coefficient transformed by DCT,and a watermark removing method which is realized by modifying the part of intermediate frequency coefficient transformed by DCT; the algorithm is simple and reliable, the method is suitable for beingrealized by the internet, neither the extracting or removing of watermark needs the participation of the original image; and the embeded invisible watermark has stronger capability of anti-JPEG compression attack, also has extremely strong robustness to sharpening attack and shearing attack, and is used for implicit identification digital image copyright.

A unique high performance digital video recorder having a number of novel features. The recorder's electronics are all on a unitary printed circuit board. The recorder also requires at least one hard disk drive and audio and video input analog signals (from a source such as video camera or broadcast media) as well as a suitable monitor for receiving output audio and video analog signals. A external time code generator (i.e., VITC digital clock) is also required for synchronization. Also required are various manual control devices (i.e., panel controls) for mode selection. The electronics of the preferred embodiment comprise A-to-D and D-to-A converters, a hard disk interface, a JPEG compression encoder/decoder, a multi-port DRAM and DMA subsystem, a microprocessor with RS-232 and RS-422 access ports, various working memory devices and bus interfaces and a 16-bit stereo digital audio subsystem. Novel features of the preferred embodiment include use of an index table for disk addresses of recorded frames, a multi-port memory controller in the form of a field programmable gate array (FPGA), loop recording using dual channels, and dynamic JPEG compression compensation.

The invention discloses a color halftoning image watermarking algorithm based on a support vector machine. In the algorithm, based on the support vector machine, watermarking embedded in a halftoning process is realized through adjusting error diffuse nuclei and a threshold value in a self-adapting manner. The algorithm comprises the following steps of: selection of two-dimension watermarking, encrypting and dimension reduction, selection of digital watermarking embedding position, embedding process of digital watermarking, extraction process of digital watermarking and the like; and the experiment shows that the algorithm has good watermarking imperceptibility and also has better robustness to attacks such as random alteration, noise superposition, geometric cutting, low-pass filtering, JPEG (joint photographic experts group) compression, printing and scanning and the like.

The invention discloses a sparse representation-based deblocking method, which mainly solves the problem of the presence of a blocking effect in a block discrete cosine transform (BDCT) compressed image. The method comprises the following implementation steps of: (1) selecting a clean training image set and training a general dictionary with a kernel singular value decomposition (KSVD) algorithm and a batch processing orthogonal matching pursuit algorithm; (2) compressing a test image by controlling a quality factor during joint photographic experts group (JPEG) compression so as to obtain a JPEG compressed image; (3) calculating the noise standard deviation of the JPEG compressed image; (4) automatically estimating an error threshold according to the quality factor and the noise standarddeviation; (5) constructing an image block matrix of the JPEG compressed image so as to obtain a de-noised sparse representation matrix; and (6) obtaining a deblocking result image by using the general dictionary and the sparse representation matrix. Compared with the prior art, the invention has the advantages that: a higher or similar peak signal to noise ratio can be obtained, the visual effect of a deblocked image is good, computation complexity is low, and a blocking effect in a BDCT compressed image can be eliminated.

A method for producing a compressed bit-stream from a digital image includes the steps of a) processing the digital image to produce a main subject belief map containing a continuum of belief values relating to the importance of subject and background regions in the image, b) performing a spatio-frequency transformation on the digital image to produce an array of transform coefficients, c) deriving a distortion-weighting factor for each transform coefficient from the belief map, and d) producing a compressed bit stream using an image compression system that is responsive to the distortion-weighting factors. The specific image compression system may be selected from a variety of image compression systems, including JPEG compression, JPEG2000 compression or vector quantization. The production of the main subject belief map involves the extraction of at least one structural saliency feature and at least one semantic saliency feature from the image, and the integration of the structural saliency feature and the semantic feature using a probabilistic reasoning engine into an estimate of a belief that a region of the digital image is the main subject.

The invention discloses a multi-channel video transmitting system and method. The method comprises a transmitting end and a receiving end. The transmitting end comprises a video source and a video code flow transmitting device. The receiving end comprises a video code flow receiving device. The transmitting end of the invention further comprises a multi-channel JPEG coder for performing JPEG compression to the video code flow to generate a coded image sequence. The receiving end further comprises a multi-channel JPEG decoder for performing JPEG decompression to the video coded image sequence to generate the video code flow. The invention can fully utilize the parallelism and low complexity of JPEG to compress the high definition video and can make the transmitting bandwidth based on the IP network satisfy the real-time requirement of the high definition video in order to realize the optimal transmitting effect of the high definition video with comparatively low development cost under limited network bandwidth.