JPEG XR is the latest image compression standard. In this paper, two graph-based soft decision quantization (SDQ) methods are developed to optimize the rate-distortion performance of JPEG XR. The first approach uses a...
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JPEG XR is the latest image compression standard. In this paper, two graph-based soft decision quantization (SDQ) methods are developed to optimize the rate-distortion performance of JPEG XR. The first approach uses a full graph, whose number of states is determined by the block size. The second method employs a fast and adaptive event-based graph, where the number of states depends on the number of nonzero indices in a normalized block, which is usually much less than the block size. Experimental results show that the fast method performs as good as the full graph method, and both methods can achieve up to 0.5 dB gain over JPEG XR.
Recently, an efficient file searching method related to the crime for the digital evidence is spotlighted in computer forensics. However, traditional cryptographic hashes cannot provide proper similarity between two s...
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Recently, an efficient file searching method related to the crime for the digital evidence is spotlighted in computer forensics. However, traditional cryptographic hashes cannot provide proper similarity between two similar files because even a single bit difference between two files brings a drastic change of the hash results. This paper introduces the techniques which measure a similarity between two files and compares the efficiency of the implemented tools as utility. Moreover, we also propose the method to detect similar files which include the different GPS information based on LBS.
Digital forensics is a branch of forensic science to monitor, analyze and examine digital media or devices. File carving is the art of recovering files from digital data storage with corrupted or unavailable file syst...
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Digital forensics is a branch of forensic science to monitor, analyze and examine digital media or devices. File carving is the art of recovering files from digital data storage with corrupted or unavailable file system metadata and it is very useful in a digital forensics investigation. However, earlier generation file carver like Scalpel and Foremost only deals with non-fragmented files. We proposed an automatic image and thumbnail carving tool called myKarve which is useful in digital forensics investigation and presentation of evidential information that is able to carve contiguous and linearly fragmented images caused by garbage. myKarve is designed on a new architecture to deal with thumbnail and fragmentation issues. The tool is tested with images obtained from the Internet. myKarve is found to be a more efficient automated image and thumbnail carver compared to the original Scalpel with the following advantages: detects more headers using validated headers; carves more images and thumbnails by using the newly introduced image patterns; and is able to discard garbage from linearly fragmented images. The results from myKarve are invaluable in the field work of digital forensic analysis that can produce technical evidence against cybercrime activities to prosecution cases.
File carving is the process of recovering files without the help of (file system) storage metadata. A host of techniques exist to perform file carving, often used in several tools in varying combinations and implement...
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File carving is the process of recovering files without the help of (file system) storage metadata. A host of techniques exist to perform file carving, often used in several tools in varying combinations and implementations. This makes it difficult to determine what tool to use in specific investigations or when recovering files in a specific file format. We define recoverability as the set of software requirements for a file carver to recover files in a specified file format. This set can then be used to evaluate what tool to use or which technique to implement, based on external factors such as file format to recover, available time, engineering capacity and data set characteristics. File carving techniques are divided into two groups, format validation and file reconstruction. These groups refer to different parts of a file carver's implementation. Additionally, some techniques may be emphasized or omitted not only because of file format support for them, but based on performance effects that may result from applying them. We discuss a simplified variant of the GIF image file format as an example and show how a structured analysis of the format leads to design decisions for a file carver.
In H.264, intra-prediction is used to improve the efficiency of I-frame encoding. There are many kinds of intra-prediction modes in H.264, so we have to select a suitable prediction mode for each frame, and the result...
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In H.264, intra-prediction is used to improve the efficiency of I-frame encoding. There are many kinds of intra-prediction modes in H.264, so we have to select a suitable prediction mode for each frame, and the result of our selection must transfer to the decoder. So it needs extra bites to transport the mode selection information. In order to reduce the amount of mode selection information and the complexity of encoding, we optimize the method of mode selection in intra-prediction in this paper. In the method, it first calculates and quantifies the prediction residual matrix, then according to the result of quantified to select an optimal prediction mode. Experiment results show that the improved method can obviously speed up the encoding rate and has a good practicability.
This paper proposes a new method for multiplexing - demultiplexing of AVS video and AAC audio stream that uses frame numbers as time stamps for achieving lip synchronization during playback. The packetization layers a...
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This paper proposes a new method for multiplexing - demultiplexing of AVS video and AAC audio stream that uses frame numbers as time stamps for achieving lip synchronization during playback. The packetization layers adopted for multiplexing the video and audio streams before their transmission conform to the MPEG-2 systems framework.
Digital Imaging and Communications in Medicine (DICOM) is a standard for handling, storing, printing, and transmitting information in medical imaging. DICOM viewer tool is required to view and analyze these DICOM imag...
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Digital Imaging and Communications in Medicine (DICOM) is a standard for handling, storing, printing, and transmitting information in medical imaging. DICOM viewer tool is required to view and analyze these DICOM images. There are many commercially available algorithms which process Dicom images; however these algorithms are typically tuned for particular image types. This paper describes a universal transcoder for reading Dicom images and compressing these using lossy as well as lossless schemes such as Dicom rle, jpeg, and jpeg 2000. The compression technique to be used is either automatically selected based on image parameters, or as specified by the user. This paper also describes results from research conducted in the conversion of images from DICOM format into any other image format, reducing the dependence of specialized DICOM viewer tools for viewing medical images. The idea is to convert DICOM formatted files into bitmap format first, and then convert these bitmaps into other common image files. Our transcoder outputs an image that is best suited for viewing on wireless handhelds (mobile phones) as well as built-in viewers on computers, which facilitates further analysis and research to be conducted on these images.
In this paper we present a unique approach towards parallelizing the Software MPEG-2 Video Encoder. The approach involves the division of encoding process spatially, between four similar processors with distributed me...
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In this paper we present a unique approach towards parallelizing the Software MPEG-2 Video Encoder. The approach involves the division of encoding process spatially, between four similar processors with distributed memory system, in such a way that each frame of the input video sequence is divided into four separate sections, each individually processed by a processor. The results thus produced were compared with those of the Sequential Encoder for a number of different input bitstreams and a speedup in the range of 3 to 3.5 with four processors was successfully obtained.
The video streaming in the multimedia resource database,running in the campus network, its core is the video streaming technology application based on the MPEG format (including MPEG-1, MPEG-2, and MPEG-4, etc). By th...
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ISBN:
(纸本)9781612847719
The video streaming in the multimedia resource database,running in the campus network, its core is the video streaming technology application based on the MPEG format (including MPEG-1, MPEG-2, and MPEG-4, etc). By the design and calculation about the video of MPEG format in the multimedia resource database,this article has provided a design method that the video streaming system of MPEG format in the multimedia resource database is appropriate transmission system, and the system is running in the actual campus network.
This paper presents a signaling method for high definition dual-stream 3DTV services using multiple RF channels. A dual-stream 3DTV program consists of 2 video streams in order to serve full resolution for the left an...
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This paper presents a signaling method for high definition dual-stream 3DTV services using multiple RF channels. A dual-stream 3DTV program consists of 2 video streams in order to serve full resolution for the left and right view's image. In this case, the 3DTV program can be transmitted over 2 RF channels because of channel capacity or other reasons. In the presented signaling method, 2 descriptors based on MPEG are proposed for providing compatibility to a previous 2DTV receiver.
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