An enhanced wavelet-based compression scheme for satellite image is proposed in this paper. The Consultative
Committee for Space Data System (CCSDS) presented a recommendation which utilizes the wavelet transform and the
bit plane coder for satellite image compression. The bit plane coder used in the CCSDS recommendation encodes the
coefficient block of bit planes one by one and then truncates the unnecessary bit plane coefficient blocks. By this way,
the contexts of bit planes are not considered as the redundancy embedded data which may be compressed further. The
proposed scheme uses a bit plane extractor to parse the differences of the original image data and its wavelet transformed
coefficients. The output of bit plane extractor will be encoded by a run-length coder and will be sent to the
communication channel with the CCSDS compressed data. Comparing with the recommendation of CCSDS, under a
reasonable complexity, the subjective quality of the image will maintained or even better. In addition, the bit-rate can be
further decreased from 85% to 95% of the CCSDS image compression recommendation at the similar objective quality
level. By using the lower bit rate lossy mode compression and bit plane compensation, it is possible to obtain lower bit
rate and higher quality image than which the higher bit rate lossy mode compression can achieve.
In this paper, a near lossless medical image compression scheme combining JPEG-LS with cubic spline interpolation (CSI) is presented. The CSI is developed to subsample image data with minimal distortion and to achieve image compression. It has been shown in literatures that the CSI can be combined with the transform-based image compression algorithm to develop a modified image compression codec, which obtains a higher compression ratio and a better subjective quality of reconstructed image than the standard transform-based codecs. This paper combines the CSI with lossless JPEG-LS to form the modified JPEG-LS scheme and further makes use of this modified codec to medical image compression. By comparing with the JPEG-LS image compression standard, experimental results show that the
compression ratio increased over 3 times for the proposed scheme with similar visual quality. The proposed scheme reduces the loading for storing and transmission of image, therefore it is suitable for low bit-rate telemedicine application. The modified JPEG-LS can reduce the loading of storing and transmitting of medical image.
In this paper, a modified image compression algorithm using cubic spline interpolation (CSI) and bit-plane compensation
is presented for low bit-rate transmission. The CSI is developed in order to subsample image data with minimal
distortion and to achieve image compression. It has been shown in literatures that the CSI can be combined with the
JPEG or JPEG2000 algorithm to develop a modified JPEG or JPEG2000 CODEC, which obtains a higher compression
ratio and better quality of reconstructed images than the standard JPEG and JPEG2000 CODECs in low bit-rate range.
This paper implements the modified JPEG algorithm, applies bit-plane compensation and tests a few images.
Experimental results show that the proposed scheme can increase 25~30% compression ratio of original JPEG data
compression system with similar visual quality in low bit-rate range. This system can reduce the loading of
telecommunication networks and is quite suitable for low bit-rate transmission.
In this paper, a modified medical image compression algorithm using cubic spline interpolation (CSI) is presented for
telemedicine applications. The CSI is developed in order to subsample image data with minimal distortion and to
achieve compression. It has been shown in literatures that the CSI can be combined with the JPEG algorithms to
develop a modified JPEG codec, which obtains a higher compression ratio and a better quality of reconstructed image
than the standard JPEG. However, this modified JPEG codec will lose some high-frequency components of medical
images during compression process. To minimize the drawback arose from loss of these high-frequency components,
this paper further makes use of bit-plane compensation to the modified JPEG codec. The bit-plane compensation
algorithm used in this paper is modified from JBIG2 standard. Experimental results show that the proposed scheme can
increase 20~30% compression ratio of original JPEG medical data compression system with similar visual quality. This
system can reduce the loading of telecommunication networks and is quite suitable for low bit-rate telemedicine
applications.
KEYWORDS: Image compression, Medical imaging, Image quality, Telemedicine, Digital imaging, Data compression, Algorithm development, JPEG2000, Computer programming, Standards development
In this paper, a new medical image compression algorithm using cubic spline interpolation (CSI) is presented for
telemedicine applications. The CSI is developed in order to subsample image data with minimal distortion and to
achieve image compression. It has been shown in literatures that the CSI can be combined with the JPEG or JPEG2000
algorithm to develop a modified JPEG or JPEG2000 codec, which obtains a higher compression ratio and a better
quality of reconstructed image than the standard JPEG and JPEG2000 codecs. This paper further makes use of the
modified JPEG codec to medical image compression. Experimental results show that the proposed scheme can increase
25~30% compression ratio of original JPEG medical data compression system with similar visual quality. This system
can reduce the loading of telecommunication networks and is quite suitable for low bit-rate telemedicine applications.
This paper proposed an adaptive wavelet-based deblocking algorithm for MPEG-4 video coding standard. The novelty of this method is that the deblocking filter uses a wavelet-based threshold to detect and analyze artifacts on coded block boundaries. This threshold value is based on the difference between the wavelet transform coefficients of image blocks and the coefficients of the entire image. Therefore, the threshold value is made adaptive to different images and characteristics of blocking artifacts. Then one can attenuate those artifacts by applying a selected filter based on the above threshold value. It is shown in this paper that the proposed method is robust, fast, and works remarkably well for MPEG-4 codec at low bit rates. Another advantage of the new method is that it retains sharp features in the decoded frames since it only removes artifacts. Experimental results show that the proposed method can achieve a significantly improved visual quality and increase the PSNR in the decoded video frame.
In this paper, the cubic spline interpolation (CSI) is shown to be performed by a direct computation for the encoding and decoding processes of image coding. A pipeline structure can be used to implement this new CSI. Such a new CSI algorithm can be used along with the JPEG standard to obtain the new CSI-JPEG codec and while still maintaining good quality of the reconstructed image for higher compression ratios. In this paper, it is shown that this new CSI-JPEG codec makes possible a pipeline compression algorithm that is naturally suitable for hardware implementation.
This paper develops a bit-plane coding technique to achieve the subtitle enhancement in MPEG-4 for very low bit rate streaming video. The original video frame that contains subtitle information is encoded by the use of MPEG-4 codec and then the MPEG-4 decoded Y frame is subtracted from the original one to generate a residue. Because the subtitle information usually appears on the special region of a video frame, one can pre-set the position of the subtitle region and just process this residue subtitle region for subtitle enhancement. The pixel value of the residue subtitle region will be transferred from decimal number to binary number. Thus one can obtain 8 bit-planes of the residue subtitle region. For each bit-plane, (RUN, EOP) symbols are formed and then encoded via the variable length coding to produce the output bitstream. It has been shown that such a bit-plane coding technique is very efficient and its decoding procedure can be easily performed. From various experimental results, using MSB, MSB-1 and MSB-2 planes can obtain a satisfied subtitle visual enhancement with only increasing 5% bit rate.
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