Adaptive and Proadaptive Image Compression
نویسنده
چکیده
The most of well-known algorithms on the basis of the "past" (processed) samples make the local properties of the image more precise and adjust some own parameters. At decoding of the image on the basis of restored samples the same decisions are taken. It is the classical adaptive scheme. In the offered proadaptive approach for tuning parameters of algorithm the prolongation of a signal is used. For estimate of statistical properties of an encoded (current) sample are used both "past", and "future" samples and even current sample. Certainly, the reliability of the estimation will increase. But it is necessary to pay for information on "future" – to save some additional information. The proadaptive algorithm tunes the parameters only at encoding, and at decoding the saved values of parameters are used. The more size of additional data, the more often and/or precisely are adjusted parameters of algorithm and the better efficiency of encoding of the main data stream. If parameters of the coder are adjusted in each image fragment by size W×W, the entropy of the code words in the main and additional data streams will depend from the size of the image fragment like in figure 1. Under some conditions their sum has an optimum. The experimental probing on the real and artificial images have shown that the optimum is present always, but the conditions for its achievement essentially depend of the image context. I
منابع مشابه
Block-Based Compressive Sensing Using Soft Thresholding of Adaptive Transform Coefficients
Compressive sampling (CS) is a new technique for simultaneous sampling and compression of signals in which the sampling rate can be very small under certain conditions. Due to the limited number of samples, image reconstruction based on CS samples is a challenging task. Most of the existing CS image reconstruction methods have a high computational complexity as they are applied on the entire im...
متن کاملImplementation of VlSI Based Image Compression Approach on Reconfigurable Computing System - A Survey
Image data require huge amounts of disk space and large bandwidths for transmission. Hence, imagecompression is necessary to reduce the amount of data required to represent a digital image. Thereforean efficient technique for image compression is highly pushed to demand. Although, lots of compressiontechniques are available, but the technique which is faster, memory efficient and simple, surely...
متن کاملMEDICAL IMAGE COMPRESSION: A REVIEW
Within recent years the use of medical images for diagnosis purposes has become necessity. The limitation in transmission and storage space also growing size of medical images has necessitated the need for efficient method, then image Compression is required as an efficient way to reduces irrelevant and redundancy of the image data in order to be able to store or transmits data. It also reduces...
متن کاملImage Compression Method Based on QR-Wavelet Transformation
In this paper, a procedure is reported that discuss how linear algebra can be used in image compression. The basic idea is that each image can be represented as a matrix. We apply linear algebra (QR factorization and wavelet transformation algorithms) on this matrix and get a reduced matrix out such that the image corresponding to this reduced matrix requires much less storage space than th...
متن کاملارائه روشی برای پیشپردازش تصویر جهت بهبود عملکرد JPEG
A lot of researchs have been performed in image compression and different methods have been proposed. Each of the existing methods presents different compression rates on various images. By identifing the effective parameters in a compression algorithm and strengthen them in the preprocessing stage, the compression rate of the algorithm can be improved. JPEG is one of the successful compression...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001