Data Compression

... single color.Our second way of classifying data compression methods is shown in Table 27-1b. Most data compression programs operate by taking a group of data fromthe original file, compressing ... samples from a data acquisitionsystem, etc. Typically, these easy-to-use encoding methods require data files about twice as largeas actually needed to represent the information. Data...

Ngày tải lên: 13/09/2012, 09:50

... 2: Data compression In-Lab: Wednesday, January 20, 2010 Due: Monday, January 25, 2010 Overview Assume that the data consists of stream of symbols from a finite alphabet. Compression ... alphabet. Compression algorithms encode this data such that it can be transmitted/stored with minimum size. Huffman coding is a lossless data compression algorithm developed by David ... updated...

Ngày tải lên: 25/04/2013, 08:07

... watermark. 1 Approaches to Compression How can a given a data file be compressed? Compression amounts to eliminating the redundancy in the data, so the first step is to find the source of redundancy in each type of data. ... redundancy in a given type of data, we can propose an approach to eliminating the redundancy. This chapter covers the basic approaches to the compression of differ...

Ngày tải lên: 14/12/2013, 15:15

... codewords for the particular data being compressed. In the second pass the encoder actually compresses the data by replacing each data symbol with its Huffman codeword. An adaptive compression algorithm ... asymmetric compression method). It reads the next input item and determines whether it is a token or raw data. A token is used to obtain data from the dictionary and write it o...

Ngày tải lên: 14/12/2013, 15:15

... which makes it so useful in data compression, is that it takes correlated input data and concentrates its energy in just the first few transform coefficients. If the input data consists of correlated ... most data compression methods that employ the DCT use this value of n. The following experiment illustrates the power of the DCT in one dimension. We start with the set of eight corr...

Ngày tải lên: 14/12/2013, 15:15

... that data unit. The output for the second data unit will be 1114 − 1118 = −4 (also Huffman encoded), followed by the 63 (encoded) AC coefficients of that data unit, and the output for the third data ... bitmap rows. JPEG has been designed as a compression method for continuous-tone images. The main goals of JPEG compression are the following: 1. High compression ratios, especially...

Ngày tải lên: 14/12/2013, 15:15

... compression ratios of 0.5, whereas in order to make a serious dent in the huge amount of data in this collection, compressions of about 1 bpp or better are needed. What is needed is a lossy compression ... can select any of those. 7.3.1 BOCU-1: Unicode Compression The acronym BOCU stands for binary-ordered compression for Unicode. BOCU is a simple compression method for Unicode-ba...

Ngày tải lên: 14/12/2013, 15:15

... grayscale compression) , color space, 184 companding, 14 companding (audio compression) , 229–231 compression factor, 17, 273 compression gain, 17, 273 compression performance measures, 16–17 compression ... (See also Zip.) Dictionary-Based Compression. Compression methods (Chapter 3) that save pieces of the data in a “dictionary” data structure. If a string of new data is...

Ngày tải lên: 14/12/2013, 15:15

... in data compression and there are the all-important error-control codes for added robustness (See also ASCII, Unicode.) Compression Factor. The inverse of compression ratio. It is defined as compression ... (See also Zip.) Dictionary-Based Compression. Compression methods (Chapter 3) that save pieces of the data in a “dictionary” data structure. If a string of new data is id...

Ngày tải lên: 14/12/2013, 15:15

... TRIỂN KH&CN, TẬP 11, SỐ 03 - 2008 Trang 49 DEVELOPMENT OF AN AUTOUMATIC DATA PROCESSING FOR TRIAXIAL COMPRESSION TEST Pham Hong Thom (1) , Le Minh Son (2) , Phan Tan Tung (1) , Nguyen ... the second one to the first one by using some simple and low cost data acquisition systems using a personal computer. The data acquisition systems must attain some advantages, such as:...

Ngày tải lên: 10/12/2013, 06:15