Method and apparatus for selecting compression method and for compressing file using the selected method
First Claim
1. A machine implemented method of analyzing a file, comprising the steps of:
- obtaining a file;
determining a frequency of occurrence of bit patterns in the file;
determining characteristics of the file by analyzing the frequency of occurrence of the bit patterns in the file;
determining a number of byte values which have a frequency less than a predetermined threshold;
determining a number of consecutive byte values which have a frequency less than the predetermined threshold; and
determining the file is not an image file when the number of consecutive byte values which have a frequency less than the predetermined threshold exceeds a predetermined number.
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Accused Products
Abstract
A method and system for automatically determining a compression method to be used on a file. A histogram of the file is constructed in order to determine if there are a predetermined number of consecutive byte patterns below a set threshold. If this condition exists, the file is not an image file and compression can be performed using the lossless Lempel-Ziv compression method. If, over the range of the histogram, the file is above the predetermined threshold, the histogram is examined to determine if the average value in the histogram is in a central portion of the histogram. If it is not, the file does not represent an image and again, the Lempel-Ziv compression method is used. If both the byte patterns and the histogram exceed the predetermined threshold and the average of the histogram is in a central portion, the file is determined to contain an image. Based on the gradation or number of bits necessary to represent the byte patterns of the file, an appropriate image compression method is used to compress the file.
72 Citations
49 Claims
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1. A machine implemented method of analyzing a file, comprising the steps of:
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obtaining a file; determining a frequency of occurrence of bit patterns in the file; determining characteristics of the file by analyzing the frequency of occurrence of the bit patterns in the file; determining a number of byte values which have a frequency less than a predetermined threshold; determining a number of consecutive byte values which have a frequency less than the predetermined threshold; and determining the file is not an image file when the number of consecutive byte values which have a frequency less than the predetermined threshold exceeds a predetermined number. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system for analyzing a file, comprising:
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means for determining a frequency of occurrence of bit patterns in a file; means for determining characteristics of the file by analyzing the frequency of occurrence of the bit patterns in the file; means for determining a number of byte values which have a frequency less than a predetermined threshold; means for determining a number of consecutive byte values which have a frequency less than the predetermined threshold; and means for determining the file is not an image file when the number of consecutive byte values which have a frequency less than the predetermined threshold exceeds a predetermined number. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A computer program product having a computer readable medium having computer program logic recorded thereon for analyzing a file, comprising:
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means for determining a frequency of occurrence of bit patterns in a file; and means for determining a file type from a plurality of file types by analyzing the frequency of occurrence of the bit patterns in the file. - View Dependent Claims (36, 37, 38, 39, 40, 41)
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42. A machine implemented method of analyzing a file, comprising the steps of:
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obtaining a file; determining a frequency of occurrence of byte patterns in the file; and determining a file type from a plurality of file types by analyzing the frequency of the byte patterns in the file. - View Dependent Claims (43, 44, 45)
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46. A system for analyzing a file, comprising:
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means for obtaining a file; means for determining a frequency of occurrence of byte patterns in the file; and means for determining a file type from a plurality of file types by analyzing the frequency of the byte patterns in the file. - View Dependent Claims (47, 48, 49)
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Specification