Apparatus and method for coding binary image with improved efficiency
First Claim
1. An apparatus for coding a binary image representing an object shape, comprising:
- an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image;
a divided portion generating unit which divides a rectangular block of the given area into divided portions;
a map information generating unit which generates map information for each one of the divided portions, the map information indicating whether a corresponding one of the divided portions has the inferior symbol included therein; and
a coding unit which encodes only the divided portions that have the inferior symbol included therein, wherein an identification of the inferior symbol, the map information, and the encoded divided portions are output from said apparatus.
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Abstract
An apparatus for coding a binary image representing an object shape includes an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image, a divided portion generating unit which divides a rectangular block of the given area into divided portions, a map information generating unit which generates map information for each one of the divided portions, the map information indicating whether a corresponding one of the divided portions has the inferior symbol included therein, and a coding unit which encodes only the divided portions that have the inferior symbol included therein, wherein an identification of the inferior symbol, the map information, and the encoded divided portions are output from the apparatus.
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Citations
16 Claims
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1. An apparatus for coding a binary image representing an object shape, comprising:
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an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image;
a divided portion generating unit which divides a rectangular block of the given area into divided portions;
a map information generating unit which generates map information for each one of the divided portions, the map information indicating whether a corresponding one of the divided portions has the inferior symbol included therein; and
a coding unit which encodes only the divided portions that have the inferior symbol included therein, wherein an identification of the inferior symbol, the map information, and the encoded divided portions are output from said apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for coding a binary image representing an object shape, comprising:
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an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence;
a divided portion generating unit which divides a block of the binary image into divided portions; and
a coding unit which encodes only the divided portion that have the inferior symbol included therein.
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10. A method of coding a binary image representing an object shape, comprising the steps of:
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deciding which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image;
dividing a rectangular block of the given area into divided portions; and
encoding only the divided portions that have the inferior symbol included therein. - View Dependent Claims (11, 12)
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13. An apparatus for coding macro blocks on a macro block-by-macro-block basis, wherein a binary image representing an object shape is divided into the macro blocks each including at least one of interior pixels and exterior pixels of said object shape, the apparatus comprising:
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a first unit configured to receive binary image data of one of the macro blocks, to obtain frequencies of occurrences of the interior pixels and the exterior pixels with respect to said one of the macro blocks, to decide a less frequent one of the interior pixels and the exterior pixels as an inferior symbol and a more frequent one of the interior pixels and the exterior pixels as a superior symbol, to output inferior symbol information indicative of which one of the interior pixels and the exterior pixels is the inferior symbol, and to output the binary image data of said one of the macro blocks as a bit pattern represented by the inferior symbol and the superior symbol, a second unit configured to generate bit patterns of small blocks by dividing the bit pattern corresponding to said one of the macro blocks into a plurality of the small blocks;
a third unit configured to receive the inferior symbol information and the bit patterns of the small blocks, to check whether each of the small blocks includes the inferior symbol, to output a block map information indicative of the check result, and to output only the bit patterns of the small blocks that include the inferior symbol;
a fourth unit configured to receive the output bit patterns of the small blocks that include the inferior symbol, to obtain frequencies of occurrences of the interior pixels and the exterior pixels with respect to each of the received bit patterns of the small blocks, to output new inferior symbol information, to output binary image data of the small blocks that are bit patterns having the inferior symbol and the superior symbol exchanged with each other if the frequencies of occurrences are reversed, and to output the received bit patterns without a change if the frequency of occurrences are not reversed;
a fifth unit configured to divide the bit patterns of the small blocks output from said fourth unit into horizontal or vertical pixel lines to generate bit patterns of pixel lines;
a sixth unit configured to receive the new inferior symbol information and the bit patterns of the pixel lines, to check whether each of the pixel lines includes the inferior symbol, to output the check result as pixel-line map information, to output only the bit patterns of the pixel lines that include the inferior symbol; and
a seventh unit configured to encode, on a pixel-line-by-pixel-line basis, only the pixel lines that include the inferior symbol. - View Dependent Claims (14)
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15. An apparatus for coding macro blocks on a macro block-by-macro-block basis wherein a binary image representing an object shape is divided into the macro blocks each including at least one of interior pixels and exterior pixels of said object shape, the apparatus comprising:
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a first unit configured to receive binary image data of one of the macro blocks, to obtain frequencies of occurrences of the interior pixels and the exterior pixels with respect to said one of the macro blocks, to decide a less frequent one of the interior pixels and the exterior pixels as an inferior symbol and a more frequent one of the interior pixels end the exterior pixels as a superior symbol, to output inferior symbol information indicative of which one of the interior pixels and the exterior pixels is the inferior symbol, and to output the binary image data of said one of the macro blocks as a bit pattern represented by the inferior symbol and the superior symbol, a second unit configured to generate bit patterns of small blocks by dividing the bit pattern corresponding to said one of the macro blocks into a plurality of the small blocks;
a third unit configured to receive the inferior symbol information and the bit patterns of the small blocks, to check whether each of the small blocks includes the inferior symbol, to output a block map information indicative of the check result, and to output only the bit patterns of the small blocks that include the inferior symbol;
a fourth unit configured to receive the output bit patterns of the small blocks that include the inferior symbol, to obtain frequencies of occurrences of the interior pixels and the exterior pixels with respect to each of the received bit patterns of the small blocks, to output new inferior symbol information, to output binary image data of the small blocks that are bit patterns having the inferior symbol and the superior symbol exchanged with each other if the frequencies of occurrences are reversed, and to output the received bit patterns without a change if the frequency of occurrences are not reversed;
a line-direction identifying unit configured to receive the new inferior symbol information and the bit patterns of the small blocks output from said fourth unit, and to select a pixel-line direction that is one of a horizontal direction and a vertical direction that produces fewer pixel lines including the inferior symbols when the received bit patterns of the small block are divided into horizontal pixel lines or vertical pixel lines;
a fifth unit configured to divide the bit patterns of the small blocks output from said fourth unit into pixel lines extending in the selected pixel-line direction to generate bit patterns of pixel lines;
a sixth unit configured to receive the new inferior symbol information and the bit patterns of the pixel lines, to check whether each of the pixel lines includes the inferior symbol, to output the check result as pixel-line map information, to output only the bit patterns of the pixel lines that include the inferior symbol; and
a seventh unit configured to encode, on a pixel-line-by-pixel-line basis, only the pixel lines that include the inferior symbol. - View Dependent Claims (16)
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Specification