Systems and Methods for Efficient Halftone Screening
Systems, methods, and devices described herein provide schemes for performing halftoning operations on image data using a first halftone pattern with a first data width on a SIMD-capable processor with a second data width, wherein second data width is not an integral multiple of the first data width. In some embodiments, the method can operate iteratively and comprises deriving a halftone pattern for an iteration based on a start location in the first halftone pattern, wherein the derived halftone pattern can be of the second data width; loading image data for the iteration until the image data is exhausted, or until the image data occupies the entire width of a register in the processor; and performing halftone computations on the image data using the derived halftone pattern.
1 . A method for performing halftoning operations on image data using a first halftone pattern with a first data width on a SIMD-capable processor with a second data width, wherein the method comprises at least one iteration and the second data width is not an integral multiple of the first data width, the method comprising:
deriving a halftone pattern for the iteration based on a start location in the first halftone pattern, wherein the derived halftone pattern is of the second data width;
loading image data for the at least one iteration into a register in the processor, until the image data is exhausted, or until the width of the image data equals the second data width; and
performing halftone computations on the image data using the derived halftone pattern.
2 . The method of claim 1 , wherein deriving a halftone pattern for the iteration based on a start location in the first halftone pattern further comprises:
rotating the first halftone pattern by R bits to obtain a second halftone pattern, wherein R is the bit position of the start location in the first halftone pattern for the iteration;
repeatedly concatenating the second halftone pattern to obtain a concatenated pattern that is greater than or equal to the second data width; and
truncating any terminal portion of the concatenated pattern so that the resulting derived pattern is of the second data width.
3 . The method of claim 1 , wherein the method is performed using a Digital Signal Processor coupled to a printer.
4 . The method of claim 1 , wherein the halftoning operations include threshold halftoning.
5 . The method of claim 2 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in a table.
6 . The method of claim 2 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in distinct processor registers.
7 . The method of claim 1 , wherein the method is used to perform halftoning operations on at least one entire image.
8 . The method according to claim 5 , wherein the table is stored in memory internal to a printer.
9 . The method of claim 1 , wherein the method is performed using one or more of:
a computer coupled to a printer;
a print controller coupled to a printer; and
a printer.
10 . A computer-readable medium that stores instructions, which when executed by processor perform steps in a method for performing halftoning operations on image data using a first halftone pattern with a first data width on a SIMD-capable processor with a second data width, wherein the method comprises at least one iteration and the second data width is not an integral multiple of the first data width, the steps comprising:
deriving a halftone pattern for the iteration based on a start location in the first halftone pattern, wherein the derived halftone pattern is of the second data width;
loading image data for the at least one iteration into a register in the processor, until the image data is exhausted, or until the width of the image data is equal to the second data width; and
performing halftone computations on the image data using the derived halftone pattern.
11 . The computer-readable medium of claim 10 , wherein deriving a halftone pattern for the iteration based on a start location in the first halftone pattern further comprises:
rotating the first halftone pattern by R bits to obtain a second halftone pattern, wherein R is the bit position of the start location in the first halftone pattern for the iteration;
repeatedly concatenating the second halftone pattern to obtain a concatenated pattern that is greater than or equal to the second data width; and
truncating any terminal portion of the concatenated pattern so that the resulting derived pattern is of the second data width.
12 . The computer-readable medium of claim 10 , wherein the method is performed using a Digital Signal Processor coupled to a printer.
13 . The computer-readable medium of claim 11 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in a table.
14 . The computer-readable medium of claim 11 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in distinct processor registers.
15 . The computer-readable medium of claim 10 , wherein the method is used to perform halftoning operations on at least one entire image.
16 . A system comprising a computer coupled to a printer, wherein the computer and printer perform steps in a method performing halftoning operations on image data using a first halftone pattern with a first data width on a SIMD-capable processor with a second data width, wherein the method comprises at least one iteration and the second data width is not an integral multiple of the first data width, the method comprising:
deriving a halftone pattern for the iteration based on a start location in the first halftone pattern, wherein the derived halftone pattern is of the second data width;
loading image data for the at least one iteration, until the image data is exhausted, or until the image data occupies the entire width of a second register in the processor; and
performing halftone computations on the image data using the derived halftone pattern.
17 . The system of claim 16 , wherein deriving a halftone pattern for the iteration based on a start location in the first halftone pattern further comprises:
rotating the first halftone pattern by R bits to obtain a second halftone pattern, wherein R is the bit position of the start location in the first halftone pattern for the iteration;
repeatedly concatenating the second halftone pattern to obtain a concatenated pattern that is greater than or equal to the second data width; and
truncating any terminal portion of the concatenated pattern so that the resulting derived pattern is of the second data width.
18 . The system of claim 17 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in a table.
19 . The system of claim 17 , further comprising storing distinct derived halftone patterns that correspond to distinct start locations in the first halftone pattern in distinct processor registers.
20 . The system of claim 15 , wherein the method is used to perform halftoning operations on at least one entire image.