Means for combining data of different frequencies for a raster output device

Abstract

A circuit for enabling the raster display of text or line art in one constant color against a background of another constant color or against a continuous-tone picture, or the display of a continuous-tone picture through an arbitrary shape. The circuit has four channels, one each for constant colors, continuous-tone images, image masks, and instructions. The constant colors are stored in the first channel in the form of two 8-bit colors, one for the text or line art and one for the background. Any color pair can be read from this memory, divided into two 8-bit colors, and presented at two inputs of a final multiplexer. The second channel stores continuous tone color pictures and presents this information at a third input of the multiplexer. The third channel receives masks or outlines in the form of bitmaps and the fourth channel receives instructions which may be run-length encoded. These two channels combine their data, which is then used to control the multiplexer.

Claims

1. A controller for generating a series of output pixels to be output to a raster output device from a plurality of continuous tone image pixels, binary image bits and two constant colors, comprising:

means for storing and outputting said two constant colors,

means for generating a continuous tone pulse for each continuous tone image pixel,

first memory means, responsive to said continuous tone pulse for storing and outputting said continuous tone image pixels,

means for generating a pixel clock pulse for each output pixel,

instruction memory means, responsive to said pixel clock pulse, for storing and outputting an instruction which selects two of the three outputs of said first memory means and said means for storing,

means for generating a binary clock pulse for each binary image bit, said means for generating a binary clock pulse having a different frequency from said means for generating a continuous tone pulse for each continuous tone image pixel,

second memory means, responsive to said binary clock pulse, for storing and outputting said binary image bits,

means responsive to said instruction and said binary image bits from said second memory means for determining one of the two outputs selected by said instruction, and

multiplexing means for receiving said two constant colors from said means for storing said two constant colors and said continuous tone image pixels from said first memory means and generating a series of output pixels therefrom in response to the output of said means for determining.

2. The controller of claim 1, for use in a multi-pass raster output device, wherein said instructions do not change between passes.

3. The controller of claim 1, for use in a multi-color raster output device, wherein said instructions and binary image do not change with a change of colors..Iadd.

4. A method for generating output data for outputting an image on a raster output device, comprising the steps of:

storing sampled color data corresponding to continuous tone portions of the output image;

storing constant color data corresponding to constant color portions of the output image;

supplying fixed color data corresponding to fixed color portions of the output image;

storing mask data corresponding to foreground and background portions of the output image;

storing instruction data;

reading the stored instruction data;

selectively reading the stored mask data, the stored sampled color data and the stored constant color data based on the read instruction data;

selectively combining one of first read constant color data, second read constant color data, read sampled color data, and the supplied fixed color data as a background portion of the output image with another of the first read constant color data, the second read constant color data, the read sampled color data, and the supplied fixed color data as a foreground portion of the output image, based on the read instruction data and mask data, to form the output data; and

outputting the output data to the raster output device to form the output image..Iaddend..Iadd.5. The method of claim 4, wherein:

storing the sampled color data comprises appropriately compressing the sampled color data; and

reading the stored sampled data step comprises appropriately decompressing the compressed stored sampled color data..Iaddend..Iadd.6. The method of claim 4, wherein:

storing the constant color data comprises appropriately compressing the constant color data; and

reading the stored constant color data comprises appropriately decompressing the compressed stored constant color data.

.Iaddend..Iadd. The method of claim 4, wherein:

storing the mask data comprises appropriately compressing the mask data; and

reading the stored mask data comprises appropriately decompressing the compressed mask data..Iaddend..Iadd.8. The method of claim 4, wherein:

storing the instruction data comprises appropriately compressing the instruction data; and

reading the stored instruction data comprises appropriately decompressing the compressed instruction data..Iaddend..Iadd.9. A method for forming an output image on a raster output device from an input image representation containing a plurality of different identified data types, each data type requiring at least one of a different color change resolution and a different spatial change resolution for optimal output representation, wherein image data of different data types can be overlapped, the method comprising:

separating image data of the input image representation according to the plurality of different data types into a plurality of separated signals, the plurality of separated signals allowably containing overlapping image data and allowably being of differing resolutions;

separately compressing at least two of the plurality of separated signals;

storing the at least two compressed signals and the uncompressed ones of the plurality of separated signals in a storage device;

reading the plurality of compressed signals and the uncompressed ones of the plurality of separated signals from the storage device; and

forming the output image on the raster output device from the at least two compressed signals and the uncompressed ones of the plurality of separated signals read from the storage device..Iaddend..Iadd.10. The method of claim 9, wherein compressing at least two of the plurality of separated signals includes using at least two compression methods, each compression method being optimized for a corresponding one of the plurality of the

separated signals..Iaddend..Iadd.11. The method of claim 9 further comprising the step of generating at least one control signal from the image data of the input image representation, wherein the forming step comprises:

decompressing each compressed signal; and

merging the plurality of separated signals to form the output image responsive to the at least one control signal..Iaddend..Iadd.12. The method of claim 9, wherein:

the separating step comprises separating from the image data at least one spatial signal corresponding to spatial information in the input image representation and at least one color signal corresponding to color information in the input image representation, and

the forming step comprises selectively combining the at least one color signal based on the at least one spatial signal..Iaddend..Iadd.13. The method of claim 12, wherein the at least one spatial signal comprises at least one instruction signal..Iaddend..Iadd.14. The method of claim 13, wherein the at least one spatial signal further comprises at least one mask signal..Iaddend..Iadd.15. The method of claim 12, wherein the at least one color signal comprises at least one constant color signal and at least one sampled color signal..Iaddend..Iadd.16. The method of claim 15, wherein the at least one color signal further comprises at least one predetermined fixed color value..Iaddend..Iadd.17. The method of claim 15, wherein the at least one constant color signal is a low color change resolution, high spatial change resolution signal comprising a predetermined color component and a plurality of components corresponding to different levels of multiple-level data in the input image representation..Iaddend..Iadd.18. The method of claim 12, wherein:

the at least one color signal comprises a plurality of color separation signals corresponding to color output components of the output device; and

the forming step comprises reusing the at least one spatial signal for each of the plurality of color separation signals to selectively combine each of the plurality of color separation signals to form the output image.

.Iaddend..Iadd.19. The method of claim 9, wherein:

the separating step further comprises separating, from at least one of the plurality of separated signals, portions of the input image representation having a color value corresponding to at least one fixed predetermined color value;

the separately compressing step includes eliminating the portions corresponding to the at least one predetermined value, and

the forming step includes replacing the eliminated portions by selecting said at least one fixed predetermined value..Iaddend..Iadd.20. A method for generating output data for an output image and having a resolution corresponding to an output resolution of a raster output device, comprising the steps of:

defining at least one predetermined color value corresponding to portions of the output image containing a predetermined output data value;

storing first resolution data corresponding to continuous tone portions of the output image;

storing second resolution data corresponding to graphics and text portions of the output image;

storing third resolution data corresponding to foreground and background portions of the output image;

storing instruction data, the instruction data specifying runs of at least one of the first resolution data, the second resolution data, and the at least one predetermined color value, the runs corresponding to the foreground and background portions of the output image;

reading the instruction data and the third resolution data;

reading and combining the specified runs of at least the first resolution data and the second resolution data based on the read instruction data and the read third resolution data to form the output resolution output data..Iaddend..Iadd.21. The method of claim 20, wherein the first resolution data is medium resolution color data..Iaddend..Iadd.22. The method of claim 21, wherein the medium resolution color data is sampled color data..Iaddend..Iadd.23. The method of claim 20, wherein the second resolution data is at least one of high spatial change resolution color data and low color change resolution color data..Iaddend..Iadd.24. The method of claim 20, wherein the second resolution color data is constant color data.

.Iaddend..Iadd.25. The method of claim 20, wherein the third resolution data is high resolution mask data..Iaddend..Iadd.26. The method of claim 25, wherein the mask data is binary data..Iaddend..Iadd.27. A method for forming an output image on a raster output device from an input image representation which contains a plurality of different identified data types, each data type having at least one of a different color change resolution and a different spatial change resolution for optimal output representation, wherein image data of different types can be overlapped, the method avoiding the step of forming a raster image in memory and comprising the steps of:

decomposing the input image representation according to the plurality of different data types into control data describing spatial content of the input image representation and color data describing color content of the input image representation;

transmitting said control data and said color data to a combining circuit;

selecting the color data using the combining circuit based on the control data; and

transmitting said selected color data to the raster output device to form an output image which is formed as a complete raster image for the first time on the raster output device..Iaddend..Iadd.28. The method of claim 27, wherein the control data comprises at least one instruction signal for controlling merging of overlapping data types of differing resolutions..Iaddend..Iadd.29. The method of claim 28, wherein the control data further comprises at least one mask signal describing foreground and background portions of said input image representation..Iaddend..Iadd.30. The method of claim 27, wherein the color data comprises at least one of a continuous tone signal, a constant color signal, and a fixed color signal..Iaddend..Iadd.31. A method for generating output data for outputting an image on a raster output device, comprising the steps of:

storing sampled color data corresponding to continuous tone portions of the output image;

storing constant color data corresponding to constant color portions of the output image;

storing control data for combining the sampled color and constant color data;

selectively reading portions of the stored control data;

selectively combining the sampled color data and the constant color data based on the read portions of the control data; and

outputting the combined data as the output data to the raster output

device..Iaddend..Iadd.32. The method of claim 31, wherein the control data comprises at least one of instruction data and mask data..Iaddend..Iadd.33. The method of claim 32, wherein the mask data is binary data..Iaddend..Iadd.34. A method for forming a high resolution color output image on a raster output device from an input image, comprising the steps of:

separating the input image into constant color data, sampled color data, and spatial data;

generating combination instructions for recombining the constant color data and the sampled color data based on the spatial data;

storing the constant color data;

storing the sampled color data;

storing the spatial data;

storing the combination instructions;

reading the combination instructions and the spatial data;

generating output data by selectively combining the constant color data and the sampled data based on the combination instructions and spatial data; and

outputting the high resolution color output image on the raster output device based on the output data..Iaddend..Iadd.35. An output resolution data generator for generating output resolution data suitable for forming an output resolution image on a raster output device, comprising:

a memory storing at least one of first resolution data corresponding to continuous tone portions of the output image, second resolution data corresponding to graphics and line art portions of the output image, third resolution data corresponding to foreground and background spatial information in the output image, and instruction data;

an instruction executing circuit inputting and executing portions of the instruction data;

a selection circuit selectively inputting portions of the first resolution data, the second resolution data and the third resolution data based on the inputted instruction data; and

a combining circuit combining at least the selected portions of the first resolution data and the second resolution data based on the instruction data and the third resolution data to form the output resolution print

data..Iaddend..Iadd.36. The output resolution data generator of claim 35, wherein the first resolution data is medium resolution color data..Iaddend..Iadd.37. The output resolution data generator of claim 36, wherein the medium resolution color data is sampled color data..Iaddend..Iadd.38. The output resolution data generator of claim 35, wherein the second resolution data is at least one of high spatial change resolution color data and low color change resolution color data..Iaddend..Iadd.39. The output resolution data generator of claim 35, wherein the second resolution color data is constant color data..Iaddend..Iadd.40. The output resolution data generator of claim 35, wherein the third resolution data is high resolution mask data..Iaddend..Iadd.41. The output resolution data generator of claim 40, wherein the mask data is binary data..Iaddend..Iadd.42. A controller for generating print data based on constant color data comprising a plurality of constant colors, continuous tone data comprising a plurality of sampled color pixels, at least one fixed color, at least one mask, and instruction data, the print data comprising a plurality of output pixels and being output to a raster output device, the controller comprising:

first storage means for storing the constant color data;

first control means for controlling the first storage means to selectively store and output the constant color data;

second storage means for storing the continuous tone data;

second control means for controlling the second storage means to selectively store and output the continuous tone data;

third storage means for storing the at least one mask;

third control means for controlling the third storage means to selectively store and output portions of the at least one mask;

fourth storage means for storing the instruction data;

fourth control means for controlling the fourth storage means to selectively store and output portions of the instruction data;

fifth storage means for storing the at least one fixed color;

selection means for selectively outputting one constant color of the constant color data, one sampled pixel of the continuous tone data, a fixed color of the at least one fixed color from the first, second and fifth storage means as the print data based on the outputted portions of the instruction data and the mask output from the third and fourth storage means; and

selection control means for controlling the first-fifth storage means and the selection means..Iaddend.