Apple Inc.

Xerox Corporation

Stuart L Claassen

Kok S Chen

Riaz A Moledina

Anitta L Bliss

Donald James Curry

James Loran Ball

Todd W Thayer

Chein-Hwa S Tsao

Larry W Lin

David Kasle

Joseph Ku

Jon Q J Pocock

An apparatus and method for an improved stack comprises an advantageous indexing scheme and stack arrangement allowing more efficient performance of stack operations. The most-recently-used stack item appears at the top of the stack and the least-recently-used item is at the bottom of the stack. Values in between the top and bottom items are ordered from top to bottom with succeedingly less recently used items. An indexing scheme is used to indirectly reference locations of the stack items in the stack. A set of registers is used to reference the locations of the stack items in an embedded memory array. The registers function as pointers to the memory array locations. To promote an item to the top of the stack, the item is identified as the most-recently-used and the contents of the other registers are changed to specify the new locations, e.g. these pointers are shifted down one. Similarly, to insert a new item on to the top of the stack, the pointers are shifted and a new item is written into the memory array location that contains the least-recently-used item.

Method and apparatus for an improved stack arrangement and operations thereon

Finite response filters (FIRs) are divided into partial filters that filter a same portion of image data to generate partial filtered results. The partial filtered results may be saved and later retrieved to generate complete filter outputs.

Finite impulse response filter method and apparatus

A distributed digital imaging processing system having a number of processing units and circular FIFO buffers connected together using data transforming streams. Processing units read data from buffers using a transforming read streams. These read streams reorder the buffer data to form patches representing neighborhood pixels and may provide the same data multiple times. After processing a patch, a processing unit writes the resultant patch into a buffer using a transforming write stream which reorders the data into the storage format of the buffer. Several buffers can feed a single processor and one processor can feed several buffers. All the details of each data stream (buffer, current buffer location, patch size, access pattern) are stored in a table entry, along with a pointer to the data stream that it must follow in the buffer to avoid the hazards of reading and writing data out of order. In the case where a buffer has multiple read streams, requiring read streams to maintain a particular order reduces the work necessary to check for either a write or read hazard to comparing the location of a stream with it's leader. A single state machine computes from each table entry all addresses for all data transfers between the processors and buffers, and updates the table entry after each cycle. Since table entries define the streams which link processors to memory, communication paths between processors is completely under software control.

System for controlling read and write streams in a circular FIFO buffer

Method and apparatus for an improved stack arrangement and operations

A system and method for efficient image encoding begins by loading a series of image blocks. A current block is compared with an immediately preceding image block for coincidence, and coded as matching or nonmatching based on the comparison results. The system further compares the nonmatching image blocks with a stack containing a list of the most recently encountered image blocks. Image blocks matching an entry in the list are coded by reference to the appropriate entry in the list. In the event a match is still unavailing, the system determines if the image blocks may be categorized as a bilevel text block, a bilevel image block, a block containing only one gray pixel, or a block containing multiple gray pixels. Each nonmatching block is classified according this classification criteria.

System and method for variable encoding based on image content

A system and method for efficient image compression begins by segmenting an input image into a current and previous window using a loading module. An encoding module compares the current and the previous window. If the current window does not match the previous window, the encoding module alters the dimensions of the current and previous windows and repeats the comparison. If a match is found, the encoding module instructs the loading module to continue to segment the image using the altered window dimensions. In this manner, the system's segmenting is in step with the natural cycle of repetition in the input image.

System and method for compressing data using a dynamically changing

A printer and a method for printing is described in which bleed between secondary color regions having different colors is minimized by the formation of a border strip which has a color which is common to both secondary color regions. In a printer assembly which includes a print head for depositing ink onto a media, an improved image may be formed by processing the data before the image is printed such that a border strip is formed between adjoining regions of different secondary colors. The border strip is printed in a color which is common to both of the secondary color regions. Thus, because the color which is common to both secondary color regions is printed in the border region, the contrast between the three areas of different colors is minimized. In addition, the reduced volume of ink within the border strip further minimized ink bleed. Thus, a border strip which is significantly less visible to the naked eye, is formed which minimizes bleed between the two secondary color regions.

Printing apparatus and method for printing color boundary regions having

A method is described for optimizing printing a first print dot, a second print dot, a third print dot, and a fourth print dot adjacent to each other on a sheet of paper. The method first determines whether the first, second, third, and fourth print dots to be printed are in black color. If any one of the first, second, third, and fourth print dots is in the black color, then the respective one of first, second, third, and fourth print dots needs to be double printed with the black color. If the first and second print dots are in the black color and the third and fourth print dots are color print dots, then the first and second print dots are printed with the black color and the third color print dot is printed during a first print pass by the printer. The first and second print dots are then double printed with the black color and the fourth color print dot is printed during a second print pass by the printer such that the first and second print dots are double printed with the black color and the third and fourth print dots are alternately printed by the first and second print passes. Color bleeding is minimized between the third and fourth color print dots while the first and second print dots can be double printed with the black color by only the first and second print passes to increase print density with a resulting increase in the throughput of the printing.

Minimizing color bleed while maximizing throughput for color printing

A method of depositing spots of liquid ink upon selected pixel centers on a substrate having poor ink absorptive properties so as to prevent the flow of liquid ink from one spot to an overlapping adjacent one. The line of information is printed in at least two passes so as to deposit spots of liquid ink on selected pixel centers in a checkerboard pattern wherein only diagonally adjacent pixel areas are deposited in the same pass. On the second pass the complementary checkerboard pattern is deposited. Ink is not deposited on horizontally or vertically adjacent pixel areas during the single pass since the spots on these adjacent areas have overlapping portions.

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Santa Clara, CA, United States of America

Stuart L Claassen