Hewlett-packard Company

Hewlett-packard Development Company, L.P.

Terrence M Shannon

Russell Campbell

Burton H Poppenga

Shane R Konsella

James Phillip Slupe

Michael George Fuchs

An embodiment of a manual printer is particularly well suited for forming images on the surface of uneven objects. The embodiment of the manual printer includes a microprocessor for controlling its operation. Image data is stored in RAM and the firmware for controlling the operation of the microprocessor is stored in ROM. A print head interface generates drive signals for a print head using data received from the microprocessor. A signal is generated by an emitter. A receiver in the manual printer receives the signal. The signal includes an x-component, a y-component, and a z-component. The microprocessor determines the position of the manual printer with respect to a reference location using the components of the signal. A distance sensor in the manual printer measures the distance of the print head from the surface of the object. A tilt sensor in the manual printer measures an angle between a longitudinal axis in the manual printer and the surface of the object. An acceleration sensor in the manual printer measures the acceleration resulting from movement by a user. A display in the manual printer allows the user to preview and select images for performing an imaging operation. A user begins forming an image by depressing a button while moving the manual printer over the surface of the object. If the microprocessor determines that position, distance, angle, and acceleration are within allowable limits, ink is ejected from the print head to form the image.

Manual imaging device

A system and method is provided for storing public and secure font data in a font file. The system and method include public glyph data stored in the font file. Secure glyph data is also provided that corresponds to the public glyph data and the secure glyph data is stored in the font file in an encrypted form. A security logic module is included and configured to allow the secure glyph data to be used when a decryption key is provided by a user to decrypt the secure glyph data.

System and method for storing public and secure font data in a font file

A computer operable to encode a string of tokens is described. The computer operates to identify a group of tokens in the string. The identified group of tokens are those tokens that follow a token having a first value. The computer further operates to assign a Huffman codeword to each token value present in the group. The Huffman codewords are assigned based upon the local frequencies of the group. The computer then operates to replace each token in the group with the codeword assigned to its value. The computer further operates to replace each token that is not a member of group with a codeword so as to generate a string of Huffman codewords that is representative of the string of tokens.

System and method for encoding and decoding data

A computer operable to encode a string of tokens is described. The string of tokens includes a group of tokens that immediately follow a token having a first value. The Computer operates to select a token value that occurs most often in the group. The computer can then operate to convert the first string of tokens into a second string of tokens by substituting each occurrence of a token-pair unit in the first string with a single token. The token-pair unit includes a first token having the first value and a second token having the selected value. The computer then operates to identify a group of tokens in the second string. The identified group of tokens are those tokens that follow a token having the first value. The computer then operates to Huffman encode the second string. In part, this is accomplished by Huffman encoding the identified group based upon the identified group's local frequencies.

System and method for compressing data

Raster images are highly compressed by first reordering the data. Next the reordered data is indexed to encode any and all predicted runs and literal runs. Each piece of the present line of the raster image is compared to a previous line. If there is a match, then the present piece is a predicted run and indexed accordingly. If there is no match, then the present piece is a literal run and indexed accordingly. A predicted run can have a minimum run length of one piece, and a maximum run length of the image width in pieces divided by the number of strings. The same is true for literal runs. The index strings are then compressed using a lossless compression method such as Huffman encoding. If Huffman encoding is used, the Huffman tables are predefined and known to both the compressor and decompressor. As the compressor compressed the index strings, the Huffman tables are adapted. The decompressor is notified by the compressor when the adapted tables are to be used.

Method for compressing raster data

The present invention reduces the amount of data sent to a printer from a printer driver. Data reduction is achieved by using a dither matrix that is designed to produce compressible images, then using a lossless compression scheme that matches the dither matrix.

Utilizing a contrived dither matrix to enhance the compressibility of

A source image is scaled to a destination image using a method which determines a first destination pixel position corresponding to a given source image pixel. The method comprises the steps of: compiling a scale table having one entry per source pixel in a 'pixel group', the end destination pixel of a pixel group positioned where a first accumulation (i.e., 'Scale Source Sum') of sets of m pixels, equals a second accumulation (i.e., 'Scale Destination Sum') of sets n pixels, the Scale Source Sum derived by successively adding an m pixel set value for each successively read source pixel, and the Scale Destination Sum derived by successively adding an n pixel set value for each written destination pixel; factoring both an n source pixel set value and an m destination pixel set value by y, where y is a largest common denominator of both n and m, to derive 'n (factored source)' and 'm (factored destination)'; using the n(factored source) to determine an integer number of pixel groups between the first source image pixel and the initial source pixel, and determining a total number of destination pixels encompassed by the integer number of pixel groups; determining a position of the given source image pixel within a pixel group on the source raster image scan line; using the scale table to determine a corresponding destination pixel within the pixel group; finding the first destination pixel and positioning the scaled version of the source image thereat.

Method for determinig a destination pixel location from an arbitrary

Apparatus for processing and displaying binary pixel image data includes a printer for receiving image data and for presenting the image data as bilevel pixel values. The printer includes a processor for altering the received image data into an output image. A host processor stores multi-bit-per-pixel image data and further includes image processing software and data transmission circuitry coupled to the printer. The host processor compares the bilevel pixel data size and the multi-bit-per-pixel data size and, based upon a size relationship determined from the comparison, processes the multi-bit-per-pixel image data into bilevel pixel values in either the printer or the host processor so as to transmit the least amount of image data between the host processor and the bilevel printer.

Image processing load balancing for a host processor with a connected

A processor unit converts source image data to a rasterized monochrome bit map and includes a random access memory, a storage memory containing a gray scale conversion table, dithering matrices, procedures for determining destination image dithering tiling locations, scaling conversion procedures and sub routines for establishing a gray scale value array indexed to a bit mask array. The processor unit performs a method of converting source image data to a rasterized compressed monochrome bit map which involves a conversion cycle for converting source pixels to gray scale value and output position bits within the two arrays. Testing is performed to determine all of the source pixels converted to the same gray scale value, and if so, a read ahead cycle commences, reading ahead in the source pixel row for as long as the unconverted source image data bytes are the same as for those converted in the conversion cycle. The converted output position bits of the converted source pixels are dithered. Optionally, an attempt is made to generate a compressed data repeated run entry with a default to a literal run entry based upon dithering of only the converted source pixel output position bits and a count of repeating source pixels.

Method to convert bitmaps to monochrome data

A peripheral unit converts source color image data to a rasterized monochrome bit map and includes a random access memory, a storage memory containing a gray scale conversion table, dithering matrices, procedures for determining destination image dithering tiling locations, scaling conversion procedures and sub routines for establishing a gray scale value array index to a bit mask array. The peripheral unit performs a method of converting color source image data to a rasterized compressed monochrome bit map which involves a conversion cycle for converting source pixels to gray scale value and output position bits within the two arrays. Testing is performed to determine all of the source pixels converted to the same gray scale value, and if so, a read ahead cycle commences, reading ahead in the source pixel row for as long as the unconverted source image color data bytes are the same as for those converted in the conversion cycle. The converted output position bits of the converted source pixels are dithered, and an attempt is made to generate a compressed data repeated run entry with a default to a literal run entry based upon dithering of only the converted source pixel output position bits and a count of repeating source pixels.

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Kuna, ID, United States of America

Terrence M Shannon