Canon Kabushiki Kaisha

Peter William Mitchell Ilbery

Noribumi Koitabashi

James Philip Andrew

Kieran Gerard Larkin

George Politis

Shoji Kanemura

Yu-Ling Chen

David Robert James Monaghan

Dixon De Sheng Deng

James Robert Metcalfe

Michael Alexander Oldfield

Ian Robert Boreham

Michael Richard Arnold

Evgeny Vostrikov

Ian Geoffrey Combes

James David Clark

Anthony John Arnold

Mindy Xie

A method of stroking a curved path with a fill of pre-determined thickness, where the path has line segments defined by a number of points, the method being performed by forming a number of projection lines normal to the curved path at the points, where each of the projection lines has a length based on the fill thickness, determining an intersection between a set of the projection lines, the intersection indicating the occurrence of a void in stroking the curved path, and then constructing one or more polygons filling in the void in the stroked path.

Method for stroking paths

Methods, apparatuses, and computer program products for rendering a piece-wise smooth image are disclosed. The image is specified by image values along opposite sides of paths. The paths are converted to chains of straight line segments, and image values are set for each side of each segment. Coefficients are determined for each line segment. A first coefficient for each segment is based on a difference between specified image values on opposite sides of the segment. A second coefficient for each segment is obtained using an average of image values on opposite sides of the segment and a system of linear equations. Each image value is calculated as the addition of a sum over all segments of the product of first coefficient for a segment with a dipole field value for the segment and a sum over all segments of the product of second coefficient for a segment with a logarithmic field value for the segment.

Rendering piece-wise smooth image from colour values along paths

A Hybrid Compressor and method of compressing a tile of pixels within an image are disclosed. An Edge Processor of the Hybrid Compressor analyzes pixel runs of the tile and generates boundary data defining one or more regions comprising pixels of substantially identical color. A Palette Processor of the Hybrid Compressor generates data defining a color value for each region. An Image Processor of the Hybrid Compressor generates a representation of pixels not included in the one or more regions.

Method and apparatus for hybrid image compression

A method () of compressing an input image () is described. The method () starts by extracting image gradient data representing pixel differences along contours of the image. Next, the method forms an edge based image from the image gradient data and a low resolution image derived from the input image. The method then computes a residual image representing a difference between the edge based image and the input image, and finally compresses the input image by encoding the image gradient data, the low resolution image, and the residual image.

Mixed content image compression with two edge data representations

A method of determining a quality value for an image frame is disclosed. The method comprises dividing (in a step) the frame into a plurality of tiles () and determining attributes (in a step) of each said tile based upon pixel values of the tile, and pixel values of a corresponding tile of a preceding frame. The method then establishes (in steps) the quality value of the frame by testing the tile attributes of the frame against pre-determined criteria. The method then defines (in a step) the quality value of the frame depending upon results of the testing.

Method for detecting and selecting good quality image frames from video

An image recording apparatus () is disclosed, which comprises forming elements () for forming an image, a memory () indicating relative desirability of utilising the forming elements () for forming the image, and processing means () for computing image recording signals using input image signals () and the stored data. The use of a particular forming element is thereby biased dependent upon the relative desirability data of other forming elements, the corresponding input signal for the particular forming element, and a term for the particular forming element.

Defective nozzle compensation

An apparatus () for halftoning an image is disclosed. The apparatus comprises means for determining an output value of a current pixel on a current scanline using a sum of an input value () for the current pixel and a neighborhood error value () at the current pixel, means () for determining an error at the current pixel as the difference between (i) the sum of the input value () for the current pixel and the neighborhood error value () at the current pixel, and (ii) the output value () of the current pixel; and means () for adding a proportion of the error at the current pixel to neighborhood error values at as yet unprocessed pixels of a subsequent scanline in accordance with a next scanline error impulse response; wherein said next scanline error impulse response approximates a function which spreads with self-convolution in proportion to a degree of self-convolution.

Error diffusion using next scanline error impulse response

Methods and apparatus for processing an image is disclosed. First an output value of a first current pixel (in ), which is not at an edge of the image, is determined using a first influence value (W ) for a first current pixel which equals a first sum, over a first set of pixels, of the product of a pixel weight value and a corresponding pixel value, where the pixel weight value is substantially equal to a weight factor (X, Z) raised to the power (i) of the distance of the pixel from the first current pixel. An output value for a second current pixel (in ), is determined using a second influence value (W ) determined as either a product of a weight value reducing factor (X) and the first influence value, or a product of weight value reducing factor and the sum of the first influence value and a value for the first current pixel, where the second influence value equals a second sum over a second set of pixels of the product of a pixel weight value and a corresponding pixel value, and where each pixel weight value is substantially equal to a weight factor raised to the power of the distance of the pixel from the second current pixel.

Geometrically reducing influence halftoning

A method of halftoning input image data intended for reproduction on a display ( ) having a plurality of pixels ( ) and a limited pixel response time (see FIG. ) is disclosed. In a first halftone cycle (K&equals;n), the method comprises (first) halftoning an input value ( ) to display an extreme representable (100% or 0%). In a second halftone cycle (K&equals;n&plus;1), (second) halftoning the input value ( ) to display an intermediate value such that the average of the extreme representable value and the intermediate value is substantially equal to the input value.

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Dundas, Australia

Peter William Mitchell Ilbery