Abstract: A system for generating a warped contone image that compensates for beam scan trajectory distortions. The system includes an image buffer for storing a portion of a received contone image. An interpolation coefficient generator provides interpolation coefficients associated with a warped pixel within the warped contone image in response to an input identifying the warped pixel. A pixel interpolator is coupled to the image buffer and the interpolation coefficient generator and provides an output signal that identifies the warped pixel within the warped contone image. The pixel interpolator further retrieves pixels from the contone image stored in the image buffer using the interpolation coefficients and generates the warped pixel by combining the retrieved pixels into a single pixel value.

Abstract: An image data interpolation apparatus includes an image data obtaining unit for obtaining image data representing an image as dot-matrix picture elements, a picture element interpolating unit capable of selectively executing one of a plurality of interpolating processes when the image data is interpolated so that the number of constituent picture elements thereof is increased, an interpolating scale factor obtaining unit for obtaining an interpolating scale factor suitable for the image data, and an interpolating process selecting unit for selecting one of the interpolating processes capable of obtaining an optimum result of interpolation according to the interpolating scale factor obtained by the interpolating scale factor obtaining unit and causing the picture element interpolating unit to execute the selected interpolating process.

Abstract: Using an image processing apparatus for carrying out general interpolation processing which can freely adjust a frequency response characteristic regardless of an enlargement or reduction ratio, an image whose frequency response characteristic almost agrees visually with the frequency response characteristic of an optimal diagnostic image obtained by interpolation processing of another kind can be easily obtained. The image processing apparatus comprises conversion means for converting the characteristic of interpolation processing by first enlargement or reduction processing means to a characteristic corresponding to that of interpolation processing by second enlargement or reduction processing means so that a visible image reproduced by a network printer almost agrees visually with a visible image reproduced by a CR printer, in terms of the enlargement or reduction ratio and the response characteristic.

Abstract: An image data adjusting method for increasing/decreasing the number of pixels of input image data in a given direction with a desired magnification to obtain output image data. The method includes deriving an integral magnification for each of all the pixels of the input image data per direction in which the number of pixels of the input image data is increased/decreased, and copying a pixel value of each of the pixels based on the integral magnification to obtain the output image data.

Abstract: The invention relates to a method for reducing the computational overhead of bicubic interpolation while still providing a similar level of accuracy. The invention takes into account the fact that sampled points surrounding a point whose value is to be determined have respective first, second and third order effects on the calculated value. The invention combines linear interpolation, ignoring points having a third order effect, with cubic interpolation of points having a first and second order effect to derive the value.

Abstract: A pixel filling system or method begins with an initial set of image data that is a subset of data values in a data array fk,l representing data values at corresponding positions (k,l). Some of the fk,l values are initially undefined, while others, at positions where both k and l are even numbers, have initially defined values.

Abstract: An interpolation processing apparatus includes: an interpolation processing unit that performs interpolation processing on a color image expressed through a colorimetric system constituted of a predetermined plurality of color components to determine an interpolation quantity corresponding to a value representing a missing color component in each pixel; and a color composition identification unit that identifies a color component composition of the color image. And the interpolation processing unit is capable of performing a plurality of types of interpolation processing in correspondence to color component compositions of the color image, selects a type of interpolation processing corresponding to the color component composition identified by the color composition identification unit and performs the type of interpolation processing that has been selected on the color image.

Abstract: A method and apparatus for determining a small number of parameters that spectrally characterize colorants by a small number of parameters and for using such colorant parameters to accurately predict the spectral reflection or transmission characteristics of such colorants when deposited on top of one another, either on an opaque, transparent or semitransparent carrier of a particular type, each colorant deposited with a certain coverage percentage, for example, dot percentage in the case of offset printing, the colorant parameters of any colorant being substantially independent of the color of the substrate and including dependency on the colorants deposited before and after. The method involves making measurements of sets prints of varying coverage percentages of a colorant on a number of backgrounds, and solving the resulting set of equations for the colorant. Colorants that are defined by a recipe of basic colorants can be characterized from measurements on prints of the basic colorants.

Abstract: A video filter unit is described which is implemented as a three-stage filter comprising a vertical filter, a horizontal decimation filter, and a horizontal interpolation filter. The three stages of the filter unit preferably connect serially with the vertical filter comprising the input first stage, the horizontal decimation filter comprising the second stage and the horizontal interpolation filter comprising the third stage which provides the output filtered image from the filter unit. As such, the video data to be filtered is provided to the vertical filter which provides its output to the horizontal decimation filter. After horizontal decimation, which can be disabled if desired (i.e., no horizontal decimation), the video data is then horizontally interpolated. The horizontal interpolation filter stage can also be disabled if desired. The vertical filter can be configured to operate either as a decimation filter or an interpolation filter.

Abstract: An image processing apparatus and method which can reduce the size of circuits for &agr;-blending and dithering and realize high speed processing which perform in parallel processing for finding an amount of update of present image data to be drawn with respect to image data already stored in a display buffer by using a blending coefficient in a subtractor and a multiplier and processing for adding noise data to the image data already stored in the display buffer in a first adder and adding the data obtained by the two processing at a second adder so as to find data comprised of noise data added to data obtained by linear interpolation of two colors, then extracting color valid values at a clamp circuit, thinning out the extracted data in a rounding-off circuit, and writing it back to the display buffer.

Abstract: A streamlined technique for obtaining interpolated color output values from corresponding color input values based on color output values stored in a color look-up table, with tetrahedral interpolation being applied so as to dissect each cubic grid of the color look-up table into plural tetrahedrons. According to the invention, processing efficiency is increased by avoiding the use of conditional branches when making a determination as to which of the plural dissected tetrahedrons a particular color input value falls. Preferably, rather than making such a determination, weights for all possible tetrahedrons for one cube are stored in a temporary look-up table, and an index into the temporary look-up table is calculated based on the magnitude of component values for each color input value. The index is calculated in a block of code that does not include conditional branches that are conditioned on the relative magnitude of the component values of the color input value.

Abstract: In a method of colour printing using arrays of threshold value for interpolating between grey levels, the threshold values for each of the colours are provided by defining rows of threshold values, with each row having the same repeating sequence but offset. The repeating sequences are different for each colour but the offset is the same for all colours. The arrays best take the form Tijc=(i*pc−j*qc)%(rcS).

Abstract: A method for converting color coordinate values of a target color from a first three-dimensional color space to a second three-dimensional color space, includes looking up the target color in a look-up table and interpolating each color component of the target color only in a single dimension between adjacent grid points in the look-up table. Preferably, each color component value shares a common grid point upon which interpolation is based for all color component values, with the common grid point lying on the neutral gray axis when a cube enclosing the target color includes the neutral gray axis of the first three-dimensional color space.

Abstract: An image processing apparatus for effecting image processing by N-point interpolation, utilizing lattice points stored in a table corresponding to image data, includes input unit for entering image data, and interpolation unit for effecting an interpolation process employing, according to the image data, lattice points not exceeding N points and including a lattice point outside an interpolating solid represented by N lattice points where the image data is located.

Abstract: A method for operating a data processing system to generate a full color image from a partially sampled version of the image. The full color image includes a first two-dimensional array of vectors having components representing the intensity of a pixel in the full color image in a corresponding spectral band at a location determined by the location of the vector in the first two-dimensional array. The method generates the first two-dimensional array from a two-dimensional array of scalars. Each scalar determines one of the first, second, or third intensity values at a corresponding location in the two-dimensional array of vectors. The method determines the remaining ones of the first, second, and third intensity values. The method starts by assigning a value to each one of the components of the vectors in the first two-dimensional array of vectors that is not determined by one of the scalars.

Abstract: A method for converting color coordinate values of a target color from a first three-dimensional color space to a second three-dimensional color space, includes looking up the target color in a look-up table and interpolating each color component of the target color only in a single dimension between adjacent grid points in the look-up table. Preferably, each color component value shares a common grid point upon which interpolation is based for all color component values, with the common grid point lying on the neutral gray axis when a cube enclosing the target color includes the neutral gray axis of the first three-dimensional color space.

Abstract: A picture encoding apparatus and the method in which the quantization step width of the lower hierarchy data having a resolution higher than that of the upper hierarchy data is determined for each predetermined block of respective hierarchy data based on the quantization step width determined by the upper hierarchy data having a low resolution, so that the additional code indicating the characteristics of quantizer can be omitted thereby the compression efficiency can be improved and the deterioration of picture quality can be reduced when picture data is hierarchical-encoded.

Abstract: Interpolating operations are carried out on an original image signal and in accordance with first and second interpolating operation processes for obtaining interpolation images having different levels of sharpness, a feature measure, which represents the sharpness of the original image signal, being thereby obtained. An interpolating operation is carried out on the original image signal and in accordance with a third interpolating operation process, an interpolation image signal being thereby calculated. The interpolation image signal is corrected in accordance with the feature measure, and a final interpolation image signal is thereby obtained. Image size enlargement and reduction with interpolating operations are thus capable of being carried out such that the sharpness at a certain portion of the image may be altered.

Abstract: There is disclosed a resolution conversion apparatus for converting an original digital image into a digital image having a different number of pixels in accordance with an instructed conversion magnification factor. In the apparatus, a determination circuit determines the number of pixels to be interpolated in each block of the original image and positions where they are interpolated in accordance with the conversion magnification factor. The block includes a predetermined number of pixels of the original image. A converted image generation circuit generates pixel data for the interpolation pixels at the positions where they are interpolated in accordance with a predetermined interpolation equation whose coefficients are determined with the positions and data values of the pixels in the block, and combines the pixel data for the digital original image and the generated pixel data to output a converted digital image. The interpolation equation includes spline functions and Bezier functions.

Abstract: In a method for interpolating color values with a view to converting an initial color space into an output color space, the initial color space is divided into a multidimensional network. For grid points, converted components of the output color space are prescribed as interpolation nodes. The converted components, located between the grid points are obtained by interpolating said nodes. For the purpose of interpolation, the components of an initial color to be interpolated are broken down in a multiple of the grid point spacing and a remainder, and the remaining values are classified by order of magnitude. At the grid points of a sub-space comprising the initial color to be interpolated, the interpolation nodes are selected in a series determined by the classification of the remaining values, and the initial color is interpolated based on the selection of interpolation nodes.

Abstract: A method and system for an approximation of a filter function for computing a characteristic value of an output pixel based on characteristic values of a plurality of input pixels is provided. A filter response curve adjustment value is obtained, preferably from a lookup table, based on a distance interval between coordinates of the output pixel and coordinates of a selected input pixel. A normalized filter response curve input value is computed based on the distance interval and the filter response curve adjustment value, preferably by adding the values together. The characteristic values at a plurality of input pixels are obtained. A linearly interpolated value for the characteristic value of the output pixel is then computed based on the characteristic values of the plurality of input pixels and the normalized filter response curve input value.

Abstract: The host computer 2 defines a color gamut as a solid of a three dimensional space to represent a color reproduction area of a color reproduction device, and instructs to display the color gamut in accordance with combinations of information on the color reproduction area on the basis of second and third axes extending to both the positive and negative directions in a plane perpendicular to a first axis of the defined three dimensional space and coordinates of the first axis. For example, the information on the color reproduction area in the plane perpendicular to the first axis can be represented by a two dimensional area, a two dimensional coordinate area, bit map data, or two dimensional vector data, thereby the color gamut for realizing a color gamut checking function is easily confirmed.

Abstract: The invention involves selecting a path through a multi-dimensional hyper-cube from a base vertex to an opposite corner or vertex of the hyper-cube. The path is selected by ranking the fractional components of the point or value to be interpolated. An N-dimensional interpolation is performed according to this sequence. During an interpolation a base vertex for an input color value is determined. The output value for the base vertex is accumulated. The fractional values of the input color value are sorted and ranked according to magnitude to produce an interpolation sequence. The interpolations are performed for each axis of the N-dimensions by selecting an axis for interpolation based on the order, performing an interpolation corresponding to the selected axis producing an interpolation result, and accumulating the interpolation result.

Abstract: What is disclosed is an integrated color interpolation and color space conversion technique and apparatus. A raw image that is arranged in a Bayer pattern where each pixel has only one of the color components needed to form a full color resolution pixel may be converted using this technique directly to a XYZ space image without any intermediate conversion or interpolation steps. Specifically, in one instance, an 8-bit Bayer pattern raw image may be converted directly to a 24-bit XYZ space in a single pass approach. Such an integrated technique may more readily and inexpensively implemented in hardware such as on a digital camera, or in software.

Abstract: What is disclosed is an integrated color interpolation and color space conversion technique and apparatus. A raw image that is arranged in a Bayer pattern where each pixel has only one of the color components needed to form a full color resolution pixel may be converted using this technique directly to a XYZ space image without any intermediate conversion or interpolation steps. Specifically, in one instance, an 8-bit Bayer pattern raw image may be converted directly to a 24-bit XYZ space in a single pass approach. Such an integrated technique may more readily and inexpensively implemented in hardware such as on a digital camera, or in software.

Abstract: A system for processing images includes an image file subsystem providing a source signal representing an input image; a color transformation subsystem coupled to the image file subsystem and accepting as input the source signal and producing a target signal therefrom, and an image forming subsystem coupled to the color transformation subsystem and forming a physical manifestation of the input image in response to the target signal, the color transformation subsystem being configured to establish a memory “cube” area representative of possible source signals, to define a sub-cube portion of the memory area as representative of the source signal; to determine possible target signals corresponding to the sub-cube portion; and to determine the target signal responsive to the possible target signals. If interpolation is found to be accurate for a mini-cube portion of the sub-cube, truncation or interpolation are used to derive the target signal; otherwise, the target signal is determined directly.

Abstract: In addition to linear conversion parameters V1 to V8 which are used in an interpolation calculation, non-linear conversion parameters VV1 to VV8 are calculated. Each time an input color is fetched, whether the linear conversion parameters are used or the non-linear conversion parameters are used is discriminated. The interpolation calculation of a high precision using the non-linear conversion parameters is performed for a region where it is necessary to guarantee a gradation, thereby preventing a reversal of an output color in a region including an achromatic gradation axis. Regions other than such a region are processed by the interpolation calculation using the linear conversion parameter at a high speed.

Abstract: An electronic imaging system includes a receiver for receiving a digital representation of an input image, and a conversion processor for converting the input image to an output image, typically defined by distinct color spaces. The conversion processor is configured as a multidimensional look up table containing nodes at each of series of predefined input addresses. Each node is preloaded with an output color value corresponding to the input addresses. The look up table can accommodate a more efficient placement of nodes within N-dimensional space by a particular method of multidimensional interpolation. The method includes applying an interpolation algorithm in N−1-dimensional space, and then performing a 1-dimensional linear interpolation in the remaining dimension between the resulting values. Such a method allows for nodes to be allocated to rapidly changing areas within the color space represented by the LUT, while less dynamic areas can be suitably served by fewer nodes.

Abstract: A pipeline processor for scaling and converting RGB color input images to CMYK at a magnification specifiable in 1 percent increments up to 400% includes a scaler having predefined main scale factors including one at maximum scale. An interim scale factor is selected from the main scale factors as one nearest the specified magnification toward the high end of the range. A pixel transformation is made at the interim scale factor between a subset of the source pixels and a corresponding subset of intermediate pixels using hardware circuits. The intermediate pixels are then interpolated to produce a scaled image by dropping an evenly spaced subset of the intermediate pixels when the magnification is less than the interim scale factor. A set of enhanced pixels is derived from the scaled image by proportionally weighting center pixels against average values of diagonally neighboring pixels.

Abstract: An image processing apparatus includes a pixel number transforming section for processing input image data composed of a plurality of regions, each being represented by a plurality of pixels with a pixel number transformation, by performing an interpolation or a decrimation on a pixel. It further includes a region decision value extracting section for extracting a region decision value of a region that a target pixel belongs to, based on characteristic amounts representing characteristics of a block composed of the target pixel and a plurality of pixels around the target pixel, each pixel of the image data being considered to be the target pixel. A controller controls a sequential order of a filtering process and pixel number transformation process to be applied to a region, based upon the transformation increasing or reducing a number of pixels in a region.

Abstract: An image processor converts an input signal into first and second color components and a component. A plurality of output device dependent color-component data is read from a look-up table on the basis of the first and second color components and the brightness component. Interpolation processing is performed on the basis of the read plurality of color component data to generate output device dependent color-component data corresponding to the input signal.

Abstract: A method for transforming a first image defined by a first multi-dimensional color space (RGB) into second image defined by a second multi-dimensional color space (CMYK). The method computes the transformation using information derived from a previous transformation of said second image into said first image. The method then minimizes the error produced while transforming the second image back into the first image. As such, an image editing system can display on a video monitor an image that is defined in one multi-dimensional color space (RGB), print using a printer that prints images using a second multi-dimensional color space (CMYK) and edit an image using any multi-dimensional color space (either RGB or CMYK) that facilitates rapid and accurate image editing.

Abstract: An interpolation processor interpolates reference correction data stored in a ROM according to the level (gray scale) to generate correction data DHr which correspond to gray scales available for image data, for each of a plurality of reference coordinates. The correction data DHr are stored in a correction table. From the correction data DHr stored in the correction table, an address generator specifies storage locations at which correction data DHr1 to DHr4 are stored, which correspond to four reference coordinates surrounding the coordinates, based on X-coordinate data, Y-coordinate data, and the image data. An arithmetic unit interpolates the correction data DHr1 to DHr4, which are read from the correction table, according to the coordinates and generates correction data Dh. An adder adds the correction data Dh to the image data to generate corrected image data. It is thus possible to remove nonuniformity of luminance and nonuniformity of color in a display screen.

Abstract: An apparatus for converting an input image in an input color space to an output image in an output color space. The apparatus has a cache memory for storing from external memory, sparsely located output color values corresponding to input pixels closest to the current input pixel of an image stream, if not already present in the cache memory. The apparatus also has retrieval means for retrieving, from said cache memory, the sparsely located output color values corresponding to the current input pixel of the stream. The retrieved output color values are interpolated by interpolation means to derive an output color value in said output color space.

Abstract: What is disclosed is a method comprising defining a scaling region by indicating in a CFA (Color Filter Array) a starting location, and generating a super-pixel which is a downscaled version of the scaling region, the super-pixel fully color interpolated, the downscaling and the color interpolation achieved in an integrated manner.

Abstract: An object of the present invention is to obtain, in an accurate and stable manner, an image density at a tone rise point in a low-density region in order to form a stable image.

Abstract: The present invention relates to an image processing device for converting the number of pixels or scanning lines. In particular, the image processing device according to the present invention comprises an operator for carrying out interpolation operations and a memory for storing filter coefficient sets utilized in the interpolation operations. The memory stores filter coefficient sets each corresponding to each of the phases when the pixel interval of the original image is divided by a prescribed dividing number. Out of these filter coefficient sets, a filter coefficient set that corresponds to the phase closest to that of the pixel data to undergo interpolation operations is then outputted to the operator. The operator then carries out interpolation operations on the pixel data using these filter coefficient sets so that arbitrary format conversion becomes possible.

Abstract: To obtain an interpolating operation apparatus which provides an interpolation image in which the sharpness in kept high and noise due to hue variations is kept small after the interpolating operation. For a primary image signal Sorg (R, G, B) which is inputted into an interpolating operation apparatus 30, R, G, and B color signal components, which represent each of picture elements in a color image represented by an orignal image signal, are converted into YCC luminance and color difference signal components through a first signal conversion means 31. With a cubic spline interpolating operation means 32, an interpolated luminance signal component Y′ is obtained with respect to luminance signal components Y. With a B spline interpolating operation means 33, interpolated color difference signal components C1′ and C2′ are obtained with respect to color difference signal component C1 and C2.

Abstract: A device and method of printing a color image using a lookup table that indicates the amount of at least two concentrations of a given ink color to use. Initially, several color wedges made from uniformly distributed digital counts for each color from lightest to darkest are printed. The color lightness value for each wedge is then measured as an L* value of the CIELAB system along with a granularity value. An interpolation process is then performed to determine the color lightness values and granularity values for color values between wedges. A diluted ink minimum color lightness point is identified by determining the darkest color that can be generated using only diluted ink. Ink patterns are then selected using only diluted ink for color lightness values lighter than the diluted ink minimum lightness point in the lookup table. A zero diluted ink starting point is then identified by determining that granularity improvement cannot be achieved significantly when adding more diluted ink to a pixel matrix.

Abstract: Color patches established at given intervals are calorimetrically measured to determine a relationship between color signals Y, M, C, a lightness index L*, and chromaticnesses a*, b*. The determined relationship is processed by a dual regression analysis to determine color signals to be interpolated with priority in the order in which changes in the indexes are progressively greater as a color signal changes. The color signals are then interpolated with priority in the above order, and a highly accurate color conversion table is generated.

Abstract: What is disclosed is method that interpolates missing color components for an original pixel by utilizing color gravities for surrounding blocks of green pixels. A new pixel is output which has complete color information which is a function of the original pixel and interpolated color components. The interpolated pixel is a true representation of both luminance and chrominance information.

Abstract: A color conversion device includes a region judging section for judging which region of a three-dimensional color space contains an input value, and/or a representative points-dispersed axis selecting section for selecting a representative points-dispersed axis which is nearest to said input value. Additionally, the color conversion device includes a representative points selecting section for selecting representative points in the vicinity of the input value among representative points discretely arranged along (or within) the selected representative points dispersed axis; a look-up table (LUT) which stores coordinates of representative points and color correction data; and a linear interpolation section for performing color conversion by weighting based on the selected representative points.

Abstract: In a photographic film scanner having a film transport drive stepper motor, an illuminant head having a plurality of spectrally separate light source, a light sensor and data collection and transfer circuits, each operationally responsive to a programmed controller. The controller is provided with a common timer and is programmed with a plurality of lookup tables (LUT), each LUT is populated with a sequence of elements defining timing of an operating activity in a respective one of the illuminant head light sources, the stepper motor and the light sensor data transfer circuits. The program operates to use the common timer to step synchronously through the elements of the LUTs to output value states from the elements of each of the LUTs; to control the actuation timing of the respective light sources, stepper motor and data collection and transfer circuits.

Abstract: In a method for producing index prints from photographic originals, each of the photographic originals is photoelectrically scanned in a scanning station of a photographic printer by a color- sensitive scanning system of low to medium local resolution in a plurality of first scanning regions. Using the scanning data, a digital color data set is determined for each original, with the aid of which set a digital representation of the picture content of the original is prepared for each original. The individual digital representations are grouped into a digital composite picture, from which an index print can be produced by an output device. The originals are also photoelectrically scanned in a scanning station by a locally high-resolution density scanner in a plurality of second scanning regions.

Abstract: A color image processing device includes color conversion means for outputting color adjusted signals having been chromatically adjusted in accordance with the input of separated color signals obtained from a scanner and a variable factor signal other than color signals. The color conversion means includes a memory device for discretely storing only the color adjusted signals that correspond to predetermined separated color signals and a predetermined variable factor signal, and color adjusting means for, when the inputted separated color signal or the inputted variable factor signal directly corresponds to none of the color adjusted signals stored in the memory means, outputting color adjusted signals having been interpolated in accordance with the known color adjusted signals found in a neighborhood of the inputted separated color signals and variable factor signal.

Abstract: Scanning printheads form a color image as inkdrops in a pixel grid on a print medium. Pixel row spacing equals nozzle pitch. Apparatus holds and provides (or creates in real time) a printmask using location rules that prevent addressing, within each scan, immediately neighboring pixels in any horizontal, vertical or diagonal direction. The mask is applied to control the heads. In other aspects of the invention, the rules also prevent addressing, in each scan, horizontally neighboring pixels within the entire width of the mask; or vertically neighboring pixels within its entire height; or immediate neighbors in any direction across a boundary--horizontal, vertical, or either--between abutting masks. Specific masks are set forth implementing these aspects.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by applying a mathematical relationship which allows computation of sub-cube vertex values through a series of logical AND, logical OR and averaging operations.

Abstract: A method to reduce the distortion introduced by lossy compression of interpolated images. The interpolation represents a constraint. If the output of the compression algorithm does not satisfy the constraint then the estimate of the output can be improved by re-imposing the constraint. An alternating projection algorithm is used to impose both the interpolation constraint, and the requirement that the image compress to the observed compressed output. This involves finding the orthogonal projection alternately on the space of interpolated images, and on the set of images that quantize to the appropriate image produced by the compression algorithm. Although this algorithm is not restricted to the correction of errors in block coding schemes, the explicit introduction of the interpolation constraint allows this algorithm to outperform all other iterative algorithms that attempt only to remove blocking artifacts introduced by transform coders.

Abstract: New interpolation techniques allow improved efficiency and speed in performing color space conversions. A radial interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by averaging a selected vertex value with the vertex values of each of the remaining vertices. A pruned radial interpolation technique employs a subset of the vertex values of the initially selected cube to generate the result of the interpolation, thereby improving upon the efficiency of the radial interpolation. A tetrahedral interpolation technique accomplishes an interpolation by generating successive sub-cubes. A value of a vertex of the final sub-cube generated is used as the result of the interpolation. Sub-cubes are generated by applying a mathematical relationship which allows computation of sub-cube vertex values through a series of logical AND, logical OR and averaging operations.

Abstract: An interpolation method for color correction generates correction signals Y, M and C from input signals R, G and B through interpolation. In this interpolation method, a triangular prism is selected from plural unit triangular prisms in RGB space, based on x, y and z coordinates of the input signals, a gradient factor and an intercept factor of the selected prism are read out from a memory, and correction data corresponding to the input signals is calculated through interpolation using the gradient and intercept factors from the memory, so that the correction signals are generated based on the calculated correction data.