68 results about "Tone scale" patented technology

A method of producing a tone scale function which operates on a source digital image to improve tonal characteristics, includes receiving a source digital image including a plurality of pixels; and producing a tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, and that is adapted to operate on the source digital image, wherein the highlight tone scale segment is defined by a different mathematical function than the shadow tone scale segment; at least one of the highlight tone scale or shadow tone scale segments have at least one inflection point; the highlight tone scale segment is defined for points that are equal to or greater than the reference point; and the shadow tone scale segment is defined for points that are equal to or less than the reference point.

A method of processing data from a digital image to optimize the tonescale to a printer being used without operator intervention adjusts the gain and offset of the input image data to occupy the full range of the printer, adjusts the shadow and highlight regions of the input image data to move that data distribution to that expected of the printer and then uses a gamma correction stage to move the mean level of the image data toward that expected for the printer.

A method of adjusting exposure of a digital camera based on range information, including a digital camera capturing a first digital image at a selected exposure of a scene having objects; providing range information having two or more range values indicating the distance from the digital camera to objects in the scene; using the range information and pixel values of the captured digital image to determine an exposure adjustment amount for the selected exposure; and applying the exposure adjustment amount to the digital image to produce a second digital image with adjusted exposure.

The present invention addresses the quantification of a printed tone scale for each individual color in a printing system, developing a linear tone scale derived in an independent color space and referenced from the shade of the unprinted substrate. The present invention determines the threshold for excessive ink coverage of a printing system on a specified substrate. This determination is based on a subjective evaluation of acceptable thresholds for bleed, cockle, show through, and image density. The method works in conjunction with a predefined test pattern printed on the specified substrate at fixed printing parameters, such as speed, dryer temperature, and web tension. This invention also includes an ability to limit the ink of each independent color in the system as a fraction of the total upper ink limit. Furthermore, this invention allows calibration of the tone scale of each color in the system using the color of the paper as a reference point. In addition, this invention facilitates the generation of separate sets of tone scale transformations for both graphics and text for each color in the system.

Spot colors reproduce high value brand colors to supplement conventional process colors for printed images and packaging A printing press can utilize hi-fidelity process inks with at least three unique colors and black, and spot colors for printing solid brand colors and for printing over other colors to produce wide-gamut, half-toned color reproductions printing logos on a substrate includes (i) printing the spot colors using spot inks, and (u) printing the remainder of the image using a substituted original process ink set. Such method can alternatively include (in) reading the spectral characteristic of the inks, (iv) determining if any color in the image is identified by a color management method from the default process ink set palette, (v) processing the out-of-palette-colors using spot colors and the standard process ink set, and (vi) applying a tone scale value increase (TVI) to the process color sets

A method of enhancing the tonal and spatial characteristics of a digital image includes receiving a source digital image wherein the source digital image is in a luminance-chrominance representation having a luminance digital image channel and at least two chrominance digital image channels; generating a tone scale function that can be used to enhance the tonal characteristics of the source digital image; and classifying the tone scale function into one of two or more categories wherein the classification categories include expansive and compressive. The method further includes using the tone scale function, a spatial filter, and the luminance digital image channel to generate an enhanced luminance digital image channel when the tone scale function has been classified as compressive, and using the tone scale function and the luminance digital image channel to generate an enhanced luminance digital image channel when the tone scale function has been classified as expansive.

A method of enhancing the tonal and spatial characteristics of a digital image, includes receiving a source digital image including a plurality of pixels; producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; classifying the tone scale function into one of two or more categories, wherein the classification categories include expansive and compressive; and using the tone scale function, the source digital image, and a first spatial filter to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function, the source digital image, and a second spatial filter to produce an enhanced digital image when the tone scale function has been classified as expansive.

A method of producing a tone scale function which can operate on a source digital image to improve tonal characteristics, includes generating the tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, and that is adapted to operate on the source digital image to improve its tonal characteristics by: using a first function with a monotonically decreasing slope characteristic to produce the highlight tone scale segment that includes points that are equal to or greater than the reference point; and using a second function with a monotonically increasing slope characteristic to produce the shadow tone scale segment that includes points that are equal to or less than the reference point.

A method of processing a color digital image having a luminance channel and one or more chrominance channels to improve the tone scale characteristics of the image, includes the steps of: producing a control signal from the one or more chrominance channels; generating a pedestal signal containing mainly low frequency modulation by filtering the luminance channel with a spatial filter, whereby the operation of the spatial filter is modulated by the control signal; and producing a texture signal by subtracting the pedestal signal from the luminance channel.

A method of enhancing the tonal and chrominance characteristics of a digital image, includes receiving a source digital image including wherein the source digital image is in a luminance-chrominance representation having a luminance digital image channel and at least two chrominance digital image channels; producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values of a processed digital image wherein the classification categories include expansive and compressive; using the tone scale function and the luminance digital image channel to produce an enhanced luminance digital image channel; and amplifying the chrominance digital image channels to produce modified chrominance digital channels when the tone scale function has been classified as expansive.

A method of generating a tone scale function for a sparsely sampled extended dynamic range digital image, includes the steps of: providing a sparsely sampled extended dynamic range image sensing device having fast photosites with a predetermined response to light exposure interspersed with slow photosites with a slower response to the same light exposure; using the image sensing device to produce a sparsely sampled high resolution digital image having fast pixel values produced by the fast photosites and slow pixel values produced by the slow photosites; and generating the tone scale function using only slow pixel values from the sparsely sampled high resolution digital image.

A method of enhancing a digital image comprising: providing a digital image; decomposing the provided digital image into a multi-frequency band representation including a low frequency band image and multiple different high frequency band images; multiplying each of the high-frequency band images with a gain factor; summing together the unmodified low frequency band image and the modified high-frequency band images to produce a reconstructed digital image; and mapping the reconstructed digital image through a tone-scale look-up-table to map the reconstructed digital image to optical densities

A method of processing a digital image to improve tone scale, includes the steps of: generating a multiresolution image representation of the digital image including a plurality of base digital images and a plurality of residual digital images; applying a texture reducing spatial filter to the base digital images to produce texture reduced base digital images; combining the texture reduced base digital images and the residual digital images s to generate a texture reduced digital image; subtracting the texture reduced digital image from the digital image to produce a texture digital image; applying a compressive tone scale function to the texture reduced digital image to produce a tone scale adjusted digital image having a compressed tone scale in at least a portion of the image; and combining the texture digital image with the tone scale adjusted digital image to produce a processed digital image, whereby the contrast of the digital image is improved without compressing the contrast of the texture in the digital image.

A method for forming a color transform for a color printing device having a plurality of colorant channels that includes applying a tone scale adjustment function and a total colorant load limit. An optimization process is used to optimize a merit function including a tone scale reproduction accuracy term and a gamut shape term. The method involves determining an initial merit function value responsive to an initial total colorant load limit and an initial set of tone scale adjustment parameters for a tone scale adjustment function. Modified tone scale adjustment parameters and a modified total colorant load limit are determined that provide an improved merit function value subject to a constraint that an average total colorant load is no more than a predefined threshold for a predefined distribution of input colors.

A method of applying a tone scale function that is compressive, expansive or a combination of both to a digital image, the method including decomposing the tone scale function into two or more composite functions that can be applied sequentially to the digital image; applying the first composite function to the digital image with a tone scale applicator to produce a tone scaled digital image; and applying the second composite function to the tone scaled digital image to produced an enhanced digital image.

A novel process of visual calibration of a computer display or the like in volves adjusting the appearance and relative appearance of targets and su targets displayed on the display. An objective method is provided for determining the precisely optimal brightness setting for CRT displays, which method is also applicable to the setting of the “Black Level” control on some FPDs. A precise method is provided to visually determine conformity of a display's tonality to a given standard tone curve, for example a gamma 1.8 curve, which is embodied in one of the preferred calibration target sets. The need to sense and therefore be able to control and to verify the correct gray balance of the entire tone scale of the display is met. The problem of verifying the similarity of the tone curve in the display profile and that of the actual calibration is solved. By converting a preferred RGB gamma target into CIE Lab image data through an ideal display profile of the correct gamma, a new kind of target is taught.

The present invention provides a method for processing tone scale of a digital color image in which the histogram of tone scales (for example, of RGB, YC_rC_b, Lab or Luv) is considered for deciding the semi-S curve. The semi-S curve suits the digital color image and improves the brightness contrast and color saturation for the image output device. A weighting procedure can also be used for compensating those high occurrence colors in the image, and rearrange and analysis the histogram of tone scale, so as to decrease the influence of the high occurrence colors to the calculation and process of tone scale.

A method of displaying on a display a visual reproduction of an original scene with a preferential tone mapping; said display having a selected display white point and a selected display black point separated by more than 3.5 decades of luminance; the method comprising the steps of capturing original scene parameters, performing a transformation on said captured scene parameters, and displaying a visual reproduction of the scene on the display from the transformed captured scene parameters; wherein said transformation, taken in conjunction with untransformed characteristics of the capturing and displaying steps, results in a reproduced tone mapping having: a. a dynamic range greater than 3.5 decades; b. a first derivative value of minus log reproduced luminance relative to log original scene luminance between −1.1 and −1.51 inclusive for a log scene luminance of −0.6, measured relative to a 100% diffuse reflector in the original scene; c. a first derivative value less than or equal to −1.9 and greater than −4.0 for a log scene luminance of −1.9; d. a first derivative value between −1.5 and −3.0 inclusive for a log scene luminance of −2.0; and e. a first derivative value at a log scene luminance of −2.5 greater than the first derivative value at a log scene luminance of −2.0.

A method for adjusting the tone scale reproduction of a color image composed of pixels provided in a plurality of color channels is based on generating a reference image from a combination of the color channels, whereby each spatial coordinate of the reference image is characterized by a reference image level. Channel averages of the color channel values of the pixels that correspond to the different valued reference image levels are generated. A channel tone scale transformation is formed by relating each channel average to its corresponding reference image level, and the channel tone scale transformation is utilized on a pixel by pixel basis in the respective channels of the digital color image to produce a processed digital color image having improved tone scale reproduction.