Toshiba Tec Kabushiki Kaisha

Kabushiki Kaisha Toshiba

Toshiba Corporation

Sharp Laboratories of America, Inc

Sharp Laboratories of Ameirca, Inc.

William C Kress

Jonathan Yen

James Zhixin Chang

Scott J Daly

Hiroki Umezawa

Ronald Pellar

Jack Van Oosterhout

Stephen K Herron

Robert Poe

Systems and methods for backlit scene detection are described. The method includes performing a pre-test on an electronic image to determine that the electronic image does not include a disqualifying characteristic. Next, the method includes performing a type test on the electronic image to determine an image type of the electronic image from a first set of predetermined backlit image types. Next the method includes performing a post test on the electronic image to determine that the image darkness density does not exceed a predetermined density. Finally, the method includes performing a second post test on the electronic image to determine that the electronic image is one of a second set of predetermined backlit image types or that the edge percentage of the electronic image exceeds a predetermined percentage.

Backlit scene type detection

Image tone adjustment systems and methods are disclosed. The system of the present invention includes an input to accept an input image. A curve generator is also disclosed that is used to generate a tone reproduction curve including a contrast stretch of the input image, a white stretch of the input image and a black stretch of the input image. Backlit correction is also applied by the tone adjustment corrector to thereby generate a tone adjusted image.

Digital image tone adjustment

The subject application is directed to a system and method for detecting backlit images. Encoded color image data is first received into a computer having a processor and associated data storage. Histogram data is then calculated from the received encoded color image data, and a mid-tone range in normalized histogram data is then detected. A zone of normalized pixel counts within the mid-tone range is then selected. Data representing an entry point and an exit point of the normalized histogram data relative to the selected zone is then generated. A plateau area is detected in the histogram data in the selected zone between the entry point and the exit point. Thereafter, a backlit image detection signal is generated indicating whether a backlit image portion is present in the color image data according to the plateau detection.

System and method for backlit image detection

The present invention is directed to a system and method for halftone screening. A system for halftone screening includes means adapted to receive image data having a number of tonal levels representative of a continuous tone image. The system further includes a memory including a LUT having a number of alternative halftone cell arrangements for each tonal level. Each cell of the LUT consists of a number of device dots describing a particular gray value. For each gray value, there are several alternative cells with different arrangements of the same number of device dots. The LUT is configured with the cells of different arrangements in rows. The rows increase in the number of device dots; hence, each column describes halftone cells of increasing tonal values. The system then communicates the image data having a tonal level to the LUT, and randomly selects a halftone cell arrangement to generate a halftone output.

Method to improve a halftone by combining halftoning with algorithmic processing

The subject application is directed to a system and method for image fog scene detection. Electronic image data is first received and divided into image regions, with each region consisting of a plurality of pixels. Next, a comparison matrix is generated corresponding to each image region based upon a comparison of minimum intensity values associated with corresponding pixels to a threshold value. An entry of at least one of the comparison matrices is then tested for a preselected value. The received electronic image data is then identified as inclusive of a fog scene based upon the output of the test on the entry of the comparison matrix. Based upon the identification, fog scene detection data representing an identified fog scene is then generated.

System and method for image fog scene detection

A method and apparatus for enhancing electronic images allows for improved characteristics between light areas and dark areas, and is particularly effective for backlit images. A transition between light and dark image portions is detected. A determination is made from an analysis of spectral distributions as to whether an image portion is backlit. Upon detection, image data is adjusted to lighten or darken image portions to allow for improved image viewing. Use of cumulative probability distribution data associated with an electronic image facilitates isolation of backlit image portions and object image portions.

Automatic image enhancement using computed predictors

In accordance with the present invention, a system and method are described for producing pure gray tones on a multi-color document output device that includes a system for operating on device independent color data having multiple color components, which color data corresponds to one or more associated electronic documents. The system and method function to extract gray data by the use of tristimulus values in a range specified by a functional relationship of a selected tristimulus value.

System and method for extracting grayscale data in accordance with a prescribed tolerance function

A system and method for converting an image to a constrained color palette representation receives a specified color or hue from which an image is to be defined. A conversion is then made from an input color space to a CIELAB representation. Data is converted in CIELAB space, in accordance with a specified hue, to a color space set by the specified color. Once converted, data is converted to a color space corresponding to that of an associated document rendering device.

System and method for two color document rendering

A method for performing visual calibrations on a color printer. For calibrating relative intensities of colors, a predetermined image is printed by an image output apparatus. A user then selects a bias color and an intensity from a reference. The image output apparatus then adjusts its print engine based on the selection. For density calibration an image is printed, preferably once with a light background, and once with a dark background. The user then selects an adjustment after visually comparing the printed image with a reference image and adjusts the printer by noting whether details are missing from the printed image on the light background image or the dark background image.

Color and density calibration of color printers

The present invention is directed to a system and method for parameter based visual characteristic control. The system includes input means adapted for receiving image data representative of at least one visual characteristic of an associated image. The system further includes means adapted for storing data representative of a selected polynomial relationship. The system still further includes storage means adapted for storing at least one selected constant value associated with the selected polynomial relationship, which constant values are chosen so as to define at least one curve associated with the selected polynomial relationship. The system also includes calculating means adapted for calculating an output value in accordance with the selected polynomial relationship, stored constant values, and received image data.

System and method for optimizing image output quality

A color enhancement system with variable color saturation addresses issues of clipping of an output image by analysis and application of color correction to individual pixels. Encoded image data is received, and the elements are converted from a color space representation, such as RGB, into another color space where the individual picture elements are color corrected. The color correction is accomplished by application of a correction matrix. Once correction has been applied, the values are converted back to the original color space representation.

System and method to eliminate clipping during color conversion

Artifact reduction is achieved by altering the growth of sub-cells for each super-cell in either a pre-determined or random manner. The means of alteration is selected such that the sum of all the groups equals a halftone value. In another embodiment, the random group is selected by using predetermined patterns which are different among sub-cells, such as different means of constructing a dot. Preferably a different pattern is used in adjacent super-cells. In yet another embodiment, the method selects sub-cells patterns that are not aligned on the super-cell boundaries.

Halftone super-cell optimization for artifact reduction

A method of determining colorant amounts to be laid down in a color printer includes determining an initial set of cyan, magenta and yellow (CMY) values; ordering the initial set of CMY values to determine the largest, middle and smallest values of the three values and generating an ordering vector; selecting a gamut center black generation LUT and two gamut boundary black generation LUTs from a set of black generation LUTs from a selection table; indexing the selected black generation LUTs to determine black values for each black generation LUT as a function of the minimum of the CMY values; interpolating a final output black colorant amount from the black values, and interpolating final output CMY colorant amounts from the initial set of CMY values, the maximum CMY ink limit constraint, and a set of boundary threshold values.

Black generation method for CMYK color printer using multiple lookup tables and interpolation

A method of transforming scanned RGB values into a colorimetric color space includes identifying multiple input media types to be scanned; assigning a weighting factor to each input media type; dividing input color space into segments; assigning a weighting factor to each input color space segment; applying regression and interpolation techniques to minimize color error; and generating a colorimetric output.

Construction of a color transform to reduce effects of scanner metamerism

A method for improving chromatic text resolution includes transforming a color image signal into chrominance (C1, C2) image signal components and a luminance (L) image signal component. A mask is created for a selected image object from the luminance image signal components. The C1 and C2 image signal components are modified by the mask into new image signal components, C1.sub.NEW, C2.sub.NEW, respectively. The new image signal components are transformed, with L, into a new color image signal that does not have chromatic blur.

Growing community of inventors

Mission Viejo, CA, United States of America

William C Kress