Showing papers by "Andrew C. Gallagher published in 2002"

Enhancing the tonal and color characteristics of digital images using expansive and compressive tone scale functions

Abstract: 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.

Method for constructing an extended color gamut digital image from a limited color gamut digital image

Abstract: A method for constructing an extended color gamut digital image from a limited color gamut digital image which was derived from a first extended color gamut image includes providing a modified inverse color adjustment function which when such function operates on a limited color gamut digital image an extended color gamut digital image having reduced highlight color saturation for highlight color values when compared with corresponding color values of the first extended color gamut image is produced, and operating on the limited color gamut digital image with the modified inverse color adjustment function to construct the extended color gamut digital image with reduced color saturation for highlight color values that results in reduced levels of color contouring and quantization artifacts.

Multiresolution method of spatially filtering a digital image

Abstract: 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.

Method of enhancing the tone scale of a digital image to extend the linear response range without amplifying noise

Abstract: A method of processing a digital image to improve contrast, the digital image being derived from an image captured by a recording medium having a nonlinear response to light, includes the steps of: applying a spatial filter to the digital image to produce a noise reduced digital image; subtracting the noise reduced digital image from the digital image to produce a difference digital image; applying a tone scale function to the noise reduced digital image to produce a tone scale adjusted digital image having the appearance of being derived from an image captured by a recording medium having a linear response; and combining the difference 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 amplifying noise.

Method of spatially filtering a digital image using chrominance information

Abstract: 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.

Appliance communication system

Abstract: An appliance capable of performing a task initiated by a human operator, including an input device for receiving operator contact information for sending a message to the human operator; a computer for processing the operator contact information; and a transmitter that uses the operator contact information to communicate a message from the appliance to the human operator.

Electronic imaging system having a sensor for correcting perspective projection distortion

Abstract: An electronic imaging system for capturing an image of a scene includes an optical system for producing an optical image of the scene, an imaging sensor having a surface in optical communication with the optical system, and a plurality of imaging elements distributed on the surface of the imaging sensor according to a distribution representable by a nonlinear function in which the relative density of the distributed imaging elements is greater toward the center of the sensor. Such a distribution provides physical coordinates for the imaging elements corresponding to a projection of the scene onto a non-planar surface, thereby compensating for perspective distortion of the scene onto the non-planar surface and alleviating the need to perform geometric warping of the images after they have been captured.

Method for sharpening a digital image

Abstract: A method of sharpening a digital image having image pixels values includes the steps of: determining a Dmin value, representing a value corresponding to a minimum possible exposure for a system that produced the digital image; for each pixel value in the digital image providing a gain factor that is dependent on the difference between the pixel value and the Dmin value, such that pixel values nearer the Dmin value have smaller gain factors; and using the gain factors to sharpen the digital image.

Method for sharpening a digital image with signal to noise estimation

Abstract: A method of sharpening a digital image having image pixels according to its noise content, includes the steps of providing an image sharpener having a variable parameter of sharpening; generating a noisy pixel belief map corresponding spatially to the image pixels having belief values indicating the likelihood that the modulation about respective pixels are due to system noise; and using the noisy pixel belief map to vary the parameter of the image sharpener.

Method of detecting clipped image pixels

Abstract: A method is described for detecting the clipped pixels of a digital color image The method includes the steps of: (a) producing a uniformity map from the digital color image, where the uniformity map indicates locations within the digital color image that are substantially uniform; (b) providing a threshold value; and (c) using the uniformity map, the threshold value, and the digital color image to produce a map indicating the location of clipped pixels within the digital color image

Method for sharpening a digital image without amplifying noise

Abstract: A method of sharpening a digital image having image pixels according to its material content, includes the steps of: generating a subject matter belief map corresponding spatially to the image pixels, having belief values indicating the likelihood that respective image pixels are representative of a particular subject matter, generating a noisy pixel belief map corresponding spatially to the image pixels having belief values indicating the likelihood that the modulation about respective pixels are due to system noise; generating gain map from the subject matter belief map and the noisy pixel belief map having values that indicate the degree of sharpening to be applied to the image pixels; and using the gain map to sharpen the image.

Colour image pickup device with improved colour filter array

Abstract: An image sensing device having an array of light-sensitive elements, including: a first type of element sensitive to a spectral region corresponding to luminance; a second type of element sensitive primarily to red light; a third type of element sensitive primarily to green light; and a fourth type of element sensitive primarily to blue light, the four types of elements occurring in repeating patterns.

Method and system for correcting non-symmetric distortion in an image

Abstract: Non-symmetric distortion generated by an imaging system producing a distortion predominantly in one image dimension is corrected by providing a distortion model capable of correcting the non-symmetric distortion in an image that is predominantly in the one image dimension, providing one or more correction parameters, wherein at least one correction parameter relates to the distortion predominantly in the one image dimension, and generating an image corrected for the non-symmetric distortion by using the distortion model and the one or more correction parameters.

Method and apparatus for generating and storing extended dynamic range digital images

Abstract: An image capture system for generating and storing an extended dynamic range digital image, includes 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 for producing 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; a digital image processor that employs the slow pixel values to expand the dynamic range of the fast pixel values in the sparsely sampled high resolution digital image to form a full resolution digital image having an extended dynamic range; a color encoder for reducing the dynamic range of the full resolution digital image to fit within the dynamic range of a storage color space having a dynamic range less than the dynamic range of the full resolution digital image to form a limited dynamic range digital image represented in the storage color space and for producing a residual image representing a difference between the full resolution digital image and the limited dynamic range digital image that can be used with the limited dynamic range digital image to reconstruct the full resolution digital image; and a digital image store for storing the limited dynamic range digital image in association with the residual image.

Digital image enhancement method based on pixel color

Abstract: PROBLEM TO BE SOLVED: To provide a method for independently controlling enhancement to be applied to details, large edges and noisy areas. SOLUTION: The method for enhancing a color digital image comprises first specifying local points or their vicinities of pixels, including an object pixel and then using a color value for one or more pixels at the local point or its vicinity for calculating the weighting factor for the object pixel. A space filter is applied to values fo the pixels at the local points or their vicinities for calculating first and second signal values for the object pixel. A color weighting factor is used for correcting either the first or second value, and the enhanced pixel value is generated for the object pixel with the combination of the first and second values. This process is repeated for other pixels for the color digital image.

Method and apparatus for effectively extending dynamic range of image pickup device and use of residual image

Abstract: PROBLEM TO BE SOLVED: To express an image signal with a standard form compatible with a flow of a general image by synthesizing extended dynamic range image signals from a single imaging device and accompanying a single image signal. SOLUTION: An image capture system for generating and storing an extended dynamic range digital image includes a sparsely sampled extended dynamic range image sensing device having fast pixel values produced by fast photosites and slow pixel values produced by slow photosites, a digital image processor that employs the slow pixel values to expand the dynamic range of the fast pixel values, a color encoder for producing a residual image representing a difference between a full resolution digital image and a limited dynamic range digital image, and a digital image store for storing the limited dynamic range digital image in association with the residual image. COPYRIGHT: (C)2002,JPO

Sparsely sampled imaging device having color and luminance photosite

Abstract: PROBLEM TO BE SOLVED: To provide an imaging device which does not have loss in small parts in space or spatial resolution loss, even in a state of excessive exposure. SOLUTION: The imaging device comprises a first type of element sensitive to a spectral region corresponding to luminance, a second type of element which is sensitive primarily to red light, a third type of element which is sensitive primarily to green light, and a fourth type of element which is sensitive primarily to blue light. An array of light-sensitive elements is structured so that the four types of elements occur in repeating patterns.

Method for making an exposure adjustment on a rendered image

Abstract: A method of adjusting the balance of a digital image including a plurality of pixel values inverts the pixel values and applies a gamma value (γ) individually to each inverted pixel value to raise each inverted pixel value to the power of the gamma value. The gamma value is related to an exposure adjustment amount (A) indicating a desired exposure adjustment of the original scene. Then the inverted pixel values are themselves inverted after application of the gamma value, thereby providing modified pixel values representative of a modified digital image that is adjusted for exposure.

Image compression method

Abstract: PROBLEM TO BE SOLVED: To compress efficiently and effectively a digital image obtained by an electronic image sensor having a fast pixel value generated from a fast photosite with a predetermined response to radiation and s low pixel value generated from a slow photosite with a slow response to the same irradiation. SOLUTION: In an image compression method, images expanded in a dynamic range with sparsely sampling from a perfect resolution by an imaging element 10 and an A/D converter 14 are supplied, the sparsely sampled images from the perfect resolution by a compressor 312 are separated to fast images having only the fast pixel value and slow images having only the slow pixel value to individually compress the fast images and the slow images. The compressor 312 compresses independently the respective the slow pixel and the fast pixel with separating by a separator for pixel kinds.

Method and system of noise removal for image sensing device

Abstract: PROBLEM TO BE SOLVED: To provide a method and system that removes noise from a sparsely sampled digital image with an extended dynamic range. SOLUTION: This invention provides the method for removing noise from an image sparsely sampled with an extended dynamic range from an image generated by an image sensing device provided with fast photosites having a response to a light exposure for producing fast pixel values and slow photosites having a response to the same light exposure for producing slow pixel values, includes a step where the sparsely sampled digital image with the extended dynamic range is generated, a step where a noise filter method is used, only slow pixel values are used to generate slow noise reduced pixel values, only fast pixel values are used to generate fast noise reduced pixel values so as to remove noise from the sparsely sampled digital image with the extended dynamic range and a step where combining the slow noise reduced pixel values and the fast noise reduced pixel values generates the noise reduce digital image.