Showing papers on "Bilateral filter published in 1999"

Resolution improvement from multiple images of a scene containing motion at fractional pixel values

Abstract: A high-resolution image is derived from multiple low resolution images each having an array of low-resolution pixels. Motion vectors are derived at each of the unknown high-resolution grid points for each of the multiple low-resolution images. One motion vector is generated at each one of the high-resolution grid locations for each one of the multiple images. The motion vectors at the high-resolution grid points associate high-resolution grid points, whose values are unknown, with inter-pixel positions on the associated low-resolution images. Low-resolution pixels are identified that have the closest distance to each inter-pixel position. One or several of the identified low-resolution pixels having the shortest distance are used to determine the pixel value at each one of the high-resolution grid points. Pixel intensity values are then mapped into the high-resolution grid points according to the selected low-resolution pixels.

Multiresolutional critical point filter and image matching using the same

Abstract: A multiresolutional filter called a critical point filter is introduced. This filter extracts a maximum, a minimum, and two types of saddle points of pixel intensity for every 2×2 (horizontal×vertical) pixels so that an image of a lower level of resolution is newly generated for every type of a critical point. Using this multiresolutional filter, a source image and a destination image are hierarchized, and source hierarchical images and destination hierarchical images are matched using image characteristics recognized through a filtering operation.

Motion detection method and apparatus

Abstract: The present invention provides a method and apparatus for detecting motion in an input sequence of images. Each image comprises a number of lines and each line has a number of pixels. Values of a region of pixels of a current image are transformed to determine a set of representation values. The set of representation values are indicative of the region of pixels at a number of resolution levels. The set of representation values of the region of pixels of the current image are compared with a set of representation values of a corresponding region of pixels from a stored previous image. Based on the comparing step, a difference measure is determined between the region of pixels and the corresponding region of pixels that is indicative of the presence or absence of motion in the current image.

A test efficient method of classifying image quality of an optical sensor using three categories of pixels

Abstract: A multi-threshold optical binning method for classifying the image quality of an optical sensor (104) is presented. In accordance with the invention, a sensor tester (102) causes a sensor pixel image (105) to be generated by a sensor under test (104). The sensor pixel image (105) is comprised of a plurality of pixels, each represented by an associated quantized intensity level. The quantized intensity level of a pixel may fall into one of a first pixel class, a second pixel class, or a third pixel class, for example, a dark pixel class, a dim pixel class, and an acceptable pixel class. An image filter (106) processes the sensor pixel image (105), filtering out all pixels that fall within the acceptable pixel class, to generate a defective pixel map (108). The defective pixel map (108) includes those pixels which have a quantized intensity level that falls within the first and/or second pixel class but not the third pixel class.

Solid-state color imager

Abstract: A solid-state color imager comprising a solid-state color imaging element (2) having a color separating filter in which arrangement patterns are repeatedly provided, each arrangement pattern has four pixels adjacent to one another vertically and horizontally, the two upper pixels are a full color transmission filter and a cyan transmission filter arranged from the left, and the two lower pixels are a yellow transmission filter and a full color transmission filter arranged from the left, storage means (5) for receiving color signals outputted from the pixels and storing them therein, correlation calculating means (6) for calculating the correlations of pixels around interpolation object pixels comprised of the cyan signal pixels and yellow signal pixels stored in the storage means, and interpolating means (7) for performing interpolation in the direction in which the correlation increases and calculating full color transmission signals in the positions of the interpolation object pixels.

A method and a system for processing images

Abstract: The present invention relates to a method and a system for processing images. The invention relates in particular to a method and a system for processing an image using interpolating. The method determines a variation value for different sets of pixels in a CCD, and the set of pixels with the highest correlation (lowest numeric value) is selected. A missing colour at a given pixel is expressed in terms of the information contained in the selected set of pixels. If the variation value is below a certain threshold, due to noise or other factors, an alternative set of pixels using a different variation method may be selected. The missing colour is estimated as a weighted sum of e.g. the green samples divided by the weighted sum of e.g. the red samples multiplied by the sampled value from the pixel to be estimated.

System and process for repairing a binary image containing discontinuous segments of a character

Abstract: A system is provided for repairing a binary image image containing discontinuous segments of a character. The binary image comprises a two-dimensional array of pixels, and the system comprises a device for storing the binary image, and a processor for performing various steps, including (1) creating a morphological filter, (2) mapping the morphological filter onto a selected region of the binary image, wherein each element of the morphological filter corresponds to a pixel of the binary image, (3) for each of the elements of the morphological filter of the first filter type, determining whether the corresponding pixel of the binary image is set and any of the pixels of the binary image corresponding to the elements of the morphological filter of the second filter type are set, and (4) setting the pixel of the binary image corresponding to the center element of the morphological filter, responsive to the previous step.

Data processor, data processing method, medium, noise removal device and noise removal method

Abstract: PROBLEM TO BE SOLVED: To more effectively remove noise. SOLUTION: In an addition pixel decision part 2, a pixel (called a similar pixel) whose difference from a noticed pixel is within the range of ±e is extracted and the continuity of the similar pixels (whether pixels before and behind the similar pixel are also similar pixels, for example) is judged. In an addition pixel decision part 2, only the similar pixels having continuity are extracted out of the similar pixels. In an addition processing part 3, the similar pixels having continuity are added. The added result is outputted as the noise removal result of the notice pixel.

Subsampled texture edge antialiasing

Abstract: The present invention provides a method for antialiasing texture edges by generating texture alpha coverage values for edge pixels from subsamples of the pixels in a computer graphics system. The antialiasing method of the present invention maps a texture onto a graphics primitive, preferably a polygon, to generate a plurality of pixels within the graphics primitive. Each of the pixels generated is characterized by a texture alpha value representing opacity. Among the generated pixels, a block of NxN pixels are selected where N is an integer greater than 1. For each pixel within the block of NxN pixels, a set of subsample points are generated. Then, the present invention computes an alpha value for each subsample point in each pixel by either interpolation or extrapolation. The computed alpha values for the sample points in each pixel are then used to generate an antialiased pixel in each of the pixels within the blocks of NxN pixels.

Method and apparatus for interlaced image enhancement

Abstract: A method for image enhancement for an interlaced display includes receiving a first group of pixels aligned about an axis, detecting a second group of pixels within the first group of pixels, each pixel of the second group of pixels having a luminous disparity between adjacent pixels less than a first threshold, determining whether each pixel within the second group of pixels is part of a line or edge, the determination including a comparison of luma or chroma disparities between neighboring pixels and filtering each pixel determined to be part of a line or edge. An apparatus for image enhancement for an interlaced display includes an interface for receiving video data, a vertical filter coupled to the video data interface to detect inter-line correlation between pixels, a horizontal filter coupled to the output of the vertical filter to detect line correlation between pixels when inter-line correlation is detected and a flicker filter coupled to the output of the horizontal filter to filter pixels having horizontal correlation.

Image printer for controlling the shape of pixels based upon correlation values

Abstract: An image printer for printing images with less cross-talk between images and less image flickering is provided. A plurality of images are interleft in one or a plurality of line units and a lenticular lens is used to make it possible for each individual pixel to be distinguished. The difference in brightness between an attentional pixel and the surrounding pixels that surround this attentional pixel is taken, and a correlation value is produced, the correlation value being reduced if the difference is large and increased if the difference is small. The image printer is equipped with a pixel shape controller that makes the printed pixels smaller in a region where the correlation value is low, and makes the printed pixels larger in a region where the correlation value is high.

Method and device for identifying structure image component

Abstract: PROBLEM TO BE SOLVED: To provide a procedure for identifying the structure of pixel data expressing a discrete pixel image and distinguishing the structure from non- structure. SOLUTION: Structure is identified by comparing the level of a gradient with a selected gradient value and mutually comparing the gradient directions of adjacent pixels. The number of pixels having required relation is counted and a focus parameter is applied to the counted number of pixels. A final gradient threshold is determined based on the number of pixels and the focus parameter. The gradient threshold identifies a structure pixel. An isolated adjacent area 52 can be removed from the structure. Edges delimited by the structure are processed by binary order statistic quantity filtering and the delimtation of final structure is reached. Structure pixels and non-structure pixels can be furthermore processed to emphasize the image for succeeding display.

Method for interpolating between scanning lines of a video signal

Abstract: Values of actual pixels existing on upper and lower scanning lines of a pixels to be interpolated are detected, and a differential of each of the actual pixels is calculated. Each of the actual pixels is weighted in accordance with the differential and both the weighted values of the pixels are added together. The sum of the addition is used as a value of the pixel to be interpolated.

k-means classification filter for speckle removal in radar images

Abstract: A new adaptive speckle removal filter for synthetic aperture radar (SAR) images based on a k-means classifier is presented. This filter is able to identify different regions in an image by classifying the image into classes. Speckle is removed by averaging only within a class. This eliminates the effect of smoothing over edges. The filter is shown to preserve edges better than local statistics filters. Performance studies with simulated images of known speckle distributions show that the k-means filter outperforms most existing adaptive speckle removal filters. Simulated images are used to quantify the performance of the filter for single-look and multi-look images. A threshold parameter is defined for 1-look, 4-look and 10-look images. Optimum filter parameters are identified for different image contrasts and speckle noise levels. The filter is also used with real SAR images. The filter is shown to preserve the contrast between different regions while smoothing out the speckle within a region.

Method and system for filter type approximation in computer graphics processing

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.

Pixel interpolation method

Abstract: PROBLEM TO BE SOLVED: To suppress a dot noise especially to enhance image quality of an image including a thin line object with respect to the pixel interpolation method suitably employed for a digital camera. SOLUTION: Whether or not a 1st condition is satisfied is discriminated where both of values of two pixels vertically adjacent to a target pixel are not smaller than and not larger than both of values of two pixels horizontally adjacent to the target pixel (S2). When the 1st condition is satisfied, whether or not a means value of the two pixels vertically adjacent to the target pixel is closer to a mean value of a plurality of surrounding pixels at the outside of the four pixels vertically and horizontally adjacent to the target pixel than the mean value of the two pixels horizontally adjacent to the target pixel is discriminated (S3). When the discrimination indicates closer, the mean value of the two pixels horizontally adjacent to the target pixel is given to a pixel value G12 of the target pixel (S4), and when the discrimination indicates not closer conversely, the mean value of the two pixels vertically adjacent to the target pixel is given to the pixel value G12 of the target pixel (S5). When the 1st condition is not satisfied, the median of the four pixels vertically and horizontally adjacent to the target pixel is given to the pixel value G12 of the target pixel (S6).

Process for separating dynamic and static components of a sequence of images

Abstract: A process for the separation of static and dynamic components of a sequence of images separated in time and taken under the same conditions. The process includes recording a first intensity of a first pixel in at least one area in the sequence of images, recording subsequent intensities for identical pixels to the first pixel in subsequent recorded images, and using pixel intensity sort criteria on intensity changes between the first intensity and the subsequent intensities to discriminate in the subsequent recorded images pixels showing minimal intensity changes from pixels showing larger intensity changes as the sequence process. The process includes forming from the pixels showing minimal intensity changes a part of the static component of the sequence of images.

Method for removing distortion in decoded electronic image from image expression subtected to block transformation and encoding

Abstract: PROBLEM TO BE SOLVED: To prevent the occurrence of distortion in a decoded electronic image by determining boundary pixels as pixels in a prescribed area consisting of the prescribed number of low accurate pixels in a decoded electronic image, filtering the boundary pixels by one of plural filters in order to obtain one or more boundary substituting pixel values and substituting one or more boundary substituting pixel values for one or more pixels on the boundary. SOLUTION: A block averaging/smoothing device 80 adjusts the mean value of image blocks for executing the inverted block division processing of a reconstituted image outputted from a decoder. A gradient calculating and pixel labeling processor 90 determines which pixel of the image averaged and adjusted in each block is low accurate and which pixel is a boundary pixel. When a pixel label is included in a prescribed pixel, the label is used for determining which type of smoothing is to be executed. A pixel smoother 100 smoothes the pixels of the image averaged and adjusted in each block in accordance with the label outputted from the processor 90.

Image forming apparatus for printer or copier

Abstract: The apparatus includes a detector for sensing the condition of the pixels surrounding a pixel. A correction device corrects pixel data for this pixel based on the difference in density between the this pixel and the surrounding pixels. The degree of correction may be varied for pixels in the horizontal direction and pixels in the diagonal direction. A method of forming a graduated pixel image is also claimed.

An edge-preserving fuzzy filter based on differences between pixels

Abstract: This paper presents a novel fuzzy filter structure for edge-preserving smoothing of an image corrupted by impulsive and white Gaussian noise. This filter structure is expressed as an adaptive weighted mean filter that uses fuzzy control. The coefficients of the proposed filter can be varied adaptively by fuzzy control laws based on differences between pixels in the window. In the setting of fuzzy control laws, the method takes the distance between the center and each pixel in the window into account. Finally, simulation results demonstrate the effectiveness of the proposed technique.