190 results about "Artifact reduction" patented technology

Methods and apparatus for reducing plenoptic camera artifacts. A first method is based on careful design of the optical system of the focused plenoptic camera to reduce artifacts that result in differences in depth in the microimages. A second method is computational; a focused plenoptic camera rendering algorithm is provided that corrects for artifacts resulting from differences in depth in the microimages. While both the artifact-reducing focused plenoptic camera design and the artifact-reducing rendering algorithm work by themselves to reduce artifacts, the two approaches may be combined.

Method for reducing artifacts in a subsurface physical properties model (120) inferred by iterative inversion (140) of geophysical data (130), wherein the artifacts are associated with some approximation (110) made during the iterative inversion. In the method, some aspect of the approximation is changed (160) as the inversion is iterated such that the artifacts do not increase by coherent addition.

A method is presented for obtaining characteristics of a target physical entity by providing an excitation signal to the target physical entity and simultaneously measuring the response of the target physical entity. Analog signal processing is performed on the measured response to eliminate artifacts arising from a signal path outside the target physical entity and determining the characteristics from the signal processed measured response. The excitation signal and the analog signal processing are selected such that after analog signal processing of the measured signal, the analog measured signal contains artifacts which are localized in time.

A system and method is provided for processing a demosaiced image using a color aliasing artifact reduction (CAAR) algorithm in order to reduce color aliasing artifacts. The CAAR algorithm computes the L level wavelet transform for the demosaiced color planes R, G and B. Thereafter, the CAAR algorithm estimates the correct color value at each pixel location for the colors not associated with that pixel location. For example, to determine the green value at red pixel locations, the CAAR algorithm performs an inverse wavelet transform using the green approximation signal and the red detail signals. This process is repeated for each of the colors (e.g., green values at blue pixel locations, red values at green pixel locations, etc.). In addition, the CAAR algorithm performs an inverse wavelet transform on each of the color planes themselves, so that the pixel values of the color associated with each pixel location are not altered. Thereafter, the inverse wavelet transform of each color plane is combined with the inverse wavelet transform of each of the estimated color values for that color plane to produce correlated R, G and B color planes. It is these correlated R, G and B color planes that may later be compressed using a wavelet-based image compression method, such as the JPEG 2000 standard.

A method and apparatus to remove human features utilizing at least one transmitter transmitting a signal between 200 MHz and 1 THz, the signal having at least one characteristic of elliptical polarization, and at least one receiver receiving the reflection of the signal from the transmitter. A plurality of such receivers and transmitters are arranged together in an array which is in turn mounted to a scanner, allowing the array to be passed adjacent to the surface of the item being imaged while the transmitter is transmitting electromagnetic radiation. The array is passed adjacent to the surface of the item, such as a human being, that is being imaged. The portions of the received signals wherein the polarity of the characteristic has been reversed and those portions of the received signal wherein the polarity of the characteristic has not been reversed are identified. An image of the item from those portions of the received signal wherein the polarity of the characteristic was reversed is then created.

Some configurations of the present invention provide a method for reconstructing an image of an object of a computed tomographic imaging system having a detector array and a radiation source, wherein an arc of the detector array is not concentric to a focal spot of the radiation source. The method includes scanning the object with the computed tomographic imaging system to obtain a fan beam dataset, rebinning the fan beam dataset into a set of parallel datasets; and reconstructing an image utilizing the set of parallel datasets.

An apparatus using a compact blocked and Wavelet transform pair suppresses block artifacts in image compression systems by re-purposing one or more block transform coefficients with Wavelet coefficients. A general architecture and class of transforms is disclosed including integer types having Wavelet features but which can be processed one block at a time. An exemplary integer, non-separable two-dimensional Wavelet Transform is disclosed to partner with a Walsh-Hadamard blocked transform to serve as the core for the apparatus then tailored to function as a DCT, DST or other signal transform.

A video quality adaptive coding artifact reduction system has a video quality analyzer, an artifact reducer, and a filter strength controller. The video quality analyzer employs input video quality analysis to control artifact reduction. The video quality analyzer accesses the video quality of the decoded video sequence to estimate the input video quality. The filter strength controller globally controls the filter strength of the artifact reducer based on the video quality estimate by the video quality analyzer. For low quality input video, the filter strength controller increases the artifact reduction filter strength to more efficiently reduce the artifact. For high quality input video, the filter strength controller decreases the artifact reduction filter strength to avoid blurring image detail.

A method for generating an image of an object is provided. The method comprises acquiring projection data at one or more projection views along a circular scan trajectory and generating a corrected projection dataset based upon a weighted derivative applied to a subset of the projection data. The method further comprises backprojecting the corrected projection dataset along one or more projection rays associated with one or more of the projection views, to generate a reconstructed image of the object.

X-ray therapy EPI artifact reduction and control of imaging is provided. Scanning of images is synchronized with the pulse rate of the x-rays. The scanning period is longer than the pulse rate period, so artifacts are generated within the resulting images. Due to the synchronization, the pulse variation artifacts are aligned across multiple images. The synchronization and resulting alignment of linear artifacts allows for gain correction as a function of lines within the image. Such gain correction reduces or removes non-linearities associated with pulse rate variation.

Artifact reduction in steady state free precession magnetic resonance imaging uses weighting of acquired image data to emphasize higher signals and then establishing an image signal based on the combined weighted signals. In one embodiment, a SSFP imaging sequence uses phase cycling and acquired image data is squared with the squared data then combined. The final image signal is based on the square root of the squared data.