93 results about "Low spatial frequency" patented technology

A camera acquires a 4D light field of a scene. The camera includes a lens and sensor. A mask is arranged in a straight optical path between the lens and the sensor. The mask including an attenuation pattern to spatially modulate the 4D light field acquired of the scene by the sensor. The pattern has a low spatial frequency when the mask is arranged near the lens, and a high spatial frequency when the mask is arranged near the sensor.

A technique of reconstructing a high resolution image from at least one image sequence of temporally related high and low resolution image frames wherein each of said high resolution image frames includes a low spatial frequency component and a high spatial frequency component is described. The high-resolution image reconstruction technique uses spatial interpolation to generate a low spatial frequency component from a low-resolution image frame of the image sequence. The technique is adapted to generate a high spatial frequency component from at least one high resolution image frame of the image sequence which is closely related to the low resolution image frame, and to remap the high spatial frequency component to a motion-compensated high spatial frequency component estimate of the low resolution image frame. The motion-compensated high spatial frequency component estimate is added to the generated low spatial frequency component to form a reconstructed high-resolution image of the low-resolution image frame.

A system and method for tracking an airborne target including an illumination source (e.g., a diode laser array) is used to enhance a target signature and a detector (e.g., a passive high-speed camera) is used to detect to electromagnetic radiation (e.g., infrared radiation) reflected off the target. The received electromagnetic radiation may be processed by a digital computer and passed through a spatial filter that implements a band limited edge detection operation in the frequency domain. The filter may remove low spatial frequencies that attenuate soft edged clutter such as clouds and smoke as well as filter out artifacts and attenuated medium to high spatial frequencies to inhibit speckle noise from the detector as well as speckle from the laser return off the target.

A new class of algorithms has been developed to estimate spectral reflectance in remote sensing imagery. These algorithms are called Surface Prior Information Reflectance Estimation (SPIRE) algorithms and estimate surface spectral reflectance using prior spatial and spectral information about the surface reflectance. This paper describes SPIRE algorithms that employ spatial processing of single channel data to estimate local changes in spectral reflectance under spatially and spectrally varying multiplicative and additive noise caused by variations in illumination and atmospheric effects. Rather than modeling the physics of the atmosphere and illumination (using a physics-based code such as ATREM), or using ground truth spectra at known locations to compensate for these effects (using the Empirical Line Method), prior information about the low spatial frequency content of the scene in each spectral channel is used instead. HYDICE VNIR-SWIR hyperspectral data were used to compare the performance of SPIRE, ATREM, and ELM atmospheric compensation algorithms. The Spatial SPIRE algorithm performance was found to be nearly identical to the ELM ground-truth based results, while Spatial SPIRE performed better than ATREM overall, and significantly better under high clouds and haze.

A method and apparatus are presented for acquiring MR cardiac images in a time equivalent to a single breath-hold. MR data acquisition is segmented across multiple cardiac cycles. MR data acquisition is interleaved from each phase of a first cardiac cycle with MR data from each phase of a subsequent cardiac cycle. Preferably, low spatial frequency data are interleaved between multiple cardiac cycles, and the subsequent cardiac cycle acquisition includes sequential acquisition of high spatial frequency data towards the end of the acquisition window. An MR image can then be reconstructed with data acquired from each of the acquisitions that reduce ghosting and artifacts. Volume images of the heart can be produced within a single breath-hold. Images can be acquired throughout the cardiac cycle to measure ventricular volumes and ejection fractions. Single phase volume acquisitions can also be performed to assess myocardial infarction.

A sampling system adapts the sampling rate for sampling analog signals and/or the stored number of samples to the fixed or video image content, such that a higher rate, and equivalently a larger number of samples, are acquired for an image or video segment containing higher spatial frequencies while a lower number of samples (lower sampling rate) are retained for image or video segments containing lower spatial frequencies. The Nyquist theorem may still be satisfied for each individual image segment, while information necessary for edge enhancement is retained.

In order to prevent obstruction of a view of a subtitle due to synthesis of the subtitle onto an object area such as a person and display of the synthesized subtitle, an image synthesizing device includes: an image synthesizing unit which synthesizes a graphics object onto an image; and a display area detecting unit which outputs a display position of an area having the lowest spatial frequency; and a drawing control unit which causes the graphics object to be drawn at the display position.

An original image is divided into a plurality of blocks that are made up of a plurality of picture elements, and in each block, from encoded image-data which is obtained by encoding a spatial-frequency component of the block as a plurality of spatial-frequency coefficients, reduced encoded image-data is produced which is encoded data on a reduced image that is obtained by reducing the original image to a given reduction rate. If the block in the encoded image-data of the original image is in an area where the value of the function is small due to gentle change in brightness or color of the image, for example, only the direct-current component coefficient of is used for the block. On the other hand, if the block is in a area where the value of the function is large because the area is a boundary area, for example, such as an outline in the image, limited number of lower spatial frequency-coefficients are used for the block. The number is based on the reduction rate of the image.

A laser projection system including a system controller, a visible light source, and a light disrupting element is provided. The visible light source includes at least one laser and the laser projection system is programmed to scan a scanned optical signal of the visible light source across a plurality of image pixels. The scanned optical signal comprises a low spatial frequency beam and a high spatial frequency beam, and the low spatial frequency beam generates a low spatial frequency image having spatial frequencies below a spatial frequency threshold, the high spatial frequency beam generates a high spatial frequency image having spatial frequencies that are above the spatial frequency threshold, and the scanned laser image is a sum of the high spatial frequency image and the low spatial frequency image. The low spatial frequency beam is altered by an out of focus light disrupting element.

A method for rendering an image including objects defined by surfaces. A rendering application selects an object in a first image and determines a surface of the object. An initial set of illumination values is calculated and is separated into low and high spatial frequency components associated with the surface of the object. The rendering application independently adjusts the illumination values of the low and high spatial frequency components based lighting information in the first image, and generates a modified set of illumination values by combining the adjusted low and high spatial frequency components. The surface of the object is then rendered using the modified set of illumination values. Advantageously, embodiments of the invention provide techniques for rendering an object without introducing halo effects around the object. Additionally, embodiments of the invention provide for rendering a sequence of frames without introducing fluctuations in the low frequency components from across frame.

A filter section performs color carrier component removal and high-frequency level correction according to color image signal data, and a correction section performs edge enhancement correction. By these operations, luminance signal data is obtained. The characteristics of the filter section are established adaptively in accordance with the luminance signal level of low spatial frequency components in the color image signal data, the luminance signal edge level in the color image signal data, whether or not a predetermined color is exhibited in the color image signal data, a color difference edge level in the color image signal data, or whether or not the RGB data reaches the saturation level in the color image signal data.

The present invention relates to method for spatial up-scaling of an original video frame comprising p rows and q colums of pixels, where p and q are integers. Said up-scaling method comprises a step of constructing high-low (HL), low-high (LH), and high-high (HH) virtual spatial frequency subbands comprising p rows and q colums of pixels from the use of high-pass filtering of the original video frame, considered as a low-low spatial frequency subband (LL), in horizontal, vertical, and both directions, respectively. Said up-scaling method further comprises a step of applying an inverse wavelet transform (IWT) to the constructed subbands and to the original video frame in such a way that an up-sampled version of the original image is obtained.

An apparatus and method for at-wavelength EUV mask-blank characterization for inspection of moderate and low spatial frequency coating uniformity using a synchrotron or other source of EUV light. The apparatus provides for rapid, non-destruction, non-contact, at-wavelength qualification of large mask areas, and can be self-calibrating or be calibrated to well-characterized reference samples. It can further check for spatial variation of mask reflectivity or for global differences among masks. The apparatus and method is particularly suited for inspection of coating uniformity and quality and can detect defects in the order of 50 μm and above.

CT scanner is disclosed for providing an image of a region comprising: at least one X-ray cone beam for illuminating mthe region with X-rays; a plurality of rows of X-ray detectors that generate signals responsive to line attenuation of X-rays from the at least one controller that controls providing an image of a region comprising: at least one X-ray cone beam for illuminating the region with X-rays; a plurality of rows of X-ray detectors that generate signals responsive to line attenuation of X-rays from the at least one X-ray source that pass through the region; a controller that controls the at least one X-ray cone beam to acquire line attenuation data for the region for different view angles of the region; and a processor that receives the signals and: a) determines low spatial frequency components of the image from the data; b) generates a first spatial image of the region from the low high spatial frequency components of the image from the data; d) generates a second spatial image of the region from the high frequency components; and e) combines the first and second images to generate the image.

A process for the electronic stabilization of the images of a scene of a snapshot capturing apparatus of an imaging system in which, in a terrestrial reference frame, the images of the scene captured by the apparatus are filtered in a low-pass filter, so as to retain only the low spatial frequencies thereof, and the optical flow equation is solved to determine the rotations to be imposed on the images in order to stabilize them with regard to the previous images is provided. The invention also relates to a process for correcting offsets in grey levels of a snapshot capturing apparatus of an imaging system whose images are stabilized according to the process of the invention, where the calculation of the offsets is deduced from the steps of the stabilization process.

Low spatial frequencies of an original image and an upscaled filtered image are analyzed. Differences will be observed in the low frequency components of the two images in the general case since the pixel art upscaler filter as a side effect introduces low frequency changes. A modification to images produced by the PAU is applied to attempt to match the brightness of the original images in the low frequency spectrum. From a viewer perspective (e.g., based on typical blurring visual effects), the original image and the modified filtered image will look the same—demonstrating that there is no low frequency brightness creep or resulting increased photosensitivity concerns.

The present invention relates to a low spatial frequency calibration arrangement for scanning systems. In the method and system of the present invention, calibration is performed to compensate for non-uniformities introduced when light scattering media is scanned. This calibration results in a non-uniformity mapping at each scanning pixel location.

Preferred embodiments of an image display system achieve mapping of high dynamic range image data to render on a lower dynamic range display device a corresponding image characterized by stable global intensity levels and visually perceptible local area detail. The high dynamic range image data include representations of relatively low intensity contrast, high spatial frequency details and relatively low spatial frequency intensities. Data derived from the high dynamic range image data are applied to a nonlinear intensity transform. The nonlinear intensity transform preserves or enhances the low intensity contrast, high spatial frequency details and maintains a visually perceptible representation of the relatively low spatial frequency intensities to thereby provide visually perceptible local area detail. An exemplary embodiment derives high dynamic range image data from a thermal infrared camera for use with aircraft.