1057 results about "Point source" patented technology

A volumetric computed tomography system with a large field of view has, in a forward geometry implementation, multiple x-ray point sources emitting corresponding fan beams at a single detector array. The central ray of at least one of the fan beams is radially offset from the axis of rotation of the system by an offset distance D. Consequently, the diameter of the in-plane field of view provided by the fan beams may be larger than in a conventional CT scanner. Any number of point sources may be used. Analogous systems may be implemented with an inverse geometry so that a single source array emits multiple fan beams that converge upon corresponding detectors.

An optical improvement for angular position sensors, which may be used to determine the spatial coordinates of a small source of light (or other energy) in a 3-dimensional volume. Such sensors normally include a linear photosensitive image detector such as a photodiode array or a charge-coupled device (CCD). An irregular pattern of parallel slits is described which increases the amount of light gathered while avoiding the undesirable characteristics of lens optics for this application. One optimal type of irregular pattern is the uniformly redundant array. A mathematical correlation function together with a polynomial interpolation function can determine the displacement of the image on the detector and thereby the location of the source relative to one angular dimension. Given the locations and orientations of several sensors in a 3-dimensional coordinate system and given the angles measured by each, the location of the point source can be computed.

An apparatus and method to determine the surface orientation of objects in a field of view is provided by utilizing an array of polarizers and a means for microscanning an image of the objects over the polarizer array. In the preferred embodiment, a sequence of three image frames is captured using a focal plane array of photodetectors. Between frames the image is displaced by a distance equal to a polarizer array element. By combining the signals recorded in the three image frames, the intensity, percent of linear polarization, and angle of the polarization plane can be determined for radiation from each point on the object. The intensity can be used to determine the temperature at a corresponding point on the object. The percent of linear polarization and angle of the polarization plane can be used to determine the surface orientation at a corresponding point on the object. Surface orientation data from different points on the object can be combined to determine the object's shape and pose. Images of the Stokes parameters can be captured and viewed at video frequency. In an alternative embodiment, multi-spectral images can be captured for objects with point source resolution. Potential applications are in robotic vision, machine vision, computer vision, remote sensing, and infrared missile seekers. Other applications are detection and recognition of objects, automatic object recognition, and surveillance. This method of sensing is potentially useful in autonomous navigation and obstacle avoidance systems in automobiles and automated manufacturing and quality control systems.

A patterned mask is located at a distance from a linear detector array. A point radiating source illuminates the aperture to cast an image onto the array. A computer is employed to identify frequencies in the frequency domain to determine the image scale and shift along the detector array axis. Determination of the magnification of the aperture image is made employing frequency domain techniques, the aperture pattern being re-scaled to match that of the actual image, so that determination of pattern shift can be made. A first embodiment of the present invention has two variations, one of which employs the use of multiple single frequency components and phase methodology, the second of which uses multiple single frequency components as well as a variable frequency component. In a second embodiment, a composite image is also used except that only one single frequency component is used in addition to a non-periodic function.

A sensor for determining the angular position of a radiating point source in two dimensions includes a mask encoded in two skewed directions with waveforms consisting of several frequencies in prescribed patterns. The frequency spectra of the received detector patterns are computed. In order to facilitate such computations, the constituent frequencies are separated so as to be distinguished in the Fast Fourier Transform (FFT). Each of the frequency patterns that are coded on the variable transmissivity mask consists of a series of low frequencies followed by a series of variable frequencies, and a series of high frequencies. The variable frequencies exhibit frequency changes responsive to various image positions. The low and high frequencies are responsive in phase to variations in image position. The frequency variations in the variable frequencies are used to indicate coarse position while the phases of the fixed low and high frequencies are used to indicate medium and fine position. In a second embodiment, the mask pattern is formed by a first pattern including low variable and high frequency components, a second pattern with fixed low and high frequency components, and a third pattern with variable frequency components. The method of determining position is also disclosed.

A system and method for enabling an audio conference server (ACS) to provide an application program with multi-point weight controllable audio conferencing. The ACS manages a plurality of audio conferences, receives audio data from a plurality of audio clients, mixes the audio data to provide distance-based attenuation according to decay characteristics for each sound, and delivers the mixed audio data to a plurality of audio clients. Audio clients include set-top box (STB) audio clients and point source audio (PSA) audio clients. The ACS mixes the audio data by identifying a decay factor. Pre-defined decay factors include an audio big decay factor, an audio small decay factor, an audio medium decay factor, and a constant decay factor. One can also develop a customized decay factor. A weighted value for a source audio client based on the identified decay factor and the distance between the source audio client and a target audio client is determined. A mix table is generated using the weighted values for each source/target audio client pair. Then an actual mix value for each target audio client is calculated using the mix table. The present invention also includes means for refining the actual mix value.

Embodiments of a device and a technique are disclosed for locating the angular position of a radiating point source with respect to a detector comprising a point source of radiation, a variable transmissivity mask with pseudo-random variations, a multi-element detector and computing means for interpreting the detected image. The mask pattern, when illuminated by a point source of radiation, casts an image on the detector array. Computing means determine the pattern shift to allow determination of point source angular location in two dimensions. The mask transmissivity pattern and corresponding image vary in two dimensions, in such a manner as to yield two correlation peaks that indicate the incident angle in two dimensions. The differential shift and common mode shift in correlation peaks indicate the respective angles of incidence, allowing determination of the angular position of the light source.

Techniques are described for modeling layered facial reflectance consisting of specular reflectance, single scattering, and shallow and deep subsurface scattering. Parameters of appropriate reflectance models can be estimated for each of these layers, e.g., from just 20 photographs recorded in a few seconds from a single view-point. Spatially-varying specular reflectance and single-scattering parameters can be extracted from polarization-difference images under spherical and point source illumination. Direct-indirect separation can be employed to decompose the remaining multiple scattering observed under cross-polarization into shallow and deep scattering components to model the light transport through multiple layers of skin. Appropriate diffusion models can be matched to the extracted shallow and deep scattering components for different regions on the face. The techniques were validated by comparing renderings of subjects to reference photographs recorded from novel viewpoints and under novel illumination conditions. Related geometry acquisition systems and software products are also described.

Methods, systems, and articles of manufacture consistent with the present invention provide for determining the orientation of natural fractures in the Earth resulting from hydraulic fracturing treatment. Data attribute information from a far-field point-source signal profile for a microseismic event is extracted in the time domain. An estimate of the orientation of the natural fracture is calculated in the time domain based on the extracted data attribute information.

A Multiple Aperture Ultrasound Imaging system and methods of use are provided with any number of features. In some embodiments, a multi-aperture ultrasound imaging system is configured to transmit and receive ultrasound energy to and from separate physical ultrasound apertures. In some embodiments, a transmit aperture of a multi-aperture ultrasound imaging system is configured to transmit an omni-directional unfocused ultrasound waveform approximating a first point source through a target region. In some embodiments, the ultrasound energy is received with a single receiving aperture. In other embodiments, the ultrasound energy is received with multiple receiving apertures. Algorithms are described that can combine echoes received by one or more receiving apertures to form high resolution ultrasound images. Additional algorithms can solve for variations in tissue speed of sound, thus allowing the ultrasound system to be used virtually anywhere in or on the body.

The invention relates to a slope protection forming method of a landscape-type multi-level stepped constructed wetland, which has the effect of intercepting and purifying pollutants entering river channels in the form of surface sources. Sand-free concrete piles and slabs are inserted to form pile-slab components, and a slope protection system from high to low is formed on the river bank slope from the bank slope to the river bed. Planting areas are set on the side of the pile slabs, and there are fillers inside. Geotextiles are installed on the bankside side of the slab, so that when the non-point source pollutants flow from the river bank to the river, the plants planted in the planting area absorb the eutrophication in the polluted water, and the biofilm is formed on the surface of the filler to absorb and degrade the pollutants. After this The sewage treated at the first stage continues to infiltrate or overflow, enters the second row, and goes down step by step. Finally, the sewage is purified to a greater extent and flows into the river. It solves the defects of natural, hard and ecological slope protection. The structure is simple, easy for industrial production, the construction amount is small, the land is saved, and the landscape is beautified.

A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.

A system and method provide for more accurate SPECT/CT image registration. CT data is utilized to establish a global spatial coordinate system of a common test phantom. The common test phantom is then used to obtain a set of point source nuclear images. Three-dimensional CT point source data is mapped to a two-dimensional image plane of corresponding point source data, to obtain a pair of intersecting projection cones that are used to obtain a set of detector head position correction parameters to correct detector head positioning in the CT coordinate system when obtaining SPECT projection images of the same object.

The temperature distribution associated with a design of an integrated circuit is calculated by convoluting a surface power usage represented by a power matrix with a heat spreading function. The heat spreading function may be calculated from a simulation of a point source on the integrated circuit using a finite element analysis model of the integrated circuit or other techniques. To account for spatial variations on the chip, the heat spreading function may be made dependent on position using a position scaling function. Steady-state or transient temperature distributions may be computed by using a steady-state or transient heat spreading function. A single heat spreading function may be convolved with various alternative power maps to efficiently calculate temperature distributions for different designs. In an inverse problem, one can calculate the power map from an empirically measured temperature distribution and a heat spreading function using various de-convolution techniques. While the forward problem is analogous to image blurring, the inverse problem is analogous to image restoration.

There is provided a method and a system for registration of real time position of tennis ball relatively to boundary lines on tennis court. The method and system comprise sensitive to near-infrared radiation at least one video camera, outputting video image of court and the method and system further include at least one point source of near-infrared radiation, illuminating tennis court and displaced relatively to the video camera. It is suggested a simple and inexpensive way of determining if a tennis ball bounces in or out of court by determining point of intersection of trajectories of the tennis ball and its shade from near-infrared radiation and comparing the position of the determined point of intersection with previously calibrated boundary lines of court.