137 results about "Oblique projection" patented technology

A method and system for displaying predictions on a spatial map includes using a data analyzer for analyzing heterogeneous data having a spatial component to find utilizable data and using machine learning to automatically extract relationships from the utilizable data. The extracted relationships are used to make a prediction about at least one location on the spatial map and present that prediction in an oblique or perspective view. An interface presents the prediction on the spatial map in the form of a heat map overlying a 3-D topographical map. Although the 3-D map can be shown as any form of graphical projection including an oblique projection or orthographic projection, preferably a perspective view is used. It is also preferred that the graphical projection be interactive. The heat map may be 2-D or 3-D and be selectively displayed depending on the preference of a user.

A triangulation system including a laser beam, optics focusing the laser beam on an object, a light detection unit detecting light reflected from the object due to impingement of the beam on the object, and an arrangement for determining, based on the detected light, object feature dimensions. The wavelength of the laser beam may be shorter than of infrared radiation, which allows for a reduced spot size without significant loss of depth of field. So as to reduce aberrations or a sensitivity to aberrations due to the shortened wavelength, the system may include (i) a polarization dependent coating matching the index of refraction of an element of the light detection unit to that of air for a range of angles, (ii) tilted projection optics, (iii) a prism wavefront corrector, and/or (iv) a positioning assembly, which provides for increased precision in positioning the laser diode with respect to a collimator lens.

An oblique projection optical system enlarges an image formed on a display device surface, and obliquely projects the enlarged image on a screen surface. The oblique projection optical system has, in the order from a reduction side: a refraction optical portion having a positive optical power, a concave reflection surface having a positive optical power, and a convex reflection surface having a negative optical power. The refraction optical portion includes a rotationally symmetric coaxial refraction group. An intermediate image of the image formed on the display device surface is formed between the refraction optical portion and the concave reflection surface. An aperture stop image is formed between the concave reflection surface and the convex reflection surface. The concave reflection surface and the convex reflection surface fulfill prescribed conditional formulae.

In an oblique projection optical system for performing enlargement projection from a primary image surface on the reduction side to a secondary image surface on the enlargement side, at least one reflective surface having an optical power is provided, and, assuming that of the aforementioned surfaces, the reflective surface located on the most secondary image surface side in the optical path is a first curved reflective surface, the first curved reflective surface has a portion having a positive optical power and a portion having a negative optical power.

In a projection type image display apparatus, for enlarging an image on a image display apparatus 1 by means of a projection lens 2, thereby projecting the enlarged image onto a screen 6, obliquely, being inclined thereto, between the projection lens 2 and a rear-surface mirror 5, there are disposed free shaped surface mirrors 3 and 4, each having a free shaped surface for compensating a trapezoidal distortion due to oblique projection of the enlarged image. The surface configuration of the free shaped surface mirror is so shaped as to satisfy a following equation:

|L1−L2|>1.4·Dv

if assuming that a distance for a light beam of an upper end of the enlarged image to reach the screen after being reflected upon a free shaped surface is “L1”, a distance for a light beam of a lower end of the enlarged image to reach the screen after being reflected upon the free shaped surface is “L2”, and a distance from an upper end of an image on the screen to a lower end thereof is “Dv”.

The invention relates to a single-channel fetal electrocardiogram blind separation device based on oblique projection and a separation method. The separation device comprises a single-channel electrocardiogram signal acquisition module, a Doppler fetal heart sound acquisition module, an analog to digital conversion module, a microprocessor and a PC (personal computer) upper computer for separating and displaying signals. A switch-in end of the single-channel electrocardiogram signal acquisition module for acquiring aliasing electrocardiogram signals is connected with an electrocardiogram lead cable, an input end of the Doppler fetal heart sound acquisition module for acquiring fetal heart sound signals is connected with an ultrasonic probe, a switch-out end of the single-channel electrocardiogram signal acquisition module and a switch-out end of the Doppler fetal heart sound acquisition module are respectively connected with an analog input end of the analog to digital conversion module, a data output port of the analog to digital conversion module is connected with the microprocessor, and the microprocessor is connected with the PC upper computer. The separation method includes a fetal electrocardiogram QRS (quantum resonance spectrometer) wave group positioning method based on oblique projection and single-channel fetal electrocardiogram signal blind separation based on oblique projection. The separation device is reasonable in design and is convenient and practical; and the separation method is convenient and practical.

A two-dimensional scanning apparatus has light source means, deflecting means for deflecting a beam emitted from the light source means in a two-dimensional direction, and scanning optical means for directing the beam deflected by the deflecting means onto a surface to be scanned. The scanning optical means has one or more scanning optical element, and one or more surfaces of one or more of the aforementioned one or more scanning optical elements are anamorphic surfaces, and the anamorphic surfaces on the aforementioned one or more surfaces are anamorphic surfaces monotonously changing in a radius of curvature of which the absolute value of the radius of curvature in a first one-dimensional direction continuously decreases from one side toward the other side along a second one-dimensional direction orthogonal to the first one-dimensional direction. Thus, there can be supplied a two-dimensional scanning apparatus which can well correct TV distortion caused by the two-dimensional deflection of the beam by the deflecting means and trapezoid distortion caused by an image being obliquely projected onto a surface to be scanned, and a scanning type image displaying apparatus using the same.

There is provided a projection apparatus using an oblique projection optical system, which generates little reflection loss by providing a linear Fresnel lens at an incident surface in the case where the apparatus is used as a linear system, wherein said linear Fresnel lens makes total reflection of image light, and is capable of obtaining total surface property with good brightness in a region with small incident angle onto a screen, by using a total reflection Fresnel lens and a refraction Fresnel lens in combination. In addition, total surface property with further good brightness can be obtained by using a plurality of projection image display apparatuses in the same projection apparatus.

The invention discloses a radar adaptive beam forming method based on oblique projection filtration. The method comprises the following steps: (1) signals received by N array elements in an array are set to be x(t), and interference and noise are included; a covariance matrix Rxx for the signals x(t) received by the N array elements is built, eigenvalue decomposition is carried out on the matrix, and interference signal subspace UJ and noise signal subspaceUn are obtained; (2) an interference judgment rule is built, and signal subspace Em for main lobe interference and signal subspace for side lobe interference are determined respectively in the interference signal subspace UJ; (3) an oblique projection operator B is built to carry out oblique projection filtration treatment on the signals x(t) received by the N array elements, signals y(t) after oblique projection filtration treatment are obtained, and a covariance matrix Ryy is built; (4) noise in the covariance matrix Ryy for the signals y(t) after oblique projection filtration treatment is corrected, and a covariance matrix R after correction is obtained; and (5) according to the covariance matrix R after correction, adaptive beam forming is carried out on the signals x(t) received by the N array elements, and signals z(t) after adaptive beam forming are obtained.

A self-contained sign, illuminated by laser or other source of substantially parallel beams, presenting intensely lighted and vividly colored displays, is programmable to display one or more user designed images through controlled deflection of projected beams. The sign comprises a backlit illuminated apparatus of low depth to display dimension ratio, astigmatically correcting distortion of the projected dot resulting from oblique projection angles, such correction occurring in the projected beam's light path prior to controlled beam deflection. Embodiments further normalize obliquely incident light by employing a transmissive refractive right angle structure. Distortion of a projected image is minimized by appropriate pre- or post-processing of display data. Embodiments enable animation of images and are adaptable to networked control.

The invention provides a method for eliminating self-interferences of cascade time-frequency domain processing and polarization domain processing during full-duplex communication and belongs to the technical field of wireless communication. A quadrature dual polarized antenna used for transmitting and receiving polarization signals is equipped at every communication node, and a local node is subjected to polarized digital signal processing. The method includes that self-interferences of radio frequency of a time-frequency domain are eliminated by a receiving end; polarized signals subjected to radio frequency self-interference elimination are transmitted to a base band via down conversion, an oblique projection polarization filtering operator is constructed according to a transcendental self-interference polarization state and an expected signal polarization state, and polarization filtering is performed; matching and receiving of expected signals are performed according to the principle that the output signal to interference plus noise power ratio is maximum. The method for eliminating self-interferences of cascade time-frequency domain processing and polarization domain processing during full-duplex communication has the advantages that the problem that self-interferences and expected signals in a traditional scheme are overlapped and difficult to distinguish, self-interference elimination is performed by utilizing polarized dimensionality information of the signals in the base band, repeated utilization of time frequency information is avoided, self-interference elimination gain is increased and the purpose of eliminating self-interferences is realized.

A projection optical system which has a short projection distance and a compact structure, and allows oblique projection. The projection optical system projects luminous flux from an image forming element for forming an original image onto a projection surface which is oblique to a central principal ray which is a principal ray of luminous flux traveling from the center of the original image to the center of a finally formed image. The system includes a plurality of reflecting surfaces each having a curvature. In addition, the projection optical system satisfies a predetermined expression (1).

The invention discloses a radar signal motion disturbance spatial-polarizational domain combined stable filtering method. The method comprises, firstly, performing real-time estimation of disturbance signal subspace on the horizontal channel data of a polarized sensitive array through a PASTd (projection approximation subspace tracking with deflation) algorithm and meanwhile estimating the azimuth angles of disturbance signals through an MUSIC (multiple signal classification) algorithm; then estimating disturbance spatial-polarizational models through the estimated disturbance signal azimuth angles, and after obtaining the disturbance spatial-polarizational models, performing spatial domain orthogonal projection filtering through the disturbance subspace obtained during the disturbance angle real-time estimation process; lastly, performing oblique projection polarization filtering. The radar signal motion disturbance spatial-polarizational domain combined stable filtering method is simple and practical, can accurately estimate the disturbance signal directions and timely achieve spatial-polarizational domain combined disturbance suppression through spatial-polarizational characteristic models and accordingly can be applied to suppression of motion disturbance in the fields of radars, communication and the like.

The invention provides a hybrid field signal source positioning method based on a symmetrical nested array. The hybrid field signal source positioning method comprises the following steps that an antenna array is set, wherein the antenna array is the symmetrical nested array; a far-field signal DOA is estimated to obtain an estimation value of the far-field signal DOA; the near field component isseparated from the far field component; a fourth-order cumulant virtual difference array of a near-field signal is calculated; an estimation value of the near-field signal DOA is obtained by using spectral peak search; and according to the near-field signal DOA estimation value, the near-field signal distance is estimated to obtain a near-field signal distance estimation value. The hybrid field signal source positioning method uses mixed-order statistics, and compared with a second-order statistic algorithm, the hybrid field signal source positioning method solves the problems of Gaussian noise interference and reduction of degree of freedom by half; the symmetric nested array and the fourth-order cumulant virtual differential array are used for improving the estimation accuracy of far-field DOA, near-field DOA and a near-field distance; oblique projection technology is utilized to separate the far-field and near-field components, and thus, it is not necessary to distinguish the far-field signal from the near-field signal according to distance parameters; and therefore, the number of search is reduced, and the computational complexity of the algorithm is further reduced.

An oblique projection optical system for leading rays of light from a display surface on which an image is displayed to a projection surface in such a way that the ray of light from the center of the display surface is obliquely incident on the projection surface in order to project a magnified image of the image displayed on the display surface onto the projection surface includes a plurality of reflecting surfaces having a power. At least two of the reflecting surfaces have a free-form curved surface, and, of all the reflecting surfaces, the one closest to the projection surface has a negative power and at least one of the other has a positive power. Alternatively, in a rear projection optical system having a projection optical system for projecting an image displayed on a panel display surface onto a screen surface, the projection optical system includes at least four curved-surface reflecting mirrors.