16 results about "Parallel projection" patented technology

The invention discloses a VR scene automatic generation method based on a parallel projection design drawing, and the method comprises the following steps: S1, importing a two-dimensional CAD drawing containing building design information, and analyzing a primitive set in the drawing; s2, performing component type identification on the primitives, and establishing a mapping relation between a primitive set and spatial semantics; s3, performing geometric reconstruction based on a mapping relation between the primitive set and spatial semantics, and generating a three-dimensional component model with a unique name identifier; s4, establishing a multi-stage mapping model, and realizing size conversion from a drawing scale to a space coordinate system of the virtual reality system; s5, completing three-dimensional coordinate positioning and automatic assembly according to the multi-stage mapping model, and generating a three-dimensional structure layout of an overall building or park level; and S6, importing the assembled three-dimensional structure layout into a virtual reality rendering engine to generate a virtual reality scene. According to the invention, an automatic, precise and integrated conversion process from a two-dimensional design drawing to a three-dimensional virtual reality scene is realized.

The present invention discloses a method for generating a channel spectrum response difference correction table and a channel spacing correction table, a computer program, a computer readable storage medium and a computer tomography device. The method for generating a channel spectrum response difference correction table and a channel spacing correction table includes using parallel projection P paral (k, r) determines the channel position corresponding to the center of the phantom, and calculates the simulated parallel projection and the ideal projection P accordingly sim (k, r), and finally according to the projection difference diff(k, l, r) and the simulated ideal projection P sim (k, r), calculate the channel spectrum response difference correction table t CCR (k, l) and channel spacing correction table t spacing The method, computer program, computer-readable storage medium, and computer tomography device of the present invention for generating a channel spectrum response difference correction table and a channel spacing correction table are not affected by residual beam hardening and can effectively generate ideal projections.

The invention discloses a method and a device for detecting blocky impurities in a homogeneous cylinder and CT (Computed Tomography) equipment. The method comprises the following steps: S102, performing CT (Computed Tomography) rotary scanning on the homogeneous cylinder to obtain an original projection P (k, l, r); s104, rearranging the original projection P (k, l, r) into a parallel projection Pparal (k, l, r); s106, determining the position C (l, r) of the homogeneous cylinder according to the parallel projection Pparal (k, l, r); s108, translating the parallel projection Pparal (k, l, r) according to the position C (l, r) of the homogeneous cylinder, so that the center of the homogeneous cylinder is located at the same channel, thereby obtaining a second parallel projection PISO (x, l, r); s110, translating the reading of the second parallel projection PISO so as to obtain a third parallel projection which has a projection angle deviation alpha 0 relative to the second parallel projection PISO at the same reading; s112, calculating the difference diff between the second parallel projection PISO and the third parallel projection; and S114, comparing the projection difference diff with a threshold value T, and judging whether blocky impurities exist in the homogeneous cylinder or not. According to the method and device for detecting the blocky impurities in the homogeneous cylinder and the CT equipment, the state of the blocky impurities in the homogeneous cylinder can be automatically detected, the efficiency is high, and the effect is good.

The invention discloses an unsupervised learning 2D and 3D image registration method, and belongs to the field of computer medical image processing. According to the method, a CNN-Transform parallel network and improved projection space transformation based on a parallel projection mode are constructed, specifically, 3D TOF and 2D DSA data are obtained and preprocessed, the improved projection space transformation based on the parallel projection mode is constructed, a parallel CNN-Transform double-branch network (CTNet) is constructed, and the method is used for evaluating feature similarity, training the CTNet and achieving precise registration of the 2D DSA and the 3D TOF. The system is used for interventional operation navigation, provides three-dimensional guidance for catheter path planning and embolism treatment, is used for complex lesion assessment, and provides multi-aspect support for disease diagnosis and treatment. According to the method, global and local features can be extracted more comprehensively for feature similarity evaluation, and the registration performance is improved; the projection image is generated by adopting the improved projection space transformation based on the parallel projection mode, and the generated projection image is more matched with the TOF imaging principle.

The application discloses a kind of VR scene automatic generation method based on parallel projection design drawing, comprising the following steps: S1, import two-dimensional CAD drawing containing architectural design information, parse the graphic primitive set in drawing;S2, component type identification is carried out to graphic primitive, and the mapping relationship between graphic primitive set and space semantics is established;S3, geometric reconstruction is carried out based on the mapping relationship between graphic primitive set and space semantics, and three-dimensional component model with unique name identification is generated;S4, multi-stage mapping model is established, and size conversion from drawing scale to virtual reality system space coordinate system is realized;S5, according to multi-stage mapping model, complete three-dimensional coordinate positioning and automatic assembly, and generate overall building or park-level three-dimensional structure layout;S6, the three-dimensional structure layout assembled is imported into virtual reality rendering engine, and virtual reality scene is generated.The application realizes the automatic, accurate and integrated conversion process from two-dimensional design drawing to three-dimensional virtual reality scene.

An object recognition device includes a three-dimensional data acquisition section that acquires three-dimensional data composed of a plurality of points each having three-dimensional information, a parallel projection conversion section that generates a two-dimensional image by parallel projecting each point of the three-dimensional data onto a projection plane, and a recognition processing section that detects a target object from the two-dimensional image by template matching.

A projection unit for a head-up display including a projector element and a mirror arrangement. The projector element is configured to emit a light beam. The mirror arrangement includes a first mirror and a second mirror. The first mirror is a flat mirror. The second mirror is a flat mirror spaced apart from and in parallel to the first mirror. The projector element is configured to emit the light beam towards the first mirror at an angle of incidence. The first mirror and the second mirror are arranged at a first distance from each other such that the light beam is repeatedly reflected from the first mirror towards the second mirror, and from the second mirror back towards the first mirror before leaving the mirror arrangement. At least one of the first distance between the first mirror and the second mirror, and the angle of incidence is adjustable.

The application discloses a simulation method for radiation flux density distribution of a tower type photo-thermal power station receiver considering refraction influence. Since a heliostat usually adopts a silver-coated glass reflector, the method considers the refraction effect of light on the glass layer, specifically comprising the following steps: obtaining heliostat field parameters, performing heliostat rotation focusing, and performing light incidence and shielding analysis; using a pre-trained full connection neural network to infer radiation flux density distribution parameters; after sampling the mirror field, a Monte Carlo ray tracing method considering refraction is used to simulate reflected light spots on the imaging plane; an elliptical Gaussian function with a cross term is used to fit the light spots and extract parameters, and a training set is constructed based on the sampling, simulation and fitting data to optimize the neural network; finally, the radiation flux density distribution of each heliostat on the imaging plane is calculated through the neural network inference parameters and the elliptical Gaussian function with the cross term, and is projected obliquely and parallelly to the receiver surface. The application combines high-precision simulation and neural network, and realizes efficient and accurate heliostat field light spot analysis.

The invention discloses a radiotherapy adaptive planning system and method based on target region change and flux prediction, and relates to the technical field of big data analysis, and the method comprises the steps: carrying out the parallel projection of each cross section of a target region through collecting historical target region records containing the target region and the real flux of the target region, and forming a target region projection data set; constructing a flux prediction model, and calculating a target region enhancement loss function; constructing a training set training flux prediction model; collecting a new fractional target region, converting the new fractional target region into a standard format, projecting the new fractional target region, inputting the new fractional target region into a trained model to obtain an initial predicted flux, screening effective data through a rack angle mask, and generating a new plan data support list containing predicted flux distribution and dose parameter suggestions; the system comprises a historical target region projection module, a flux prediction model construction module, a training data set construction module and a new fractional plan generation module which are connected in sequence. The method can shorten the radiotherapy plan time consumption, improve the flux prediction accuracy, reduce the dose deviation, and provide support for precise radiotherapy.

Screen with an image sensor (2) which uses a first grid of pixels P to display image content Bild exhibits, further comprising a first switchable light filter (5), in turn comprising - a first optical element (1), itself comprising • a multitude of light-absorbing transition dipole moments, • wherein the majority of the transition dipole moments are permanently or at least in a first state aligned with a tolerance of at most 20° parallel to a first preferred direction selectable for the first optical element (1) or vary around it, • so that light which enters the first optical element (1) is transmitted or at least partially absorbed depending on its polarization state and its direction of incidence relative to the first optical element (1), - Means for selectively generating at least one first electric field EF1 or one second electric field EF2, which is directed into a second grid with pixels P LC are divided - a liquid crystal layer (3) arranged in front of or behind the first optical element (1), onto which the respective pixel P is applied LC The generated electric field acts, and depending on this, it influences the polarization state of light passing through it. - wherein the transmission properties of the switchable light filter (5) differ between a first operating mode B1 at corresponding pixels P LC , where the first electric field EF1 is applied, and a second operating mode B2 at corresponding pixels P LC , where the second electric field EF2 is applied, distinguish, - wherein the first and second rasters differ in at least one of the parameters resolution, pixel shape, pixel size, raster shape, base angle of the coordinate axes of both rasters, orientation of the coordinate axes and / or number of the respective pixels P LC or P Bild differ, and - where, in parallel projection of the second raster onto the first raster along the perpendicular bisector of the first raster, less than 50% of the edges of pixels P LC of the second grid on any edge of pixels P Bild of the first grid, thereby reducing visually visible overlaps of the image source (2) and other components of the screen.

[Problem] To enable a further improvement in the user experience of communication via video. [Solution] This information processing system includes a display control unit that generates a display screen including a display of an object that moves in accordance with motion data, wherein the display control unit performs data processing including placement processing for placing the object at a second position that is spaced apart from a first position, indicated by the motion data, in a reference direction along a reference plane by a length corresponding to the distance from the reference plane to the first position, and generates the display screen by parallel-projecting the object after the data processing has been performed onto the reference plane.

The invention discloses a spatial multi-degree-of-freedom pose vision ultra-precision measurement system and method, the system is mainly composed of a multi-view imaging system and a pose measurement algorithm, in the multi-view imaging system, a low-distortion telecentric lens is selected as a lens, and auxiliary industrial cameras are distributed around a main industrial camera, so that the multi-view imaging system is differentiated into multiple groups of binocular systems; the method comprises the following steps of: fixing a mark plate printed with any mark pattern on a target plane in a position and posture measurement algorithm, and extracting a position and posture through the position and posture measurement algorithm corresponding to the observed mark pattern. And due to the parallel projection characteristic of the telecentric lens, at most five-degree-of-freedom pose measurement is realized, so that a sixth degree of freedom is obtained by utilizing complementary information provided by the binocular system, and space six-degree-of-freedom ultra-precision measurement is realized. The method can be applied to the field of precision measurement and robots, and visual ultra-precision measurement of spatial multi-degree-of-freedom poses can be realized by selecting proper cameras and lenses and combining the algorithm.

The invention discloses a three-dimensional to two-dimensional dimension reduction coding and decoding method for lossless dimension reduction and high-fidelity restoration, which comprises the following steps of: mapping any point P in a three-dimensional space to a two-dimensional projection plane through one-time T parallel projection, and calculating to obtain coordinates of the point on the two-dimensional projection plane to finish three-dimensional to two-dimensional dimension reduction coding. Key depth information of an original three-dimensional space is implied in the two-dimensional coordinates, efficient compression and reservation of information are achieved, and lossless dimension reduction transformation from three dimensions to two dimensions can be achieved; in the decoding process, two-dimensional coordinates and projection parameters corresponding to the two-dimensional coordinates are read, an equation set with target three-dimensional point coordinates (X, Y and Z) as unknown numbers is constructed according to the mapping function relation to be solved, high-fidelity and reversible restoration from P'to P are achieved, the complex space relation can be clearly expressed in an unambiguous mode, good universality and robustness are achieved, and the method can be widely applied to the field of decoding. And compact storage, efficient transmission and accurate reconstruction of three-dimensional data are facilitated. The invention further discloses a drawing method, a computer storage medium and a drawing device.

The application relates to the technical field of ship communication, and particularly discloses a ship space deployable antenna profile division comparison method, which comprises the following steps: performing profile division on a space deployable antenna to obtain a plurality of sub-planes; obtaining characteristic nodes of each sub-plane, calculating the area of the sub-plane by using a vector cross product method to obtain the total area of the sub-plane; projecting the sub-plane on an ideal paraboloid based on parallel projection to correspondingly obtain a plurality of sub-paraboloids; obtaining characteristic nodes of each sub-paraboloid, calculating the area of the sub-paraboloid by using a node area error numerical integration method to obtain the total area of the sub-paraboloid; determining the precision value of the profile division according to the total area of the sub-plane and the total area of the sub-paraboloid, comparing the precision values obtained by using different profile division modes, and determining an optimal profile division mode. The comparison method is suitable for the division and comparison of different space deployable antenna profiles, and can determine a profile division mode with high profile precision.

This invention belongs to the field of laser processing and relates to a method for processing a glass hemispherical dome using a double-sided femtosecond laser. The method includes the following steps: 1) constructing processing units on the glass hemispherical dome; 2) obtaining the actual pattern trajectory to be processed using parallel projection based on the calculated position coordinates; 3) obtaining the processing path based on the pattern trajectory obtained in step 2); and 4) processing the processing units obtained in step 1) according to the processing path obtained in step 3). This invention provides a glass hemispherical dome double-sided femtosecond laser processing method with high positioning accuracy and effectively improved processing efficiency.

Various embodiments of the teachings herein include an apparatus for measuring a magnetic field of a conductor of an electric current. The apparatus may include three magnetic field sensors arranged on a circumference of a non-circular ellipse defined by parallel projection or orthogonal projection of a circle. Three first positions are arranged equidistantly on a circumference of the circle. The three first positions emerge from the parallel projection or the orthogonal projection onto at least three second positions on the ellipse. The three magnetic field sensors are arranged at the three second positions. The magnetic field is measured without using a flux concentrator.