46 results about "Parallel projection" patented technology

An apparatus and method for real-time volume processing and universal three-dimensional rendering. The apparatus includes a plurality of three-dimensional (3D) memory units; at least one pixel bus for providing global horizontal communication; a plurality of rendering pipelines; at least one geometry bus; and a control unit. The apparatus includes a block processor having a circular ray integration pipeline for processing voxel data and ray data. Rays are generally processed in image order thus permitting great flexibility (e.g., perspective projection, global illumination). The block processor includes a splatting unit and a scattering unit. A method for casting shadows and performing global illumination in relation to light sources includes sweeping a two dimensional array of rays through the volume can also be implemented with the apparatus. A method for approximating a perspective projection includes using parallel projection.

A CT scanner system provides projection-like images of a patient volume. After a CT scan is obtained and a three-dimensional model of the patient is created, any synthetic view can be generated by choosing any array of projection lines, e.g. between a point and a surface (a flat plane, curved plane, spherical, etc) or between two surfaces (parallel or not) and summing across the projection lines. The synthetic projections can mimic certain traditional views, such as a ceph scan, Water's view, Caldwell's projection, etc or can provide a new view that is impossible or impractical with traditional x-ray equipment, such as a perfect parallel projection, or a projection that does not pass all the way through the patient.

A parallel-beam optical tomography system (4) for imaging an object of interest (1) includes a parallel ray beam radiation source (35) that illuminates the object of interest (1) with a plurality of parallel radiation beams (36). After passing through the object of interest (1) the pattern of transmitted or emitted radiation intensities is magnified by a post specimen optical element or elements. An object containing tube (2) is located within an outer tube (32), wherein the object of interest (1) is held within or flows through the object containing tube (2). A motor (34) may be coupled to rotate and / or translate the object containing tube (2) to present differing views of the object of interest (1). One or more detector arrays are located to receive the emerging radiation (68) from the post specimen magnifying optic. Two- or three-dimensional images may be reconstructed from the magnified parallel projection data.

The invention discloses a robot autonomous tracking method based on vision, and belongs to the technical field of automatic robots. According to the invention, the target position is determined and the surrounding environment planning path is perceived by using the scene segmentation model based on the GOTURN tracking model and the SegNet so as to avoid obstacles; the system establishes a mappingrelationship between pixel coordinates and two-dimensional plane coordinates through parallel projection, constructs a local grid map under polar coordinates by fusing visual positioning with an environmental mathematical model, and finally plans an optimal trajectory between a robot and a target through an A * algorithm. And relatively strong tracking capability and relatively long tracking distance can be realized in indoor and corridor environments.

The invention provides a space curved surface foldable array mechanism configuration method based on Flasher origame and a space curved surface foldable array mechanism. The space curved surface foldable array mechanism configuration method comprises the steps of: (1) determining the array center, the number of array layers, the number of array rings and the shape of a space curved surface of the space curved surface foldable array mechanism, and establishing a plane foldable and unfoldable array mechanism model based on Flasher paper folding as a reference; 2) calculating to obtain a folding valley / folding peak top point on a midline folding mark of each folding and unfolding partition and a folding ridge top point on a connecting folding mark of an adjacent folding and unfolding partition when the established planar foldable array mechanism model is in a completely-unfolded state, wherein the folding valley / folding peak top point and the folding ridge top point are formed on a midline folding mark of each folding and unfolding partition of the planar array; 3) performing parallel projection towards the spatial curved surface; 4) solving a fitting error of a feasible solution meeting the constraint; and 5) repeating calculation for multiple times to obtain all curved surface array vertex positions of the curved surface foldable array mechanism model, and completing the configuration of the curved surface foldable array mechanism model. The method has the advantages of light weight, large and variable folding-unfolding ratio, high curved surface fitting precision and the like.

Embodiments of the present disclosure are directed to a system for generating three-dimensional images of a target region of a patient. The system may include at least one computer system. The computer system may be configured to receive a plurality of non-parallel projection images of the target region of the patient, convert the plurality of non-parallel projection images into a non- spatial domain, reconstruct a three-dimensional image from the plurality of non- parallel projection images in the non-spatial domain, and convert the reconstructed three-dimensional image from the non-spatial domain to the spatial domain.

The invention discloses an automatic detection method for the geometric deformation of the surface of a three-dimensional mural based on the comparison of the contour lines of a laser point cloud by four-dimensional curved surface fitting. First, use the ICP algorithm to roughly register the point cloud data of the two 3D murals, then use the PCA algorithm to obtain the point cloud normal vector, project the normal vector onto the unit Gaussian sphere, and use the multi-view Gaussian sphere parallel projection method to extract the point cloud Finally, the extracted contour lines are compared by the four-dimensional surface fitting method. The invention makes full use of the contour feature information of the point cloud data, and uses the change of the point cloud surface to accurately detect the change of the surface of the three-dimensional mural: the method does not require or only requires very little manual intervention in the entire detection process. It has the characteristics of fast data update, low cost and high precision, and it can also judge the changing nature of the changing area, which provides an effective detection method for the field of cultural relics protection and detection.

The invention discloses a sphere illustrative diagram, a composition method of the North Pole position thereof and a used template. The used template is characterized by comprising a meridian template and a latitude line template. The method of using the template to determine the North Pole position comprises the steps: in the T parallel projection direction, a sphere center O is taken as a circle center, the minor semi-axis of an equator ellipse is used as a radius for drawing a circle, and the circle and the major semi-axis of the equator ellipse intersect at a point A; the points A and O are connected; a vertical line of AO is drawn through the circle center O toward the North Pole direction of a sphere and intersects with a contour circle of the sphere at a point D; a vertical line of AO is drawn through the point A toward the North Pole direction of the sphere and intersects with the contour circle of the sphere at a point B; a parallel line of AO is drawn through the point B to obtain a point of intersection C where the parallel line intersects with DO, and the point of intersection C is the North Pole position of the sphere illustrative diagram. The determination method of South Pole position and the determination method of the North Pole position are identical, but the directions are opposite. Meridians of the sphere are drawn through the North Pole and the South Pole to complete the drawing of the sphere illustrative diagram. The meridians and latitude lines of the sphere in a general state can be conveniently drawn by the template.

The invention discloses a radiation energy density simulation method of a focusing type heliostat in a tower type solar thermal power station, which belongs to the technical field of tower type solarthermal power station simulation, and comprises the following steps: (1) determining the relative positions of sub-plane mirrors in local coordinates, and integrally adjusting the positions and orientations of the sub-plane mirrors according to the incident direction of sunlight; (2) defining an approximate imaging plane according to the reflected light direction of the focusing type heliostat; (3) uniformly dividing the three-dimensional space, and calculating heliostats having shadow and shielding relationships with the heliostats; (4) performing rasterization representation on the approximate imaging plane; (5) calculating radiation energy density distribution on the virtual imaging plane; and (6) projecting the radiation energy density distribution on the virtual imaging plane to a receiving plane through oblique parallel projection. The convolution assignment law and the approximate imaging plane are utilized to obtain the accumulation of the projection areas of the sub-plane mirrors, i.e., the weighted effective reflection areas, so that the solving efficiency of the focusing type heliostat model is improved.

The invention discloses a large screen fusion projection method comprising steps of: constructing a 3D model of a scaled-down exhibition hall by using a D modeling method and establishing an exhibition hall local 3D coordinate system; splicing the projection images of multiple projectors into a whole projection image by using an image splicing method and storing a whole projection image effect picture of a scaled-down whole projection image; simulating an effect model, projected onto a parallel screen, of the whole projection image effect picture by using a parallel projection method; acquiring control points on an annular screen, homonymous points, corresponding to the control points, on the effect model, and pixels on the whole projection image effect picture; computing a third transformation equation based on the control point coordinate values, homonymous point coordinate values, and pixel coordinate values; performing transformation computation on the real projection image according to the third transformation equation in order to project each pixel of the projection image into a correct position on the annular screen, thereby finishing geometric correction of a large screen projection image.

The invention discloses a double-point measurement method and device for the liquid mouth distance of a single crystal furnace with a guide tube as a reference. Step 1: use a CCD camera to photograph the bottom end of the guide tube and obtain the parallel position of the guide tube on the liquid surface. Schematic diagram of the projected image; Step 2: Set three measurement lines at equal pixel intervals on the reflection circle of the image diagram; Step 3: Calculate the liquid outlet distance directly by using the three measurement lines obtained and the determined value obtained when the guide tube is installed . Using only three measurement lines and the determined value obtained when the CCD camera is installed to calculate the liquid outlet distance, avoiding the introduction of proportional coefficients and the corresponding points of the selected boundary points in the reflection, and improving the efficiency and accuracy of the liquid outlet distance.