393 results about "Projection direction" patented technology

Dual-energy imaging of a recording region is provided by a recording arrangement with an X-ray tube assembly and an X-ray detector for receiving X-rays of an X-ray field emitted by the X-ray tube assembly in cone beam geometry. The field has a central beam, and the recording arrangement is rotated around the recording region for recording projection data of different directions of projection for two different X-ray spectra. For each X-ray spectrum, a three-dimensional image dataset of the recording region is reconstructed from the respective projection data. The projection data of the two X-ray spectra is recorded during the rotation that covers at least 360°. For each X-ray spectrum, an associated portion of the X-ray field is fixed over the rotation, and a corresponding, associated, fixed portion of the X-ray detector is used.

The invention provides an infrared scene reconstruction and rendering method and device based on three-dimensional Gaussian splashing, and the method comprises the steps: carrying out the processing of preprocessed infrared image data through employing an SfM algorithm, obtaining a sparse three-dimensional point cloud and a camera pose, and setting a Gaussian ellipsoid at the center position of the sparse three-dimensional point cloud, so as to construct a three-dimensional Gaussian point cloud model; inputting the camera pose into a Gaussian microrasterized renderer to render the three-dimensional Gaussian point cloud model to obtain a two-dimensional image of a corresponding view angle; the two-dimensional image and the infrared image data of the camera pose are compared through a loss function, the model is trained, a trained three-dimensional Gaussian point cloud model is obtained, and the loss function comprises a temperature gradient field, the projection position of a Gaussian ellipsoid in a pixel plane under the current camera visual angle and the main axis projection direction; and processing the trained three-dimensional Gaussian point cloud model by using a three-dimensional graphic engine and a 3D Gaussian rasterization renderer to obtain an infrared simulation image. And the authenticity of reconstruction and rendering of the infrared scene is relatively high.

The invention discloses a dynamic projection method and system for vehicle-mounted laser point cloud data, and the method comprises the steps: obtaining the point cloud data through vehicle-mounted laser, firstly, according to a principle that a point close to a laser radar has higher density than a point far away from the laser radar, recognizing a radar scanning track through a region with high point cloud density; and secondly, aligning the projection direction with the radar scanning direction, adaptively constructing a dynamic coordinate axis and a horizontal cylindrical projection for each point cloud area, and obtaining fitted projection parameters (such as radius, center point, height and the like), thereby better enhancing ground feature retention in the dense point cloud, relieving ground feature deformation in the projection process to a greater extent, and improving the robustness of the radar. Compared with the prior art, the method has the advantages that less ground objects are shielded, semantic confusion is reduced, the effect of the point cloud semantic segmentation network is improved, the artificial intelligence reasoning speed is increased, and automatic driving map construction, three-dimensional model reconstruction, smart city development and the like can be assisted.

The invention relates to the field of X-ray image processing, and discloses an X-ray image reconstruction method based on direction perception tensor modeling. The method comprises the following steps: acquiring a plurality of X-ray projection images with different incident angles, and establishing a projection direction mapping matrix in combination with tissue direction distribution; constructing a high-order direction perception tensor field based on the mapping matrix and the structure prior information, wherein the high-order direction perception tensor field is used for describing the dominant structure direction and anisotropic response characteristics of each image position; a direction enhancement response diagram is generated through tensor-guided gradient calculation, and dynamic enhancement of local edges is achieved; then structure response intensity is extracted to construct a structure sensitive function graph, and the structure sensitive function graph serves as a weighting factor in image reconstruction; based on the weighted graph and the tensor field, an image reconstruction objective function containing direction consistency constraint is constructed, joint optimization is executed, a regularization item is dynamically updated, and high-fidelity reconstruction of the image under the low-dose condition is achieved. According to the method, the image detail keeping and noise suppression capabilities are improved, and the method has relatively high adaptability and robustness.

The invention discloses a wafer front and back surface detection system and method, and the system comprises a first scanning system which comprises a first light source module and a first camera module, and a second scanning system which comprises a second light source module and a second camera module. Light spot positions formed on the front surface and the back surface of the wafer by the first light source module and the second light source module are mutually staggered along projection positions on the front surface or the back surface of the wafer, or the projection directions of illumination light emitted by the first light source module and illumination light emitted by the second light source module are different; the first camera module and the second camera module respectively collect front or back images of the wafer to obtain a scanning result, and the analysis module analyzes the scanning result to obtain a detection result. The illumination light spots on the front and back surfaces of the wafer are staggered or the projection directions of the illumination light are different, so that the problem of mutual interference of light beams generated in the synchronous detection process of the front and back surfaces of the wafer is avoided, and the accuracy of the detection result of the front and back surfaces of the wafer is improved.

An evaluation method and system for fine division of the water richness of an unconsolidated aquifer in a mine shaft. The method comprises: using an aquifer thickness, a sand and gravel bed thickness, a lithology-thickness index, a sandstone-to-formation thickness ratio and the number of sand and gravel beds to constitute evaluation indexes, and thus establishing an evaluation index matrix; unifying variation ranges of different evaluation index data, performing normalization processing to obtain a processed standard evaluation matrix, and thus constructing a water richness evaluation index system of a "bottom aquifer"; in light of the constructed water richness evaluation index system of the "bottom aquifer", according to the principle of a projection pursuit model, establishing an aquifer water richness evaluation model by means of DPS software; in the aquifer water richness evaluation model, performing linear projection and constructing a projection objective function; optimizing the projection objective function to determine an optimal projection direction; and substituting the optimal projection direction into an expression of linear projection to obtain projection eigenvalues capable of reflecting each evaluation index information, so as to perform comprehensive evaluation on an evaluation object.

The embodiment of the invention relates to a system, a method, a device and equipment for detecting the overlap amount of a material joint, and a medium, which are used for improving the efficiency and the precision of detecting the overlap amount of the material joint. The system is applied to a tire building machine, a to-be-measured material is attached to a belt drum / building drum of the tire building machine, the system comprises a laser, a depth camera and a processing device, the laser is used for emitting laser and projecting the laser to the belt drum / building drum, and the projection direction of the laser is parallel to the axis direction of the belt drum / building drum; the depth camera is used for shooting a laser image on the belted drum / forming drum in the laminating process of the to-be-detected material and acquiring a depth image of the belted drum / forming drum in the laminating process of the to-be-detected material; the processing equipment is used for acquiring a depth image, acquired by the depth camera, of the belt drum / forming drum in the laminating process of the to-be-detected material; and determining the joint overlap amount of the to-be-measured material according to the obtained depth image.

The invention discloses an image processing method and device, equipment, a medium and a program product. The method comprises the following steps: acquiring three-dimensional image data and a two-dimensional projection image of a target bone segment; determining a target bone part in the two-dimensional projection image of the target bone segment according to the projection direction of the two-dimensional projection image of the target bone segment; segmenting the three-dimensional image data of the target bone segment to obtain three-dimensional image data of the target bone part; determining two-dimensional contour data of the target skeleton part based on the three-dimensional image data of the target skeleton part; and superposing the two-dimensional contour data of the target bone part into the two-dimensional projection image of the target bone section to generate a target image marked with the contour of the target bone part. According to the method, the display effect of the image is remarkably improved, and the readability and the information amount of the image in medical diagnosis and research are enhanced.

The invention provides a humidifying tank and breathing assisting equipment, the humidifying tank comprises a tank body, a base plate and a sealing piece, the sealing piece is installed between the inner surface of the side peripheral wall of the tank body and the base plate, and the sealing piece is used for keeping the tank body and the base plate sealed and connected; a first fixing part is arranged at the open end of the tank body, the chassis comprises a second fixing part, and the second fixing part is connected with the first fixing part in a matched mode, so that the chassis is installed at the open end of the tank body and defines an inner cavity with the tank body to contain liquid; a limiting part is arranged on the tank body or the base plate and used for being matched with a main machine of the breathing assisting device to install the humidifying tank. The orthographic projection of the limiting part and the orthographic projection of the sealing piece on the same projection plane at least partially coincide in the projection direction perpendicular to the axial direction of the side peripheral wall. The technical problem that the sealing ring shields the water level height in the humidifying tank is mainly solved, and low-water-level recognition of the breathing assisting device is achieved; the chassis and the tank body are respectively provided with a fixing part, so that firm connection is ensured, and meanwhile, disassembly and assembly are convenient.

The invention provides a vehicle-mounted radar target course angle filtering tracking method and system. The method comprises the steps that S1, the radial speed of clustered point cloud is converted into the absolute radial speed relative to the ground; s2, when a new track is created, an independent course angle extended Kalman filtering tracking module is synchronously initialized; s3, setting a projection direction based on a course angle estimated value output by the module, and completing data association between the point cloud and the track and track state updating through projection; and S4, extracting a position variable quantity based on the updated track state, forming an observed quantity by combining the absolute radial speed of the associated point cloud, inputting the observed quantity to a course angle module for extended Kalman filtering updating, outputting an updated course angle estimated value, and feeding back the updated course angle estimated value to the step S3 of the next frame. According to the invention, by constructing a cooperative closed loop of course angle estimation and data association, the stability of course angle estimation and the overall tracking robustness are significantly improved.

The utility model discloses a display module and a household appliance display panel with double-layer diaphragms matched for display, and belongs to the technical field of display panels, the display module comprises a first diaphragm and a second diaphragm, the first diaphragm is located on the lower layer in the light source projection direction, the second diaphragm is located on the upper layer in the light source projection direction, and after the first diaphragm and the second diaphragm are matched with a light source, the first diaphragm and the second diaphragm are matched. The display module only displays the background image-text and the function key image-text. According to the utility model, the two diaphragms, the two groups of light guide plates and the double-layer diaphragm are matched to realize the display of images and texts, the upper light guide plate and the diaphragm realize the slight brightness and constant brightness of background light, and the lower light guide plate realizes the highlight of the images and texts corresponding to the area when the touch key area is operated, so that the operation of a user is more convenient. The background light sources and the touch key light sources on the upper layer and the lower layer are independently controlled, and the light guide plate is arranged in a double-layer mode, so that background images and texts and function key images and texts do not affect each other, and display of the background images and texts and the function key images and texts is attractive and striking.

The invention relates to the technical field of numerical simulation modeling, in particular to a complex section open channel flow velocity comprehensive solving method under a multi-point emission mechanism, which comprises the following steps of: performing joint grouping, density statistics and sequence screening on open channel section parameters, disturbance source distribution characteristics and water level gradient data; a dynamic partitioning process driven by structural parameters is established, a lattice structure better fitting non-uniform boundary characteristics is constructed, extension layering is performed on a disturbance projection direction and a propagation path, and a graph neural network is fused to extract the correlation degree between disturbance nodes and construct a propagation path graph, so that the propagation path graph is extracted, and the propagation path graph is constructed. The problem of local propulsion offset in particle propulsion is effectively eliminated, continuity of multi-point disturbance response in an open channel and coordination of particle propagation paths are guaranteed by gradually constructing a multi-scale disturbance response mechanism and dynamic synchronous propulsion logic, and the distribution simulation capability of irregular boundaries and dynamic disturbance fields is remarkably enhanced.

A computer-implemented method for operating an X-ray device for acquiring projection images of an acquisition area, from which a three-dimensional image dataset of the acquisition area is reconstructed. The X-ray device has an acquisition arrangement with an X-ray generator and an X-ray detector for receiving X-ray radiation of an X-ray field which has a central beam and which is transmitted by the X-ray generator. For acquiring projection images of different projection directions, the acquisition arrangement is moved rotationally to cover a projection angular range encompassing at least 360° about the acquisition area. An opacification device is used that includes an opacification pattern that includes a section opacifying the X-ray radiation with at least two opacifying areas and a section permeable to the X-ray radiation with at least two permeable areas separated by an opacifying area. The opacification device is arranged in the X-ray field between the X-ray generator and the acquisition area such that each voxel to be reconstructed in the acquisition area, and which is opacified in a partial area of the rotation, is scanned by non-opacified X-ray radiation in another partial area of the rotation, that includes at least substantially the same number of acquisition geometries and / or encompasses a 180° angular section with respect to the projection of the projection direction into the plane of rotation.

The invention discloses a face recognition method based on adaptive sine angle robust principal component analysis, and belongs to the technical field of face recognition, and the method comprises the steps: obtaining a face image, and carrying out the preprocessing of the face image; constructing a robust principal component analysis model based on an adaptive sine angle, and training the robust principal component analysis model by using the training set; solving an optimal projection matrix by using a non-greedy iterative algorithm; mapping the original face features to a discrimination space by using the optimal projection matrix; and performing face recognition by using a nearest neighbor classifier, and performing robustness evaluation on a recognition result. According to the method, the adaptive sine angle is added, abnormal values can be effectively suppressed in the face of noise data, the influence of the abnormal values on the projection direction is reduced, and the method plays a key role in improving robustness.

The invention discloses a hand posture recognition method, a head-mounted display device and a storage medium, and relates to the field of man-machine interaction. In the method, projection correction is carried out on an image of a first hand region in a current frame image by iterating a projection direction for multiple times; the present invention corrects an image captured due to inclination of an observation line of sight into an image in which the line of sight is perpendicular to the center. In this way, the hand image sent into model reasoning overcomes the distortion influence, and the positions and the relative distances of the hand joint points obtained through model reasoning are more accurate. According to the invention, the problem that the coordinates of the predicted 3D hand articulation points are inaccurate due to image distortion is solved.

The utility model provides a display device and a lawn mower, relates to the technical field of lawn mowers, and is used for solving the technical problem that a lawn mower in the related technology is single in display function, the display device comprises a lattice screen and a light-emitting assembly, the light-emitting assembly is arranged around the periphery of the lattice screen, and an area surrounded by the light-emitting assembly is a display area of the lattice screen; the display device is further provided with a display panel, and patterns displayed independently or in a combined mode through the lattice screen and the light-emitting assembly are achieved on the display panel. The display device is detachably connected to the mower, in the overlooking projection direction, the distance between the edge of a display area of the display device and the edge of the display panel is smaller than 1 cm, and the ratio of the projection area of the display area of the display device to the projection area of the mower is larger than 5%. Large-screen display of the display device is achieved, operation and maintenance of technicians are facilitated, meanwhile, more content is displayed, the display function of the mower is optimized, and more man-machine interaction is achieved.

The utility model relates to a 3D display device. The 3D display device comprises a carrier, which is provided with a plurality of optical projection units; wherein each optical projection unit is provided with a plurality of independent projection surfaces, and the projection surfaces comprise a first projection surface which is vertically formed in a first direction and a second direction, a second projection surface which is vertically formed in the first direction and a third direction, and a third projection surface which is vertically formed in the second direction and the third direction; the projection direction provided by the projection surface of the single optical projection unit is a unidirectional outward direction, the projection direction of the first projection surface is a unidirectional outward first projection direction penetrating through the first projection surface, and the projection direction of the second projection surface is a unidirectional outward second projection direction penetrating through the second projection surface. The projection direction of the third projection surface is a third projection direction which passes through the third projection surface in a unidirectional outward manner.

The present invention relates to the field of atmosphere lamps, and in particular to a multi-meteor projection structure, a multi-meteor starry sky lamp and a multi-meteor projection control method. The multi-meteor projection structure comprises a plurality of light path structures; light rays generated by first light sources can sequentially pass through intersection points, first convex lenses and prisms, and are then projected to the outside; light spots formed by the light rays passing through the intersection points move along with the movement of the intersection points, and are amplified by the first convex lenses, the projection angle is changed by the prisms, and the meteor effect can be formed on the ceiling and / or the wall; and the light rays generated by the multiple first light sources can achieve the effect of generating multiple meteors at the same time by means of the respectively corresponding light path structures. By adjusting the rotation speed of a rotating disc and permutation and combination of the projection directions of multiple groups of first slits, second slits and prisms, a user can obtain numerous gorgeous and unduplicated meteor effects, and compared with a single-meteor effect, the user experience is improved to obtain a qualitative leap.

The invention discloses a ship spherical global image splicing method and system based on image processing, and the method comprises the following steps: obtaining multi-camera images which are distributed at the top, the bottom and the annular direction, and executing camera calibration and distortion correction; performing hemispherical projection and cylindrical projection by using a hybrid projection link; feature point extraction and matching are carried out, and an initial registration relation between adjacent view fields is established; executing APAP gridding local registration of projection perception, and generating local homography by applying an anisotropic weight kernel consistent with the region projection direction to obtain a partition alignment result set; carrying out weighted fusion and stitching suppression on the overlapped region to generate a panoramic spliced image; and converting the panoramic spliced image into an interactive three-dimensional panoramic view. According to the method, mixed projection and projection perception APAP algorithms are fused, ship spherical surface global high-precision splicing and three-dimensional immersion display are achieved, and the method has the advantages of being small in distortion, high in precision and high in visibility.

An electronic device including a projector; a memory storing at least one instruction, and at least one processor configured to execute the at least one instruction stored in the memory to receive a selection of first projection information from among at least one piece of projection information included in a projection information list, wherein each piece of the at least one piece of projection information includes a projection location, which corresponds to a position of the projector, and a projection purpose, adjust a projection direction of the projector to the first projection location, and control the projector to project, from the first projection location, first content corresponding to the first projection purpose.

The invention discloses a colon adenoma identification method and device based on Mueller matrix polarization measurement and regularization, a storage medium and electronic equipment. The method comprises the following steps: acquiring a polarization image corresponding to a fresh medical sample containing colon adenoma and normal tissue through a light polarization system, and preprocessing the polarization image; fourier analysis is carried out on a detection signal in the light polarization system to obtain a Mueller matrix, and a Lu-Chipman polarization decomposition algorithm is used for carrying out polarization decomposition on the Mueller matrix to obtain three polarization decomposition parameters; obtaining polarization data of a plurality of channels based on the Mueller matrix, and constructing a sample set based on the polarization data; constructing a target function based on the projection function and the sample set, solving the target function to obtain an analytic solution of the optimal projection direction, and calculating a characteristic value based on the analytic solution of the optimal projection direction; and classifying the polarization images corresponding to the fresh medical samples of the colon adenoma and the normal tissue based on the feature values to obtain a classification result. The lesion recognition rate can be improved.

A method is disclosed to automatically detect overhangs from images with depth taken around an object during a scan of the object. An overhang detector can use an intersection of three filters based on these images and depth data associated with the images. The first filter looks for negative depth gradients along a 2D projection of a gravity vector, which is generally a vertical axis for images taken using a portrait orientation. The second filter selects the depth gradients that are oriented towards the projection of the gravity vector. The third filter is a salient object detection mask computed from the image. An intersection of the three filters can then be used to obtain overhangs. The method can be implemented in real time with a User Interface (UI) directing a user of a location of the overhang so that an image below the overhang can be taken.

The invention relates to a roadway surrounding rock deformation monitoring device, system and method, and belongs to the field of industrial and mining equipment. According to the technical scheme, the roadway surrounding rock deformation monitoring device comprises a laser emitting assembly and a plurality of laser sensing assemblies, the laser emitting assembly comprises a plurality of laser emitting units, each laser emitting unit comprises a mounting frame, two laser positioning lamps are rotationally mounted in each mounting frame, and the multiple laser emitting units are arranged in the extending direction of a roadway; the laser induction assemblies are located in the projection directions of the multiple laser positioning lamps, and the multiple laser induction assemblies are electrically connected with the controller. According to the scheme, the laser emission unit is arranged to be a plurality of groups of paired laser positioning lamps, the projection angles of the laser positioning lamps are adjustable, and the laser induction assemblies with the corresponding number are matched, so that multiple positions of the surrounding rock of the roadway in one section are monitored, the monitoring is more comprehensive and perfect, and the reliability of monitoring data is improved; and the angle-adjustable form can adapt to roadways with different section shapes and sizes, so that the use is more flexible.

The invention relates to the technical field of costume design, and discloses a three-dimensional digital garment design garment platform which is characterized in that supporting columns extending in the height direction are arranged at the four corners of a supporting platform, and a cross beam is arranged at the tops of the supporting columns. The rotating disc is rotatably arranged in the center of the upper surface of the supporting platform through a driving device and used for supporting a human body. The supporting platform is provided with a sliding rail surrounding the rotating disc, and the scanning part is arranged on the sliding rail through a moving structure. The first projection part is movably arranged on the cross beam in the height direction, and the projection direction of the first projection part right faces the rotating disc in the height direction. The four second projection parts are movably arranged on the corresponding supporting columns in the height direction. The first projection component and the second projection component can enable a user to quickly try on clothes and more conveniently observe in all directions, and under the cooperation of the scanning component, the generated clothes image can better conform to the human body contour features of the user, the manufacturing of substantial clothes is not needed, and the waste of raw materials is avoided.

The invention relates to a method for generating an image, a method and a device for training an image generation model, computer equipment and a storage medium. The method comprises the following steps: acquiring a first projection view and a second projection view of an object in an orthogonal relationship in a projection direction; performing feature expansion processing on the first projection view and the second projection view to obtain a first three-dimensional feature map corresponding to the first projection view and a second three-dimensional feature map corresponding to the second projection view; performing fusion processing on the first three-dimensional feature map and the second three-dimensional feature map to obtain a fused feature map; and performing decoding reconstruction processing on the fused feature map to obtain a reconstructed image corresponding to the object. By adopting the method, the purpose of completing three-dimensional image reconstruction only by using two orthogonal projection views can be achieved.

This utility model provides a fully automatic multi-style handle cutting device, including a frame, a worktable, a first baffle, a second baffle, a cutting component, a feeding cylinder, and a discharging cylinder. The worktable and cutting component are mounted on the frame. The first and second baffles are arranged parallel to each other on the worktable, forming a first feeding channel between them. The cutting component is located at one end of the first feeding channel, and the discharging cylinder and feeding cylinder are located at the other end of the first feeding channel. The feeding cylinder and discharging cylinder are mounted on the worktable. The central axis of the feeding cylinder is parallel to the center line of the first feeding channel, and the central axis of the discharging cylinder is perpendicular to the central axis of the feeding cylinder in the orthographic projection direction. Compared with other handle cutting methods, this device has high working efficiency, can meet the needs of large-scale production, and significantly improves operational safety. It also improves processing accuracy, enhances the stability of the handle's forward movement, and can meet various handle cutting requirements.

A sheet feeding apparatus includes a stacking portion, a rotary feeding member configured to feed the sheet in a sheet feeding direction, a first separation portion including a separation surface, the detachable unit including a second separation portion. A direction that intersects both the sheet feeding direction and a rotation-axis direction of the rotary feeding member, and that extends from the separation surface toward the rotary feeding member is defined as a projection direction. The second separation portion is positioned downstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion. Another portion of the detachable unit other than the second separation portion is positioned upstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion.

The invention relates to the technical field of data processing, in particular to a handwritten font recognition and storage method for cold data archiving management. The method comprises the following steps: dividing a single font image into an intrinsic structure main body area and a style induction offset area based on the number of effective pixel points in each projection direction; determining a style influence degree according to the main body area and the offset area; clustering the single font images according to the style influence degree to form a cluster; according to the number of the single-font images in the clustering cluster and the style influence degree numerical range, the aggregation degree of the clustering cluster is determined; determining font structure ambiguity according to aggregation degree difference characteristics among the clusters; determining the overall font ambiguity by combining the font structure ambiguity; inputting the text image and the overall font ambiguity into a pre-training style correction model, and outputting a corrected text image; according to the method, the OCR algorithm is adopted to recognize and correct the handwritten fonts in the text image and store the handwritten fonts, so that the false recognition rate of handwritten font recognition is effectively reduced.

The application discloses a particle screenshot method and related equipment, the method comprises the following steps: acquiring a particle image to be processed, and cutting a field of view region from the particle image based on a preset frame selection range; performing integral projection on the field of view region to obtain a one-dimensional sequence group; performing weighted standardization on the initial one-dimensional sequence based on the field of view size of the field of view region in the projection direction to obtain a weighted one-dimensional sequence; performing smoothing processing on the weighted one-dimensional sequence to obtain a smoothed one-dimensional sequence; performing local peak marking based on the smoothed one-dimensional sequence to obtain a local peak position; converting the local peak positions corresponding to two projection directions of the horizontal direction and the vertical direction to obtain a particle position; and cutting a particle screenshot of a target particle from the field of view region based on the particle position. By introducing the weighted standardization link based on the field of view size, and combining the bidirectional integral projection, sequence smoothing and local peak detection, the particle positioning and screenshot can be efficiently and accurately realized. The application can be widely applied in the field of image processing technology.

The utility model discloses a visual communication projection device, and relates to the technical field of projection devices, the visual communication projection device comprises a bottom plate, the rear side of the top of the bottom plate is fixedly provided with a hollow stand column, an L-shaped rod is inserted in the hollow stand column, one end of the L-shaped rod is fixedly provided with a steering engine, and the output end of the steering engine is fixedly provided with a placing assembly. A projector is mounted in the placement assembly; universal wheels are fixedly installed at the four ends of the bottom of the bottom plate, hand-screwing bolts are installed on the upper sides of the outer surfaces of the hollow stand columns in a threaded mode, a plurality of through holes are formed in one side of the outer surface of each L-shaped rod from top to bottom at equal intervals, and the through holes are matched with the hand-screwing bolts. Through the innovation points of flexible height and position adjustment, free projection direction adjustment, efficient heat dissipation design, stable clamping protection and the like, the use flexibility and applicability of the projector are greatly improved, and the diversified requirements in the fields of modern multimedia display, education and teaching, business conferences and the like are met.