49 results about "Cardinal point" patented technology

The invention relates to the technical field of detection, in particular to a complex shell detection method and system based on structured light scanning. The method comprises the following steps: calculating a wrapped phase value and a phase modulation amplitude of each pixel point under each frequency, calculating discrete probability distribution containing candidate stripe series and a corresponding probability for each pixel point based on a multi-frequency wrapped phase difference, generating an initial pixel confidence map, and constructing an energy function; the penalty weight of the smooth item is determined according to the phase modulation amplitude and the wrapped phase gradient local variance, obtaining an initial fringe order distribution diagram, updating discrete probability distribution by using an initial pixel confidence map, re-minimizing an energy function to obtain a corrected fringe order distribution diagram, and reconstructing a final three-dimensional shape. And iteratively optimizing a projector principal point and a radial distortion coefficient in system calibration parameters. According to the scheme, the geometric details of the surface can be reserved, and the processing effect and the measurement precision of the complex curved surface and the high-curvature area are improved.

The invention discloses a depth measurement method, a camera calibration result evaluation method, equipment and a storage medium, and relates to the technical field of machine vision, and the method comprises the steps: obtaining an object distance and a collection image for a target feature point; calculating a sight line included angle according to the pixel coordinates of the target feature point in the acquired image; acquiring a principal point offset between the center and the optical center of the camera lens; and calculating depth information of the target feature point according to the triangle theorem in combination with the main point offset, the object distance and the sight line included angle. Therefore, the method can dynamically adapt to the spatial relationship between different feature points and the camera, corrects the measurement error caused by the fact that the attitude position of the feature point relative to the optical center is not considered in a traditional method, and improves the depth measurement precision of the camera.

The invention relates to a method for preparing a composite structure, comprising the following steps: 1) providing a composite structure comprising a growth layer made of monocrystalline silicon carbide, a free face of which extends along a main plane, which growth layer is arranged on a support substrate, the growth layer being delimited by a peripheral perimeter and having a crystallographic orientation such that there is: a disorientation angle between a given crystallographic plane and the free face, a disorientation direction, which corresponds to a projection of an axis normal to the free face onto the crystallographic plane, and a reference direction, which corresponds to a projection of the disorientation direction onto the main plane; 2) forming a trench in the growth layer, the trench having an inner edge which extends at a distance and continuously along the peripheral perimeter, following a contour such that, by defining four cardinal points (North-South-West-East) on the peripheral perimeter, with the West-East direction corresponding to the reference direction: the contour passing through the cardinal points North-West-South follows the general shape of the peripheral perimeter, and the contour passing through the cardinal points North-East-South has a saw-toothed pattern. The invention also relates to a composite structure capable of being made using the aforementioned preparation method.

The invention discloses a three-dimensional imaging method and system based on multiple cameras and a computer readable storage medium. The method is applied to a three-dimensional imaging system comprising a plurality of cameras, and comprises the following steps: shooting a target object by using the calibrated three-dimensional imaging system; searching pixel points on the image shot by the first camera to obtain sub-pixel points on images shot by other cameras; carrying out normalization and distortion removal on pixel points on the image of the first camera and sub-pixel points on the images of other cameras to obtain projection points on a normalized imaging plane; for each group of projection points, leading out a plurality of straight lines pointing to the projection points from the main point of each camera; and for each group of straight lines, obtaining a space point coordinate with the minimum Euclidean distance sum from each straight line in the group of straight lines in the space as a three-dimensional space coordinate of the target object. According to the three-dimensional imaging method and system and the computer readable storage medium, positioning can be carried out more accurately, and the precision of three-dimensional reconstruction is improved.

The invention relates to the technical field of data processing, and provides a target motion estimation method and device based on an optical flow method, and the method comprises the steps: collecting k continuous images corresponding to a to-be-detected target through an image collection device, and obtaining a to-be-detected target image set; determining optical flow field information of the to-be-detected target according to the to-be-detected target image in the to-be-detected target image set based on an optical flow method to obtain first optical flow field information; scene flow information of a to-be-detected target is determined according to equipment parameters of an image acquisition device and the first optical flow field information, first scene flow information is obtained, and the equipment parameters of the image acquisition device comprise the focal length and main point position information of the image acquisition device; and performing motion estimation on the to-be-detected target according to the first scene flow information to obtain a motion estimation result, so that the light flow information of the to-be-detected target can be adopted to perform motion estimation to obtain the motion estimation result, and the accuracy of determining the motion estimation result is improved.

The application discloses a kind of three-dimensional imaging method, system and computer readable storage medium based on multiple cameras.The method is applied to the three-dimensional imaging system including multiple cameras, comprising: using the three-dimensional imaging system of calibration takes target object;For the pixel point on the image that first camera takes, find the sub-pixel point on the image that other cameras take;For the pixel point on the image of first camera and the sub-pixel point on the image of other cameras, by normalization and distortion removal, obtain the projection point on the normalized imaging plane;For each group of projection points, from the principal point of each camera, multiple straight lines pointing to the projection point are drawn;For each group of straight lines, obtain the spatial point coordinates of the minimum Euclidean distance from each straight line in the group of straight lines in space, as the three-dimensional space coordinates of target object.The above-mentioned three-dimensional imaging method, system and computer readable storage medium can be more accurately positioned, improve the accuracy of three-dimensional reconstruction.

The present application relates to underwater optical imaging, in particular to a method for calculating the distance of underwater laser radar based on Shash imaging and a method for calculating the distance resolution, in order to solve the problem that the existing underwater laser radar based on Shash imaging does not establish a related imaging model, resulting in that the underwater Shash imaging mainly relies on post calibration to improve the detection accuracy, and the underwater operation amount of post calibration is huge, the method for calculating the distance of underwater laser radar based on Shash imaging is provided with an underwater Shash imaging system, the laser is vertically irradiated to the target under water, the camera images the diffuse reflection laser line on the surface of the target, then the object distance of the target can be directly calculated, so as to obtain the distance of the object main point of the target relative to the horizontal plane of the camera, and the distance resolution is further calculated by using the above object distance.

The application is a method for calibrating the center of a linear in unit sphere model projection hyperboloid camera, characterized by using only one image containing two straight line images, five internal parameters of the camera are recovered. First, the pixel coordinates of the edge points of the two straight line images and the mirror profile image are extracted from one image respectively, and the equations of the two straight line images and the mirror profile image are obtained by using the least square method. On the basis of obtaining the equations of the two straight line images and the mirror profile image, the common vanishing point of each straight line image and the mirror profile image is obtained by solving the generalized eigenvector, and the vanishing line of the mirror profile image corresponding to the support plane is recovered by connecting the two common vanishing points. According to the polar point-polar line relationship, the polar point of the mirror profile image corresponding to the vanishing line is recovered, that is, the principal point. Because the two straight line images and the mirror profile image correspond to three different support planes, the vanishing line of the support plane corresponding to the two straight line images can be recovered by using the principal point. The vanishing line is associated with the corresponding straight line image, and the constraints of three pairs of independent circular ring point images are recovered. The image of the absolute quadratic curve is Cholesky decomposed and inversely solved, and the camera internal parameter matrix is uniquely determined.

The application provides a high-precision calibration method, device and equipment for mapping camera interior orientation elements and a storage medium. The method comprises the following steps: firstly, using a collimator and an electronic theodolite to independently calibrate the rotary table angle positioning error and the parallel light tube optical axis pointing deviation, respectively, to generate an error correction model and a space angle matrix, and converting the device system error into a known quantity that can be compensated; secondly, using a positive and negative mirror center-finding method to iteratively converge to determine the accurate intersection point of the sight axis and the target surface as the main point initial observation value and the sight axis reference angle, and eliminating the uncertainty of the main point; finally, starting from the reference angle to perform full field scanning and collection, and jointly substituting the corrected angle data, the angle matrix and the main point observation value into the collinearity condition equation for overall adjustment solution, so that the interior orientation elements and the distortion parameters purely reflecting the characteristics of the camera itself are solved under the premise that various system errors have been stripped one by one.

This invention discloses a method for extrinsic parameter calibration between a camera and a lidar based on the vanishing point method, comprising the following steps: S1, acquiring an optical image of a target reference object using a camera, and acquiring laser point cloud data of the target reference object using a lidar; S2, determining the principal point and focal length of the camera based on the optical image; S3, processing the laser point cloud data based on the determined principal point and focal length of the camera to obtain a lidar projection image; S4, calibrating the extrinsic parameters between the camera and the lidar using the vanishing points of the optical image and the lidar projection image, and obtaining the extrinsic parameter calibration results; S5, further optimizing the camera's principal point, focal length, and extrinsic parameter calibration results using an iterative optimization method to obtain optimized extrinsic parameter calibration results. This invention utilizes vanishing points to solve the extrinsic parameter calibration problem between a camera and a lidar in scenarios without a calibration board, improving the efficiency and accuracy of extrinsic parameter calibration between lidar and camera.

This invention discloses a laboratory geometric distortion calibration method for large-aperture cameras, belonging to the field of aerospace optical remote sensor technology. The method first establishes a demonstration and verification environment for precise calibration of camera geometric distortion, with the target sphere of the laser tracker located at the infinity focal plane of the camera's main lens. The planar reflector is rotated multiple times within the full field of view of the camera's main lens. After each rotation, the target sphere is positioned at the infinity focal plane of the camera's main lens, and the current rotation angle of the planar reflector and the position of the target sphere are tested. Based on each rotation angle of the planar reflector and the position of the target sphere, the principal point, principal distance, and distortion of the camera's main lens are calculated. Through the application of this invention, high-precision calibration of the geometric distortion of large-aperture cameras is achieved.

The present invention provides a self-position estimation device and method that enable highly accurate self-position estimation of a camera without being affected by refraction errors caused by a light-transmitting part placed in front of the target. [Solution] The self-position estimation device 50 includes a self-position estimation unit 62 that estimates the self-position of the camera 20 based on an image taken by the camera 20 of a target group 16 in which a transparent window material 30 is placed in front of a plurality of targets 24; a line of sight detection unit 68 that detects a line of sight L from the principal point of the camera 20 toward the target 24 through the transparent window material 30 based on the self-position of the camera 20 estimated by the self-position estimation unit 62; and a correction unit 70 that corrects the self-position of the camera 20 based on the distance between the line of sight L and the target 24.

The application discloses a light center and principal point testing method, testing equipment and storage medium of a camera module. The light center and principal point testing method of the camera module comprises a light center test. The light center test comprises obtaining a calibration plate image. The calibration plate image comprises a plurality of color block patterns corresponding to color blocks on the calibration plate. A curved surface fitting algorithm is used to remove the color block patterns in the calibration plate image to obtain a light center test image. The middle region of the light center test image has a high gray value, and the surrounding region has a low gray value. A pixel point set with a gray value greater than a threshold Threshoc is selected to obtain a light center region. The center coordinates (OCx, OCy) of the light center region are calculated as the coordinates of the light center of the camera module. The calibration plate image is used for light center calculation, which is beneficial to avoid light center testing by an additional uniform light source, thereby simplifying the process of light center and principal point testing and improving the efficiency of light center and principal point testing.

The present application relates to the technical field of detection, and particularly relates to a complex shell detection method and system based on structured light scanning. The method comprises the following steps: calculating the wrapped phase value and phase modulation amplitude of each pixel point at each frequency, calculating the discrete probability distribution containing the candidate fringe order and the corresponding probability for each pixel point based on the multi-frequency wrapped phase difference, generating an initial pixel confidence map, constructing an energy function, determining the penalty weight of the smoothing term according to the phase modulation amplitude and the local variance of the wrapped phase gradient, obtaining a preliminary fringe order distribution map, updating the discrete probability distribution by using the initial pixel confidence map, re-minimizing the energy function to obtain a corrected fringe order distribution map, reconstructing the final three-dimensional topography, and iteratively optimizing the projector principal point and the radial distortion coefficient in the system calibration parameters. That is, the scheme of the present application can preserve the surface geometric details, improve the effect of processing the complex curved surface and the high-curvature area, and improve the measurement accuracy.

An anti-vibration mechanism for an imaging device is provided in an imaging device including a camera shake correction mechanism. Provided is an optical system which, in an imaging device provided with an optical system that moves in the direction of an optical axis and includes a focus adjustment mechanism, has an anti-vibration mechanism that performs camera shake correction by preventing vibration of an imaging element, and which, in order from the object side, is provided with an imaging lens group, an anti-vibration mechanism, and an imaging element on the anti-vibration mechanism. The image pickup element on the anti-vibration mechanism is rotated with respect to the optical axis of the image pickup lens group, and camera shake correction is performed.

A light source module includes: a plurality of optical units, wherein each of the plurality of optical units includes: a semiconductor laser element that emits laser light; a fast axis cylindrical lens (FACL); a first fast axis adjustment lens (first lens); and a slow axis collimator lens (SACL), and α satisfies Formula 1: α=F2 / F1 (Formula 1), β satisfies Formula 2: β=d / F2 (Formula 2), and when F2>0, α and β satisfy Formula 3, Formula 4, Formula 5, and Formula 6: α>1 (Formula 3), αβ>1 (Formula 4), β<(1 / α)+(⅓) (Formula 5), β<1 (Formula 6), where F1 denotes an effective focal length of the FACL, F2 denotes an effective focal length of the first lens, and d denotes a distance between a principal point of the FACL and a principal point of the first lens.

The embodiment of the invention discloses a multi-lens camera calibration method and system and a storage medium, and is applied to the technical field of information processing. According to the initial camera parameters of the multi-lens camera, extracting a plurality of feature point sets in a matching space with overlapped images among all sub-lens panoramic images synchronously shot by a plurality of lenses of the multi-lens camera respectively, and determining three-dimensional space points corresponding to the plurality of feature point sets; in this way, when camera parameters are calibrated according to three-dimensional space points, the rotation and the position of the main lens in the multiple lenses are fixed, and two rounds of calibration are conducted on the image main points of the multiple lenses and the rotation of the auxiliary lens under the two conditions that the multiple lenses share the focal length or do not share the focal length. In this way, multiple rounds of calibration are carried out on part of camera parameters, under-fitting caused by too poor initial camera parameters can be reduced, and the situation that when the initial camera parameters are too far away from an ideal camera parameter combination, a loss function falls into a local optimal solution due to the fact that all the parameters are optimized at the same time is avoided.

The application provides a camera intrinsic parameter automatic calibration method, comprising the following steps: S1, acquiring a set of original images of a general scene shot by a camera; S2, extracting first edge information of each original image in the set of original images through an edge detection algorithm, wherein the first edge information comprises image coordinates and gradient directions of first edge points; S3, performing straight line detection on the first edge information based on a 4D Hough space, and acquiring an initial estimated value of a lens distortion parameter; S4, counting a total number of effective straight lines in the set of original images; S5, judging whether the total number of effective straight lines is greater than a given first threshold value, if yes, entering S6, otherwise, returning to S1; S6, iteratively optimizing camera intrinsic parameters based on the 4D Hough space by using the effective straight lines; and S7, updating the camera intrinsic parameters and performing image correction. The application calibrates a principal point of the camera and the lens distortion parameter by using images of a general scene, and can simplify a calibration process of camera intrinsic parameters.

This invention provides a thermal drift compensation method and system for a 3D structured light camera. It uses fixed physical markers within the scene to provide a reference ground truth, monitors and quantifies the scan amplitude contraction and static origin drift caused by galvanometer thermal drift in real time, calculates the deviation between the current wrapped phase and the reference phase, and performs forced phase alignment compensation across the entire field to avoid misjudgment of multi-frequency heterodyne unwrapping order. It dynamically reconstructs the projector intrinsic parameter matrix, uses the scaling factor s and translation vector t to correct the equivalent focal length and principal point coordinates in real time, and uses the calibration plate depth residual for closed-loop iterative optimization. This invention does not rely on a temperature model, effectively eliminates thermal hysteresis, ensures the stability of phase unwrapping and the geometric accuracy of 3D reconstruction across the entire temperature range, and is ready to use upon startup. It overcomes the shortcomings of traditional open-loop temperature compensation, and compensates for thermal drift errors in real time through closed-loop feedback, improving the stability and accuracy of 3D reconstruction in the structured light system.

The invention provides a camera calibration method, calibration device and system based on a single-frame single calibration board, and relates to the technical field of computer vision, and the method comprises the steps: calculating the second position information of each target feature point in a camera coordinate system according to the first position information of a plurality of selected target feature points in a world coordinate system; inputting the second position information and the spatial translation vectors of the origin of the world coordinate system and the origin of the camera coordinate system into a radial constraint equation, and calculating to obtain an initial focal length and a principal point coordinate of the camera to be calibrated; determining an initial distortion coefficient according to the initial focal length, the principal point coordinates, a preset radial distortion equation and a radial constraint equation; and performing multiple iterative calculations on the initial distortion coefficient by using the focal length optimization function to determine the final internal reference of the to-be-calibrated camera. According to the invention, calibration of the camera is realized only by using a single frame of image and a single calibration board, the calculation amount is small, and the camera calibration efficiency is improved.

The invention discloses an optical center and principal point testing method and testing equipment of a camera module and a storage medium, the optical center and principal point testing method of the camera module comprises the steps of optical center testing and optical center testing, the optical center testing comprises the steps of obtaining a target image, the target image comprises a plurality of color block graphs, and the color block graphs correspond to color blocks on the target; a curved surface fitting algorithm is adopted, color block graphs in the target plate image are removed, so that an optical center test image is obtained, the gray value of the middle area of the optical center test image is high, and the gray value of the surrounding area of the optical center test image is low; selecting a pixel point set of which the gray value is greater than a threshold value Threshoc to obtain an optical center region; and calculating the center coordinates (OCx, OCy) of the optical center region as the coordinates of the optical center of the camera module. Therefore, optical center calculation is carried out by using the target plate image, and optical center testing through an extra uniform light source is avoided, so that the optical center and principal point testing process can be simplified, and the optical center and principal point testing efficiency can be improved.

A light source module (10) includes: a plurality of optical units (1 to 6), wherein each of the plurality of optical units (1 to 6) includes: a semiconductor laser element (200) that emits laser light; a fast axis cylindrical lens (FACL) (110); a first fast axis adjustment lens (first lens) (120); and a slow axis collimator lens (SACL) (170), and α satisfies Formula 1: α=F2 / F1 β satisfies Formula 2: β = d / F2 (Formula 2), and when F2 > 0, α and β satisfy Formula 3, Formula 4, Formula 5, and Formula 6: α>1 αβ > 1 (Formula 4), β<1 / α+1 / 3 β<1 where F1 denotes an effective focal length of the FACL (110), F2 denotes an effective focal length of the first lens (120), and d denotes a distance between a principal point of the FACL (110) and a principal point of the first lens (120).

The embodiment of the invention discloses an all-time field astronomical measurement system calibration method and device. A specific embodiment of the method comprises the following steps: setting an infrared control point with a fixed position; controlling the all-day field astronomical measurement system to perform back-measurement observation on the infrared control points from a plurality of observation directions to obtain an observation data set; and according to the observation data set and a pre-constructed observation equation, through a least square method, carrying out measurement calibration to obtain a horizontal direction value and a vertical direction value corresponding to the infrared control point, a camera main distance, a first-order radial distortion coefficient and an image plane rotation angle, and respectively carrying out disc left image main point coordinate calibration and disc right image main point coordinate calibration. According to the embodiment, high-precision camera parameters can be obtained.

The invention relates to the technical field of attitude detection, in particular to a visual and spatial attitude alignment camera system, which comprises a focal length texture construction module, a guide pattern generation module, a boundary point location extraction module, a feature sequence screening module and an attitude line structure adjustment module. According to the method, the brightness jump direction and amplitude are obtained in the image focal length difference, the response structure is constructed in combination with the block directivity difference, the superposition range is limited through alignment of the brightness direction and the pattern, the boundary action area is extracted, interference points are eliminated according to the boundary direction and gradient consistency, and then a direction set is formed. And comparing an image inter-frame sequence order to screen a continuous principal point set, and combining a frame acquisition time change trend and a drift frequency compression matching window to integrally realize directional extraction of a weak edge structure in the image, spatial sequence stability verification and fine analysis of an attitude change rhythm. And the posture recognition precision under shielding interference and illumination variation is enhanced.

This eliminates the need to acquire pattern images from multiple viewpoints to obtain the camera's optical parameters, improving robustness against shifts in shooting position. [Solution] A camera calibration method that acquires a pattern image obtained by photographing calibration boards 30 and 32, each equipped with two spaced-apart pattern boards, using cameras 10, 12, and 14; obtains principal point coordinates indicating the position of the lens optical axis on the image sensor based on the patterns displayed on the two pattern boards captured in the pattern image; and uses the principal point coordinates and the relative positional relationship between cameras 10, 12, and 14 and the calibration boards 30 and 32 to acquire optical parameters other than the principal point coordinates, including the focal length, based on the pattern image.

The invention discloses a method and a device for calibrating a camera by observing a far target. The method comprises the following steps: S1, determining a principal point coordinate of the camera according to a characteristic that an image of a line segment coinciding with an optical axis on the camera is a principal point; s2, in combination with celestial body observation, acquiring real field angles of at least two remote targets relative to the optical center of the camera; s3, solving the focal length of the camera based on the principal point coordinates and the real field angle; and S4, gradually expanding from a distortion known region in the center of the pixel plane, and solving the full-pixel plane distortion characteristic of the camera. The required equipment is simple, and the cost is low; wherein the far target can be simulated by an optical method, so that the target identification degree is improved and the calibration field is reduced. The calibration process is carried out step by step, large-scale parameter optimization and falling into local minimum are avoided, and the reliability of the calibration result is improved.

The application provides a distortion correction method and device, electronic equipment and storage medium, wherein the method comprises: determining actual coordinates corresponding to a plurality of calibration points according to target images obtained by photographing the plurality of calibration points by a target camera; determining principal point coordinates and focal length of the target camera according to the actual coordinates corresponding to the plurality of calibration points; constructing a mixed effect model of the target camera based on the actual coordinates corresponding to the plurality of calibration points, the principal point coordinates and the focal length of the target camera, wherein the mixed effect model comprises a fixed effect model and a random effect model; and performing distortion correction on an imaging area of the target camera through the mixed effect model. The mixed effect model constructed by the application can capture global trends of distortion and correct local residual distortion, thereby achieving high-precision correction of full-field distortion, improving adaptability and robustness of distortion characteristics of different cameras, and being able to adapt to significant differences in regional distortion of large-field cameras.

A method includes identifying a passthrough transformation associated with a VST XR device. The VST XR device includes see-through cameras that are (i) offset from forward axes extending from expected locations of a user's eyes and / or (ii) rotated such that optical axes of the see-through cameras are angled relative to the forward axes. The method also includes obtaining images captured using the see-through cameras, applying the passthrough transformation to the images to generate transformed images, and displaying the transformed images on one or more display panels of the VST XR device. The passthrough transformation is based on (i) a first transformation between see-through camera viewpoints and viewpoint-matched virtual camera viewpoints and (ii) a second transformation that aligns principal points of the see-through cameras and principal points of the one or more display panels.

The application discloses a depth and width estimation method based on binocular stereo vision and belongs to the field of computer vision. The method uses a binocular stereo camera to acquire images, establishes a mathematical model by using the relationship between the depth of an observation target distance imaging plane and the parallax and the relationship between the observation point's approximate width and the parallax, calibrates the depth and the width respectively, and thus provides a method for solving the real distance from the observation point to the principal point of the camera in a world coordinate system. The method also considers the error caused by the different principal points of the left and right cameras due to the camera installation problem, and improves the calculation precision of the depth and the width by fitting.

This invention discloses a method, apparatus, medium, and device for evaluating camera distortion correction effects. The method includes: performing affine transformation processing on a target object image after distortion removal, ensuring the target object is within the image range and that the feature points in the middle and edge portions of the processed target object image have consistent scales; detecting all feature points in the processed target object image and performing line fitting on feature points located on the same straight line to obtain the straight line containing each feature point; calculating the distance error from the feature point to the straight line containing the feature point for each feature point, and converting the distance error corresponding to the feature point into an angular error from the feature point to the principal point of the camera lens; and evaluating the distortion correction effect based on the angular errors corresponding to all feature points. This invention, by converting the straightness error from distance error to angular error, enables the use of a unified evaluation standard, thereby achieving a unified evaluation of the camera distortion correction effect.