627 results about "Checkerboard" patented technology

The invention discloses an accurate part positioning method based on binocular microscopy stereo vision, which belongs to the technical field of computer visual measuring and relates to an accurate precision part positioning method based on the binocular microscopy stereo vision. A binocular microscopy stereo vision system is adopted, two CCD (charge coupled device) cameras are adopted to acquire the images of the measured parts, the image information in the to-be-measured area on the measured part is amplified by a stereo microscope, a checkerboard calibrating board is adopted to calibrate the two CCD cameras, and a Harris corner point detecting algorithm and a sub-pixel extracting algorithm are adopted to extract feature points. The extracted feature points are subjected to the primary matching and correcting of matching point pairs, and the feature point image coordinates are inputted to a calibrated system to obtain the space actual coordinates of the feature points. The accurate part positioning method based on the binocular microscopy stereo vision solves the measuring difficult problems generated by the small size of the to-be-measured area, high positioning demand, non-contact and the like. The accurate positioning of the precision part is well finished by adopting the non-contact measuring method of the binocular microscopy stereo vision.

The invention belongs to the field of digital image processing and discloses a fisheye image correction method after calibration conducted by a fisheye lens. The method includes the steps that firstly, a complete fisheye camera projection and distortion model is established and is a commonly-used fisheye model, a self-made planer calibration board and the commonly-used fisheye model are used for calibrating model parameters of a fisheye camera, and the calibrated lens distortion parameters are used for restoring circular distortion fisheye images to perspective images meeting the requirements for the human eye visual effect. The fisheye lens calibration and fisheye distortion correction method based on a planar checkerboard is quite suitable for occasions such as visual navigation and mobile monitoring. The method is suitable for the circular fisheye images and incomplete fisheye images can be corrected as well.

An integrated imaging element for an interferometer generates at least one interference image that includes multiple interference portions with different relative phase shifts interleaved in a pattern having a high spatial frequency in the image. The interleaved pattern is at least partially determined by the pattern of a high density relative retarder array used in the integrated imaging element. In various embodiments, the multiple interference portions are interleaved in a checkerboard-like pattern across the entire surface of a detector device. As a result, various non-common mode errors present in various interferometers that generate separate non-interleaved images for each relative phase are reduced or eliminated.

The invention proposes a panoramic camera calibration method. First two calibration plates are manufactured on the same electronic display screen, and left and right calibration plates are distinguished through design of different calibration graphs or different sizes of checkerboards; then a calibration reference coordinate system is established based on the calibration plates, relative position posture transfer relations between left and right camera coordinate systems and the calibration reference coordinate system are calculated separately; a relative relation matrix calibrated by a ''back-to-back'' type binocular camera under the same calibration reference coordinate system is obtained; and a plurality of groups of images are shot, and taking a minimum error of a reprojection image point and an actual image point as an objective function, iterative optimization is performed, thereby realizing accurate calibration. The method provided by the invention can be popularized to a plurality of cameras, and can be used for calibration of application scenes of back-to-back binocular cameras, annularly arranged multiple cameras and the like.

The invention relates to a method for detecting the angular points of checkerboards under a complicated background, and belongs to the technical field of computer information image processing. The method comprises the following steps: firstly, down-sampling an image, then up-sampling the image, dividing the image into three passages RGB at the same time, detecting the regions respectively, extracting the border of the image by adopting Canny operator, and then dividing the image by adopting an adaptive threshold; approximating the rectangles in the image by adopting the Douglas-Peucker method so as to detect the rectangular regions in the image; obtaining the peak of each rectangle after detecting the rectangles, and clustering angular points of the same type; and statistically averaging the angular points of the same type, of which the amount is maximum in a neighbor range to detect the obtained angular points. The invention provides a method for detecting angular points on the basis of rectangles. The method which detects specific angular points by utilizing the symmetry and rectangular characteristic of the image of a checkerboard has the advantages of good real-time property and reliability.

The invention discloses a calibration plate used for binocular camera calibration and a binocular camera calibration method. In an existing camera calibration method technology, a high precision calibration reference object is difficult to make, cost is high, operation is complex and tedious, calibration precision is not high and so on. By using the calibration plate and the method, the above problems are solved. The calibration plate used for binocular camera calibration comprises an electronic equipment terminal machine and a display, wherein the electronic equipment terminal machine is used for receiving resolution information and outputting plane checkerboard image driving information according to a resolution; and the display is used for receiving the plane checkerboard image driving information and displaying a plane checkerboard image.

The invention relates to an open area target detection and tracking method based on binocular vision sparse point matching. The open area target detection and tracking method based on the binocular vision sparse point matching comprises the following steps. Calibration of video cameras is achieved by utilizing a Zhang checkerboard calibration method, and a transformational relation between a video camera coordinate system and a user-defined world coordinate system is established. Afterwards, related algorithm of the method is executed, wherein synchronous images of two video cameras are input. The images are first corrected to an extreme line parallel state, and then sparse characteristic point matching is achieved by utilizing extreme line constraint. Matching points are mapped to the world coordinate system and projected to a ground plane. Discrete point clustering is achieved by means of human body type information and a golden section ratio. Finally, robust detection and tracking of pedestrian targets in a monitoring area are achieved with the clustering as a unit and by combining joint probability data association and target color information. According to the open area target detection and tracking method based on the binocular vision sparse point matching, the operating amount is enabled to become small, and the target detection and the tracking are enabled to be accurate.

The invention relates to an outer parameter calibration device and calibration method of a laser radar and a visual camera. The device comprises a support with universal wheels, a telescopic sleeve, an expansion link inserted into the upper end of the telescopic sleeve and of which the position is fixed by an expansion link fixing nut, a ball cup fixed at the upper end of the expansion link, a ball support connected with the call cup and a calibration plate connected with the ball support arranged in sequence; the calibration plate is a circular black plastic plate with a smooth surface, and acircular hole is formed closed to the edge position of the circular black plastic plate; square slots are milled in the surface of the calibration plate according to a checkerboard, and white squarealuminum alloy sheets are embedded into the slots, so that the aluminum alloy sheets and the calibration plate are formed into a rectangular black-white checkerboard form with the smooth surface. Compared with the prior art, the outer parameter calibration device and calibration method have the advantages of being practical, simple, convenient and strong in universality.

The invention discloses a method for improving camera calibration accuracy by using a multi-plane calibration board. The method comprises the following steps: splicing two calibration substrates drawnwith checkerboard dot patterns to obtain a calibration board; calculating three-dimensional world coordinates of chessboard corners, and merging the three-dimensional world coordinates in the same three-dimensional world coordinate system; acquiring an image of the calibration plate by using a to-be-calibrated camera, and performing filtering preprocessing to obtain a calibration image; determining target corner points on the calibration image and obtaining image pixel coordinates, wherein the image pixel coordinates of the target corner points are in one-to-one correspondence with the three-dimensional world coordinates of the chessboard corner points; calculating and solving a reprojection transformation equation, and performing decomposing to obtain a rotation vector and a translationmatrix; converting the rotation vector into a corresponding rotation matrix, and optimizing the rotation matrix and the translation matrix through a bundle adjustment method after reprojection. The multi-plane calibration plate is formed by splicing the two calibration substrates, the camera calibration precision can be improved, and the problem that errors are large in camera pose estimation is effectively solved.

The invention discloses a robust lens distortion correction method. The invention provides a method for separating lens distortion from camera parameters to be solved separately. The method comprisesthe following steps of: performing a feature extraction from a checkerboard calibration object by firstly performing angular point detection utilizing a Shi-Tomasi operator, then performing screeningaccording to the specific characteristics of symmetry and large variance of the checkerboard angular point, and finally obtaining an sub-pixel coordinate with accurate checkerboard angular point by utilizing a sub-pixel optimization algorithm; establishing a camera imaging model and a lens distortion model to obtain an optimized objective function with respect to a distortion parameter; and solving the distortion parameter by utilizing a nonlinear optimization algorithm for distortion correction. According to the robust lens distortion correction method, a calculation of all main distortion parameters can be accomplished with only one calibration object image containing the checkerboard, the model is simple, the calculation efficiency and stability are high, the application adaptability isgood in an industrial field, and the calculation accuracy is comparable to a traditional method.

A device includes a coder or a codec configured for interleaved image data utilizing diamond shaped blocks for motion estimation and / or motion compensation and utilizing square or orthogonal transforms of residual data. In various embodiments, the decoder may be configured, among others, to perform de-blocking on edges of the diamond shaped blocks and / or data padding at boundaries of the image data. Additionally a method is proposed in which at least one of a transform and quantization process to be applied to de-multiplexed data is modified. One application is to combine left and right stereoscopic images, interleaved in a checkerboard manner.

The invention discloses a directional calibration target for camera inner and outer parameter calibration. The directional calibration target is characterized by comprising a checkerboard and directional mark patterns, wherein the checkerboard is formed by black squares and white squares in alternate distribution; the directional mark patterns are arranged in a position near the center position of the checkerboard; the directional mark patterns are three mark circular rings or three mark circles; intersection points of any two diagonally connected black squares or intersection points of any two diagonally connected white squares are used as feature corner points of the directional calibration target; the feature corner points are used for camera calibration; and the directional mark patterns are used for judging the rotation direction of the directional calibration target. The directional calibration target has the advantages that in the camera calibration process, a computer can automatically judge the rotation direction of the directional calibration target; the intelligence and the flexibility of the camera calibration are improved; and the calibration complexity is reduced.

The invention provides an efficient marking method combining laser point cloud and an image. The method comprises: performing initial external parameter automatic calibration through the planar checkerboard target image data and the laser point cloud data; pre-annotation is realized through an automatic segmentation algorithm; image annotation information is further refined in combination with a small amount of manual intervention and calibration; the method comprises the following steps: determining a three-dimensional laser point cloud corresponding to an image marking object in a back projection mode, then obtaining an accurate three-dimensional point cloud of a to-be-marked target in a re-segmentation clustering and growth mode, and finally performing external parameter further optimization through the accurately matched three-dimensional point cloud and the image marking object. According to the efficient marking method combining the laser point cloud and the image, a large amountof manual intervention is not needed, the difficulty of laser point cloud marking is reduced, the marking efficiency is improved, and meanwhile the high marking precision is achieved. Not only can the point-by-point category information of the laser point cloud be obtained, but also novel labeling data such as image and laser point cloud object level joint labeling information can be obtained.

An imaging apparatus consists of multiple miniaturized microscopes arranged into an array capable of simultaneously imaging a portion of an object. A step-and-repeat approach is followed to scan the object and generate multiple sets of checkerboard images. In order to improve the quality of the composite image produced by concatenation or stitching of the checkerboard images, the performance of each microscope is normalized to the same base reference for each relevant optical-system property. Correction factors are developed through calibration to equalize the spectral response measured at each detector; to similarly balance the gains and offsets of the detector / light-source combinations associated with the various objectives; to correct for geometric misalignments between microscopes; and to correct optical and chromatic aberrations in each objective.

With an object of solving problems existing in the prior art, the invention provides a fully automatic calibration method for a high performance camera under a complicated background. The method is combined with a Robust's checkerboard corner detection method, and two groups of checkerboards corners are adopted to serve as filters on the basis of the characteristics of the corners to filter marker images. Eight filters of two types are reduced to four filters of two types, which means that the wave processing amount halves and therefore, the calibration speed increases. Further, the method utilizes a Zhang's camera calibration method to mark the camera calibration parameters. The method utilizes the marked camera calibration parameters to standardize images to be corrected, and a normalized correlation of the standardized images is calculated, and then sub-pixel precision checkerboard corners are obtained. The method then re-projects the coordinate of the checkerboard corners onto image space to obtain a precise coordinate of the corner image. The newly obtained coordinate of the corners is then substituted into the Zhang's calibration method to obtain new computed camera parameters. By repeating the above steps, a performer can obtain highly precise camera parameters. According to the embodiments of the invention, it is possible for a performer to complete automatic corner detection and camera calibration without having to resort to human-machine interactive operations.

The DRAM structure arranges active region of each storage crystal cell on substrate solely; and designs pattern of deep groove as checkerboard type arrangement a fixed pitch is maintained between each adjacent pattern of deep groove. Active regions of diagonal adjacent each two storage units are connected electrically by using long type bit line contact plug. A contact window is setup at each long type bit line contact plug in order to connect bit line. Thus, same bit line can control diagonal adjacent storage units.

A process for enrobing a core, such as a tablet core, uses a coating that is made of a patterned film having portions that are visually distinct (e.g, differently colored) from one another and having a transition line segment between these visually distinct portions. At least a portion of an outer surface of the core is covered with the film, such that the transition line segment forms a substantially continuous transition line on the coating and such that a film seam is formed which is different from the transition line. Alternatively, the coating is formed from two such patterned films, in which case the outer surface of the core is covered with the two films such that the two transition line segments cooperate to form a substantially continuous transition line on the coating and a film seam is formed which is different from the transition line. Prior to covering the outer surface of the core, the two films may be oriented such that the resulting enrobed core has a bi-colored coating with two visually distinct portions each lying on opposite sides of the transition line of the coating. The two films may also be oriented such that the resulting enrobed core has four alternately arranged colored portions, two of which are of a first color and the other two of which are of a second color, thereby resulting in a “checkerboard” effect.

The invention discloses a camera and robot hand-eye calibration method based on an ROS. According to the camera and robot hand-eye calibration method based on the ROS, through setting up of a visual system, a mechanical arm and an operation object of the mechanical arm are within the view field of the camera; then, communication mechanisms between the camera and the ROS and between the mechanicalarm and the ROS are established, on one hand, motion control over the mechanical arm is achieved, on the other hand, the images of the camera and the state of the mechanical arm are obtained, and datacollection is conducted; calibration of internal reference and external reference of the camera is conducted, and parameters of the camera are obtained; and finally, according to different installation manners of the camera, hand-eye calibration of the camera and the mechanical arm is conducted, and a hand-eye calibration matrix is obtained. By the adoption of the camera and robot hand-eye calibration method based on the ROS, automatic hand-eye calibration of the camera and the mechanical arm is achieved, manual intervention is reduced, terminal commands are just called twice in the whole calibration process, the autonomous degree is high, the limitation of the type and number of the camera is avoided, the limitation of the type of mechanical arm is avoided, the expandability is high, itis just needed to print a piece of A4 checkerboard paper in the calibration process, no mark is needed, and the camera and robot hand-eye calibration method based on the ROS is convenient to perform and practical.

Reduction Talbot interference imaging is carried out using a glass or fused silica prism, where at least two surfaces within the prism allow for an increase in the propagating ray angles at the image plane compared to the object (the photomask) plane. Furthermore, by adding a second orthogonal pair of surfaces, X and Y order recombination is made possible thus allowing for the imaging in an orthogonal direction with a two-order interference scheme as well as repeating checkerboard (island and hole) patterns with a four-order interference scheme. A benefit of the invention is the reduced requirements of the photo mask, allowing for diffraction limited imaging with UV wavelengths in a media with index of unity (air) or larger (an immersion fluid). The prism interferometer is known as a Smith-Talbot prism lens.

The invention relates to a mixed visual system calibration method based on a Kinect camera. A mixed visual system comprises the Kinect camera and a panoramic camera. The calibration method comprises the steps of carrying out calibration on an RGB camera of the Kinect camera and the panoramic camera, acquiring internal parameters of the RGB camera and the panoramic camera, setting a calibration board based on a checkerboard, and establishing a checkerboard coordinate system; and constructing virtual camera projection plane located in front of a panoramic camera coordinate system in space, calculating and acquiring a transformation matrix from the virtual camera projection plane to the checkerboard coordinate system, and further acquiring external parameters from an IR camera of the Kinect camera to the panoramic camera. The mixed visual system calibration method based on the Kinect camera can acquire the internal parameters of the Kinect camera and the external parameters of the mixed visual system, has low requirements for calibration conditions and a space configuration relation of the mixed visual system, and is flexible in use.

The invention discloses a monocular visual error measurement system for a cooperative target and an error limit quantification method. The monocular visual error measurement system is specifically characterized in that visual marker points are formed in the outer surface of the cooperative target, a calibration target adopts a black and white checkerboard like pattern and is used for the intrinsic and extrinsic parameter calibration of a camera, the camera is used for acquiring the images of the visual marker points and the images of the calibration target in one frame and transmitting the images to the computer, a first theodolite and a second theodolite are used for observing the calibration target to obtain an observation value A, observing the visual markers to obtain an observation value B and transmitting the observation value A and the observation value B to a computer, and the computer is used for receiving the calibration target image and marker image acquired by the camera, the observation value A and the observation value B, computing the camera pose measurement value and the real pose value of the cooperative target relative to the camera and computing a measurement error. By adopting the error limit quantification method, the measurement error can be quantified and decomposed so that each key parameter index is in the error limit.

Methods for energy-sensitive computed tomography systems that use checkerboard filtering. A method of enhancing image analysis of projection data acquired using a detector configured with a checkerboard filter includes disposing in a system a detector to receive a transmitted beam of X-rays traversing through an object, where the system is configured so the detector receives both high- and one of total- and low-energy projection data; receiving the high- and one of total- and low-energy projection data at the detector; and then estimating an effective atomic number of the object and / or processing the projection data so as to mitigate reconstruction artifacts. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appended claims.

The invention discloses a projector area calibration method by utilizing concentric circular rings on the basis of a lens distortion rule, and solves a problem of low calibration precision when a field of view is enlarged at present while a problem of insufficient optical lens distortion processing is solved. The method comprises the following steps: firstly, projecting a specially-designed checkerboard image onto a plane calibration board by utilizing a DLP (Digital Light Processing) projector, and capturing a calibration object image which contains a pasting checkerboard and a projection checkerboard by a CCD (Charge Coupled Device) camera; changing the position of the plane calibration board for multiple times to obtain multiple pairs of calibration object images; according to the lens distortion rule, taking the center of each calibration image as a center of a circle, calculating distance between each angle point to the center of a circle, and comparing the distance with a given radius value to divide the concentric circular ring areas; on the basis of each concentric circular ring, calibrating a camera, carrying out distortion correction to the data of the projection checkerboard by utilizing calibration parameters so as to calibrate the projector to obtain the internal and external parameters of the projector of a corresponding area; and repeating the above operations to the circular ring areas to finish the calibration of the projector.

Conversion of interleaved data and / or correction of color samples or other data are corrected by recognizing an underlying arrangement or format of different data sets within a data stream and a conversion process applied that causes bleeding between the sets The data sets are, for example, separate channel views of a 3D display, and the corruption occurs, for example, upon up-conversion of color samples that take into account both views together rather than individually. The invention is embodied, for example, as part of a playback device, display, or as a stand alone converter box that corrects the corrupted samples by at least one of substitution, filtering, or interpolation with appropriately selected samples (e.g., neighboring samples of a same view). In one embodiment, the invention comprises a conversion from a received format (e.g., checkerboard) to a delivery format (e.g., native format of a 3D ready display).

A steady-state visual evoked potential signal classification method based on a convolutional neural network comprises the following steps: firstly, presenting checkerboard stimuli flipped at differentfrequencies to a user at the same time, and acquiring an electroencephalogram signal when the user watches a specific target by using an electroencephalogram acquisition device; making original multi-channel electroencephalogram signals when the user watches different stimulation targets into a data set with labels, and dividing the data set into a training set, a verification set and a test set;inputting the training set into a designed deep convolutional neural network model for training, performing network optimal parameter selection by using a verification set, and finally inputting thetest set into the trained deep convolutional neural network model to complete the recognition of the stimulation target. Accurate identification of steady-state visual evoked potential signals can beachieved, the characteristic of adaptively extracting signal characteristics is achieved, manual preprocessing is not needed, and meanwhile individual difference can be better adapted through data learning.

A method of improving resolution for an image is disclosed. The method for improving resolution of an image includes loading a first image and creating a first super grid image based on the first image. The method also includes loading a second image and creating a second super grid image based on the second image. The method then arranges the first super grid image and a second super grid image into an unprocessed super grid image having a checkerboard like pattern. Next the method calculates a pixel value from at least two pixel values of the unprocessed super grid image. Then the method will insert pixels into a super resolution image and display that super resolution image on a display.

The present invention discloses a three-dimensional laser scanner station set-up and oriental device. The device comprises a digital wide-angle optical camera, a three-dimensional laser scanner and four black and white checkerboard targets; the camera is located on a horizontal cross shaft of a rotation mirror in the three-dimensional laser scanner, the four black and white checkerboard targets are arranged around the three-dimensional laser scanner, and the three-dimensional laser scanner is located on a center point of a graph encircled by the four black and white checkerboard targets. The present invention further provides a three-dimensional laser scanner station set-up and oriental method. The three-dimensional laser scanner station set-up and oriental device and method can effectively reduce the density of scanning point cloud of the scanner on the premise of ensuring transmission precision of the position and the direction of the three-dimensional laser scanner so as to save thetime of obtaining the point cloud by the scanner and reduce the requirement for the scanner to obtain the highest resolution ratio of the point cloud, and are suitable for low-cost set-up and orientation usage through the three-dimensional laser scanner.