70 results about "Cardinal point" patented technology

A wide-angle lens system is formed, sequentially from an object side, with a first group having a positive power, a second group having a negative power and a third group having a positive power, and at the time of focusing, only the second group is moved on an optical axis. The lens system satisfies conditional formulas of 0.3<BH1/T1<0.7 and 0.9<f3/f<1.8 (where BH1 is a distance from the final surface of the first group to a principal point position on the back side of the first group, T1 is a distance on the optical axis from a lens element surface of the first group closest to the side of the object to a lens element surface closest to the side of the image, f3 is the focal length of the third group and f is the focal length of the entire system).

This method is characterized in that a ring-shaped jig is disposed on a workpiece on a machine tool, and the optical axis of a camera is aligned parallel to a single axis of the coordinate system of the machine tool. The jig is photographed using the camera in which the horizontal direction or the vertical direction of the camera is aligned with an axial direction other than the signal direction of the machine tool, and the circumferential shape of the jig in the image photographed by the camera is extracted as a contour. The center position of the jig in the image is calculated from the contour while all the distortion correction coefficients in tangential direction and all the distortion correction coefficients in the radial direction are ignored and set to zero. The displacements of the main point of the camera are all set to zero so as to be included in the translation distance of the camera. The translation distance, which is an external parameter of calibration, is calculated on the basis of the center position of the jig in the image and the known three-dimensional center position of the jig.

The present invention discloses a calibration template, a calibration method, a calibration operation method and a calibration system. A substrate to be calibrated and a calibration template matching with at least two spherical calibration pieces are subjected to camera calibration, a camera to be calibrated collects a calibration image facing the calibration template, the at least two spherical calibration pieces are projected to an ellipse in the imaging of the camera to be calibrated, the calibration image comprises an array image having a fixed spacing and at least two ellipses, the major axes of the at least two ellipses are interacted, the interaction is employed to calculate the main point coordinate parameters of the camera to be calibrated. The calibration template, the calibration method, the calibration operation method and the calibration system can complete camera calibration based on a calibration image and a calibration template, and is high in practicability, fast in calibration speed and high in precision, etc.

Disclosed herein is a zoom lens including a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group. The zoom lens satisfies following conditional expressions (1) and (2),

0.03<H1′/f1<0.3  (1)

0.3<|f2|/√(fw·ft)<0.65  (2)

where H1′ is an interval from a vertex of a surface nearest to the image side in the first lens group to a principal point on the image side of the first lens group (− denotes the object side, and + denotes the image side), f1 is focal length of the first lens group, f2 is focal length of the second lens group, fw is focal length of an entire lens system at a wide-angle end, and ft is the focal length of the entire lens system at a telephoto end.

An apparatus comprises a first interface for receiving a plurality of partially overlapping images of an object from a corresponding plurality of cameras being arranged along a first and a second direction according to a camera pattern. The apparatus comprises an analyzing unit configured for selecting at least one corresponding reference point in an overlap area of a set of images, and for determining displacement information along the first and the second direction of the reference point in each of the other images of the set of images. A misalignment of the plurality of images along the first and the second direction is compensated by the displacement information so as to obtain aligned images. The apparatus comprises a determining unit configured for determining offset information between principal points of the plurality of cameras using at least three aligned images. The apparatus comprises a second interface for providing calibration data based on the displacement information and based on the offset information. The calibration data allows for calibrating the plurality of images so as to comply to the camera pattern.

The invention discloses a zoom camera calibration method, and belongs to the field of camera calibration in machine vision. According to the invention, modeling is carried out on the imaging process and related parameters of the zoom camera, and the constraint condition that the position of the main point of the camera is not changed in the zoom process is provided. Based on the constraint condition, a calibration method based on a zoom image sequence is provided to obtain the accurate position of the main point of the camera. Aiming at a zoom camera focal length calibration problem, a self-calibration method containing additional constraint conditions is provided. Simulation test and actual calibration test results show that the method provided by the invention has high precision and canbe used in actual calibration tasks.

The present invention relates to a method for calibrating a parabolic catadioptric camera by using a separate image of double balls and an image of a circular point. An image of double balls used as targets is shot by using the parabolic catadioptric camera, and the targets are separated on an image plane. A main point of an intrinsic parameter of the camera is determined by four groups of imaginary antipodal image points, which are correspondingly formed by imaginary intersection points of ball images in the catadioptric image and imaginary intersection points of antipodal ball images; on the basis of obtaining the main point, vanishing lines of planes where two groups of parallel projection small circles of double balls on a unit virtual ball are positioned are solved, so that the image of the circular point on the plane is determined and finally, other intrinsic parameter of the camera are solved by using the constraint of image of the circular point to the intrinsic parameter of the camera. According to the method provided by the present invention, full automatic calibration can be implemented, and errors caused by measurement in the calibration process are reduced. Since all the projection contour lines of the balls in the image can be extracted, thereby improving the calibration accuracy of the camera.

A tilt lens system includes a focus lens unit movable during focusing; a diaphragm sharing a primary optical axis with the focus lens unit; and a tilt lens unit, arranged on an image side of the focus lens unit and the diaphragm, having a negative refractive power and an optical axis tiltable with respect to the primary optical axis. Conditional Expressions (1) and (2) are satisfied as follows,

1.3<βt<1.7  (1)

0<P<H1  (2)

where βt is a lateral magnification of the tilt lens unit in a not tilted state, P is a distance from a most object side surface of the tilt lens unit to a rotating center of the tilt lens unit in a tilted state, and H1 is a distance from the most object side surface of the tilt lens unit to a first principal point of the tilt lens unit.

The invention discloses an external field measurement method for star point centroid position precision of a star sensor. Matched star point centroid coordinates and corresponding right ascension and declination coordinates are obtained through an external field star observation experiment of the star sensor; the star point centroid coordinates, the optimal principal point and the focal length value are used to calculate a star diagonal distance measurement value; calculating is carried out by using the corresponding right ascension and declination coordinates to obtain a star diagonal distance theoretical value; then, the star diagonal distance error can be calculated; the relationship between a star diagonal distance error and a star point mass center position error is deduced theoretically on the basis; and finally, the position precision of the mass center of the star point is calculated, and a reliable evaluation means is provided for evaluating the position precision of the mass center of the star point of a high-precision matching type star sensor and a small-field-of-view single-star tracker. The error caused by utilizing a single-star simulator and a parallel light tube to simulate the starlight of a fixed star in a laboratory is reduced, so that the measurement and evaluation of the star point mass center position precision of the star sensor are more accurate.

To provide a lens system which is to be used with a virtual system and which can curtail time and labor required by settings of the virtual system by outputting data pertaining to an angle of view, an object distance, and a principal point position, all being required by the virtual system, the lens device of an actual camera used for photographing an actual video to be used by the virtual system includes a CPU determining information about the angle of view, the object distance, and the principal point position, all being required to set a virtual camera in the virtual system, on the basis of a zoom position and a focus position detected by encoders, and transmits the information to the virtual system.

The invention discloses a mobile robot which comprises a robot body, a camera and a central processor, wherein the camera is used for acquiring an image of the surroundings for the mobile robot; the central processor is connected with the robot body and the camera and is used for processing the image data acquired by the camera and controlling a traveling component of the robot body to respond according to the processed image data; wherein, the optic center of the camera is far away from the center of the robot body; and the orthographic projection of the principal optic axis of the camera on the upper surface of the robot body and the orthographic projection of a straight line on the upper surface form a first included angle greater than o degree, and the straight line passes through the center of the robot body and a principal point on an image plane of the camera. When the mobile robot turns, the optical parallax of the camera is larger, and the image acquisition direction greatly varies to improve positioning precision and scene recognition precision. The invention further discloses another mobile robot.

Disclosed is a system for measuring solar radiation, with a camera having a hemispherical objective and light sensor, and a processor to: perform a geometric calibration of the camera establishing correspondence between coordinate systems of the image pixels and the camera; calculate the solid angle occupied by each pixel; perform a second calibration by comparing the theoretical position of the sun and its position in the image, establishing correspondence between the camera coordinate system and the cardinal points; calculate the angles between: each pixel and the zenith; each pixel and the azimuth; the sun and the zenith; and the sun and the azimuth; then each pixel and the sun. The next steps are: obtain a high-dynamic-range image of the sky; calculate the global horizontal irradiance, the direct normal irradiance, and the diffuse horizontal irradiance; and convert, into global horizontal luminance, direct normal irradiance and diffuse horizontal irradiance, respectively.

The invention provides a calibration method of an image acquisition device. The calibration method of the image acquisition device comprises the following steps: receiving an image uploaded by a userand displaying the image on a user interface, wherein the image is acquired by the image acquisition device; responding to an input operation of a user, and obtaining two parallel datum lines in the image; calculating vanishing point coordinates according to the two parallel datum lines; calculating a yaw angle and/or a pitch angle according to the vanishing point coordinates, a preset focal length and a preset principal point offset, wherein the preset focal length and the preset principal point offset are the focal length and the preset principal point offset of the image acquisition devicewhen the image acquisition device acquires the image; and outputting calibration information of the image acquisition device. In addition, the invention further provides computer equipment and a storage medium. A user only needs to adjust or draw two datum lines which are not parallel to the imaging plane of the image in the image, special professionals are not needed for processing, the application range of user groups is wider, and operation is simpler and more convenient.

The invention relates to a star sensor on-orbit calibration method based on star angular distance subtraction, and belongs to the field of astronomical navigation. The research method comprises the following steps: establishing a pinhole imaging camera model based on a physical process of imaging a scene object to an imaging plane; establishing a star sensor angular distance model; conducting starsensor subtraction; performing observability analysis; improving a star angular distance method; and carrying out simulation experiment. According to the invention, through the improved ADS (adaptivedistance subtraction) algorithm, the precision of u0 and the precision of v0 are respectively improved by 64.0% and 21.7% compared with the traditional AD (angular distance) algorithm, and the main point calibration precision is effectively improved.

The invention discloses a geometric calibration method and device for a multi-focal-plane spliced large-view-field off-axis camera, relates to the technical field of optical precision measurement, and solves the problem of high-precision ground geometric calibration of a space remote sensing long-focal-length, large-view-field and multi-focal-plane spliced off-axis camera. Firstly, a collimator, slit targets and a theodolite are used for testing splicing areas of all detectors on a focal plane, the relative position relation between the detectors is obtained through calculation, then through a high-precision single-axis rotary table, the slit targets are imaged on all the detectors on the uplink and the downlink of a camera at unequal intervals, collected images are processed, and the detection result is obtained. And extracting a centroid coordinate, converting the centroid coordinate to the same coordinate system through a relative position relation, and calculating through a resolving formula to obtain a principal point, a principal distance and a distortion calibration result of the camera. According to the invention, by selecting a proper collimator, a slit target and a single-axis turntable, high-precision geometric calibration of a camera in any focal plane splicing form is completed.

The invention provides a lens assembly, imaging equipment, detection equipment and a detection system. The lens assembly is applied to a lens and comprises a plurality of lens elements which are arranged in a manner of sharing the same optical axis; the entrance pupil position and the front focal point of the lens assembly are both located outside the lens assembly and located at the object side of the lens assembly; the object-side principal point of the lens assembly is farther from the lens assembly than the front focal point; and the peripheral imaging expansion angle corresponding to thelens assembly meets the following formula: alpha=arctanH/2f, wherein alpha represents the peripheral imaging expansion angle, the alpha is greater than or equal to 18 degrees and less than or equal to25 degrees, H represents the full-view image height corresponding to the lens assembly, f represents the focal length of the lens assembly, and f is less than 0. Therefore, a single imaging device comprising the lens assembly can image the right opposite surfaces of the workpiece and the imaging device and the side peripheral surface of the workpiece at the same time, and a better imaging qualityis achieved.

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.

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.

The invention discloses an image orthorectification method for a fisheye camera. The method comprises the following implementation steps: firstly, establishing an indoor three-dimensional calibration field, establishing a free coordinate system, measuring three-dimensional space coordinates of artificial identification points, and acquiring an original fisheye image; calculating an image principal point and a camera focal length initial value, and performing coordinate transformation on an original image in combination with the spherical perspective model to remove spherical distortion; then constructing a fisheye camera optical distortion model, introducing the model into a direct linear transformation (DLT) model to obtain the fisheye camera optical distortion model, and solving an optical distortion coefficient and internal and external orientation elements of the original image; and finally, starting from a collinear conditional expression, carrying out ortho-rectification on the perspective image without spherical distortion by adopting indirect digital differential rectification to obtain a calibration field ortho-image. According to the method, the original fisheye camera image can be subjected to ortho-rectification, the serious distortion problem of the fisheye camera image is solved, and the large-scale ortho-image can be quickly obtained by adopting the fisheye camera in a narrow space area.