168 results about "Principal point" patented technology

The present invention provides a beam homogenizer for homogenizing energy distribution by making the distance between lenses small to shorten the optical path length with the use of an array lens of an optical path shortened type, and a laser irradiation apparatus using the beam homogenizer. The beam homogenizer is equipped with a front side array lens of an optical path shortened type whose second principal point is positioned ahead on a beam incidence side, a back side array lens of an optical path shortened type whose first principal point is positioned behind on a beam emission side, and a condensing lens, wherein the distance between the second principal point of the front side array lens and the first principal point of the back side array lens is equal to the focal length of the back side array lens.

Compact narrow angle lens systems that may be used in small form factor cameras. The lens system may include six lens elements with refractive power, and may provide lower F-numbers while maintaining or improving imaging quality and package size when compared to other compact lens systems. Total track length of the lens system may be 6.5 millimeters or less, for example 5.9 or 6 millimeters. Focal length of the lens system may be 7.0 millimeters or less, for example 6.6 millimeters. The lens system may include an aperture stop located behind the front vertex of the lens system, for example between the first and second lens elements, that effectively moves the ideal principal point of the camera to in front of the front vertex. The lens system may provide a focal ratio of 2.8 or less, for example 2.6 or 2.4.

A 3-dimensional image display device includes: a backlight unit; a barrier panel above the backlight unit and including unit barriers which selectively blocks light; a lenticular lens array above the barrier panel and including lenticular lenses, each having a principal point; a liquid crystal panel above the lenticular lens array; an eye tracking sensor which detects a position of eyes of a viewer and a distance between the principal point of the lenticular lenses and the eyes; and a controller which controls the backlight unit, the barrier panel and the liquid crystal panel based on an output of the eye tracking sensor, where the controller turns on and off the unit barriers such that light passes through the principal point of the lenticular lenses to apply a right-eye image to a right eye of the viewer and apply a left-eye image to a left eye of the viewer.

An internal parameter storage unit stores, in advance, a plurality of sets of internal parameters each of which can be applied to correct a pixel position in a direction from an image principal point, i.e., a plurality of sets of internal parameters for accommodating errors of different magnitudes that occur in individual directions from an image principal point. An internal parameter selection unit selects a set of internal parameters from the plurality of sets of internal parameters stored in advance on the basis of the direction of a pixel position to be corrected from the image principal point, and a distortion-corrected image generator corrects distortion on the basis of the selected set of internal parameters, so that, even when a surface of a lens is not exactly parallel to a surface of an image pickup device, distortion is corrected more accurately.

The invention discloses a high-precision camera principal point calibration method, and relates to the technical field of image measurement. The method comprises the following steps: adjusting the direction of laser emitted by a laser device to make the laser direction parallel to the optical axis of a camera and to make laser spots be displayed on a receiving display, moving the receiving display, collecting laser spot images in different positions to obtain a laser spot image set, using an image processing technology to find out the coordinates of the laser spot centers of the laser spot images in different positions, carrying out linear fitting on the obtained laser spot centers to obtain the linear equations of center connecting lines, solving the two linear equations, and finding out the intersection point of the two linear equations, wherein the coordinate of the intersection point is a camera principle point coordinate. The method has the advantages of high calibration precision, simple and easy operation, and strong practicality, and can meet rapid calibration needs of the camera principle point.

Provided is an image shake correction apparatus including: an image taking optical system for taking an image of a subject; an angular velocity detection unit for detecting an angular velocity applied to the apparatus and outputting a first signal; an acceleration detection unit for detecting an acceleration applied to the apparatus and outputting a second signal; an axial rotation angular velocity calculation unit for calculating an axial rotation angular velocity component about a principal point of the image taking optical system based on the first signal; a revolution angular velocity calculation unit for calculating a revolution angular velocity component about the subject based on the second signal and a result of the calculating by the axial rotation angular velocity calculation unit; and a control unit for performing image shake correction control based on a difference between the axial rotation angular velocity component and the revolution angular velocity component.

An eyepiece lens system for an electronic viewfinder, usable to be disposed on an optical axis between a reflective LCD of the viewfinder and a last optical surface of the viewfinder, the eyepiece lens system comprising: a first lens having a positive refractive index; a second lens having a negative refractive index; and a third lens having a positive refractive index, wherein the first lens, the second lens, and the third lens are disposed in this order from a side of the LCD to a side of the last optical surface, satisfying the conditions: 18 mm<f1<20 mm, −18 mm<f2<−16 mm, 18 mm<f3<20 mm, 19 mm<f<21 mm, and 0≦HH′ / f<+0.13 where f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f is a combined focal length of the first to the third lenses, and HH′ is distance in an optical axis direction between a rear principal point H and a front principal point H′.

An image stabilization apparatus has an angular velocity detector detecting an angular velocity applied thereto and outputting the angular velocity, an acceleration detector detecting an acceleration applied to the image stabilization apparatus and outputting the acceleration, a principal point calculation unit calculating a principal point position of a shooting optical system, an rotation angular velocity calculation unit calculating a rotation angular velocity component about the principal point of the shooting optical system based on an output of the angular velocity detector, a revolution angular velocity calculation unit calculating a revolution angular velocity component about an object based on the output of the acceleration detector and a calculation result of the rotation angular velocity calculation unit and correcting the calculated revolution angular velocity component according to the principal point position, and a controlling unit performing image stabilization control based on a difference between the rotation and corrected revolution angular velocity components.

The invention provides a step-by-step video camera self-calibration method, which comprises the following steps: in the first phase, shooting two images of the same scene at different focal lengths, performing feature extraction and matching on the images and eliminating mismatching points, and solving principal point coordinates of the video camera by using matching point pairs; and in the second phase, shooting the same scene from different angles to obtain three images available for matching, and performing feature extraction and matching on the images and eliminating mismatching points, and then based on Kruppa equation, substituting the obtained principal point coordinates into the equation to accomplish solving the three parameters of an obliquity factor, as well as scale factors of the video camera in the directions U and V axes of an imaging plane. By using the method provided by the invention, the calibration accuracy of the principal point coordinates of the video camera is relatively high, and the coefficient matrix size of the Kruppa equation is reduced, the amount of solving computation is reduced, and the method has the characteristic of being real-time. The method is applicable to video camera calibration of a vision system and can be used in the fields of three-dimensional measurement, three-dimensional reconstruction, machine navigation, augment reality and the like.

The present invention provides a method for implementing high-precision orientation and evaluating orientation precision of a large-scale dynamic photogrammetry system, including steps: a) selecting a scale bar, arranging code points at two ends of the scale bar, and performing length measurement on the scale bar; b) evenly dividing a measurement space into multiple regions, sequentially placing the scale bar in each region, and photographing the scale bar by using left and right cameras; d) limiting self-calibration bundle adjustment by using multiple length constraints, adjustment parameters including principal point, principal distance, radial distortion, eccentric distortion, in-plane distortion, exterior orientation parameter and spatial point coordinate; and e) performing traceable evaluation of orientation precision of the photogrammetry system. The present invention can effectively reduce the relative error in length measurement.

The invention relates to a camera calibration system and method thereof which is capable of easily performing camera calibration using a concentric circle pattern. According to the invention, a method of calibrating a camera calibrates the intrinsic parameters of the camera required to measure geometric information of an object using projection invariable characteristics of concentric circles. The method includes the steps of taking images of the calibration pattern consisting of two or more concentric circles located in the same plane and having different radius at different angles to obtain projected images calculating the central point of the projected images using a given algorithm, and calculating the principal point and focal point of camera using a nonlinear minimization algorithm based on the central point thus obtained.

The invention provides a method for obtaining digital photo orientation elements based on a digital map. The method comprises the following steps: step 1, a digital photo and a digital map corresponding to the digital photo are shot, wherein the digital photo comprises at least five ground object points, and the digital map comprises homologous points corresponding to the ground object points; the ground object points and the homologous points are totally called as control points; the digital photo is provided with a phone two-dimensional coordinate system, and the digital map is provided with a digital map coordinate system; step 2, coordinates of the control points in the digital map coordinate system and the phone two-dimensional coordinate system and coordinates of a photo principal point in the phone two-dimensional coordinate system are obtained, wherein the photo principal point is a perpendicular foot point of a shooting lens center on the photo; and step 3, a photogrammetric coordinate system D-XDYDZD is established. The invention utilizes the prior digital map as a condition to calculate the orientation elements of a common digital image, thereby providing a simple, convenient and rapid low-cost path for obtaining three-dimensional space information and having small field operation workloads and low expense.

The invention relates to a real-time positioning method based on monocular vision. The method comprises the following steps: firstly, calibrating a camera to obtain an inner parameter matrix R; and after calibrating the camera, solving a distance D1 from a ground specified point P to be detected to a reference point M and an angle between a vector (shown in the specification) and a center line of a trolley according a basic pin-hole imaging principle through geometric transformation. According to the method provided by the invention, on the basis of common geometric conversion positioning, a principal point of the camera is commonly not at the center of an image; the geometric correction is carried out and the measurement precision is improved.

An adapter is provided for adapting an optical instrument, such as a camera (3) or a projector, to capture or display panoramic three-dimensional images. The adapter comprises a plurality of mirrors (1a, 1b, 1c), each of which has a reflective surface which is in the shape of a curved non-circular conic section rotated about an axis of symmetry (15a, 15b, 15c). The reflective surfaces have first foci which are spaced perpendicularly from a longitudinal axis of the adapter and which are angularly spaced around the longitudinal axis. For example, the conic section may be a hyperbola with first foci equidistantly spaced from the longitudinal axis and equiangularly spaced around 15b the longitudinal axis. The axes of symmetry (15a, 15b, 15c) of the mirrors (1a, 1b, 1c) converge to intersect the longitudinal axis at a point which is coincident with the front principal point of, for example, a camera lens (12). Thus, single shot capture of all the image data for the or each panoramic three-dimensional image may be performed.

A zoom lens includes, from the object side to the image side, first to sixth lens units having positive, negative, positive, negative, positive, negative refracting powers. In zooming from the wide angle end to the telephoto end, the lens units are moved such that the distance between the first and second lens units increases, the distance between the second and third lens units decreases, the distance between the third and fourth lens units increases, and the distance between the fourth and fifth lens units decreases. In focusing from an infinitely distant object to a near object, the sixth lens unit is moved toward the image side. The distance between the rear principal point of the second lens unit and the front principal point of the rear lens group at the wide angle end, and the focal length of the rear lens group at the wide angle end are appropriately set.