RU2199150C2 - Optoelectronic system calibration device - Google Patents

Abstract

FIELD: video camera positioning devices. SUBSTANCE: device designed for correcting parameters of video cameras during their manufacture or for positioning those incorporated in machine vision system has video camera and system controller; newly introduced in device are positioning unit, control unit, image input unit, and logic circuit; video camera is calibrated by computing parameters of its positioning relative to camera this being followed by its re-positioning. EFFECT: enhanced calibration speed. 6 dwg

Description

 The invention relates to computer technology and can be used to adjust the parameters of video cameras during their production or to position a video camera operating as part of a vision system.

 Known optoelectronic system for recognition and orientation of images (US Patent 4435837, MKI G 06 K 9/32), consisting of a video camera, microprocessor controller and orientation unit of the camera. The disadvantage of this system is working only with flat objects, which reduces the scope of its application.

 Closest to the proposed one is a two-dimensional optical device that implements the automatic installation of the visible region and increases the measurement accuracy by using only one video camera equipped with a controller that controls the buzzer until a specified coordinate value is reached (Japan. Application 60-146374 , MKI G 06 K 9/32, 9/20), containing a video camera, a system controller, a main part, a buzzer.

 The disadvantage of this device is the low calibration speed.

 An object of the invention is to increase the calibration speed.

 The technical problem is solved in that an orientation unit, a control unit and an image input unit are introduced into the device containing the video camera and the system controller, the output of the video camera being connected to the input of the image input unit, the output of which is connected to the input of the system controller, whose inputs and outputs are connected to the first group of corresponding inputs and outputs of the control unit, the second group of inputs and outputs of which are connected to the corresponding inputs and outputs of the orientation unit.

 The invention is illustrated by drawings, where figure 1 shows a diagram of the device, figure 2 - the relative position of the camera and the reference object, figure 3 - image of the reference object, figure 4 shows the calculated parameters.

 The device comprises (Fig. 1) a video camera 1, an image input unit 2, a system controller 3, a control unit 4 and an orientation unit 5, the output of the video camera 1 being connected to the input of the image input unit 2, the output of which is connected to the input of the system controller 3, whose inputs - the outputs are connected to the first group of corresponding inputs and outputs of the control unit 4, the second group of inputs and outputs of which are connected to the corresponding inputs and outputs of the orientation unit 5.

The reference object is a pyramid (Fig. 2) with the following properties: the base is a square, the “top” vertex is projected at the intersection point of the base diagonals, the faces of the pyramid are painted in two different contrasting colors (black and white were used) so that the opposite faces have the same color. The pyramid is mounted on a flat surface of a uniform color, different from the two used in the pyramid, at the location where the object under study is expected to be used with the further use of the optoelectronic system, or optionally, if the internal parameters of the video camera 1 are found. The video camera 1 is mounted on a horizontal guide along which moves rectilinearly. In addition, the video camera 1 rotates about its axis in the horizontal plane (Fig. 4, angle β) and rotates relative to its attachment point to the horizontal guide in the vertical plane (Fig. 4, angle α). The horizontal guide is mounted on a vertical guide (figure 2) and rotates in the horizontal plane (figure 4, angle γ). Thus, the parameters determining the location of the camera 1 above the pyramid are:
the offset of the point O (x, y), determined by the values of x and y, relative to the point O 'in the horizontal plane P and the height h of the video camera 1 above the table plane (Fig. 4);
camera rotation angles 1 in horizontal (β) and vertical (α) planes;
angle of rotation of the horizontal guide in the horizontal plane (γ);
the offset of the camera relative to the beginning of the horizontal guide d (figure 4).

The parameters γ and d are necessary for the orientation of the camera in space, but the relative position of the video camera 1 and the reference object specify the parameters x and y, which are expressed in terms of γ and d:
x = d • sin (γ),
y = d • cos (γ).

 The device operates as follows. The image of the reference object (or the place in the space where it is supposed to be) is received from the video camera 1 through the image input unit 2 to the system controller 3, where the image is processed and the image (Fig. 3) contains the parameters (x, y, h, α , β, γ, d). Calibration consists of two main actions at each step: determining the position of the video camera 1 relative to the reference object and the subsequent reorientation of the video camera 1 taking into account the values found. At the beginning of the calibration, the displacement of the point O (x, y) (Fig. 4) relative to O 'in the horizontal plane P and the height h above the table plane, the angles of rotation of the camera 1 relative to its axis in the horizontal (β) and vertical (α) planes are calculated.

 After the deviations are found, their values from the system controller 3 are transmitted to the orientation unit 4. The execution of the program by the system controller 3 is suspended until a signal is received from the orientation unit 5 through the control unit 4, notifying the camera 1. The control unit 4 generates the signals necessary for controlling the engines that are part of the orientation unit 5. The orientation unit 5, by mechanical action exerted on the video camera 1, changes its position in space. After reorienting the video camera 1, the orientation unit 5 sends a ready signal to the control unit 4, which in turn sends a ready signal to the system controller 3. Then, the image of the reference object, which calculates the parameters x, y, h, α, is again sent to the system controller 3 β, γ, d. In the case of deviations exceeding the specified ones, the process of reorienting the video camera 1 is repeated. Otherwise, the remaining small deviations are additionally corrected, after which the calibration is considered completed. Thus, feedback is carried out through two channels - the image of the reference object and through the control unit 4.

 The proposed solution allows you to configure the optoelectronic system to work with three-dimensional objects, i.e., in addition to the necessary location of the camera in space, adjust the focus, as well as reduce the calibration time of the optoelectronic system.

Claims (1)

 A device for calibrating an optoelectronic system, comprising a video camera and a system controller, characterized in that an orientation unit, a control unit and an image input unit are introduced therein, the output of the video camera being connected to an input of an image input unit, the output of which is connected to an input of a system controller whose inputs and outputs connected to the first group of corresponding inputs and outputs of the control unit, the second group of inputs and outputs of which are connected to the corresponding inputs and outputs of the orientation unit.

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