KR101341632B1 - Optical axis error compensation system of the zoom camera, the method of the same - Google Patents

Abstract

The present invention comprises the steps of (a) moving the camera zoom to the starting zoom position to measure the coordinates of the target; (b) measuring the coordinates of the target by moving the camera zoom to the next zoom position until the entire zoom measurement interval is completed; And (c) transmitting the coordinates of the target measured in the zoom of each step to the camera when the entire zoom measurement interval is completed.

Description

Optical axis error compensation system of the zoom camera, the method of the same}

The present invention relates to a method of compensating for an optical axis error of a zoom camera, a compensation system thereof, and a zoom camera capable of realizing the optical axis error compensation.

Recently, many surveillance cameras have been installed in buildings and streets to prevent crime and theft. The images taken by these surveillance cameras are displayed on the monitors of the police station or building management office to inform the current state of the place where the surveillance cameras are installed. In general, a surveillance camera has a zoom function for zooming in or out of a subject to provide much convenience to a user.

However, a surveillance camera having such a zoom function causes an optical axis error to be caused when assembling a plurality of lens groups and an imaging device such as a charge-coupled device (CCD) to the camera, or for a number of reasons such as an optical system tolerance. The optical axis of the camera fluctuates as the zoom moves.

For example, in order to implement a privacy masking function for electronically masking a part of a screen of a photographing area for a privacy purpose in a zoom camera, when the camera is zoomed, the masking area should be simultaneously enlarged and reduced. However, when the optical axis error of a zoom camera is large, the area | region to be covered may move out of the designated masking area | region.

1 schematically illustrates a state in which a privacy masking function is performed in a conventional zoom camera.

Referring to the upper part of the drawing, the zoom of the camera is gradually moved to the maximum wide-angle end WIDE_max (Z1) => middle end (Z2) => maximum telephoto end (TELE_max) (Z3), and the subjects B1, B2, As the image of B3) is enlarged, the center (0,0) of the optical axis is gradually offset to (4,2), (8,4) (here, the horizontal direction of FIG. 1). Is the Y axis, and the vertical direction is the X axis). Referring to the bottom of the figure, the zoom of the camera is moved to the maximum wide-angle end (WIDE_max) (Z1) => middle end (Z2) => maximum telephoto end (TELE_max) (Z3), masking areas (M1, M2, M3) is expanded at the same time. However, as the zooming progresses and the offset of the center of the optical axis increases, the area of the subjects B1, B2, and B3 to be masked out of the masking areas M1, M2, and M3 does not function as a privacy mask. The case occurs.

 This phenomenon is more likely to occur in high magnification cameras and smaller areas to be covered. However, since a plurality of cameras of the same model does not have the same amount and direction of deviation, product deviation occurs, and when mass production, it is difficult to expect high quality assembly quality.

The present invention provides a method for compensating for a fine optical axis error of a zoom camera that has been manufactured and reached a certain level due to various causes of optical axis errors, a compensation system, and a zoom camera capable of compensating optical axis errors by the compensation method. The purpose is to provide.

In order to solve the above problems and other problems, the present invention, (a) moving the camera zoom to the starting zoom position to measure the coordinates of the target; (b) measuring the coordinates of the target by moving the camera zoom to the next zoom position until the entire zoom measurement interval is completed; And (c) transmitting the coordinates of the target measured in the zoom of each step to the camera when the entire zoom measurement interval is completed.

Measuring the coordinates of the target in the steps (a) and (b), (a1) capturing an image input through the camera; (a2) setting a target detection area and unifying image information in the detection area; (a3) binarizing the image information to a predetermined threshold value and separating the target from a background; And (a4) removing noise and storing coordinates of the target.

In the step (a), it may further comprise the step of confirming the mounting position of the camera at the start zoom position.

The checking of the mounting position of the camera may include: i) capturing an image input through the camera at the starting zoom position; ii) unifying image information by setting a target detection area in the captured image; Iii) binarizing the image information to a predetermined threshold value, separating the target from the background, iii) removing noise and measuring coordinates of the target, iii) whether the center of the target coincides with the center of the camera; It may include the step of identifying.

The position of the starting zoom may be the maximum telephoto end.

In another aspect, the present invention, the camera performs a zoom of a predetermined step; A chart unit including a target disposed in front of the camera; An image capture unit for capturing an image output from a camera which performs the zoom in the predetermined step; And a controller for detecting and storing coordinates of a target from the captured image and transmitting the coordinates of the target to the zoom camera.

The control unit sets a target detection area of the image captured in each predetermined zooming step, unifies the image information in the detection area, binarizes the image information to a predetermined threshold value, and separates the target from the background and makes noise. By removing, the coordinates of the target can be detected.

The camera is mounted on a fixture having a multi-axis adjustment device that enables at least one or more motions of pan, tilt, up, down and rotation. In the zooming step, the mounting position of the camera may be checked to adjust the mounting position of the camera with the fixing jig when an error occurs.

The mounting position of the camera sets a target detection area of the image captured at the starting zoom position, unifies the image information in the detection area, binarizes the image information to a predetermined threshold value, and separates the target from the background. By removing the noise, it may be performed by checking whether the center of the target coincides with the center of the camera.

The position of the starting zoom may be the maximum telephoto end.

A secondary optical system may be further disposed between the chart unit and the camera to provide an infinite light source.

The present invention also provides a zoom camera capable of realizing optical axis error compensation by zooming by the above method.

According to the optical axis error compensation method and system according to the present invention, fine optical axis error information of a zoom camera that has been manufactured and reached a certain level can be accurately and quickly obtained by software, and the information can be transmitted back to the camera. In addition, the zoom camera including the optical axis error information according to the present invention may compensate for the optical axis error due to zoom in performing a privacy masking function, an enlargement to the center of the viewing area, and a tracking function of a moving object. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a conceptual diagram of an optical axis error compensation system of a zoom camera according to an exemplary embodiment of the present invention, and FIG. 3 conceptually illustrates optical axis errors generated in each zoom step.

Referring to the drawings, the optical axis error compensation system 100 according to the present embodiment is the camera 110, the fixture 120, the chart unit 130, the secondary optical system 140, and the image capture unit 151 And a computer 150 including a control unit 152.

The camera 110 includes a plurality of zoom lenses 111 capable of performing a zoom function, and although not shown in detail in the drawing, a focus lens (not shown), an aperture (not shown), a CCD (not shown), The apparatus may further include a digital signal processor (not shown), a communication unit (not shown), and the like. A lens driver (not shown) may drive the zoom lens according to a signal of the digital signal processor, and the digital signal processor may move the zoom lens 111 in a predetermined step by a command of the computer controller 152 which will be described later. have. Alternatively, the lens driver may be directly driven by the signal of the computer controller 152. The camera 110 is a camera capable of implementing a general zoom function, and may include a still camera capable of capturing still images, a video camera capable of capturing a video, and a surveillance zoom camera.

 The camera 110 is seated on the fixture jig 120, wherein the fixture jig 120 is at least one of pan, tilt, up, down, and rotation. A multi-axis adjusting device (not shown) for enabling the above motion is provided. When the initial position of the camera 110 is set, when the center of the camera 110 is inconsistent with the center of the target T, the center of the camera 110 and the center of the target T are adjusted using the multi-axis adjusting device. Match.

In front of the camera 110, a chart unit 130 including a target T easily designed for image processing is disposed.

A secondary optical system 140 is provided between the chart unit 130 and the camera 110 to provide an infinite light source. The secondary optical system 140 may be used to reduce a work space, such as a video collimator (not shown). In addition, although not shown in detail in the drawing, the secondary optical system 140 may further include an adjustable illumination system.

The optical axis error compensation system 100 according to the present invention includes a computer 150 including an image capture unit 151 and a controller 152.

The image capture unit 151 includes an image capture device such as an image grabber. The image capturing unit 151 may fix the image information input from the camera 110 after a predetermined step, for example, fixing the camera 110 at a position of the wide-angle end WIDE_max to the telephoto end TELE_max. Converts to video information having two-dimensional pixel coordinates according to the video signal standard. At this time, the image format (RGB, YUV, etc.) is appropriately selected according to the format to be implemented.

The controller 152 may include a target coordinate detector 153 that detects the coordinates of the target T from the captured image, and an optical axis data storage unit 154 that stores the coordinates of the target T detected in each zoom step. Include.

The target coordinate detector 153 sets a target detection area of the image captured in each predetermined zoom step, and unifies the image information in the detection area, for example, color information or luminance information. The target coordinate detector 152 binarizes the image information loaded on the RAM of the computer 150 to a predetermined threshold value, and separates the desired target T from the background by using a vision algorithm such as histogram or labeling. By doing so, the coordinates of the desired target T in each zoom step can be detected. In this case, the target coordinate detector 152 may remove a target having a predetermined size or less or remove noise in order to accurately detect the coordinates of the target T. The target coordinate detector 153 repeatedly performs the above process until each preset zooming step is completed under the control of the controller 152.

Referring to FIG. 3, the zoom of the camera is gradually moved to the maximum wide-angle end WIDE_max (Z1) => middle end (Z2) => maximum telephoto end (TELE_max) (Z3), which is processed by the aforementioned vision algorithm. As the image of the targets T1, T2, and T3 is enlarged, the center of the optical axis (0,0) is gradually offset to (4,2), (8,4) (here, horizontally in FIG. 1). Direction represents the Y axis, and the vertical direction represents the X axis). Meanwhile, the vision algorithm used to detect the target coordinates shown in the drawing uses a labeling technique, and targets offset from the original optical axis center (0,0) by detecting coordinates of each rectangular point of the target (T). The optical axis reference coordinates (4, 2) (8, 4) of (T2, T3) were detected. The present invention is not limited to the above labeling method, and the offset value of the optical axis due to zoom can be obtained by various methods. As such, the coordinates of the target T offset in each zoom step are stored in the optical axis data storage unit 154 as optical axis offset data.

The optical axis data storage unit 154 stores coordinates of the target T detected in each zoom step as described above, and transmits coordinate data of the target T to the camera 110 under the control of the controller 152. .

Coordinate data of the target T transmitted to the camera 110 is stored in a storage unit (not shown) of the camera 110. The digital signal processor (not shown) of the camera 110 compensates the center of the optical axis offset when the zoom function is performed using the optical axis data stored in the camera 110.

The above-described functions of the target coordinate detector 153 and the optical axis data storage 154 may be performed by the controller 152 of the computer 150 or may be performed with the help of peripheral devices of the controller 152. In addition, although not shown in detail in the drawing, the system 100 may be further provided with a plurality of communication units (not shown) in charge of communication between the camera 110 and the computer 150.

On the other hand, the setting of the initial position of the camera 110 to mount the camera 110 to the fixed jig 120 similarly uses an algorithm for detecting the coordinates of the target described above. First, the camera 110 is fixed to the fixture 120, and then a target detection area of the image captured at the start zoom position is set. The image information in the detection area is unified with, for example, color information or luminance information. By binarizing this image information to a predetermined threshold value and separating the desired target T from the background using a vision algorithm such as histogram or labeling, the coordinates of the desired target T in each zoom step can be detected. Can be. As a result, the reference point of the target and the center of the camera are checked to match, and if it does not match, the center of the camera 110 and the reference point of the target T are matched using the above-described multi-axis adjusting device of the fixed jig.

In this case, when the position of the start zoom is performed at the telephoto end, since the center of the target T and the camera 110 can be compared while looking at a wide area of the target, more accurate optical axis error data can be obtained.

 4 is a flowchart illustrating an optical axis error compensation method of a zoom camera according to an exemplary embodiment of the present invention, and FIG. 5 is a flowchart illustrating S260 of FIG. 4 in detail. The optical axis error compensation method of the zoom camera may be implemented by the optical axis error compensation system of FIG. 2.

Referring to the figure, the optical axis error compensation method (S200) starts by moving the camera zoom to the starting zoom position (S210). The starting zoom of this zoom may start at the maximum wide-angle end WIDE_max or the maximum telephoto end TELE_max.

Next, it is checked whether the mounting position of the camera 110 is correct at the position of the start zoom (S220). This is similar to using the algorithm for detecting the coordinates of the target T as described above, the center of the target T and the center of the camera 110 does not match, that is, if an error occurs (S230) By outputting a message (S240), the center of the camera 110 and the reference point of the target (T) are matched manually or automatically using the aforementioned multi-axis adjustment device (not shown) of the fixed jig 120.

Until the entire zoom measuring section is completed (S250), the reference coordinate of the target T is measured in the corresponding zooming step (S260). Referring to FIG. 5, first, the image capture unit 151 captures an image output through the camera 110 at each zoom step (S261). Next, a target detection area of the captured image is set (S262), and image information in the detection area is unified, for example, color information or luminance information (S263). The target coordinate detector 152 binarizes the image information loaded on the RAM of the computer 150 to a predetermined threshold value (S264), and uses a vision algorithm such as a histogram or labeling to set a background of a desired target T. ), The coordinates of the desired target T in each zoom step can be detected. In this case, the target coordinate detector 152 may remove a target having a predetermined size or less or remove noise in order to accurately detect the coordinates of the target T (S266). The coordinates of the target from which the noise is removed are stored in the optical axis data storage unit 154 (S267). The target coordinate detector 153 repeatedly performs the above process until each preset zooming step is completed under the control of the controller 152 (S270).

As described above, the reference coordinates of the target T detected and stored in each zoom step are transmitted to the camera 110 under the control of the controller 152 (S280).

As described above, the coordinate data of the target T transmitted to the camera 110 is stored in a storage unit (not shown) of the camera 110. The digital signal processor (not shown) of the camera 110 may compensate for the center of the optical axis offset when the zoom function is performed using the optical axis data stored in the camera 110.

Hereinafter, various embodiments of implementing the optical axis error compensation in the zoom camera receiving the optical axis error value by the above-described method will be described with reference to FIGS. 6 to 8.

FIG. 6 schematically illustrates a state in which privacy masking is performed in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

Referring to the conventional masking method of the upper portion (A) of the figure, the zoom of the camera 110 to the maximum wide-angle end (WIDE_max) (Z1) => middle end (Z2) => maximum telephoto end (TELE_max) (Z3). As the image is gradually moved, images of the subjects B1, B2, and B3 and the masking regions M1, M2, and M3 are enlarged. However, as the center (0,0) of the optical axis by zoom is gradually offset to (4,2), (8,4), the center of the subjects (B1, B2, B3) moves, but masking. Since the centers of the areas M1, M2, and M3 do not move, the areas of the subjects B1, B2, and B3 to be covered are separated from the masking areas M1, M2, and M3.

However, in the zoom camera to which the optical axis error compensation method according to the present invention in the lower part of the figure (B) is applied, the maximum wide-angle end WIDE_max (Z1) => middle end (Z2) => maximum telephoto end (TELE_max) (Z3) As the zoom of the camera is gradually moved, the images of the subjects B1, B2, and B3 and the masking areas M1 ', M2', and M3 'are enlarged, and the offset optical axis data stored in the storage of the camera 110 is enlarged. Since the centers of the masking areas M1 ', M2', and M3 'can be corrected by the offset optical axis data of each zoom step, the centers of the masking areas M1', M2 'and M3' and the subjects can be corrected. The centers of (B1, B2, B3) become the same. Therefore, the masking areas M1 ', M2', and M3 'may cover the areas of the subjects B1, B2, and B3 to be covered.

FIG. 7 schematically illustrates a state in which a pan / tilt / zoom is performed around a predetermined area in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

Referring to the conventional method of the upper portion (A) of the drawing, when the user designates a certain area P or the center of the area that the user wants to enlarge on the output image on the monitor, the zoom is linked to enlarge the designated area, Pan / Tilt should be linked to move the center (C1) of the area to the center (O) of the monitor. However, in this case, due to the optical axis error due to the zoom, the center C2 of the area P and the subject B is not located at the center 0 of the monitor and is offset.

However, in the zoom camera to which the optical axis error compensation method according to the present invention in the lower part of the drawing (B) is applied, when the user designates a certain area P or the center of the area in the output image on the monitor, the zoom is interlocked to designate the designated area. Since the pan / tilt value is compensated by the offset value using the offset optical axis data stored in the storage unit of the camera 110, the enlarged area and the center C2 of the subject are positioned at the monitor center O. do.

FIG. 8 schematically illustrates a motion tracking function performed by a pan / tilt device in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

Referring to the conventional method of the upper portion (A) of the drawing, if the user wants to keep track of the moving object or a certain area (P1, P2) in a magnified view from the center of the screen on the output image on the monitor, Zooming is linked to enlarge the designated areas P1 and P2, and pan / tilt is linked to move the center C1 of the area to the center O of the monitor. However, in this case, due to the optical axis error due to the zoom, the corresponding area P3 or the center C2 of the subject is not located at the center 0 of the monitor and is offset.

However, in the zoom camera to which the optical axis error compensation method according to the present invention in the lower part of the drawing (B) is applied, the zoom area is interlocked so that the designated areas P1 and P2 are enlarged (P3 '), and the storage unit of the camera 110 is provided. Since the pan / tilt value is compensated by the offset value using the offset optical axis data stored in, the enlarged area P3 'of the moving object or area or the center C2 of the object is positioned at the monitor center O. .

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Accordingly, the true scope of protection of the present invention should be determined by the technical idea of the appended claims.

1 schematically illustrates a state in which a privacy masking function is performed in a conventional zoom camera.

2 is a conceptual diagram of an optical axis error compensation system of a zoom camera according to an exemplary embodiment of the present invention.

3 is a diagram conceptually illustrating an optical axis error generated in each zoom step.

4 is a flowchart illustrating an optical axis error compensation method of a zoom camera according to an exemplary embodiment of the present invention.

5 is a detailed flowchart of S260 of FIG. 4.

FIG. 6 schematically illustrates a state in which privacy masking is performed in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

FIG. 7 schematically illustrates a state in which a pan / tilt / zoom is performed around a predetermined area in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

FIG. 8 schematically illustrates a motion tracking function performed by a pan / tilt device in a zoom camera in which an optical axis error compensation method according to the present invention is implemented.

Claims (12)

(a) measuring the coordinates of the target by moving the camera zoom to a starting zoom position; (b) measuring the coordinates of the target by moving the camera zoom to the next zoom position until the entire zoom measurement interval is completed; And (c) transmitting the coordinates of the target measured in the zoom of each step to the camera when the entire zoom measurement interval is completed; Measuring the coordinates of the target in the step (a) and (b), (a1) capturing an image input through the camera; (a2) setting a target detection area and unifying image information in the detection area; (a3) binarizing the image information to a predetermined threshold value and separating the target from a background; And and (a4) removing noise and storing coordinates of the target. delete The method of claim 1, In the step (a), the optical zoom error compensation method of the zoom camera, characterized in that further comprising the step of confirming the mounting position of the camera at the starting zoom position. The method of claim 3, wherein The checking of the mounting position of the camera may include: i) capturing an image input through the camera at the starting zoom position; ii) unifying image information by setting a target detection area in the captured image; Iii) binarizing the image information to a predetermined threshold value, separating the target from the background, iii) removing noise and measuring coordinates of the target, iii) whether the center of the target coincides with the center of the camera; Compensating for the optical axis error of the zoom camera, characterized in that it comprises a step of confirming. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 3, wherein The optical zoom error compensation method of the zoom camera, characterized in that the position of the starting zoom is the maximum telephoto end. A camera which performs a zoom in a predetermined step; A chart unit including a target disposed in front of the camera; An image capture unit for capturing an image output from a camera which performs the zoom in the predetermined step; And And a controller for detecting and storing coordinates of a target from the captured image, and transmitting the coordinates of the target to the zoom camera. The control unit sets a target detection area of the image captured in each predetermined zooming step, unifies the image information in the detection area, binarizes the image information to a predetermined threshold value, and separates the target from the background and makes noise. And an optical axis error compensation system of the zoom camera to detect the coordinates of the target. delete The method of claim 6, The camera is mounted on a fixture having a multi-axis adjustment device that enables at least one or more motions of pan, tilt, up, down, and rotation, In the starting zooming step, the optical camera error compensation system of the zoom camera, characterized in that to check the mounting position of the camera to adjust the mounting position of the camera with the fixed jig when an error occurs. 9. The method of claim 8, The mounting position of the camera sets a target detection area of the image captured at the starting zoom position, unifies the image information in the detection area, binarizes the image information to a predetermined threshold value, and separates the target from the background. And removing the noise to determine whether the center of the target coincides with the center of the camera. Claim 10 has been abandoned due to the setting registration fee. 9. The method of claim 8, The optical zoom error compensation system of the zoom camera, characterized in that the position of the start zoom is the maximum telephoto end. Claim 11 was abandoned when the registration fee was paid. 9. The method of claim 8, And a second optical system disposed between the chart unit and the camera and providing an infinite light source. delete

Images