KR20090081163A - Focus Offset Compensation Device and Method of Surveillance Camera - Google Patents

Abstract

The present invention relates to an apparatus and method for compensating a focus offset of a surveillance camera. For example, when the photographing mode of the surveillance camera is a day mode, an IR cut filter is disposed in front of the imaging device. In the night mode, the dummy glass is disposed, and the position of the focus lens is variably controlled by the focus offset value caused by the material and thickness difference between the infrared cut filter and the dummy glass. In addition, when the current shooting mode is a night mode when the zoom operation is performed, the position of the focus lens is variably controlled by the focus offset value generated by infrared rays, and when the preset change operation is performed, corresponding preset information is displayed. If the shooting mode at the time of setting is different from the current shooting mode, the focus offset value caused by the replacement of the dummy glass or infrared cut filter By variably controlling the position of the lens, the focus shift caused by the shooting mode switching, the zooming operation, and the preset changing operation can be efficiently compensated, and the subject shooting operation can be performed in a more accurate focus state.

Description

Apparatus and method for compensating focus offset}

The present invention relates to a focus offset compensation device and method of a surveillance camera, for example, to switch the shooting mode of the surveillance camera to a day mode or a night mode, a zoom operation or a preset The present invention relates to a focus offset compensation device and a method of a surveillance camera for compensating for focus shift when performing a change operation.

In general, a surveillance camera used in connection with a digital video recorder (DVR) is installed at a specific place and photographs a subject, and the subject image photographed by the surveillance camera is the digital video recorder. It is transferred and stored in the hard disk or the like, or displayed on the monitor screen.

On the other hand, the shooting mode of the surveillance camera is divided into a day mode and a night mode. For example, when the day mode is set, an imaging device such as a charge coupled device (CCD) An IR cut filter is disposed at the front end to prevent excessive incidence of infrared rays IR on the imaging device.

On the other hand, when the night mode is set, the infrared cut filter disposed at the front end of the image pickup device as described above is replaced with transparent dummy glass, so that the incident light is transmitted by the infrared cut filter during the night photographing operation. To prevent it from being blocked.

However, when the shooting mode of the surveillance camera is switched from the day mode to the night mode, or the night mode to the day mode, the focus shift may occur due to the material and thickness difference between the infrared cut filter and the dummy glass. There is a problem.

In addition, when the zooming operation is performed while the photographing mode of the monitoring camera is in the night mode, a focus shift occurs due to infrared rays passing through the dummy glass and incident on the image pickup device.

In addition, when performing a preset operation to change the shooting state of the surveillance camera to a pan angle, a tilt angle, and a zoom magnification, which are set in advance as preset information, the corresponding preset information. If the shooting mode at the time of setting the current mode and the shooting mode is inconsistent, due to the difference in material and thickness between the infrared cut filter and the dummy glass, there is a problem that the focus shift occurs.

Therefore, the present invention was created to solve the above problems, for example, when switching the shooting mode of the surveillance camera from the day mode to the night mode, or from the night mode to the day mode, or zoom operation or In case of performing a preset change operation, the focus of the surveillance camera for compensating for the focus shift by variably controlling the position of the focus lens by the focus offset value caused by the replacement of the infrared cut filter and the dummy glass. It is an object of the present invention to provide an offset compensation device and method.

In the focus offset compensation method of the surveillance camera according to the present invention for achieving the above object, when the shooting mode of the surveillance camera is switched from the day mode to the night mode, the infrared cut filter disposed in front of the image pickup device dummy Replacing with glass; And variably controlling the position of the focus lens by a focus offset value generated due to the replacement of the dummy glass.

In addition, when the photographing mode of the surveillance camera is switched from the night mode to the daytime mode, replacing the dummy glass disposed in front of the image pickup device with an infrared cut filter; And variably controlling the position of the focus lens by a focus offset value caused by the replacement of the infrared cut filter.

In addition, the focus offset value, characterized in that the experimental result that is stored in advance and managed to compensate for the focus shift caused by the material and thickness difference between the infrared cut filter and the dummy glass,

In addition, the focus offset compensation method of the surveillance camera according to the present invention, when performing the zoom operation of the surveillance camera, determining whether the current shooting mode is a night mode; And, in the night mode, variably controlling the position of the focus lens by the focus offset value generated by the infrared light, in the night mode.

In addition, the focus offset value is an experimental result value which is previously stored and managed to compensate for the focus shift caused by the infrared rays passing through the dummy glass disposed at the front end of the image pickup device in the night mode. It is characterized by having a value that gradually increases as the tele change,

In addition, the focus offset compensation method of the surveillance camera according to the present invention, when performing a preset change operation of the surveillance camera, checking the shooting mode when setting the preset information; And controlling the position of the focus lens by a focus offset value caused by the replacement of the dummy glass or the infrared cut filter when the checked photographing mode and the current photographing mode are inconsistent. ,

In addition, the preset information, characterized in that the identification information for indicating whether the shooting mode when setting the preset information, day mode or night mode is stored in association,

In addition, the focus offset value, characterized in that the experimental result stored in advance to manage the compensation, to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass,

In addition, when the zoom operation is performed by the preset change operation, if the current shooting mode is a night mode, the method may further include variably controlling the position of the focus lens by a focus offset value generated by infrared rays. ,

The focus offset value may be an experimental result value which is stored and managed in advance in order to compensate for a focus shift caused by infrared rays passing through the dummy glass disposed at the front end of the image pickup device in the night mode.

In addition, the focus offset compensator of the monitoring camera according to the present invention, if the photographing mode is the daytime mode, the infrared cut filter is disposed in front of the image pickup device, if the night mode, the driving means for arranging the dummy glass; And control means for variably controlling the position of the focus lens by a focus offset value generated due to the arrangement of the dummy glass.

The control means may variably control the position of the focus lens by a focus offset value generated due to the arrangement of the infrared cut filter.

In addition, the focus offset value, characterized in that the experimental result stored in advance to manage the compensation, to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass,

In addition, the focus offset compensation device of the monitoring camera according to the present invention, the photographing mode is a daytime mode, if the infrared cut filter is placed in front of the image pickup device, if the night mode, driving means for arranging the dummy glass; And a control means for variably controlling the position of the focus lens by a focus offset value generated by infrared rays when the current photographing mode is a night mode when performing a zoom operation.

In addition, the focus offset value is an experimental result value which is previously stored and managed to compensate for the focus shift caused by the infrared rays passing through the dummy glass disposed at the front end of the image pickup device in the night mode. It is characterized by having a value that gradually increases as the tele change,

In addition, the focus offset compensator of the monitoring camera according to the present invention, if the photographing mode is the daytime mode, the infrared cut filter is disposed in front of the image pickup device, if the night mode, the driving means for arranging the dummy glass; And when performing the preset change operation, if the shooting mode at the time of setting the preset information and the current shooting mode are inconsistent, the position of the focus lens is adjusted by the focus offset value caused by the replacement of the dummy glass or the infrared cut filter. Characterized in that it comprises a control means for variable control,

In addition, the preset information, characterized in that the identification information for indicating whether the shooting mode when setting the preset information, day mode or night mode is stored in association,

In addition, the focus offset value, characterized in that the experimental result that is stored in advance and managed to compensate for the focus shift caused by the material and thickness difference between the infrared cut filter and the dummy glass,

In addition, the control means, when performing the zoom operation by the preset change operation, if the current shooting mode is a night mode, characterized in that for controlling the position of the focus lens by the focus offset value generated by infrared rays, characterized in that ,

The focus offset value may be an experimental result value which is stored and managed in advance in order to compensate for a focus shift caused by infrared rays passing through the dummy glass disposed at the front end of the image pickup device in the night mode.

In the focus offset compensation device and method of the surveillance camera according to the present invention, for example, when the photographing mode of the surveillance camera is a day mode, an IR cut filter is arranged in front of the imaging device, In the night mode, a dummy glass is disposed, and the position of the focus lens is variably controlled by a focus offset value generated due to a material and thickness difference between the infrared cut filter and the dummy glass. When the current shooting mode is a night mode when the zoom operation is performed, the position of the focus lens is variably controlled by the focus offset value generated by infrared rays, and when the preset change operation is performed, the corresponding preset information is set. If the shooting mode of the camera and the current shooting mode do not match, the focus lens The position of the control variable by writing, to effectively compensate for the focus teuleojim generated in accordance with carrying out the recording mode switch, a zoom operation, and a preset change operation, it is possible to perform a photographing operation in the subject more accurate focus state.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the focus offset compensation device and method of the surveillance camera according to the present invention will be described in detail.

The present invention can be applied to various types of surveillance cameras in which the shooting mode is divided into a day mode and a night mode. For example, the surveillance camera to which the present invention is applied is zoomed as shown in FIG. 1. Lens 10, focus lens 11, iris 12, infrared cut filter 13, dummy glass 14, imaging device 15, automatic gain control unit 16, digital signal processing unit 17, Zoom motor 18, focus motor 19, iris motor 20, day / night motor 21, iris motor driver 22, control unit 23, memory 24, timer 25, zoom motor The drive part 26, the focus motor drive part 27, the day / night motor drive part 28, etc. are comprised.

On the other hand, the control unit 23, if the shooting mode is set to the day mode, or the shooting mode is set to the day mode according to the current time counted by the timer 25, etc. Operation of the day / night motor drive unit 28 is performed so that the infrared cut filter 13 is disposed in front of the imaging element 15.

In addition, when the controller 23 sets the shooting mode to the night mode at the request of the user, or sets the shooting mode to the night mode according to the current time counted by the timer 25 or the like, FIG. As shown in FIG. 2, the day / night motor drive unit 28 is controlled to operate so that the dummy glass 14 is disposed in front of the imaging element 15.

For example, as shown in FIG. 3, when the day mode is set, the day / night motor 21 is rotated in the clockwise direction, so that the infrared cut filter 13 is the front end of the imaging element 15. 4, when the night mode is set, the main / night motor 21 is rotated in a counterclockwise direction so that the dummy glass 14 of the imaging device 15 Be placed at the front end.

On the other hand, when the infrared cut filter 13 disposed in front of the image pickup device 15 as described above is replaced with the dummy glass 14, the focus is due to the difference in material and thickness between the infrared cut filter and the dummy glass. Distortion occurs.

For example, as shown in FIG. 5, as the photographing mode is switched from the daytime mode to the night mode, the thickness of the dummy glass disposed at the front end of the imaging element 15 is thicker than the thickness of the infrared cut filter. In this case, a focus shift occurs when a beam spot focused on the imaging device 15 is formed after a predetermined distance (-D) from a fine focus point.

On the other hand, as shown in FIG. 6, when the photographing mode is switched from the day mode to the night mode, when the thickness of the dummy glass disposed at the front end of the imaging device 15 is thinner than the thickness of the infrared cut filter, The beam spot focused on the image pickup device 15 may be out of focus to be formed before the predetermined focus distance + D from the fine focus point.

Therefore, in the present invention, in order to compensate for the focus shift caused when switching the shooting mode from the day mode to the night mode or the night mode to the day mode as described above, the experiment for variably adjusting the position of the focus lens The resultant value is set to a focus offset value (Focus Offset = [wh D]) according to the shooting mode switching operation, and stored in the memory 24, for example, a nonvolatile memory such as EEPROM.

On the other hand, as shown in FIG. 7, when performing a zoom wide operation in a night mode state, a beam spot of an infrared (IR) component that passes through the dummy glass 14 is formed. The focus shift formed after a predetermined distance (-W (w)) from the fine focus point of the imaging device 15 occurs.

In a night mode, when a zoom tele operation is performed, a beam spot of an infrared (IR) component that passes through the dummy glass 14 is smaller than the predetermined distance (-W (w)). The focus shift formed at the more spaced point -W (t) occurs.

 Therefore, in the present invention, in order to compensate for the focus shift caused when performing the zoom wide or zoom tele operation in the night mode state as described above, for variably adjusting the position of the focus lens. The experimental result value is set to a focus offset value according to a zoom operation (Focus Offset = [-W (i)], i = Zoom magnification) and stored in the memory 24. For example, FIG. As shown, the focus offset value according to the zoom operation has a value that gradually increases as the zoom wide is changed to the zoom tele.

On the other hand, in the present invention, for example, as shown in Fig. 9, in order to change the pan / tilt / zoom state of the surveillance camera to any shooting state desired by the user, a preset When (Preset) information is set, identification information for checking the shooting mode at that time and identifying whether the shooting mode at the time of setting the preset information is a day mode or a night mode. D & N_Flag) is stored in association.

For example, when the pan 30 degrees, the tilt 50 degrees, and the zoom 2 times are set as the first preset information, if the shooting mode at that time is the day mode, the day / night flag is stored as the value of '0'. When the pan 45 degrees, the tilt 50 degrees, and the zoom 4 times are set as the second preset information, if the photographing mode at that time is the night mode, the day / night flag is linked and stored as a value of '1'.

When the preset change operation for variably controlling the pan / tilt / zoom operation is performed by referring to the preset information stored and managed as described above, the shooting mode when setting the preset information and the current shooting mode do not match. When it is determined that focus misalignment occurs, a focus offset (Focus Offset = [W D] + [-W (i)]) compensation operation according to a shooting mode switching operation and a zoom operation is performed.

FIG. 10 is a flowchart illustrating a method of compensating for a focus offset of a surveillance camera according to the present invention. In the control unit 23, while performing a photographing operation (S10), at the request of a user, or When switching the shooting mode in accordance with the current time counted by the timer 25 or the like (S11), the day / night motor drive unit 28 is operated to control the infrared cut filter (in front of the imaging device 15). 13) or dummy glass 14 is arranged.

For example, as described above with reference to FIG. 4, when the photographing mode is switched from the day mode to the night mode, the controller 23 controls the day / night motor driver 28 to operate the main / night motor. By rotating the night motor 21 counterclockwise, the dummy glass 14 is arranged in front of the imaging element 15.

In addition, as described above with reference to FIGS. 5 and 6, the controller 23 compensates for a focus shift caused by a material and a thickness difference between the infrared cut filter 13 and the dummy glass 14. After searching and confirming a focus offset value (for example, Offset = [ㅁ D]) according to a shooting mode switching operation stored and managed as an experimental result value in the memory 24, operation control of the focus motor driver 27 is performed. The focus motor 19 is rotated.

Accordingly, since a series of focus offset compensation operations for variably controlling the position of the focus lens 11 are performed (S12), it is possible to efficiently compensate for the focus shift caused by the shooting mode switching operation.

On the other hand, the control unit 23, while performing the zooming operation as described above, when performing the zoom operation (S13), to check the current shooting mode, for example, the current shooting mode, the dummy In the night mode state using the glass 14 (S14), as described above with reference to FIGS. 7 and 8, a focus offset value according to a zoom operation that gradually increases from zoom wide to zoom tele (eg, Offset = [ -W (i)] and i = Zoom magnification) in the memory 24, and after that, the focus motor driver 27 is operated to rotate the focus motor 19. FIG.

Accordingly, since a series of focus offset compensation operations for variably controlling the position of the focus lens 11 are performed, it is possible to efficiently compensate for the focus shift caused by the zoom operation in the night mode.

In addition, the controller 23 checks the day / night flag D & N_Flag stored in association with the preset information while performing the preset change operation while performing the photographing operation as described above (S16). You can check whether the shooting mode is set to day mode or night mode.

Then, the checked mode and the current shooting mode are compared with each other (S17). For example, when the preset information is set, the shooting mode is a day mode, and the current shooting mode is a night mode. In this case, as described above with reference to FIGS. 5 and 6, the controller 23 may provide a focus offset value (eg, Offset =) according to a shooting mode switching operation that is stored and managed as an experimental result value in the memory 24. After searching and confirming [W D]), the focus motor driver 27 is controlled to rotate the focus motor 19.

In addition, when the zoom operation is performed by the preset change operation, the control unit 23, as described above with reference to FIG. 8, focus offset value according to the zoom operation that gradually increases from zoom wide to zoom tele (example) : Offset = [-W (i)], i = Zoom magnification), after searching and checking in the memory 24, the focus motor driver 27 is operated to rotate the focus motor 19. .

As a result, since a series of focus offset compensation operations for variably controlling the position of the focus lens 11 are performed, when the preset change operation is performed, the focus shift that occurs may be efficiently compensated, thereby providing more accurate focus. In this state, the subject photographing operation can be performed.

For reference, in the present invention, a series of operations for compensating for focus misalignment by searching for the focus offset value as described above and compensating for focus misalignment or temporarily performing an auto focus operation to selectively compensate for the focus misalignment, according to a user's request It can be done with

Or more, preferred embodiments of the present invention described above, for the purpose of illustration, those skilled in the art, within the technical spirit and the technical scope of the present invention disclosed in the appended claims below, to further improve various other embodiments Changes, substitutions or additions will be possible.

1 and 2 illustrate a configuration of a surveillance camera to which the present invention is applied,

3 and 4 illustrate an embodiment in which the infrared cut filter and the dummy glass are replaced according to the present invention.

5 and 6 illustrate a process of setting a focus offset value when switching a shooting mode according to the present invention;

7 and 8 illustrate a process of setting a focus offset value when performing a zoom operation according to the present invention.

9 illustrates an embodiment of preset information in which day / night flags are linked and stored according to the present invention.

10 is a flowchart illustrating an operation of a focus offset compensation method of a surveillance camera according to the present invention.

※ Explanation of code for main part of drawing

10: zoom lens 11: focus lens

12: iris 13: infrared cut filter

14 dummy glass 15 imaging device

16: automatic gain control unit 17: digital signal processing unit

18: zoom motor 19: focus motor

20: Iris Motor 21: Day / Night Motor

22: iris motor drive unit 23: control unit

24: memory 25: timer

26: zoom motor driver 27: focus motor driver

28: day / night motor drive

Claims (22)

When the photographing mode of the surveillance camera is switched from the day mode to the night mode, replacing the infrared cut filter disposed in front of the image pickup device with dummy glass; And And varyingly controlling the position of the focus lens by a focus offset value generated due to the replacement of the dummy glass. The method of claim 1, When the photographing mode of the surveillance camera is switched from the night mode to the daytime mode, replacing the dummy glass disposed at the front end of the imaging device with an infrared cut filter; And And variably controlling the position of the focus lens by a focus offset value generated by the replacement of the infrared cut filter. The method of claim 1, The focus offset value is a focus offset compensation method of a surveillance camera, characterized in that the experimental result stored in advance to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass. Determining whether a current shooting mode is a night mode when performing a zoom operation of a surveillance camera; And And in the night mode, variably controlling the position of the focus lens by a focus offset value generated by infrared rays. The method of claim 4, wherein The focus offset value is an experimental result value which is stored and managed in advance in order to compensate for focus misalignment caused by infrared rays passing through the dummy glass disposed in front of the image pickup device in the night mode. Focus offset compensation method. The method of claim 5, The focus offset value is a focus offset compensation method for a surveillance camera, characterized in that it has a value that gradually increases as it is changed from zoom wide to zoom tele. When performing a preset change operation of the surveillance camera, checking a shooting mode when setting corresponding preset information; And And monitoring the position of the focus lens by a focus offset value caused by the replacement of the dummy glass or the infrared cut filter when the checked shooting mode and the current shooting mode do not match. Offset Compensation Method for Digital Cameras. The method of claim 7, wherein And the identification information for indicating whether the photographing mode at the time of setting the preset information is a day mode or a night mode in association with the preset information. The method of claim 7, wherein The focus offset value is a focus offset compensation method of a surveillance camera, characterized in that the experimental result stored in advance to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass. The method of claim 7, wherein When the zoom operation is performed by the preset change operation, if the current shooting mode is a night mode, the method further comprises variably controlling the position of the focus lens by a focus offset value generated by infrared rays. Focus offset compensation method of surveillance camera. The method of claim 10, The focus offset value is an experimental result value which is stored and managed in advance in order to compensate for focus misalignment caused by infrared rays passing through the dummy glass disposed in front of the image pickup device in the night mode. Focus offset compensation method. Driving means for arranging an infrared cut filter in front of the imaging device if the photographing mode is a day mode, and for placing a dummy glass in the night mode; And And a control means for variably controlling the position of the focus lens by the focus offset value generated by the arrangement of the dummy glass. The method of claim 12, And said control means variably controls the position of the focus lens by a focus offset value generated due to the arrangement of the infrared cut filter. The method of claim 12, The focus offset value is a focus offset compensation device for a surveillance camera, characterized in that the experimental result stored in advance to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass. Driving means for arranging an infrared cut filter in front of the imaging device if the photographing mode is a day mode, and for placing a dummy glass in the night mode; And When performing the zoom operation, if the current shooting mode is a night mode, the focus of the surveillance camera comprising a control means for variably controlling the position of the focus lens by the focus offset value generated by the infrared ray Offset compensation device. The method of claim 15, The focus offset value is an experimental result value which is stored and managed in advance in order to compensate for focus misalignment caused by infrared rays passing through the dummy glass disposed in front of the image pickup device in the night mode. Focus offset compensation device. The method of claim 16, The focus offset value is a focus offset compensation device for a surveillance camera, characterized in that it has a value that gradually increases as it is changed from zoom wide to zoom tele. Driving means for arranging an infrared cut filter in front of the imaging device if the photographing mode is a day mode, and for placing a dummy glass in the night mode; And When performing the preset change operation, if the shooting mode when setting the preset information and the current shooting mode do not match, the position of the focus lens is changed by the focus offset value caused by the replacement of the dummy glass or infrared cut filter. Focus offset compensation device for a surveillance camera, characterized in that it comprises a control means for controlling. The method of claim 18, The preset information, the focus offset compensation device for a surveillance camera, characterized in that the identification information for indicating whether the shooting mode when setting the preset information, day mode or night mode is stored in association. The method of claim 18, The focus offset value is a focus offset compensation device for a surveillance camera, characterized in that the experimental result stored in advance to compensate for the focus shift caused by the difference in material and thickness between the infrared cut filter and the dummy glass. The method of claim 18, When the zooming operation is performed by a preset change operation, the control means variably controls the position of the focus lens by a focus offset value generated by infrared rays when the current photographing mode is a night mode. Camera's focus offset compensation device. The method of claim 21, The focus offset value is an experimental result value which is stored and managed in advance in order to compensate for focus misalignment caused by infrared rays passing through the dummy glass disposed in front of the image pickup device in the night mode. Focus offset compensation device.

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