WO2013024946A1 - Method for controlling an autofocus system - Google Patents
Method for controlling an autofocus system Download PDFInfo
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- WO2013024946A1 WO2013024946A1 PCT/KR2012/000250 KR2012000250W WO2013024946A1 WO 2013024946 A1 WO2013024946 A1 WO 2013024946A1 KR 2012000250 W KR2012000250 W KR 2012000250W WO 2013024946 A1 WO2013024946 A1 WO 2013024946A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/60—Control of cameras or camera modules
- H04N23/67—Focus control based on electronic image sensor signals
- H04N23/675—Focus control based on electronic image sensor signals comprising setting of focusing regions
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
- G03B13/32—Means for focusing
- G03B13/34—Power focusing
- G03B13/36—Autofocus systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/60—Control of cameras or camera modules
- H04N23/69—Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
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- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
- G08B13/189—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems
- G08B13/194—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems
- G08B13/196—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems using television cameras
- G08B13/19617—Surveillance camera constructional details
- G08B13/19626—Surveillance camera constructional details optical details, e.g. lenses, mirrors or multiple lenses
Definitions
- the present invention relates to a control method of an autofocus system, and more particularly, a section point is formed as a look up table (LUT) so that the focus lens can be quickly moved with respect to the position of the zoom lens, and stored in the memory unit 20.
- LUT look up table
- the focus is searched, the default MTF value stored in the memory unit is moved to the specified position of the CW or CCW of the focus motor, and the optimum displacement is searched by comparing the calculated displacement MTF value with the mutual size. After calculating the MTF value every time, compare and analyze it to find the optimal value accurately.
- the present invention relates to a control method of an autofocus system capable of easily finding an autofocus error by automatically storing it in a LUT (Look UP Table) in a memory unit and automatically correcting the error.
- CTV Closed Circuit Television
- the initial CCTV camera is not equipped with a zoom function for adjusting the magnification of the lens like a general optical camera, there was an inconvenience of always taking a fixed magnification image.
- an imaging device such as a camera is provided with an image sensor (C harge- C oupled D evice [charge-coupled device sensor or C omplementary M etal O xide S emiconductor ) the images of the subject transmitted through the lens and the image pickup lens
- C harge- C oupled D evice charge-coupled device sensor or C omplementary M etal O xide S emiconductor
- FIG. 1 is a flowchart illustrating an example of a conventional method for controlling auto focusing (AF).
- the AF control method includes an origin return step (S10) in which the coordinates of the focus motor are returned or maintained to the home position at the time of initial power-up or system booting, and an image is requested by a zoom or a user's request.
- the main processor that receives the image of the displaced position from the camera is the average value calculating step (S12) for calculating the average value of the luminance obtained from a plurality of points of the captured image
- the contrast ratio is calculated from the same image used in the average value calculating step (S13), and the focus motor driver calculates the focus lens by controlling the driving of the focus motor with reference to the LUT (Look Up Table) stored in the memory unit.
- a focus completion step (S19) of calculating the luminance average value and the contrast ratio at that time and storing the result is performed in the memory unit.
- the focus search method focuses by calculating and comparing the contrast ratio between the average value of luminance and the edge portion of the measurement area. As a result, a large number of calculations are performed to reduce the focus search speed. In addition, as a method of calculating luminance, or brightness of a screen, a problem of increasing a search failure rate in a dark shooting environment such as at night has occurred.
- the focus search is re-searched at the existing position, and thus the focus search of the moved target may not be accurately performed.
- the present invention was created to solve the problems of the prior art as described above, and an object of the control method of an autofocus system according to the present invention is to provide a LUT (Look) section point so as to quickly move a focus lens with respect to a zoom lens position.
- UP table and store it in the memory unit 20, and it is possible to move quickly through the section movement according to the lens so as to shorten the autofocusing time, and the base MTF value and the currently calculated MTF value after the section movement according to the zoom position Are compared to each other, and the default MTF value stored in the memory unit is moved to each designated position of the CW or CCW of the focus motor so that the accuracy is increased in a dark environment or a high resolution focus search.
- the control method of the autofocus system according to the present invention for achieving the above object is the home position return step (S100) is carried out to return or maintain the coordinates of the focus motor to the home position when the initial power-up or system booting;
- the zoom lens shifting step (S200) of loading data for the zoom position and moving the zoom lens to the designated position is performed;
- a focus lens shift step S300 of loading data for a focus position and moving the focus lens to a designated position is performed;
- a target position search step (S500) for searching a partial area on the full screen divided into a plurality of areas is performed;
- a second focus search step (S600) in which a focus search is performed on the searched screen region is performed.
- control method of the autofocus system according to the present invention has the following effects.
- the focus lens can be quickly moved to match the position of the zoom lens, thereby reducing the time for the overall focus search operation.
- the basic MTF value stored in the memory unit is moved to each of the specified positions of the CW or CCW of the focus motor, and the optimal displacement is searched by comparing the calculated displacement MTF value with the mutual size.
- the accuracy is increased during the focus search, making it easy to manufacture a high-resolution autofocus camera.
- the searched position value is newly stored every time in the LUT (Look UP Table) of the memory unit connected to the main processor to easily find an autofocus error and automatically correct it.
- FIG. 1 is an exemplary configuration block diagram of an autofocus system according to the prior art.
- FIG. 2 is an exemplary structural block diagram of an autofocus system according to the present invention.
- FIG. 3 is a flowchart showing an example of an autofocus control method according to the present invention.
- FIG. 4 is a flowchart illustrating an example of a focus search method among autofocus control methods according to the present invention.
- FIG. 5 is an exemplary table representing a movement path of the focus motor shown in FIG. 4.
- FIG. 6 is a flowchart illustrating an example of a target position search method in an autofocus control method according to the present invention.
- FIG. 2 is an exemplary structural block diagram of an autofocus system according to the present invention.
- the autofocus camera system is autofocusing and zooming in and out related to the present invention in CCTV, and focus error reading and correction, RS-485 communication, Modulation Transfer function (MTF), and the like.
- a main processor 10, which is a chipset that performs overall control necessary for implementation, is provided, and is connected to the main processor 10 to store and update data under the control of the main processor 10 according to a purpose. 20 is provided.
- an output unit for outputting the contents processed by the main processor 10 to the outside, and an input unit 30 connected to the main processor to provide a user interface is provided.
- an imaging camera 70 and an image processor 40 for converting an analog signal captured by the imaging camera 70 into a digital signal and transmitting the same to the main processor are provided.
- the zoom lens 51 moves back and forth in the optical axis direction to zoom in / out the image when the subject is captured, and the focus lens 52 moves back and forth in the optical axis direction to in / out the sharpness of the image after the zoom lens is moved. do.
- a zoom motor 61 and a focus motor 62 are provided on one outer peripheral surface of the lens to drive the zoom lens and the focus lens, and are implemented as a stepping motor 60 capable of rapid driving and accurate control.
- a focus motor driver 63 and a zoom motor driver 64 are connected to the main processor 10, respectively, to control the driving of the focus motor 62 and the zoom motor 61.
- a MTF (Modulation Transfer Function) calculation unit for calculating a numerical value of the optical capability of the lens mounted on the imaging camera 70 is provided, and the memory unit 20 connected to the main processor has an MTF value for each lens. Stored.
- MTF Modulation Transfer Function
- the MTF calculation unit 80 is to load and compare the existing MTF value for each lens to find and correct the error of autofocus of the current screen.
- autofocusing is to compare a contrast ratio with an MTF value for each lens stored in the memory unit 20 of the focus zone, that is, the focus center, that is, the image after the lens is moved for autofocusing. It can be controlled simply by utilizing.
- the lens is designed to be able to move in multiple steps, and is controlled by the driver described above.
- the lens is designed to allow 6 steps of moving (5.25 times optical).
- it can be designed to allow 11 step movements (10 times optical).
- a section point that can be quickly moved is made into a look up table (LUT) and stored in the memory unit 20. Then, the focus lens can be quickly moved to a section corresponding to the position of the zoom lens according to the zoom, and the time required for focus can be shortened if a fine adjustment operation is subsequently performed.
- LUT look up table
- the focus motor driver 63 and the zoom motor driver 64 step the respective focus motor 62 and the zoom motor 61 step by step. After that, autofocusing is implemented by a point comparison method described below in a zoom in / out function when the corresponding area is reached.
- a focus error detection unit 11 is further connected to the main processor 10.
- the focus error detection unit 11 acquires a value that the lens actually moves during autofocusing and zooming in and out, and thus the actual movement value of the lens.
- the MTF value of each lens stored in the memory unit 20 is compared to check whether there is an error in focus by reading a match.
- the control method of the autofocus system starts from the home position return step S100 in which the coordinates of the focus motor 62 are returned or maintained at the home position at the time of initial power-up or system booting.
- the memory unit connected to the main processor loads data about a zoom position and transfers the data to a zoom motor driver, thereby moving the zoom lens to a designated position. (S200) is performed.
- Step S300 is performed.
- the focus search step (S400) in which the focus search of the center portion of the screen with respect to the moved position is performed.
- the focus search step (S400) is a method of comparing the MTF value currently stored using the MTF value and the MTF calculation unit () stored as a basic corresponding to the position of the current focus motor will be described in detail later Shall be.
- the position value of the current focus motor is stored in the LUT (Look UP Table) of the memory unit connected to the main processor, and the focus search is completed.
- a target location search step (S500) for searching a partial area on the full screen divided into a plurality of areas is performed.
- the LUT Look UP Table
- the focus search is terminated by moving to the successive position of the previous focus search.
- a section of several steps is set to allow rapid movement through the section movement according to the lens, and the MTF value stored basically after the section movement according to the zoom position and the currently calculated MTF value using the MTF calculating unit 600.
- the autofocusing time can be shortened by comparing with each other.
- the searched position value is newly stored in a look up table (LUT) of a memory unit connected to the main processor to easily find an autofocus error and automatically correct it.
- LUT look up table
- control method in the focus search step (S400) is the same as FIG.
- a basic MTF value loading step 410 of loading basic MTF value data for the current focus motor position is performed at the start of focus search.
- a first displacement MTF value calculation step 420 is performed in which the focus motor is moved in a clockwise direction with respect to a designated position, and the MTF value for each position is calculated and stored in a memory unit.
- a first MTF value comparison step 430 of comparing the displacement MTF value stored with respect to the position and the basic MTF value stored in the memory unit is performed.
- the displacement MTF value stored for the position is higher than the basic MTF value stored in the memory unit, the basic focus position value and the related MTF value are updated, and the process returns to the displacement MTF value calculation step 420.
- a second displacement MTF value calculation step 440 is performed to calculate the MTF value and store the MTF value.
- a second MTF value comparison step 450 of comparing the displacement MTF value stored with respect to the position and the basic MTF value stored in the memory unit is performed.
- the focus search is terminated.
- the basic MTF value stored in the memory unit is moved to each of the specified positions of the CW or CCW of the focus motor, and the optimal displacement is searched by comparing the calculated displacement MTF value with the mutual size.
- control method in the target location search step (S500) is the same as FIG.
- a table setting step of setting and storing an area where a focus search is to be started and its size among a plurality of tables divided in the screen area at the start of a target location search is performed.
- an area MTF value calculation step of calculating the set area MTF value of the stored screen is performed by updating the maximum MTF value to "0".
- a basic MTF value setting step of comparing the maximum MTF value updated to "0" with the setting area MTF value and storing the maximum MTF value as a large value is performed in the memory unit.
- the screen target checking step of loading the set default MTF value, calculating MTF values of the last stored screen and the last stored area, and comparing them with each other is performed.
- the new focus search area and its size are set and stored in the next screen area, and the process returns to the previous step of calculating the area MTF value.
- the target search return step is performed.
- control method of the autofocus system can perform the autofocus function in a short time at the same time as the zoom in / out, and can easily correct the focus error due to the variable position of the subject or the dark shooting environment.
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Abstract
The present invention relates to a method for controlling an autofocus system, which involves creating section points in a look-up table so as to quickly move a focus lens with respect to the location of a zoom lens and then storing the look-up table (LUT) in a memory unit (20), enabling a quick movement through an interval movement according to the lenses so as to shorten the autofocus time and then comparing a basic MTF value stored after the interval movement and a currently calculated MTF value according to a zoom location, searching for an optimal focus by moving the basic MTF value stored in the memory unit to four designated CW or CCW locations of a focus motor during focus searching to improve accuracy when searching for a focus in a dark environment or for a high resolution focus and then comparing a calculated displacement MTF value and mutual size, comparing and analyzing the MTF value stored as a basic value every time the MTF value is calculated to accurately search for an optimal value, and storing the searched location value in the LUT in the memory unit connected to a main processor so as to achieve the effect of easily detecting an autofocus error.
Description
본 발명은 오토포커스 시스템의 제어방법에 관한 것으로서, 보다 상세하게는 줌 렌즈의 위치에 대하여 포커스 렌즈를 신속히 이동시킬 수 있도록 구간 포인트를 LUT(Look UP Table)로 만들어 메모리부(20)에 저장하고, 오토포커싱 시간이 단축되도록 렌즈에 따라 구간이동을 통해 신속한 이동이 가능하며 줌의 위치에 따라 구간이동 후 저장된 기본MTF값과 현재 산출된 MTF값을 상호 비교하며, 어두운 환경 또는 고해상도의 포커스검색시 정확도가 상승되도록 포커스의 검색시 메모리부에 저장된 기본MTF값을 포커스모터의 CW 또는 CCW의 각 지정된 위치로 이동하며 산출된 변위MTF값과 상호 크기를 비교하여 최적의 포커스를 검색하고, 기본으로 저장된 MTF값을 매번 산출후 비교분석하여 최적의 값을 정확하게 찾도록 하며, 검색된 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 매번 새로 저장하여 오토포커스 오류를 쉽게 찾아내고, 이를 자동 보정할 수 있는 오토포커스 시스템의 제어방법에 관한 것이다.The present invention relates to a control method of an autofocus system, and more particularly, a section point is formed as a look up table (LUT) so that the focus lens can be quickly moved with respect to the position of the zoom lens, and stored in the memory unit 20. In order to shorten the auto focusing time, it is possible to move quickly by section movement according to the lens and compare the basic MTF value and the currently calculated MTF value after the section movement according to the zoom position. When the focus is searched, the default MTF value stored in the memory unit is moved to the specified position of the CW or CCW of the focus motor, and the optimum displacement is searched by comparing the calculated displacement MTF value with the mutual size. After calculating the MTF value every time, compare and analyze it to find the optimal value accurately. The present invention relates to a control method of an autofocus system capable of easily finding an autofocus error by automatically storing it in a LUT (Look UP Table) in a memory unit and automatically correcting the error.
주지된 바와 같이, 취약지역이나 사람들의 왕래가 많은 곳 혹은 산업설비 등에서 감시/관리, 차량용, 지하철 전동차용 등 다양한 분야에서 CCTV(폐쇄회로 텔리비전:Closed Circuit Television) 시스템이 설치 운용되고 있다.As is well known, Closed Circuit Television (CCTV) systems have been installed and operated in various areas such as surveillance / management, vehicles, subway trains, etc. in vulnerable areas, crowded places, or industrial facilities.
최근에는 백화점, 은행, 전시장 등은 물론 학교주변, 주택가와 같은 곳 까지 설치가 확대 운영되고 있는데, 각종 범죄로부터 안전을 확보하기 위한 일환이며, 더욱 더 확대될 전망이다.In recent years, installations have been extended to department stores, banks, exhibition halls, schools, and residential areas, which are intended to secure safety from various crimes.
여기서, 초기 CCTV 카메라는 일반 광학용 카메라와 같이 렌즈의 배율을 조정하는 줌 기능이 장착되어 있지 않았기 때문에 항상 고정된 배율의 화상만 촬영해야 하는 불편함이 있었다.Here, since the initial CCTV camera is not equipped with a zoom function for adjusting the magnification of the lens like a general optical camera, there was an inconvenience of always taking a fixed magnification image.
이를 개선하여 현재 출시되고 있는 대부분의 CCTV 카메라는 줌기능과 포커싱 기능을 갖추고 있고, 관련 특허 기술도 다수 개시되어 있다.As a result, most CCTV cameras on the market are equipped with a zoom function and a focusing function, and many related patent technologies are disclosed.
일반적으로 카메라와 같은 촬영기기는 렌즈와 렌즈를 투과한 피사체의 이미지가 촬상되는 촬상센서(Charge-Coupled Device [전하결합소자센서] 또는 Complementary Metal Oxide Semiconductor)를 구비하고 있으며, 렌즈의 위치를 가변함으로써 렌즈와 촬상센서의 거리를 조정하고, 이에 따라 촬상센서에 촬상되는 피사체의 이미지의 포커싱을 조정한다.In general, an imaging device such as a camera is provided with an image sensor (C harge- C oupled D evice [charge-coupled device sensor or C omplementary M etal O xide S emiconductor ) the images of the subject transmitted through the lens and the image pickup lens By adjusting the position of the lens, the distance between the lens and the image sensor is adjusted, and accordingly the focusing of the image of the subject imaged by the image sensor is adjusted.
렌즈의 위치를 가변하여 각 위치에서의 피사체의 이미지의 포커싱 정도를 계산하고, 최적의 포커싱을 갖도록 렌즈의 위치를 자동으로 조정하는 것이 오토포커싱이다.It is autofocusing that the position of the lens is varied to calculate the focusing degree of the image of the subject at each position, and the lens position is automatically adjusted to have the optimal focusing.
도 1은 종래의 오토포커싱(AF) 제어방법에 대한 예를 표현한 플로우차트이다.1 is a flowchart illustrating an example of a conventional method for controlling auto focusing (AF).
도 1에서와 같이, 오토포커싱(AF) 제어방법은 최초 전원인가시 또는 시스템 부팅시 포커스모터의 좌표가 홈 포지션으로 복귀 또는 유지되는 원점복귀단계(S10)와, 줌 또는 유저의 요청에 의해 영상변위가 발생되면(S11), 카메라(CCD 또는 CMOS)로부터 변위된 위치의 영상을 입력받은 메인프로세서는 촬상된 이미지의 다수 포인트에서 얻어진 루미넌스(Luminance) 평균값을 산출하는 평균값 산출단계(S12)와, 평균값 산출단계에서 사용된 동일 이미지로부터 컨트래스트 비를 산출하고(S13), 메모리부에 저장되어 있는 LUT(Look Up Table)를 참고하여 포커스모터 드라이버가 포커스모터의 구동을 제어하여 포커스렌즈를 산출된 평균 루미넌스와 컨트래스트 비에 근접한 구간으로 이동시키는 구간이동 단계(S14)와, 이동된 구간을 중심으로 포커스모터를 기본 스텝수만큼 시계방향과, 반시계방향으로 각각 회전시켜(S15) 이동된 스텝수에서의 각 이미지를 다시 획득하고, 각 이미지로부터 컨트래스트 비를 산출하는 조절단계(S16)와, 조절단계 후 메인프로세서는 산출된 두 개의 컨트래스트 비를 비교하여 컨트래스트 비의 차이가 큰 쪽 반대로 포커스모터를 설정된 스텝수만큼 회전시킨 상태에서 다시 반대방향으로 감으면서 포커스를 맞추는 포커스단계(S17),(S18)과, 포커스가 맞춰지면 그때의 루미넌스 평균값과 컨트래스트 비를 산출한 후 메모리부에 저장하는 포커스완료단계(S19)로 이루어진다.As shown in FIG. 1, the AF control method includes an origin return step (S10) in which the coordinates of the focus motor are returned or maintained to the home position at the time of initial power-up or system booting, and an image is requested by a zoom or a user's request. When the displacement occurs (S11), the main processor that receives the image of the displaced position from the camera (CCD or CMOS) is the average value calculating step (S12) for calculating the average value of the luminance obtained from a plurality of points of the captured image, The contrast ratio is calculated from the same image used in the average value calculating step (S13), and the focus motor driver calculates the focus lens by controlling the driving of the focus motor with reference to the LUT (Look Up Table) stored in the memory unit. Section moving step (S14) for moving to a section closer to the average average luminance and contrast ratio, and the focus motor is started by the number of basic steps around the moved section. Direction, and counterclockwise respectively (S15) to obtain each image in the moved step number again, and calculate a contrast ratio from each image (S16), and after the adjustment step the main processor calculates Focus phases (S17) and (S18) that focus while rewinding in the opposite direction while the focus motor is rotated by the set number of steps as opposed to the two contrast ratios, the greater the difference in contrast ratio is. When the focus is achieved, a focus completion step (S19) of calculating the luminance average value and the contrast ratio at that time and storing the result is performed in the memory unit.
상기와 같이 포커스의 검색방법은 루미넌스의 평균값과 측정영역의 엣지부분에 대한 컨트래스트 비를 산출비교 하여 포커스를 맞추게 되는데 이렇듯 다수의 연산작업을 수행하게 되어 포커스검색 속도가 저하되는 문제가 있었고, 또한 루미넌스 즉, 화면의 밝기에 대한 산출방법으로서 야간에서와 같은 어두운 촬영환경에서는 검색실패율이 상승하는 문제가 발생되고 있다As described above, the focus search method focuses by calculating and comparing the contrast ratio between the average value of luminance and the edge portion of the measurement area. As a result, a large number of calculations are performed to reduce the focus search speed. In addition, as a method of calculating luminance, or brightness of a screen, a problem of increasing a search failure rate in a dark shooting environment such as at night has occurred.
또한, 촬영대상 즉 타겟이 화면의 기존위치에서 이동 또는 가변하게 되면 기존위치에서 포커스 검색이 재검색됨으로써, 이동된 타겟의 포커스검색이 정확하게 이루지지 못하는 문제가 있었다.In addition, when the photographing target, i.e., the target is moved or changed from the existing position of the screen, the focus search is re-searched at the existing position, and thus the focus search of the moved target may not be accurately performed.
본 발명은 상기와 같은 종래 기술의 문제점을 해결하기 위해 창작된 것으로 본 발명에 의한 오토포커스 시스템의 제어방법의 목적은 줌 렌즈의 위치에 대하여 포커스 렌즈를 신속히 이동시킬 수 있도록 구간 포인트를 LUT(Look UP Table)로 만들어 메모리부(20)에 저장하고, 오토포커싱 시간이 단축되도록 렌즈에 따라 구간이동을 통해 신속한 이동이 가능하며 줌의 위치에 따라 구간이동 후 저장된 기본MTF값과 현재 산출된 MTF값을 상호 비교하며, 어두운 환경 또는 고해상도의 포커스검색시 정확도가 상승되도록 포커스의 검색시 메모리부에 저장된 기본MTF값을 포커스모터의 CW 또는 CCW의 각 지정된 위치로 이동하며 산출된 변위MTF값과 상호 크기를 비교하여 최적의 포커스를 검색하고, 기본으로 저장된 MTF값을 매번 산출후 비교분석하여 최적의 값을 정확하게 찾도록 하며, 검색된 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 매번 새로 저장하여 오토포커스 오류를 쉽게 찾아내어 보정할 수 있는 오토포커스 시스템의 제어방법을 제공함에 있다.The present invention was created to solve the problems of the prior art as described above, and an object of the control method of an autofocus system according to the present invention is to provide a LUT (Look) section point so as to quickly move a focus lens with respect to a zoom lens position. UP table) and store it in the memory unit 20, and it is possible to move quickly through the section movement according to the lens so as to shorten the autofocusing time, and the base MTF value and the currently calculated MTF value after the section movement according to the zoom position Are compared to each other, and the default MTF value stored in the memory unit is moved to each designated position of the CW or CCW of the focus motor so that the accuracy is increased in a dark environment or a high resolution focus search. Search for the optimal focus by comparing with, calculate the basic MTF value every time and compare and analyze the optimal value accurately. To seek, and the detected position value is each time newly stored in the memory portion LUT (Look UP Table) is connected to the main processor, a control method of auto focus in autofocus system errors can be corrected easily find out to provide.
상기한 목적을 달성하기 위한 본 발명에 의한 오토포커스 시스템의 제어방법은 최초 전원인가시 또는 시스템 부팅시 포커스모터의 좌표가 홈 포지션으로 복귀 또는 유지되는 원점복귀단계(S100)가 수행되고;The control method of the autofocus system according to the present invention for achieving the above object is the home position return step (S100) is carried out to return or maintain the coordinates of the focus motor to the home position when the initial power-up or system booting;
화면 또는 유저의 요청에 의해 영상변위가 발생되면 줌위치에 대한 데이터를 로드하여 줌렌즈가 지정위치로 이동되는 줌렌즈이동단계(S200)가 수행되며;When the image displacement is generated by the screen or the user's request, the zoom lens shifting step (S200) of loading data for the zoom position and moving the zoom lens to the designated position is performed;
포커스위치에 대한 데이터를 로드하여 포커스렌즈가 지정위치로 이동되는 포커스렌즈이동단계(S300)가 수행되고;A focus lens shift step S300 of loading data for a focus position and moving the focus lens to a designated position is performed;
이동된 위치에 대한 화면 중앙부분의 포커스검색이 이루어지는 포커스검색단계(S400);가 수행되는 것을 포함하여 이루어지며;A focus search step (S400) in which a focus search of a center portion of the screen with respect to the moved position is performed;
최적의 포커스검색이 실패하면, 전체화면을 다수개의 영역으로 분할된 전체화면에 일부 영역을 검색하는 타겟위치검색단계(S500)가 수행되고;If the optimal focus search fails, a target position search step (S500) for searching a partial area on the full screen divided into a plurality of areas is performed;
검색된 화면영역에 대한 포커스검색이 이루어지는 제2포커스검색단계(S600)가 수행되는 것을 특징으로 한다.A second focus search step (S600) in which a focus search is performed on the searched screen region is performed.
이와 같이 본 발명에 의한 오토포커스 시스템의 제어방법은 다음과 같은 효과가 있다.As described above, the control method of the autofocus system according to the present invention has the following effects.
첫째, 구간 포인트를 LUT(Look UP Table)로 만들어 메모리부(20)에 저장하여 줌 렌즈의 위치에 맞도록 포커스 렌즈를 신속히 이동시킬 수 있게 됨으로써, 전반적인 포커스 검색작업에 대한 시간을 감축하는 효과가 있고,First, by making a section point into a LUT (Look Up Table) and storing it in the memory unit 20, the focus lens can be quickly moved to match the position of the zoom lens, thereby reducing the time for the overall focus search operation. There is,
둘째, 렌즈에 따라 구간이동을 통해 신속한 이동이 가능하며 줌의 위치에 따라 구간이동 후 저장된 기본MTF값과 현재 산출된 MTF값을 상호 비교하는 방법으로 오토포커싱 시간을 단축하는 효과가 있다.Secondly, it is possible to move quickly by section movement according to the lens and to shorten auto focusing time by comparing the basic MTF value and the currently calculated MTF value after section movement according to the zoom position.
셋째, 포커스의 검색시 메모리부에 저장된 기본MTF값을 포커스모터의 CW 또는 CCW의 각 지정된 위치로 이동하며 산출된 변위MTF값과 상호 크기를 비교하여 최적의 포커스를 검색함으로써, 어두운 환경 또는 고해상도의 포커스검색시 정확도가 상승하게 되어 고해상도용 오토포커스카메라를 제작함이 용이해 지는 효과가 있다.Third, when searching for the focus, the basic MTF value stored in the memory unit is moved to each of the specified positions of the CW or CCW of the focus motor, and the optimal displacement is searched by comparing the calculated displacement MTF value with the mutual size. The accuracy is increased during the focus search, making it easy to manufacture a high-resolution autofocus camera.
넷째, 피사체의 위치가 가변되거나 어두운 촬영환경으로 인한 포커스의 오류를 쉽게 보정할 수 있도록, 기본으로 저장된 MTF값을 매 산출후 비교분석하여 최적의 값을 매번 정확하게 찾을 수 있게 되어 포커스 검색값이 품질이 상승하는 효과가 있다.Fourth, in order to easily correct a focus error due to a variable position of a subject or a dark shooting environment, it is possible to calculate and compare the stored MTF value basically every time so that the optimal value can be accurately found every time. This has a rising effect.
다섯째, 검색된 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 매번 새로 저장하여 오토포커스 오류를 쉽게 찾아내고, 이를 자동 보정할 수 있는 효과가 있다.Fifth, the searched position value is newly stored every time in the LUT (Look UP Table) of the memory unit connected to the main processor to easily find an autofocus error and automatically correct it.
도 1은 종래기술에 따른 오토포커스 시스템의 예시적인 구성 블럭도이다.1 is an exemplary configuration block diagram of an autofocus system according to the prior art.
도 2는 본 발명에 따른 오토포커스 시스템의 예시적인 구성 블럭도이다.2 is an exemplary structural block diagram of an autofocus system according to the present invention.
도 3은 본 발명에 따른 오토포커스 제어방법의 예를 보여준 플로우챠트이다.3 is a flowchart showing an example of an autofocus control method according to the present invention.
도 4는 본 발명에 따른 오토포커스 제어방법중 포커스검색방법에 대한 예를 보여준 플로우챠트이다.4 is a flowchart illustrating an example of a focus search method among autofocus control methods according to the present invention.
도 5는 도 4에 대한 포커스모터의 이동경로를 표현한 예시표이다.FIG. 5 is an exemplary table representing a movement path of the focus motor shown in FIG. 4.
도 6은 본 발명에 따른 오토포커스 제어방법중 타겟위치검색방법에 대한 예를 보여준 플로우챠트이다.6 is a flowchart illustrating an example of a target position search method in an autofocus control method according to the present invention.
이하, 첨부된 도면을 참조하여 본 발명의 일실시 예를 상세히 설명하면 다음과 같다.Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
도 2은 본 발명에 따른 오토포커스 시스템의 예시적인 구성 블럭도이다.2 is an exemplary structural block diagram of an autofocus system according to the present invention.
도 2에 도시된 바와 같이, 본 발명에 따른 오토포커스 카메라 시스템은 CCTV에서 본 발명과 관련된 오토포커싱 및 줌 인/아웃, 그리고 포커스 오류 판독 및 보정, RS-485 통신, MTF(Modulation Transfer function) 등 구현에 필요한 전반적인 제어를 수행하는 칩셋인 메인프로세서(10)가 구비되고, 상기 메인프로세서(10)에 연결되어 용도에 따라 메인프로세서(10)의 제어하에 데이터의 저장, 갱신 등을 수행하는 메모리부(20)가 구비된다.As shown in FIG. 2, the autofocus camera system according to the present invention is autofocusing and zooming in and out related to the present invention in CCTV, and focus error reading and correction, RS-485 communication, Modulation Transfer function (MTF), and the like. A main processor 10, which is a chipset that performs overall control necessary for implementation, is provided, and is connected to the main processor 10 to store and update data under the control of the main processor 10 according to a purpose. 20 is provided.
그리고, 상기 메인프로세서(10)에서 처리된 내용을 외부로 출력하는 출력부와, 유저 인터페이스를 제공하도록 메인프로세서에 연결된 입력부(30)가 구비된다.In addition, an output unit for outputting the contents processed by the main processor 10 to the outside, and an input unit 30 connected to the main processor to provide a user interface is provided.
또한, 피사체를 촬상하여 촬상카메라(70)와, 상기 촬상카메라(70)에 촬상된 아날로그신호를 디지털신호로 변환하여 상기 메인프로세서로 전송하는 영상처리부(40)가 구비된다. In addition, an imaging camera 70 and an image processor 40 for converting an analog signal captured by the imaging camera 70 into a digital signal and transmitting the same to the main processor are provided.
그리고, 피사체의 촬상시 영상을 줌 인/아웃 하도록 광축방향으로 전후이동하는 줌렌즈(51)와, 상기 줌렌즈의 이동후 영상의 선명도를 인/아웃 하도록 광축방향으로 전후이동 하는 포커스렌즈(52)가 구비된다.In addition, the zoom lens 51 moves back and forth in the optical axis direction to zoom in / out the image when the subject is captured, and the focus lens 52 moves back and forth in the optical axis direction to in / out the sharpness of the image after the zoom lens is moved. do.
한편, 상기 줌렌즈 및 포커스렌즈를 구동하기 위해 렌즈의 일측 외주면에 구비되어 쾌속 구동과 정확한 제어가 가능한 스태핑모터(60)로 구현된 줌모터(61)와 포커스모터(62)가 구비된다.Meanwhile, a zoom motor 61 and a focus motor 62 are provided on one outer peripheral surface of the lens to drive the zoom lens and the focus lens, and are implemented as a stepping motor 60 capable of rapid driving and accurate control.
아울러, 상기 메인프로세서(10)에는 각각 포커스모터 드라이버(63)와, 줌모터 드라이버(64)가 연결되며, 이들에 의해 상기 포커스모터(62) 및 줌모터(61)의 구동을 제어하게 된다.In addition, a focus motor driver 63 and a zoom motor driver 64 are connected to the main processor 10, respectively, to control the driving of the focus motor 62 and the zoom motor 61.
또한, 상기 촬상카메라(70)에 탑재되는 렌즈의 광학적 능력을 수치화한 값을 연산하는 MTF(Modulation Transfer Function)산출부가 구비되고, 상기 메인프로세서에 연결된 메모리부(20)에는 기존 렌즈별 MTF값이 저장된다.In addition, a MTF (Modulation Transfer Function) calculation unit for calculating a numerical value of the optical capability of the lens mounted on the imaging camera 70 is provided, and the memory unit 20 connected to the main processor has an MTF value for each lens. Stored.
특히, 상기 MTF산출부(80)는 기존 렌즈별 MTF값을 로드하여 상호 비교분석하여 현재 화면의 오토포커스의 오류를 찾아내고 보정하기 위한 것이다.In particular, the MTF calculation unit 80 is to load and compare the existing MTF value for each lens to find and correct the error of autofocus of the current screen.
그리고, 오토포커싱은 오토포커싱을 위해 렌즈가 움직인 후 포커스 존, 즉 포커스 센터 대비 이미지의 메모리부(20)에 저장된 기존 렌즈별 MTF값과의 컨트래스트 비(Contrast Ratio)를 서로 비교하는 것을 활용함으로써 간단하게 제어될 수 있다.In addition, autofocusing is to compare a contrast ratio with an MTF value for each lens stored in the memory unit 20 of the focus zone, that is, the focus center, that is, the image after the lens is moved for autofocusing. It can be controlled simply by utilizing.
이를 위해, 렌즈는 다수 단계로 구간이동이 가능하도록 설계되고, 앞서 설명한 드라이버에 의해 제어되게 되는데, 이를 테면 3-16mm 렌즈의 경우 6단계의 구간이동(옵티컬의 5.25배)이 가능하게 설계되고, 5-50mm 렌즈의 경우는 11단계의 구간이동(옵티컬의 10배)이 가능하게 설계될 수 있다.To this end, the lens is designed to be able to move in multiple steps, and is controlled by the driver described above. For example, in the case of a 3-16 mm lens, it is designed to allow 6 steps of moving (5.25 times optical). In the case of a 5-50mm lens, it can be designed to allow 11 step movements (10 times optical).
이와 같이, 신속하게 이동할 수 있는 구간 포인트를 LUT(Look UP Table)로 만들어 메모리부(20)에 저장한다. 그러면, 줌에 따른 줌 렌즈의 위치에 맞는 구간으로 포커스 렌즈를 신속히 이동시킬 수 있고, 이후 미세 조정작업이 수반되면 포커스에 걸리는 시간을 줄일 수 있다.In this way, a section point that can be quickly moved is made into a look up table (LUT) and stored in the memory unit 20. Then, the focus lens can be quickly moved to a section corresponding to the position of the zoom lens according to the zoom, and the time required for focus can be shortened if a fine adjustment operation is subsequently performed.
따라서, 유저(User)가 줌과 포커스에 관한 선택으로 명령이 하달되면, 포커스모터 드라이버(63)와 줌모터 드라이버(64)는 각각의 포커스모터(62)와 줌모터(61)를 구간별로 스태핑시킨 다음, 해당 영역에 이르렀을 때 줌 인/아웃 기능을 수행한 상태에서 후술되는 포인트 비교 방식으로 오토포커싱을 구현하게 된다.Therefore, when a user receives a command regarding selection of zoom and focus, the focus motor driver 63 and the zoom motor driver 64 step the respective focus motor 62 and the zoom motor 61 step by step. After that, autofocusing is implemented by a point comparison method described below in a zoom in / out function when the corresponding area is reached.
한편, 상기 메인프로세서(10)에는 포커스오류검출부(11)가 더 연결되는데, 상기 포커스오류검출부(11)는 오토포커싱과 줌 인/아웃시 렌즈가 실제로 움직인 값을 취득하여 렌즈의 실제 움직임 값과 메모리부(20)에 저장된 렌즈별 MTF값을 비교하여 일치 여부를 판독함으로써 포커스의 오류 여부를 확인하게 된다.Meanwhile, a focus error detection unit 11 is further connected to the main processor 10. The focus error detection unit 11 acquires a value that the lens actually moves during autofocusing and zooming in and out, and thus the actual movement value of the lens. The MTF value of each lens stored in the memory unit 20 is compared to check whether there is an error in focus by reading a match.
이때, 포커스의 오류가 발생되는 요인은 여러가지가 있을 수 있는데, 이 경우에는 자동적으로 이전 성공포지션으로 이동한 다음 재 포커싱이 이루어지도록 하여 오류를 수정하도록 설계된다.At this time, there may be a number of factors causing the error of focus, in this case, it is designed to correct the error by automatically moving to the previous success position and then refocusing.
상기와 같은 구성으로 이루어진 본 발명에 따른 오토포커스 시스템의 제어방법을 보다 상세하게 설명하기로 한다.The control method of the autofocus system according to the present invention having the above configuration will be described in more detail.
도 3에서와 같이, 오토포커스 시스템의 제어방법은 최초 전원인가시 또는 시스템 부팅시 포커스모터(62)의 좌표가 홈 포지션으로 복귀 또는 유지되는 원점복귀단계(S100)로부터 시작된다.As shown in FIG. 3, the control method of the autofocus system starts from the home position return step S100 in which the coordinates of the focus motor 62 are returned or maintained at the home position at the time of initial power-up or system booting.
이후, 화면 또는 유저의 요청에 의해 영상변위가 발생되면 상기 메인프로세서에 연결된 메모리부에서 줌위치에 대한 데이터를 로드하여 줌모터드라이버에 전달하게 되고 이로써, 줌렌즈가 지정위치로 이동하게 되는 줌렌즈이동단계(S200)가 수행된다.Subsequently, when an image displacement is generated by a screen or a user's request, the memory unit connected to the main processor loads data about a zoom position and transfers the data to a zoom motor driver, thereby moving the zoom lens to a designated position. (S200) is performed.
이어, 줌렌즈의 지정위치에 대하여 상기 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에서 포커스위치에 대한 데이터를 로드하여 포커스드라이버에 전달하게 되고 이로써, 포커스렌즈가 지정위치로 이동하게 되는 포커스렌즈이동단계(S300)이 수행된다.Subsequently, the LUT (Look Up Table) of the memory unit connected to the main processor loads the data about the focus position and transfers the data to the focus driver, thereby moving the focus lens to the designated position. Step S300 is performed.
그런 다음, 이동된 위치에 대한 화면 중앙부분의 포커스검색이 이루어지는 포커스검색단계(S400)가 수행된다.Then, the focus search step (S400) in which the focus search of the center portion of the screen with respect to the moved position is performed.
한편, 상기 포커스검색단계(S400)는 현재 포커스모터의 위치에 해당하는 기본으로 저장된 MTF값과 MTF산출부()를 이용하여 현재 산출된 MTF값을 상호 비교하는 방법으로 진행되면 상세한 내용을 후술하기로 한다.On the other hand, the focus search step (S400) is a method of comparing the MTF value currently stored using the MTF value and the MTF calculation unit () stored as a basic corresponding to the position of the current focus motor will be described in detail later Shall be.
이렇게 하여, 최적의 포커스가 검색되면, 현재의 포커스모터의 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 저장을 하고 포커스검색이 종료된다.In this way, when the optimum focus is found, the position value of the current focus motor is stored in the LUT (Look UP Table) of the memory unit connected to the main processor, and the focus search is completed.
반면, 상기 포커스검색단계(S400)에서 최적의 포커스검색이 실패하면, 전체화면을 다수개의 영역으로 분할된 전체화면에 일부 영역을 검색하는 타겟위치검색단계(S500)가 수행된다. On the other hand, if the optimal focus search fails in the focus search step (S400), a target location search step (S500) for searching a partial area on the full screen divided into a plurality of areas is performed.
그 후, 검색된 화면영역에 대한 포커스검색이 이루어지는 제2포커스검색단계(S600)가 수행되어 최적의 포커스가 검색되면, 현재의 포커스모터의 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 저장을 하고 포커스검색이 종료된다.Thereafter, when the second focus search step S600 in which the focus search is performed on the searched screen area is performed and the optimum focus is searched, the LUT (Look UP Table) of the memory unit connected to the main processor is used to determine the position of the current focus motor. Save to and focus search ends.
반면, 상기 포커스검색단계(S600)에서 최적의 포커스검색이 실패하게 되면, 이전 포커스검색의 성공위치로 이동하여 포커스검색을 종료하게 된다.On the other hand, if the optimal focus search fails in the focus search step (S600), the focus search is terminated by moving to the successive position of the previous focus search.
이와 같이, 렌즈에 따라 구간이동을 통해 신속한 이동이 가능하도록 여러 단계의 구간을 설정하고, 줌의 위치에 따라 구간이동 후 기본으로 저장된 MTF값과 MTF산출부(600)를 이용한 현재 산출된 MTF값을 상호 비교하는 방법으로 오토포커싱 시간을 단축할 수 있다.In this way, a section of several steps is set to allow rapid movement through the section movement according to the lens, and the MTF value stored basically after the section movement according to the zoom position and the currently calculated MTF value using the MTF calculating unit 600. The autofocusing time can be shortened by comparing with each other.
뿐만 아니라, 상기 검색된 위치값을 메인프로세서에 연결된 메모리부의 LUT(Look UP Table)에 새로 저장하여 오토포커스 오류를 쉽게 찾아내고, 이를 자동 보정할 수 있게 된다.In addition, the searched position value is newly stored in a look up table (LUT) of a memory unit connected to the main processor to easily find an autofocus error and automatically correct it.
한편, 상기 포커스검색단계(S400)에 제어방법은 도 3과 같다.On the other hand, the control method in the focus search step (S400) is the same as FIG.
도 4 내지 5에 도시된 바와 같이, 포커스검색 시작시 현재포커스모터의 위치에 대한 기본 MTF값 데이터를 로드하는 기본MTF값로드단계(410)를 수행한다.As shown in FIGS. 4 to 5, a basic MTF value loading step 410 of loading basic MTF value data for the current focus motor position is performed at the start of focus search.
이어, 상기 포커스모터를 지정된 위치에 대하여 CW(시계방향)로 이동하며 각 위치에 대한 MTF값을 산출하고 메모리부에 저장하는 제1변위MTF값산출단계(420)를 수행한다.Subsequently, a first displacement MTF value calculation step 420 is performed in which the focus motor is moved in a clockwise direction with respect to a designated position, and the MTF value for each position is calculated and stored in a memory unit.
이 후, 위치에 대하여 저장된 변위MTF값과 메모리부에 저장된 기본MTF값을 상호 비교하는 제1MTF값비교단계(430)가 수행된다.Thereafter, a first MTF value comparison step 430 of comparing the displacement MTF value stored with respect to the position and the basic MTF value stored in the memory unit is performed.
이때, 위치에 대하여 저장된 변위MTF값이 메모리부에 저장된 기본MTF값 보다 높다면 기본 포커스위치값과 이에 관한 기본MTF값을 업데이트하고, 상기 변위MTF값산출단계(420) 이전으로 돌아가게 된다.At this time, if the displacement MTF value stored for the position is higher than the basic MTF value stored in the memory unit, the basic focus position value and the related MTF value are updated, and the process returns to the displacement MTF value calculation step 420.
한편, 위치에 대하여 저장된 변위MTF값이 메모리부에 저장된 기본MTF값 보다 4번의 비교단계중 3번이 작거나 같다면 포커스모터에 지정된 4위치에 대하여 CCW(반시계방향)이동하며 각 위치에 대한 MTF값을 산출하고 메모리부에 저장하는 제2변위MTF값산출단계(440)를 수행한다.On the other hand, if the displacement MTF value stored for the position is less than or equal to 3 out of the 4 comparison steps, the CCW (counterclockwise) moves to the 4 positions specified in the focus motor and A second displacement MTF value calculation step 440 is performed to calculate the MTF value and store the MTF value.
이 후, 위치에 대하여 저장된 변위MTF값과 메모리부에 저장된 기본MTF값을 상호 비교하는 제2MTF값비교단계(450)가 수행된다.Thereafter, a second MTF value comparison step 450 of comparing the displacement MTF value stored with respect to the position and the basic MTF value stored in the memory unit is performed.
이때, 상기와 마찬가지로 위치에 대하여 저장된 변위MTF값이 메모리부에 저장된 기본MTF값 보다 높다면 기본 포커스위치값과 이에 관한 기본MTF값을 업데이트하고, 상기 변위MTF값산출단계(420) 이전으로 돌아가게 된다.In this case, as described above, if the displacement MTF value stored for the position is higher than the basic MTF value stored in the memory unit, update the basic focus position value and the basic MTF value related thereto, and return to the displacement MTF value calculation step 420. do.
또 한편으로 위치에 대하여 저장된 변위MTF값이 메모리부에 저장된 기본MTF값 보다 4번의 비교단계중 3번이 작거나 같다면 포커스검색을 종료하게 된다.On the other hand, if the displacement MTF value stored with respect to the position is less than or equal to three of four comparison steps than the basic MTF value stored in the memory unit, the focus search is terminated.
이와 같이, 포커스의 검색시 메모리부에 저장된 기본MTF값을 포커스모터의 CW 또는 CCW의 각 지정된 위치로 이동하며 산출된 변위MTF값과 상호 크기를 비교하여 최적의 포커스를 검색함으로써, 어두운환경에서의 포커스검색이나 고해상도의 포커스검색시 정확도가 상승하게 되고 고해상도용 오토포커스카메라를 제작할 수 있게 된다.In this way, when the focus is searched, the basic MTF value stored in the memory unit is moved to each of the specified positions of the CW or CCW of the focus motor, and the optimal displacement is searched by comparing the calculated displacement MTF value with the mutual size. When focus search or high resolution focus search, accuracy is increased and high-resolution autofocus camera can be manufactured.
한편, 상기 타겟위치검색단계(S500)에 제어방법은 도 6와 같다.On the other hand, the control method in the target location search step (S500) is the same as FIG.
도 6에서와 같이, 타겟위치검색 시작시 화면 영역에서 다수개로 구분된 테이블중 포커스검색이 시작될 영역과 그사이즈를 설정후 저장하는 테이블설정단계가 수행된다.As shown in FIG. 6, a table setting step of setting and storing an area where a focus search is to be started and its size among a plurality of tables divided in the screen area at the start of a target location search is performed.
이어, 최대MTF값을 "0"으로 업데이트한후 MTF산출부를 이용하여 상기 저장된 화면의 설정영역 MTF값을 산출하는 영역MTF값산출단계가 수행된다.Subsequently, an area MTF value calculation step of calculating the set area MTF value of the stored screen is performed by updating the maximum MTF value to "0".
그 후 "0"으로 업데이트된 최대MTF값과 설정영역MTF값을 비교하여 큰값으로 최대MTF값을 상기 메모리부에 저장하는 기본MTF값설정단계가 수행된다.Thereafter, a basic MTF value setting step of comparing the maximum MTF value updated to "0" with the setting area MTF value and storing the maximum MTF value as a large value is performed in the memory unit.
반면, 상기 설정영역MTF값이 "0"보다 적게 산출되면, 기본MTF값을 "0"으로 설정하게 되는 것도 바람직하다.On the other hand, when the setting area MTF value is calculated to be less than "0", it is also preferable to set the default MTF value to "0".
이후, 상기 설정된 기본MTF값을 로드하여 마지막 저장된 화면과 마지막 저장된 영역의 MTF값을 산출하여 상호 비교하는 화면영역체크단계가 수행된 후 포커스타겟위치검색을 종료하게 된다.Subsequently, the screen target checking step of loading the set default MTF value, calculating MTF values of the last stored screen and the last stored area, and comparing them with each other is performed.
이때, 최상의 포커스영역이 검색되지 않을시 다음 화면 영역에서 다수개로 구분된 테이블중 새로운 포커스검색이 시작될 영역과 그사이즈를 설정후 저장하고, 상기 영역MTF값산출단계 이전의 단계로 되돌아가 반복수행하는 타겟검색리턴단계가 수행된다.At this time, if the best focus area is not searched, the new focus search area and its size are set and stored in the next screen area, and the process returns to the previous step of calculating the area MTF value. The target search return step is performed.
이와 같이, 본 발명에 따른 오토포커스 시스템의 제어방법은 줌 인/아웃과 동시에 오토포커스 기능을 단시간에 수행할 수 있고, 피사체의 위치가 가변되거나 어두운 촬영환경으로 인한 포커스의 오류를 쉽게 보정할 수 있으며, 기본으로 저장된 MTF값을 매 산출후 비교분석하여 최적의 값을 정확하게 찾을 수 있게 되어 고해상도용으로 오토포커스카메라를 제작할 수 있는 장점을 제공한다.As described above, the control method of the autofocus system according to the present invention can perform the autofocus function in a short time at the same time as the zoom in / out, and can easily correct the focus error due to the variable position of the subject or the dark shooting environment. In addition, it is possible to find the optimal value accurately by comparing and analyzing the stored MTF value after every calculation, which provides the advantage of making an autofocus camera for high resolution.
본 발명은 상술한 특정의 바람직한 실시 예에 한정되지 아니하며, 청구범위에서 청구하는 본 발명의 요지를 벗어남이 없이 당해 발명이 속하는 기술분야에서 통상의 지식을 가진 자라면 누구든지 다양한 변형실시가 가능한 것은 물론이고, 그와 같은 변경은 청구범위 기재의 범위 내에 있게 된다.The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.
*부호의 설명* Description of the sign
10 : 메인프로세서 11 : 포커스오류검출부10: main processor 11: focus error detection unit
20 : 메모리부 30 : 입력부20: memory unit 30: input unit
40 : 영상처리부 51 : 줌렌즈 40: image processing unit 51: zoom lens
52 : 포커스렌즈 60 : 스탭핑모터52: focus lens 60: stepping motor
61 : 줌모터 62 : 포커스모터61: zoom motor 62: focus motor
63 : 포커스드라이브 64 : 줌드라이브63: Focus Drive 64: Zoom Drive
70 : 촬상카메라 80 : MTF산출부70: imaging camera 80: MTF calculation unit
Claims (7)
- CCTV에 내장되는 메인프로세서(10), 메인프로세서와 연결된 메모리부(20), 유저 인터페이스를 제공하도록 메인프로세서에 연결된 입력부(30), 메인프로세서에서 처리된 내용을 출력하는 출력부, 피사체를 촬상하는 촬상카메라(70), 촬상카메라에서 촬상된 아날로그 신호를 디지털신호로 변환하여 메인프로세서로 전송하는 영상처리부(40), 피사체 촬상시 영상을 줌 인/아웃 및 줌 인/아웃 상태에서 포커스를 수행하도록 구비된 포커스렌즈(52) 및 줌렌즈(51),를 포함하는 CCTV 카메라 시스템을 사용하는 오토포커스 시스템의 제어방법에 있어서;The main processor 10 embedded in the CCTV, the memory unit 20 connected to the main processor, the input unit 30 connected to the main processor to provide a user interface, an output unit for outputting the processed content from the main processor, to capture the subject Imaging camera 70, the image processing unit 40 converts the analog signal captured by the imaging camera into a digital signal and transmits it to the main processor, to perform the focus in the zoom-in / out and zoom-in / out state when capturing the subject In the control method of the autofocus system using a CCTV camera system comprising a focus lens 52 and a zoom lens 51 provided;최초 전원인가시 또는 시스템 부팅시 포커스모터의 좌표가 홈 포지션으로 복귀 또는 유지되는 원점복귀단계(S100);An origin return step of returning or maintaining the coordinates of the focus motor to the home position at the time of initial power-up or system booting (S100);화면 또는 유저의 요청에 의해 영상변위가 발생되면 줌위치에 대한 데이터를 로드하여 줌렌즈가 지정위치로 이동되는 줌렌즈이동단계(S200);A zoom lens moving step of loading data for a zoom position when the image displacement is generated by a screen or a user's request to move the zoom lens to a designated position (S200);포커스위치에 대한 데이터를 로드하여 포커스렌즈가 지정위치로 이동되는 포커스렌즈이동단계(S300);A focus lens shifting step (S300) of loading data on a focus position and moving the focus lens to a designated position;이동된 위치에 대한 화면 중앙부분의 포커스검색이 이루어지는 포커스검색단계(S400);로 이루어지고,A focus search step (S400) in which a focus search is performed on a center portion of the screen with respect to the moved position;최적의 포커스검색이 실패하면, 전체화면을 다수개의 영역으로 분할된 전체화면에 일부 영역을 검색하는 타겟위치검색단계(S500);If the optimal focus search fails, a target location search step (S500) of searching for a partial area on the full screen divided into a plurality of areas;검색된 화면영역에 대한 포커스검색이 이루어지는 제2포커스검색단계(S600);로 이루어진 것을 특징으로 하는 오토포커스 시스템의 제어방법.And a second focus search step (S600) in which focus search is performed on the searched screen area.
- 제 1 항에 있어서;The method of claim 1;상기 제2포커스검색단계(S600)에는 포커스검색 성공시 현재의 포커스모터의 위치값을 LUT(Look UP Table)에 저장을 하고, 상기 제2포커스검색단계(S600)에서 포커스검색 실패시 이전 포커스검색의 성공위치로 이동하여 포커스검색을 종료하는 것을 특징으로 하는 오토포커스 시스템의 제어방법.In the second focus search step (S600), if the focus search is successful, the position value of the current focus motor is stored in a look up table (LUT), and if the focus search fails in the second focus search step (S600), the previous focus search is performed. The control method of the autofocus system, characterized in that to end the focus search by moving to the success position.
- 제 1 항에 있어서;The method of claim 1;상기 포커스검색단계(S400)은 현재 포커스모터의 위치에 대한 기본 MTF값 데이터를 로드하는 기본MTF값로드단계(S410)와, 상기 포커스모터를 CW(시계방향)로 이동하며 각 위치에 대한 MTF값을 산출하는 제1변위MTF값산출단계(S420)와, 변위MTF값과 메모리부에 저장된 기본MTF값을 상호 비교하는 제1MTF값비교단계(S430)와, 상기 포커스모터에 CCW(반시계방향)로 이동하며 각 위치에 대한 MTF값을 산출하는 제2변위MTF값산출단계(S440)와, 변위MTF값과 메모리부에 저장된 기본MTF값을 상호 비교하는 제2MTF값비교단계(S450)로 이루어진 것을 특징으로 하는 오토포커스 시스템의 제어방법.The focus search step (S400) is a basic MTF value loading step (S410) for loading the basic MTF value data for the position of the current focus motor, and moves the focus motor to CW (clockwise) and MTF value for each position Calculating a first displacement MTF value (S420), a first MTF value comparing step (S430) for comparing the displacement MTF value with a basic MTF value stored in the memory unit, and CCW (counterclockwise) to the focus motor; A second displacement MTF value calculation step (S440) of calculating a MTF value for each position and a second MTF value comparison step (S450) of comparing the displacement MTF value with a basic MTF value stored in a memory unit; A method for controlling an autofocus system.
- 제 3 항에 있어서,The method of claim 3, wherein상기 제1MTF값비교단계(S430)는 변위MTF값이 기본MTF값 보다 높다면 포커스위치값과 기본MTF값을 업데이트하여 상기 변위MTF값산출단계(S420)이전으로 이동하여 재수행하게 되고, 변위MTF값이 기본MTF값보다 작거나 같다면 상기 제2변위MTF값산출단계(S440)로 넘어가는 것을 특징으로 하는 오토포커스 시스템의 제어방법.If the displacement MTF value is higher than the basic MTF value, the first MTF value comparison step (S430) updates the focus position value and the basic MTF value, moves to the previous displacement MTF value calculation step (S420), and repeats the displacement MTF value. If less than or equal to the basic MTF value, the second displacement MTF value calculation step (S440), characterized in that the control method of the autofocus system.
- 제 3 항에 있어서,The method of claim 3, wherein상기 제2MTF값비교단계(S450)는 변위MTF값이 기본MTF값 보다 높다면 포커스위치값과 기본MTF값을 업데이트하여 상기 제2변위MTF값산출단계(S440)이전으로 이동하여 재수행하게 되고, 변위MTF값이 기본MTF값보다 작거나 같다면 포커스검색을 종료하는 것을 특징으로 하는 오토포커스 시스템의 제어방법.If the displacement MTF value is higher than the basic MTF value, the second MTF value comparison step (S450) updates the focus position value and the basic MTF value to move to the second displacement MTF value calculation step (S440), and performs the displacement again. And focus search is terminated if the MTF value is less than or equal to the basic MTF value.
- 제 1 항에 있어서,The method of claim 1,상기 타겟위치검색단계(S500)는 화면 영역에서 다수개로 구분된 테이블중 포커스검색이 시작될 영역과 그사이즈를 설정하는 테이블설정단계(S510)와, 상기 설정된 화면의 설정영역 MTF값을 산출하는 영역MTF값산출단계(S520)와, 최대MTF값과 설정영역MTF값을 비교하여 기본MTF값을 설정하는 기본MTF값설정단계(S530)와, 상기 기본MTF값과 마지막 저장된 영역의 MTF값을 상호 비교하는 화면영역체크단계(S540)로 이루어진 것을 특징으로 하는 오토포커스 시스템의 제어방법.The target position search step (S500) is a table setting step (S510) for setting a region where the focus search is to be started and its size among a plurality of tables divided in the screen area, and an area MTF for calculating a setting area MTF value of the set screen. A value calculation step (S520), a basic MTF value setting step (S530) of setting a basic MTF value by comparing a maximum MTF value and a setting area MTF value, and comparing the basic MTF value and an MTF value of the last stored area with each other; Screen area check step (S540) characterized in that the control method of the autofocus system.
- 제 6 항에 있어서,The method of claim 6,상기 화면영역체크단계(S540)에는 포커스영역이 검색되지 않을시 다음 화면 영역에서 다수개로 구분된 테이블중 새로운 포커스검색이 시작될 영역과 그사이즈를 설정후 저장하고, 상기 영역MTF값산출단계(S520) 이전의 단계로 되돌아가 반복수행하는 타겟검색리턴단계(S541)로 이루어진 것을 특징으로 하는 오토포커스 시스템의 제어방법.In the screen area checking step (S540), when the focus area is not searched, a new area of the table divided into a plurality of tables in the next screen area is set and stored after setting the area and its size, and calculating the area MTF value (S520). The control method of the autofocus system, characterized in that the target search return step (S541) to be performed repeatedly to return to the previous step.
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