JPH06331874A - Distance measuring device - Google Patents

Abstract

PURPOSE:To provide a distance measuring device which is directly applied to a system using a camera and which hardly requires special processing such as arithmetic operation. CONSTITUTION:This device is equipped with a camera 1 provided with a zoom lens 70, a focus correcting lens 80, an imaging device 5, a zoom control mechanism 4 and a focus correcting mechanism 6; a data base in which a distance between the focus correcting lens and the zoom lens, a distance between the focus correcting lens and an image forming point, and an object distance being a distance to a subject are stored in relation to one another; a detection means 7 detecting information on the moving amount of the zoom lens and the moving amount of the focus correcting lens or the imaging device 5; and an arithmetic processing means which obtains the distance between the focus correcting lens and the zoom lens and the distance between the focus correcting lens and the image forming point based on information on the two moving amounts and obtains the object distance corresponding to the data on two distances by retrieving the data base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a distance to an object, that is, an object distance, based on operation information of an image pickup camera such as a surveillance camera which is widely used in surveillance systems.

[0002]

2. Description of the Related Art When measuring a distant object, the measuring method varies considerably depending on its purpose. When measuring the distance of an object within a distance of several hundred meters, it may be the easiest method for a measurer to measure with a tape measure or the like. However, it can be said that this method requires a measurer to directly go out and measure, and the measurement accuracy does not increase due to the labor.

On the other hand, in the field of monitoring systems, etc.
In some cases, it is necessary to covertly measure the distance to the subject, and in such a case, an indirect method must be adopted instead of the direct measurement method. It is also important to be able to measure quickly in terms of time.

A laser distance measuring device is known as a device satisfying such requirements. However, according to this apparatus, the scale of the apparatus becomes large and the cost becomes high, which is unsuitable when considering use in a monitoring system or the like. That is, in the surveillance system,
A distance measuring device must be installed at the same location as the surveillance camera and must be small. This is because the main purpose of the surveillance system is to monitor the intruder, and there is a condition that the device itself must be hard to be detected by the intruder. Also, even if the device is downsized,
Since this is a device that measures the distance of an object by irradiating the object with laser light, when the object becomes a human body, there are restrictions in use such as output when considering the effect. Further, the laser beam has a narrow luminous flux, and it is necessary to accurately irradiate the object with the light beam.

[0005]

FIG. 12 shows a system using the above-mentioned conventional laser distance measuring device. The object 200 is captured by the surveillance camera 203 and sent to the processing circuit 205. The processing circuit 205 sends the signal to the monitor device 207 and is provided to the operator 206 as an image. The operator 206 instructs the measurement circuit 200 to the processing circuit 205 from among the displayed images. In order to calculate the instructed direction of the target object 200, the processing circuit 205 directs the laser range finder from the current horizontal and vertical directivity angles of the camera directing mechanism 204 and the position of the target object 200 in the image. The orientation information required for the mechanism 202 is calculated. At this time, complicated image processing is performed to determine the position of the object 200 in the image. The orientation information is
After being sent to the laser distance measuring device directing mechanism 202 and the laser distance measuring device 201 is directed in a predetermined direction, measurement is performed. As described above, in order to accurately apply the light rays to the target object 200,
A complicated mechanism section and a processing circuit 205 are required, and the structure becomes large-scale.

The present invention has been made in order to solve the problems of the above-mentioned conventional distance measuring apparatus, and the purpose thereof is immediately applicable to a system using a camera, and almost no special arithmetic processing is required. Not to provide a distance measuring device.

[0007]

Therefore, in the present invention, a zoom lens for performing zoom imaging of a subject, and a focus correction lens for performing focus correction of an image obtained by zoom imaging by the zoom lens, An image pickup device on which light coming through the zoom lens and the focus correction lens is imaged, a zoom control mechanism for moving the zoom lens to perform zooming, and a focus correction lens or the image pickup device are moved. A camera provided with a focus correction mechanism for achieving focus correction, a distance between the focus correction lens and the zoom lens, a distance between the focus correction lens and an image forming point, and a distance to the subject. Is stored in association with the object distance, the amount of movement of the zoom lens, and the focus correction lens or the image pickup lens. A detection unit that detects information about the amount of movement of the element, and a distance between the focus correction lens and the zoom lens based on the information about the two amounts of movement detected by the detection unit, and the focus correction lens. And the image forming point of the image are obtained, and the object distance corresponding to the data of the two distances is provided with an arithmetic processing unit that is obtained by searching the database to configure the distance measuring device.

[0008]

As shown in FIG. 8, there is generally a one-to-one correspondence between the distance l1 from the center of the lens 61 to the object and the image distance l2 at which the object is clearly projected.
The relationship of curves as shown in FIG. 9 arises. In the present invention, the object distance l1 is utilized by utilizing the relationship that the image distance l2 at which the object is clearly projected is determined when the object distance is l1.
Is to seek. However, as can be seen from the curve in FIG. 9, since the characteristic of the optical lens is non-linear, it is expected that an accurate distance cannot be obtained when the object distance l1 exceeds a certain distance. Therefore, in the present invention, FIG.
As shown in (1), the control amount related to the magnification of the zoom lens 70 is taken into consideration, so that a distant object can be measured with required accuracy. In the present invention, the above-mentioned optical characteristics of the surveillance camera to be used are acquired in advance, data corresponding to the curve shown in FIG. 11 is obtained, and the data is stored as a database for distance calculation.

When measuring the distance of an object, the zoom control mechanism and the focus correction mechanism are controlled so that the object of interest is sufficiently large and is clearly visible. As the zoom magnification increases, the linearity is maintained up to the range where the object distance is long. The control amount used for control here is taken into the arithmetic processing means,
The object distance is obtained by collating with a previously stored database for distance calculation. That is, the moving amount of the zoom lens 70 and the focus correction lens 80 are detected by the detecting means.
Alternatively, information about the amount of movement of the image sensor is detected, and based on the information about the two amounts of movement detected by the detecting means, the arithmetic processing means determines the distance between the focus correction lens 80 and the zoom lens 70. , The distance between the focus correction lens 80 and the image forming point of the image is obtained, and the object distance corresponding to the data of these two distances is obtained by searching the database.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A distance measuring device according to an embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a distance measuring device according to an embodiment of the present invention. This distance measuring device is composed of a monitoring camera 1 and a processing device 2 including a computer and the like. The surveillance camera 1 has an optical system 3 including a zoom lens 70 for performing zoom image pickup of a subject and a focus correction lens 80 for performing focus correction of an image obtained by zoom image pickup by the zoom lens 70. ing. Here, the zoom lens 70 and the focus correction lens 80 do not necessarily mean one lens, but also include an assembly of a plurality of lenses.

The light taken in by the optical system 3 is imaged on the image pickup device 5. The image sensor 5 is composed of an image sensor such as a CCD. The zoom lens 70 is moved by the zoom control mechanism 4. Further, the focus correction mechanism 6 moves the image sensor 5 to correct the focus. A more specific configuration of the zoom control mechanism 4 and the focus correction mechanism 6 is shown in FIG. The screw 3a rotated by a motor (not shown) is provided with a drive mechanism 3c composed of a nut.
Is provided, and the zoom lens 70 is provided in the drive mechanism 3c.
Is mounted. The screw 3a is rotated by the rotation of the motor, and the drive mechanism 3c is moved to the left or right in accordance with this rotation to perform zooming. On the other hand, the screw 3b is configured to be rotated by a motor other than the motor that rotates the screw 3a, and the screw 3b is provided with a drive mechanism 3d composed of a nut. An image sensor is mounted on. The screw 3b is rotated by the rotation of the motor, and the drive mechanism 3d is rotated according to this rotation.
Moves to either the left or right, the distance between the focus correction lens 80 and the image sensor 5 is adjusted, and focus correction is performed.
The control signals d and e output from the zoom control mechanism 4 and the focus correction mechanism 6 in FIG. 1 are signals for controlling the rotation of the motor. The signals f and g corresponding to this control signal are given to the control information detection unit 7, digitized, and processed by the processing device 2.
Sent to. In the above, the signal f is the amount of movement of the drive mechanism 3c (a signal indicating how many times the screw has been rotated to the right or left), and the signal g is the amount of movement of the drive mechanism 3d (how many rotations of the screw have been rotated to the right or left). Signal). Such a signal is digitized into data that can be processed by a computer and arrives at the arithmetic processing unit 9 of the processing device 2.

The arithmetic processing section 9 is a section that performs central control processing of the processing device 2, and is composed of a CPU and a main memory. A database 10 is connected to the arithmetic processing unit 9. The database 10 includes the focus correction lens 8
The distance l3 between 0 and the zoom lens 70, the distance l2 between the focus correction lens 80 and the image forming point, and the object distance l1 which is the distance to the subject are stored in association with each other. Yes, for example, data stored in a magnetic storage device. The processing device 2 is provided with a monitor unit 8 including a CRT display device, a zoom control mechanism 4, and a camera control unit 11 for sending a control signal to the focus correction mechanism 6 automatically or by an operator's operation.
Here, it is assumed that the zoom control and the focus correction are performed by the operation of the operator. That is, the image information a captured by the image sensor 5 is sent to the monitor unit 8 and an image is displayed on the monitor unit 8. Looking at this image, the operator operates the camera control unit 11 so as to maximize the zoom magnification, and outputs the control signal b to the zoom control mechanism 4.
To send to. At this time, when the image projected on the monitor unit 8 is out of focus, the camera control unit 11 is operated to send the control signal c to the focus correction mechanism 6. As a result, when the subject is in focus, the camera control unit 11 is operated so as to give a calculation start instruction to the calculation processing unit 9. On the other hand, in the above, when the image is out of focus, the zoom magnification is reduced, and when the image projected on the monitor unit 8 is out of focus, the camera control unit 11 is operated to adjust the control signal c to the focus correction mechanism. Send to 6. If the focus is not achieved, the focus is corrected while the zoom magnification is reduced, and the same operation is repeated until the focus is achieved.

In the above, the arithmetic processing unit 9 which has received the instruction to start the arithmetic operation moves the driving mechanism 3c (a signal indicating how many times the screw has been rotated to the right or left) and the driving mechanism 3
The distance between the focus correction lens 80 and the zoom lens 70, the focus correction lens 80, and the image based on the information of the two movement amounts including the movement amount of d (a signal indicating how many times the screw is rotated to the right or left). The distance to the image forming point is obtained, and the object distance corresponding to the data of these two distances is obtained by searching the database 10.

FIG. 3 shows the detailed structures of the arithmetic processing unit 9 and the database 10. Reference numeral 9a is an MPU (microprocessor), 9b is a timing control circuit, 9c is an external signal input circuit, 9d is a memory, 9e is a database interface, and 9f and 9g are interfaces for transmitting and receiving signals to and from the surveillance camera 1. Further, 10a is an interface of the database 10, 10b is an access circuit of the database, and 10c is a storage medium such as a magnetic disk device. The respective signals of the two pieces of movement amount information h and i sent from the surveillance camera 1 are taken into the input circuit 9c by the control of the MPU 9a via the interfaces 9f and 9g for matching the electric levels and the like. MPU9a
Sends write / read commands m and n to the timing control circuit 9b for the peripheral circuits. The timing control circuit 9b takes in the address signal k in synchronization with these signals and provides the peripheral circuits 9c, 9d, 9e with the input / output timing of the data signal l. Input circuit 9
The data relating to the movement amount fetched in c is read into the MPU 9a and then stored in the memory 9d. Memory 9d
Is a memory for storing data and programs. The access circuit 10b is a circuit for accessing the database 10, reads data from the storage medium 10c,
Alternatively, the data is written in the storage medium 10c. The interface 10a is an interface facing the database interface 9e, and has a function of matching the interface conditions between the arithmetic processing unit 9 and the database 10. Between the interface 10a and the database interface 9e, the distance between the focus correction lens 80 and the zoom lens 70, the distance between the focus correction lens 80 and the image forming point, and the object distance data j corresponding to this data j Is transmitted. The access circuit 10b receives the data address signal o from the interface 10a,
Access control of the storage medium 10c is thereby performed.

As shown in FIG. 5, the storage medium 10c stores data in a memory table format, and receives an access control signal q from the access circuit 10b to input / output a data signal p. The memory table 30 of FIG. 5 shows a distance l3 between the focus correction lens 80 and the zoom lens 70 corresponding to the zoom magnification, and a distance l2 between the focus correction lens 80 and the image forming point corresponding to the focus correction amount. , An object distance l1 which is the distance to the subject. Therefore, the amount of movement of the drive mechanism 3c (a signal indicating how many times the screw has been rotated to the right or left), and
When the information about the two movement amounts including the movement amount of the drive mechanism 3d (a signal indicating how many times the screw is rotated to the right or left) is given, the MPU 9a causes the MPU 9a and the home stored in the memory 9d in advance. From the position of the position, the focus correction lens 80 corresponding to the above zoom magnification
The distance l3 between the zoom lens 70 and the zoom lens 70 and the distance l2 between the focus correction lens 80 and the image forming point corresponding to the focus correction amount are obtained, and the object distance l1 is obtained from the memory table 30 in FIG.

FIG. 4 shows the main flow of the operation of the distance measuring device according to this embodiment. In the distance measuring device according to the present embodiment, first, the monitoring camera 1 performs the process of focusing the image while maximizing the zoom magnification (D1). Here, the movement amount is sent from the surveillance camera 1,
The above l3 and l2 are required. This l3, l
The arithmetic processing unit 9 that has obtained 2 calculates l1 −l2 corresponding to l3.
Curve data is obtained from the database 10 (D2).
In the memory table 30 of FIG. 5, l3 on the horizontal axis is determined,
This means that a set of object distances l1 corresponding to l2 corresponding to the l3 in the vertical direction is obtained. Next, the arithmetic and control unit 9 finds the object distance l1 from the data of the above l1-l2 curve using the l2 found above (D
3). In FIG. 5, the object distance l1 is obtained from a specific l2 for a set of object distances l1 corresponding to l2 that are continuous in the vertical direction. Thus, the object distance l1 can be obtained with relatively high accuracy.

In the above embodiment, the zoom image pickup and the focus adjustment are performed by the operation of the operator.
In another embodiment, zoom imaging and focusing are automatically performed. That is, the camera control unit 11 is provided with an image processing function, and image information is given from the monitor unit 8 to the camera control unit 11 as indicated by a broken line. For example, a focus identification tag 40 as shown in FIG. 6 is attached to the subject. The vertical line interval of the focus identification tag 40 is set according to desired accuracy. When in focus, the vertical line spacing of the focus identification tag 40 becomes a clear white level. The image processing function provided in the camera control unit 11 detects this white level and uses it for focus correction. The computer of the camera control unit 11 is provided with the program of the flowchart shown in FIG. 7, and operates based on this.

That is, a control signal is given to the zoom control mechanism 4 so as to maximize the zoom (51), and it is detected based on the image of the focus identification tag 40 whether or not the focus is achieved (5).
2). At this time, focus correction is also performed. If it is out of focus, the zoom is reduced by one step to correct the focus (53), and it is detected again based on the image of the focus identification tag 40 (52). By repeating this, when the focus is achieved, the arithmetic processing unit 9 is notified of the start of measurement (54). Thereafter, the object distance l1 is obtained as in the case of the operator.

Further, in the above embodiment, the movement amount information of the zoom lens 70 and the focus correction lens 80 is obtained from the surveillance camera 1 side, but the movement amount of the zoom lens 70 and the focus correction lens 80 is determined by the camera control unit. Therefore, in another embodiment, as shown by the broken line in FIG. 1, the camera controller 11 directly sends the data to the arithmetic controller 9. With this configuration, it is not necessary for the control information detection unit 7 to capture and digitize the movement amount, and the arithmetic control unit 9 can perform A / D conversion to obtain the movement amount. Further, in the embodiment, the image pickup device 5 is moved to adjust the focus. However, in another embodiment, while maintaining a predetermined zoom magnification,
The focus correction lens 80 is moved so as to be in focus (the zoom lens 70 is moved accordingly). With such a configuration, the object distance can be measured in the same manner as above.

[0020]

As described above, according to the present invention,
Since zoom imaging is performed, when measuring the distance of an object,
The zoom control mechanism and the focus correction mechanism can be controlled so that the target object is sufficiently large and can be clearly seen, and the measurement that takes advantage of the characteristic that the larger the zoom magnification, the more linear the object distance is It will be possible. Then, the control amount used for the control is taken into the arithmetic processing means, and the object distance is obtained by collating with the previously stored database for distance calculation. That is, the detection unit detects information about the amount of movement of the zoom lens 70 and the amount of movement of the correction lens 80 or the image sensor, and based on the information about the two amounts of movement detected by the detection unit, the arithmetic processing unit The distance between the focus correction lens 80 and the zoom lens 70 and the distance between the focus correction lens 80 and the image forming point are obtained, and the object distance corresponding to the data of these two distances is obtained from the database. Since it is an indirect measurement, it has relatively good accuracy, and compared to the case of using a laser beam, it is easy to handle and highly safe. Will play.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical system according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of an arithmetic processing unit and a database according to the embodiment of this invention.

FIG. 4 is a diagram showing a flow of operations in the embodiment of the present invention.

FIG. 5 is a diagram showing a memory table of a database.

FIG. 6 is a plan view of a focus identification tag used in another embodiment of the present invention.

FIG. 7 is a flowchart for explaining the operation of another embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between an object distance and a video distance.

FIG. 9 is a diagram showing a curve of a relationship between an object distance and a video distance.

FIG. 10 is a diagram showing imaging by a zoom lens and a focus correction lens.

FIG. 11 is a diagram showing a curve of a relationship between an object distance and an image distance according to an embodiment of the present invention.

FIG. 12 is a block diagram of a conventional example.

[Explanation of symbols]

1 Monitoring Camera 2 Processing Device 3 Optical System 4 Zoom Control Mechanism 5 Image Sensor 6 Focus Correction Mechanism 7 Control Information Detection Section 8 Monitor Section 9 Arithmetic Processing Section 10 Database 11 Camera Control Section

Claims (3)

[Claims] 1. A zoom lens for performing zoom imaging of an object, a focus correction lens for performing focus correction of an image obtained by zoom imaging by the zoom lens, and the zoom lens and the focus correction lens. An image pickup element for forming an image of incoming light, a zoom control mechanism for moving the zoom lens to perform zooming, and a focus correction mechanism for moving the focus correction lens or the image pickup element to achieve focus correction. A camera provided, a distance between the focus correction lens and the zoom lens, a distance between the focus correction lens and an image forming point, and an object distance which is a distance to the subject are associated with each other. The stored database, the detection amount for detecting the movement amount of the zoom lens, and the movement amount of the focus correction lens or the image sensor. Means and the distance between the focus correction lens and the zoom lens and the distance between the focus correction lens and the image forming point on the basis of the information on the two movement amounts detected by the detection means. A distance measuring apparatus, comprising: an arithmetic processing unit that obtains the object distance corresponding to the two distance data by searching the database. 2. The distance measuring device according to claim 1, wherein the detecting means obtains the amount of movement of the zoom lens from the zoom control mechanism while obtaining the amount of movement of the focus correction lens or the image pickup device from the focus correction mechanism. . 3. A camera control unit for giving the amount of movement of the zoom lens to the zoom control mechanism while giving the amount of movement of the focus correction lens to the focus correction mechanism, wherein the detection means is the amount of movement of the zoom lens from the camera control unit The distance measuring device according to claim 1, further comprising: obtaining a movement amount of the focus correction lens or the image pickup device.