JPH06133202A - Focus adjustmen method and focus adjusting device in infrared wide-angle supervisory system - Google Patents

Abstract

PURPOSE:To adjust the focus automatically by measuring a maximum value and a minimum value of picture data at plural locations respectively and setting a position where a difference between the maximum value and a minimum value of each of the picture data is maximized to be a focal position. CONSTITUTION:At first a focus adjustment device drive control circuit 8 controls a focus adjusment element drive mechanism 12. Then a focus adjustment element 11 is driven and the focus is changed. A picture data detection section 3 detects picture data to be obtained and outputs the detected data to a maximum value measurement section 4 and a minimum value measurement section 5. The measurement sections 4, 5 receiving the data detected by the detection section 3 at plural positions measure the maximum value and the minimum value. A maximum value/minimum value difference detection section 6 detects the difference between the maximum value and the minimum value based on the measured maximum value and minimum value. Then a maximal value detection section 7 being an output destination of the detection section 6 sets a position where a difference between the maximum value and the minimum value of each of the picture data is maximized to be a focal position.

Description

Detailed Description of the Invention

(Table of Contents) Field of Industrial Application Conventional Technology (FIGS. 11 to 14) Problem to be Solved by the Invention Means for Solving the Problem (FIG. 1) Action (FIG. 1) Embodiment (FIG. 2) (Figure 10, Figure 13, Figure 14) Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting method and a focus adjusting apparatus in an infrared wide-angle monitoring system (infrared imaging system) for searching and monitoring a required range including a horizontal line over a wide range such as the entire circumference. In such an infrared imaging system, it takes several seconds to acquire one piece of image data, and therefore, not a so-called real-time continuous moving image, but only a still image that is intermittently updated can be obtained.

Therefore, even if the elements for focus adjustment are moved for focus adjustment, it takes time until the effect appears, so the amount of movement becomes improper, and this causes a difference in focus adjustment. Falling into a situation of returning and repeating,
A smooth focus adjustment operation is often difficult. For this reason, a means for providing an operation mode for temporarily acquiring a real-time image for focus adjustment is adopted.

[0004]

2. Description of the Related Art FIGS. 11 and 12 show a conventional infrared wide-angle monitoring system. FIG. 11 is a perspective view showing an optical system portion thereof, and FIG. 12 is a block diagram thereof.
1, as shown in FIG. 12, this infrared wide-angle monitoring system 1
0'has a sensor head 118. The sensor head 118 has a base 108 and a swivel unit 111.

Here, the base 108 serves to fix the device itself to a place of installation and to give a stable 360-degree rotation to the swivel part 111 provided on the upper part thereof. In addition, the turning unit 111 causes the omnidirectional (36
It receives infrared rays (0 degree) and performs a pre-stage process for converting the information obtained thereby into an image signal.

For this reason, the swivel unit 111 has a structure similar to that shown in FIGS.
As shown in FIG. 2, the case 110 is provided, and the bending mirror vibration scanning mechanism 101, the elevation angle driving mechanism 102, and the bending mirror 109, which are covered with the case 110, are provided in the upper part of the sensor head 118, that is, the upper end inside the case 110. Is attached to. Further, since the turning unit 111 bends the optical path downward by 90 degrees by the folding mirror 109, the infrared detector 107 connected to the optical system 103 and the sensor signal processing unit 113 is installed in the vertical direction.

The case 110 is transparent so that light can pass through the bending mirror vibration scanning mechanism 101 inside, and protects the internal device of the swivel unit 111 from the external environment. Bending mirror vibration scanning mechanism 101
30H _Z is usually but those fixed, which at the time of focusing, the frame frequency of the high-speed (TV bending mirror 109 provided in the narrow viewing angle in the front of the sensor
The real-time image within this viewing angle is given to the folding mirror 109 by vibrating and scanning.

The bending mirror 109 is capable of high-speed vibration by the bending mirror vibration scanning mechanism 101, and reflects incident infrared rays to the optical system 103 side. The elevation drive mechanism 102 finely adjusts the elevation angle of the folding mirror 109, and is used to change the visual field in the elevation direction. The optical system 103 is for bringing the detection element 106 into a state in which it can detect infrared rays properly, and therefore has an objective lens 103 ′ composed of a convex lens or the like.

A focus adjusting mechanism 104 'is also provided, and the focus adjusting mechanism 104' includes the focus adjusting element 10.
4, focus adjusting element drive mechanism 105, drive control circuit 112
It is configured with. Here, the focus adjustment element 10
Reference numeral 4 is for adjusting the focus position of the incident infrared ray by moving on the rail of the focus adjusting element drive mechanism 105.

The focus adjusting element drive mechanism 105 receives the focus adjusting element 10 according to a control signal from the drive control circuit 112.
4 is driven. The drive control circuit 112 is
According to the operation of the switch 117, the focus adjusting element driving mechanism 1 is controlled so that the focus adjusting element 104 is drive-controlled as specified.
This is a circuit for controlling 05. In addition, the infrared detector 107
The infrared ray sent from the optical system 103 is detected by the detection element 106, converted into an electric signal, and output as a sensor signal. Sensor signal processing unit 11
3 is for processing the sensor signal from the infrared detector 107 and outputting it as an image signal.

Further, as shown in FIG. 12, the revolving unit 111 having such a configuration has an image signal processing unit 114, a switch interface circuit 115, and a cathode ray tube (CRT).
116 and the switch 117 are connected. First, the image signal processing unit 114 processes the image signal from the sensor signal processing unit 113 of the turning unit 111 and outputs a standard TV signal to the cathode ray tube 116. CRT 116
Is for displaying a designated image according to the standard TV signal from the image signal processing unit 114.

The switch interface circuit 115 acts as an intermediary between the drive control circuit 112 of the revolving unit 111 and the switch 117. The switch 117 is a switch that is pushed when it is desired to perform focus adjustment. A trigger signal is transmitted via the interface circuit 115, and the drive control circuit 112 operates accordingly.

With such a configuration, in the infrared wide-angle monitoring system 10 ', as shown in FIG. 13, it takes several seconds for the infrared rays of the image data of all 360-degree directions to be obtained by the turning of the turning section 111. To go. As shown in FIG. 14, one piece of image data (in the display example, one piece of image data corresponding to 180 degrees on the opposite side, respectively) is obtained from the information obtained by taking several seconds in this way. The field of view data is displayed). In other words, instead of real-time continuous moving images, still images that are updated intermittently are obtained.

Then, when it becomes necessary to shift the current focus due to a change in the environment temperature, for the purpose of newly adjusting the focus, the operation mode in which the real time image can be temporarily acquired is set to the real time image. To get That is, the rotation of the sensor itself for wide-angle imaging is stopped, and the optical system 103
The bending mirror 109 provided in front of is subjected to high-speed vibration scanning to obtain a real-time image in the narrow range of the viewing angle on the cathode ray tube 116 though the viewing angle is narrow.

Then, while watching the image, the focus adjusting mechanism 104 'performs a focus adjusting operation to obtain a new focus suitable for the current situation, and the wide-angle imaging described above is restarted based on this focus. is there.

[0016]

However, in such a conventional infrared wide-angle monitoring system, an operation mode is set to a narrow visual field for focus adjustment every time it becomes necessary to readjust the focus due to a change in environmental temperature or the like. Since it has to be changed to one, the problem that the wide-angle monitoring, which is the operation purpose of the system, cannot be performed during that time.

In order to realize the real-time operation mode, a considerably large subunit such as a folding mirror capable of high-speed vibration must be mounted in the sensor head, and the optical path is bent. In addition, there is also a problem that the arrangement of the sensors is limited and the sensor head becomes large. The present invention was devised in view of the above problems, and it is possible to perform focus adjustment without impairing the operation purpose of the infrared wide-angle monitoring system or adding a large-scale subunit. An object of the present invention is to provide a focus adjusting method and a focus adjusting device in an outside wide-angle monitoring system.

[0018]

FIG. 1 is a block diagram of the principle of the present invention. In FIG. 1, reference numeral 10 denotes an infrared wide-angle monitoring system for monitoring a required range including a horizontal line. Reference numeral 10 includes a focus adjustment mechanism 1 and a focus adjustment device 2. Here, the focus adjustment device 2 is for performing focus adjustment, and for this reason, the focus adjustment device 2 includes the image data detection unit 3, the maximum value measurement unit 4,
It comprises a minimum value measuring section 5, a maximum value / minimum value difference detecting section 6, and a maximum value detecting section 7.

Here, the image data detecting section 3 detects the image data obtained by driving the focus adjusting mechanism 1 to change the focus within a range including the theoretical focus position. The maximum value measuring unit 4 includes the image data detecting unit 3
With respect to the image data obtained in step 1, the maximum value of each image data is measured at a plurality of places, whereas the minimum value measuring section 5 is a measuring section that measures the minimum value of each image data.

The maximum value / minimum value difference detecting section 6 detects the difference between the maximum value measured by the maximum value measuring section 4 and the minimum value measured by the minimum value measuring section 5, and the maximum value detecting section. Reference numeral 7 is for detecting a position where the difference between the maximum value and the minimum value of each image data detected by the maximum value / minimum value difference detecting section 6 is the maximum, as the focus position. Further, the focus adjustment mechanism 1 is
A focus control mechanism drive control circuit 8, a focus control element 11, and a focus control element drive mechanism 12 are provided.

Here, the focus adjusting element 11 adjusts the focus position of the incident infrared ray by moving on the rail of the focus adjusting element drive mechanism 12. The focus adjustment element drive mechanism 12 includes a focus adjustment mechanism drive control circuit 8
The focus adjusting element 11 is driven in accordance with the control signal from. The focus adjustment mechanism drive control circuit 8 controls the focus adjustment element 11 according to the control information from the focus adjustment mechanism 1.
Is a circuit that controls the focus adjustment element drive mechanism 12 so that the drive control is performed as specified.

[0022]

With the above-described structure, the following processes are performed when the focus is adjusted. First, the focus adjustment mechanism 1 is driven to change the focus within a range including the theoretical focus position, and with respect to image data obtained at that time, the maximum value and the minimum value of the image data are respectively obtained at a plurality of places. measure.

After that, the position where the difference between the maximum value and the minimum value of each image data is the maximum is set as the focus position, and the focus adjusting mechanism 1 is driven so that the focus becomes the focus position. That is, when the focus adjustment device 2 performs focus adjustment in the infrared wide-angle monitoring system 10 that monitors a required range including the horizontal line, first, the focus adjustment mechanism drive control circuit 8 controls the focus adjustment element drive mechanism 12. As a result, the focus adjustment element 11 is driven and the focus is changed within the range including the theoretical focus position.

Then, the image data detecting section 3 detects the image data obtained along with it and outputs it to the maximum value measuring section 4 and the minimum value measuring section 5. The maximum value measuring unit 4 and the minimum value measuring unit 5 which have received this output measure the maximum value and the minimum value of each image data at a plurality of places with respect to the image data obtained by the image data detecting unit 3, respectively.

From the maximum value measured by the maximum value measuring unit 4 and the minimum value measured by the minimum value measuring unit 5, the maximum value / minimum value difference detecting unit 6 detects the difference between the two. afterwards,
Regarding the difference between the maximum value and the minimum value of the image data with respect to each focus element position detected by the maximum value / minimum value difference detection unit 6, the maximum value detection unit 7 of the output destination determines the maximum position as the in-focus position. To be detected.

Then, the focus adjusting mechanism drive control circuit 8 which has received the in-focus position causes the focus adjusting element drive mechanism 1 to operate.
2 is controlled. As a result, the focus adjustment element 11 is driven so that the focus becomes the in-focus position detected by the maximum value detection unit 7.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. 2 and 3 show an infrared wide-angle monitoring system as an embodiment of the present invention, FIG. 2 is a perspective view showing an optical system portion thereof, and FIG. 3 is a block diagram showing a schematic configuration thereof. However, in these FIGS. 2 and 3, reference numeral 10 denotes an infrared wide-angle monitoring (infrared imaging) system. This infrared wide-angle monitoring system 10 is different from the conventional one in that the focus adjustment is automatic and the focus is adjusted. During adjustment, it is possible to search and monitor a required range (wide range such as the entire circumference) including the horizon without interrupting image processing.

Therefore, this infrared wide-angle monitoring system 10
Is provided with a base 17 which constitutes a sensor head 22, and a swivel portion 18 which is installed above the base 17 so as to be covered with a case 20. The focus adjusting device 2 shown in FIG. It is connected to the section 18. Here, first, the base 17 is functionally similar to the conventional one, and is installed on a horizontally stabilized stabilizer so as to give a rotation operation for wide-angle monitoring to the swivel unit 18. It is a thing.

The swivel unit 18 is given a rotational movement of 360 degrees by the base 17, automatically adjusts the focus, and intermittently updates the still image of the omnidirectional visual field by infrared rays without interruption. It is an operation to move.
Therefore, as shown in FIGS. 2 and 3, the swivel unit 18 is configured to include an optical system 9, an elevation angle drive mechanism 16, an infrared detector 13 having a detection element 14, and a sensor signal processing unit 15. .

Here, the optical system 9 receives the incident light at an appropriate focus. That is, in order to realize this, the optical system 9 includes the objective lenses 23,
It has a focus adjusting element 11. The objective lens 23 is
It is the same as the conventional one and is composed of a convex lens or the like. The focus adjusting mechanism 1 obtains an appropriate focus of the incident light according to the instruction of the focus adjusting device 2, and therefore, the focus adjusting element 11, the focus adjusting element driving mechanism 12,
It has a drive control circuit 8 (see FIG. 3).

Next, each device of the focus adjusting mechanism 1 will be described with reference to the schematic view of FIG. 4. On the rail 26 of the focus adjusting element driving mechanism 12, the servo motor 25 is operated to adjust the focus. The element 11 is installed so as to slide. The slide amount is detected by the focus adjustment element position sensor 24. Also,
A drive control circuit 8 is attached to the side of the focus adjusting element drive mechanism 12. A step motor may be used instead of the servo motor 25, but in this case, the focus adjusting element position sensor 24 can be omitted.

Here, the focus adjustment element 11 is drive-controlled to move on the rail 26 of the focus adjustment element drive mechanism 12, thereby adjusting the focus of the incident infrared rays. Further, the drive control circuit 8 includes the focus adjustment device 2
Is a circuit for controlling the focus adjusting element drive mechanism 12 so that the focus adjusting element 11 is controlled to be driven in accordance with the control signal from. That is, this drive control circuit 8 is similar to that shown in FIG.
As shown in FIG. 5, a focus position search operation command generation unit 41, a focus position command latch 42, a flip-flop 43, a position control loop gain / compensation unit 44, a speed control loop gain / compensation unit 45, a power amplifier 46, a buffer 47. , A switch 48 is provided.

Here, the focusing position searching operation command generation unit 41
When receiving a focus adjustment start command from the focus adjusting device 2 (input from the outside or periodically issued by a timer), a continuous movement position instruction for moving the focus adjustment element 11 back and forth to the theoretical focus position. The signals are sequentially output, and when the movement is completed, a sweep end (SWEEP END) signal is output.

The focus position command latch 42 receives the current position of the focus adjusting element 11 and, when a focus timing signal is sent from the focus adjusting device 2, latches the position of the focus adjusting element 11 at that time. It is a thing. Upon receiving the focus adjustment start command signal, the flip-flop 43 outputs a signal for instructing the switch 48 to select the output side of the in-focus position search operation command generation unit 41 via the buffer 47. . Also, this flip-flop 43
When receiving the sweep end signal, the buffer 47
The switch 48 is switched to the focus position command latch 42 side via the.

The position control loop gain / compensation unit 44 inputs the deviation obtained by subtracting the current position from the target position of the focus adjusting element 11, obtains the drive speed of the focus adjusting element 11 according to the amount of this deviation, and The speed information is output as the target speed. The speed control loop gain / compensation unit 45
The focus adjusting element 11 inputs the deviation obtained by subtracting the current speed from the target speed, converts the deviation into a driving voltage according to the amount, and outputs the driving voltage. The power amplifier 46 power-amplifies the voltage that has been sent and outputs it.

By the way, the focus adjusting element drive mechanism 12 is
The focus adjusting element 11 is driven on the rail 26 according to the control signal from the drive control circuit 8. Therefore, as shown in FIGS. 4 and 5, the focus adjusting element position sensor 24, the focus adjusting element speed sensor, and the like. 24 ', a servo motor 25, a drive mechanism 25' and the like. The focus adjusting element position sensor 24 is a sensor for detecting the current position of the focus adjusting element 11 and outputting the information to the drive control circuit 8. The focus adjusting element speed sensor 24 'is the current position of the focus adjusting element 11. The drive control circuit 8 detects the speed and outputs the information.
It is a sensor for outputting to.

The servo motor 25 generates power in proportion to the electric power from the drive control circuit 8, that is, a power source for driving the focus adjusting element 11 on the rail 26. The drive mechanism 25 'transmits the power from the servo motor 25 to the focus adjusting element 11 on the rail 26, and is a gear mechanism. By the way,
The infrared detector 13 shown in FIG. 3 detects infrared rays in the vicinity of the horizon sent from the optical system 9 by the detection element 14 as shown in FIG.
The width is 0.1 to several milliradians (mra).
It is detected by the field of view of M pixels arranged vertically in d).
Such infrared information is obtained for each sample (each azimuth angle) according to the turning direction of the turning section 18, and this is converted into an electric signal and output as a sensor signal.

That is, the infrared detector 13 sequentially obtains infrared radiation power (radiance value) for each depression and elevation as shown in FIG. 7 in each field of view described above. The elevation drive mechanism 16 mounts the optical system 9 and the infrared detector 13 (see FIG. 2), and moves the field of view of these devices by several degrees in the elevation direction in a horizontally stabilized rotating portion. The current elevation angle is notified to the focus adjustment device 2. The sensor signal processing unit 15 processes the sensor signal from the infrared detector 13 and outputs it to the image data detecting unit 3 side.

By the way, the focus adjusting device 2 operates the drive control circuit 8 while the system is picking up an image to slightly move the focus adjusting element 11 before and after the theoretical in-focus position, while actually adjusting the in-focus position. After that, this information can be output to the drive control circuit 8 to move the focus adjusting element 11 to this in-focus position. That is, when the focus changes due to some change in the environment, the focus adjusting device 2 can automatically perform the focus adjustment without interrupting the turning operation of the turning unit 18 and the still image updating operation. It has become.

Therefore, as shown in FIG. 3, the focus adjusting device 2 has an image data detecting section 3, a maximum value measuring section 4, a minimum value measuring section 5, a maximum value / minimum value difference detecting section 6, and a maximum value. Detecting unit 7, elevation angle receiving circuit 19, multi-column image data averaging unit 2
It is configured with 7. Here, the elevation angle receiving circuit 1
9 receives an elevation angle signal from the elevation angle drive mechanism 16.

The image data detector 3 drives the focus adjusting mechanism 1 to detect image data obtained by changing the focus within a range including the theoretical focus position. The image data detection unit 3 uses only a few degrees in the elevation direction with respect to the image data processed to determine the degree of focus, because the brightness variation in the vicinity of the horizontal line is only within a range of several degrees. It has become.

Therefore, the image data detecting section 3 includes an image signal processing section 31, a horizontal line neighborhood image data receiving circuit 3
2, a horizontal line image pickup pixel number calculation circuit 33 is provided. Here, every time the radiance value (see FIG. 7) for each depression and elevation in the vicinity of the horizontal line at each azimuth angle obtained in the infrared image is sequentially input, the image signal processing unit 31 outputs one piece of the image data in the vicinity of the horizontal line. Part (uniform background azimuth angle range) is detected, and the horizontal line image pickup pixel number calculation circuit 33 further detects the height from the water surface at the center of the system field of view (sensor head height) and the elevation angle reception circuit 19. From the elevation angle, the horizontal line of the obtained image data is calculated and the number of pixels of the pixels lined up in the vertical direction is calculated and output.

The near-horizontal image data receiving circuit 32 carries out a process of associating each image signal sent thereto with uniform background azimuth angle range information and horizontal line image pickup pixel number information, and outputs it. That is, the near-horizontal image data receiving circuit 32 performs a process of associating the received signals with each other, so that the focus adjusting element 11 moves back and forth, and while turning, the near-horizontal image as shown in FIG. Data for each azimuth angle taken during each azimuth angle as a field of view (radiance values for several depression / elevation angles obtained at each azimuth angle, FIG.
Can be output as a sample.

The multi-row image data averaging unit 27 is provided with image data at each azimuth angle of each pixel obtained while the turning unit 18 turns and the focus adjusting element 11 moves before and after the theoretical focusing position. Data from the horizontal line vicinity image data receiving circuit 32) are sequentially obtained, and the averaging is performed in order to reduce the influence of noise of these image data.

That is, the multi-column image data averaging unit 27, as shown in FIG. 8, detects the change of the radiance in the elevation direction, which is observed in the vicinity of the horizontal line of each azimuth angle, obtained in the infrared image for each pixel. Whenever L (L is an arbitrary natural number) sample is input, the values of each sample are added by several columns for each same pixel, divided by the number of columns, and averaged.

The maximum value measuring unit 4 measures the maximum value of each image data at a plurality of places with respect to the image data obtained by the image data detecting unit 3. That is, the maximum value measuring unit 4 detects and outputs the maximum value every time an averaged radiance value for each depression / elevation angle in each of the L azimuth angles as shown in FIG. 8 is obtained. is there. The minimum value measuring unit 5 measures the minimum value of each image data at a plurality of places with respect to the image data obtained by the image data detecting unit 3. That is, the minimum value measuring unit 5 detects and outputs the minimum value each time it obtains an averaged radiance value for each depression and elevation angle in each of the L azimuth angles as shown in FIG. is there.

The maximum value / minimum value difference detecting section 6 detects the maximum value of the image data measured by the maximum value measuring section 4 and the minimum value of the image data measured by the minimum value measuring section 5, as shown in FIG. The difference (that is, the contrast) is calculated. As shown in FIG. 8, the maximum value detecting unit 7 obtains a plurality of contrasts detected by the maximum value / minimum value difference detecting unit 6 and detects the maximum value among them, and then, in FIG. And FIG.
As shown in, the position of the focus adjusting element 11 when the maximum value is obtained is output as the focusing timing.

That is, the local maximum detecting unit 7 utilizes the fact that the contrast value received in the order of the number of samples (azimuth) becomes a convex parabola, and when it detects that this parabola starts to fall down, Immediately, the position of the focus adjusting element 11 at the time of detecting the maximum contrast value obtained so far is output as the focusing timing.

With such a configuration, in the infrared wide-angle monitoring system 10 in which the revolving unit 18 monitors the required range including the horizontal line while rotating, the image data in the vicinity of the horizontal line has a vertical line, as shown in FIG. Are sequentially updated in the turning direction for every M pixels. That is, while the turning unit 18 turns, the optical system 9 makes appropriate optical information incident on the infrared detector 13 and the infrared detector 13 converts the appropriate optical information into information by an electric signal. The sensor signal processing unit 15 converts the image data into image data and outputs the image data to the focus adjusting device 2 side and the CRT side.

When the focus adjustment is performed, as shown in FIG. 5, first, a focus adjustment start command is issued to the focus adjustment mechanism 1 of the system at regular intervals by an external input or a timer. Be started.
By the way, since the infrared wide-angle monitoring system 10 monitors the range of depression and elevation angles of several degrees centering on the horizon in most scenes of operation, the focus adjustment mechanism 1 is operated at startup or theoretically focused. In the drive control to the position, it is possible to obtain an azimuth range that does not include a region having a brightness difference due to a bird, a ship traveling, a cloud in the low sky, or the like.

Then, the above command is received by the focus position searching operation command generator 41 and the flip-flop 43 of the drive control circuit 8 of the focus adjusting mechanism 1. Upon receiving this signal, the focus position search operation command generation unit 41 receives the focus adjustment element 11
Is sequentially output to the switch 48 in order to move the position around the theoretical focus position. Since the flip-flop 43 and the buffer 47 receive only this command, during that time, the switch 48 outputs a signal for selecting the focus position searching operation command generation unit 41 side.

For this reason, the focus position searching operation command generation unit 4
The movement position signal from 1 passes through the switch 48,
Focus adjusting element position sensor 2 of focus adjusting element drive mechanism 12
4 is subtracted from the current position of the focus adjustment element 11 to obtain a deviation as a position control loop gain / compensation unit 44.
Entered in. Then, based on this deviation, the position control loop gain / compensation unit 44 causes the focus adjustment element 1 according to the amount.
1, the speed information is output, and this speed information is subtracted from the current speed information of the focus adjusting element 11 from the focus adjusting element speed sensor 24 ',
It is sent to the speed control loop gain / compensation unit 45.

The speed deviation input to the speed control loop gain / compensation unit 45 is converted into a voltage corresponding to the amount and output to the power amplifier 46, which in turn outputs this voltage. Power is amplified to operate the servo motor 25 of the focus adjusting element drive mechanism 12. In this way, the servo motor 25 drives the focus adjusting element 11 on the rail 26 to the target position at an appropriate speed through the drive mechanism 25 ′ using the prescribed prescribed force.

As a result, the focus position searching operation command generation unit 4
The focus adjusting element 11 is always moved to the target position at an appropriate speed at the current position in accordance with the continuous movement position instruction signal sequentially sent from 1. In this way, the focus adjusting element 11 is driven before and after the theoretical focusing point during the turning of the turning portion 18 by the servo mechanism having the step motor or the position sensor of the focus adjusting element 11.

Then, the maximum and minimum values in the elevation direction in each image data at a plurality of places obtained during that time are calculated, and then the position where the difference between the maximum value and the minimum value of the image data is maximum is calculated. The focus adjustment mechanism 1 is driven so that the focus is at this focus position. To describe this in detail, as shown in FIG. 3, the radiance value (see FIG. 7) at each elevation angle near the horizon at each azimuth obtained in the infrared image is calculated by the image signal processing unit 3 of the focus adjustment device 2.
1 and the image data receiving circuit 32 in the vicinity of the horizon.

At the same time, the horizontal line image pickup pixel N
o. The elevation angle information and the sensor / head height information corresponding to the above image data are input to the calculation circuit 33.
The position of the horizontal line in which the pixels are aligned in the vertical direction is calculated, and this is output to the horizontal line neighborhood image data receiving circuit 32. Then, a part (uniform background azimuth range) of the horizontal line near-field image data input to the image signal processing unit 31 is detected here, and this is also output to the horizontal line near-field image data receiving circuit 32. To be done.

The horizontal line neighborhood image data receiving circuit 32, which has received each of these data, carries out a process of associating each signal. As a result, as the focus adjustment element 11 moves back and forth and turns, data for each azimuth angle near the horizon as shown in FIG. 6 is obtained as a sample.
The image data at each azimuth angle of each pixel, which is obtained while the swivel unit 18 swivels and the focus adjusting element 11 moves before and after the theoretical in-focus position, is obtained by the above-described processes.
The data is sequentially sent to the multi-column image data averaging unit 27.

Then, the multi-column image data averaging unit 27
Repeats averaging the image data for the same pixel over L samples every L samples in order to reduce the effect of noise.
Equivalently, several tens of samples of image data for the same scene are output (see FIG. 6). Further, each time the image data for L samples is received, the maximum value measuring unit 4 and the minimum value measuring unit 5 obtain and output the maximum value and the minimum value, as shown in FIG. From the pair of values, the maximum / minimum value difference detection unit 6 obtains each contrast.

The respective contrasts thus obtained are sequentially sent to the maximum value detecting section 7, where they are compared in order of the number of samples (azimuth angle) as shown in FIG.
Then, when the maximum value detection unit 7 detects that the convex parabola of the contrast starts to fall, the maximum value detection unit 7 immediately detects the position of the focus adjustment element 11 when the maximum contrast value obtained so far is detected. Is output as the focus timing (see FIGS. 8 and 9).

In this way, the in-focus position is searched for, and
As shown by 0, if the focus adjustment element 11 is driven and controlled there, the focus can be adjusted. As a result, with respect to the focus adjustment mechanism 1 in the state described above, that is, in the state in which the focus adjustment element 11 is moved to the front and rear of the theoretical focus position, the maximum value detection unit 7 of the focus adjustment device 2 causes Focusing timing information is output.

Upon receiving this, the focus position command latch 42 of the drive control circuit 8 outputs the output of the position sensor 24 at the time of focus,
That is, the focus position is latched and the position information is output. In addition, the focus position search operation command generation unit 41
Outputs a sweep end signal to the flip-flop 43 when a series of search operation commands is completed. as a result,
By the flip-flop 43 and the buffer 47, the switch 48 is switched to the focus position command latch 42 side,
Focus position information from the focus position command latch 42 is output as a position control loop command.

With respect to the subsequent steps, the focus adjusting element 11 described above is used.
The focus adjustment element 11 is moved to the in-focus position in the same manner as the drive control of 1., and is fixed at this in-focus position until the next focus adjustment start command is input to the focus adjustment mechanism 1. With each of the above processes, the focus adjustment is completed, and the signal processing for the infrared image focused at approximately infinity is performed.
It will be applied by this system.

As described above, in the focus adjusting device 2 for adjusting the focus in the infrared wide-angle monitoring system 10, the image data detecting section 3, the maximum value measuring section 4, the minimum value measuring section 5, and the maximum value / minimum value difference detecting section. 6, the maximum value detector 7, and the focus adjustment mechanism drive control circuit 8 are provided, and when performing focus adjustment, first, the focus adjustment mechanism 1 is driven to set the focus within a range including the theoretical focus position. As the focus is changed, the maximum and minimum values of the image data are measured at multiple locations for the image data obtained at that time, and then the difference between the maximum and minimum values for each image data is the maximum. When the focus adjustment mechanism 1 is driven so that the focus becomes the in-focus position, the infrared image is recognized in the elevation direction near the horizontal line as shown in FIG. 7. It is possible to take advantage of the fact that the difference between the maximum value and the minimum value at the in-focus position maximizes the change in the diance, which makes it possible to use a bending mirror, which is a large-scale sub-unit that was required in the past, and a device accompanying it Is not necessary, and the focus adjustment can be automatically performed without interrupting the image update of the system.

[0064]

As described in detail above, according to the present invention,
Regarding the image data obtained by the image data detection unit that detects the image data obtained by driving the focus adjustment mechanism and changing the focus in the range including the theoretical focus position, and the image data obtained by the image data detection unit, A maximum value measurement unit that measures the maximum value of each image data at multiple locations, and a minimum value measurement unit that measures the minimum value of each image data at multiple locations for the image data obtained by the image data detection unit And the maximum value / minimum value difference detection unit that detects the difference between the maximum value measured by the maximum value measurement unit and the minimum value measured by the minimum value measurement unit, and the maximum value / minimum value difference detection unit. A maximum value detection unit that detects a position where the difference between the maximum value and the minimum value of each image data is maximum as the focus position, and the focus is set to the focus position detected by the maximum value detection unit. To drive the focus adjustment mechanism to When performing the adjustment, first drive the focus adjustment mechanism to change the focus within the range including the theoretical in-focus position, and regarding the image data obtained at that time, the maximum value of the image data at each of the multiple locations. And the minimum value are measured, and then the position where the difference between the maximum value and the minimum value for each image data is the maximum is set as the in-focus position, and the focus adjustment mechanism is driven so that the focus is at this in-focus position. Therefore, it is possible to automatically perform focus adjustment in the infrared wide-angle monitoring system without impairing the operation purpose of the infrared wide-angle monitoring system or adding a large subunit. Therefore, there is an advantage that it can greatly contribute to the operational improvement of the infrared wide-angle monitoring system.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a perspective view showing an embodiment of the present invention.

FIG. 3 is a block diagram showing an embodiment of the present invention.

FIG. 4 is a perspective view showing a focus adjustment mechanism in one embodiment of the present invention.

FIG. 5 is a block diagram showing a focus adjustment mechanism in one embodiment of the present invention.

FIG. 6 is a diagram illustrating an imaging format according to an embodiment of the present invention.

FIG. 7 is a diagram showing a change in radiance with respect to a depression / elevation angle in the vicinity of a horizontal line according to the embodiment of the present invention.

FIG. 8 is a diagram illustrating a focusing position in a relationship between a change in radiance and a change in position of a focus adjustment element according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating a focusing position searching method according to an embodiment of the present invention.

FIG. 10 is a diagram illustrating a procedure for controlling a focus position according to an embodiment of the present invention.

FIG. 11 is a perspective view showing a conventional example.

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

FIG. 13 is a diagram illustrating an operating status of an infrared wide-angle monitoring system.

FIG. 14 is a diagram showing an image display example of the infrared wide-angle monitoring system.

[Explanation of symbols]

 1 focus adjusting mechanism 2 focus adjusting device 3 image data detecting section 4 maximum value measuring section 5 minimum value measuring section 6 maximum value / minimum value difference detecting section 7 maximum value detecting section 8 drive control circuit 9 optical system 10, 10 'infrared Wide-angle monitoring system 11 Focus adjustment element 12 Focus adjustment element drive mechanism 13 Infrared detector 14 Detection element 15 Sensor signal processing unit 16 Elevation drive mechanism 17 Base 18 Swivel unit 19 Elevation angle reception circuit 20 Case 22 Sensor head 23 Objective lens 24 Focus adjustment Element position sensor 24 'Focus adjustment element speed sensor 25 Servo motor 25' Drive mechanism 26 Rail 27 Multi-row image data averaging unit 31 Image signal processing unit 32 Horizontal line neighborhood image data receiving circuit 33 Horizontal line imaging pixel No. Calculation circuit 41 Focus position search operation command generation unit 42 Focus position command latch 43 Flip-flop 44 Position control loop gain / compensation unit 45 Speed control loop gain / compensation unit 46 Power amplifier 47 Buffer 48 Switch 101 Bending mirror vibration scanning mechanism 102 Elevation drive mechanism 103 Optical system 103 'Objective lens 104 Focus adjustment element 104' Focus adjustment mechanism 105 Focus adjustment element drive mechanism 106 Sensing element 107 Infrared detector 108 Base 109 Bending mirror 110 Case 111 Swiveling section 112 Drive control circuit 113 Sensor signal processing Section 114 image signal processing section 115 switch I / F (interface) circuit 116 cathode ray tube (CRT) 117 switch 118 sensor head

[Procedure amendment]

[Submission date] November 16, 1993

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Claims (2)

[Claims] 1. In an infrared wide-angle monitoring system (10) for monitoring a required range including a horizontal line, when performing focus adjustment, first, a focus adjustment mechanism (1) is driven to focus a range including a theoretical focus position. The focus is changed with, and for the image data obtained at that time, the maximum value and the minimum value of the image data are measured at a plurality of places, respectively, and then the difference between the maximum value and the minimum value of each image data is calculated. A focus adjusting method in an infrared wide-angle monitoring system, characterized in that the focus adjusting mechanism (1) is driven so that the focus becomes the focus position with the maximum position as the focus position. 2. In an infrared wide-angle monitoring system (10) for monitoring a required range including a horizontal line, a focus adjusting mechanism (1) is driven to focus in a range including a theoretical focus position in order to perform focus adjustment. The image data detection unit (3) for detecting the image data obtained by changing the image data, and the maximum value of each image data at a plurality of locations with respect to the image data obtained by the image data detection unit (3). A maximum value measuring section (4), and a minimum value measuring section (5) for measuring the minimum value of each image data at a plurality of places with respect to the image data obtained by the image data detecting section (3). A maximum value / minimum value difference detection unit (6) for detecting a difference between the maximum value measured by the maximum value measurement unit (4) and the minimum value measured by the minimum value measurement unit (5); Each image data detected by the maximum / minimum difference detection unit (6) A maximum value detection unit (7) that detects a position where the difference between the maximum value and the minimum value is maximum as the focus position, and the focus is the focus position detected by the maximum value detection unit (7). A focus adjusting device in an infrared wide-angle monitoring system, which is configured to drive the focus adjusting mechanism (1).