JPH11275428A - Broad angle photographing method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broad angle photographing method by which the image at a remote place over a wide range is obtained in a short time without a camera-shake in the image. SOLUTION: An image reflection mirror 11 is placed in front of a TV camera 10 with a predetermined photographing period and a reflected image in the mirror 11 is received by the TV camera 10 by turning the mirror 11 stepwise synchronously with the photographing period of the mirror 11. A stop time at each interval of the stepwise turning is selected to be at least one photographing period, at least one image is received by the TV camera 10 for the stop time period and the received image is outputted as a division image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide-angle imaging method and apparatus suitable for obtaining a distant image at a wide angle by a TV camera, and more particularly to a wide-angle imaging method and apparatus suitable for searching for a distant moving object. . This kind of wide-angle imaging method and apparatus is suitable for searching for a moving body approaching particularly at night over a wide range.

[0002]

2. Description of the Related Art When monitoring a moving object such as an aircraft approaching from a monitoring point several km or more, particularly from an airspace, a radar is usually used. However, when a moving object enters in a very low altitude, it may be difficult to catch the radar. In that case, visual observation using a telescope or an optical sight, etc., is not possible at night. Therefore, observation is performed using an infrared camera, but in order to search a wide area, the camera must be scanned. It is conceivable to search a wide area with a wide-angle lens. However, due to the characteristics of the wide-angle lens, a small image of a moving object is captured and a moving object at a long distance cannot be recognized.

On the other hand, when the camera is step-scanned in order to prevent image blurring, in a structure in which the camera body is directly rotated, an exposure time of 1/30 sec. If it is not stationary during this exposure time, the image will be blurred, and it will not be possible to take an image while moving it continuously. This tendency is remarkable because infrared cameras have particularly poor sensitivity. In addition, the mass and moment of inertia of the movable part are large, and there is a limit to the high-speed operation. Furthermore, when driving in a stepped manner at high speed, a large acceleration is repeatedly transmitted to the camera body, which may cause a failure.

Therefore, there has been proposed an apparatus in which a mirror is provided in front of a lens of an imaging camera, and the mirror is rotated by driving a pulse motor so that a subject can be accurately placed in the field of view of the imaging camera. Have been. An imaging technique using such a rotating mirror is disclosed in, for example, Japanese Patent Application Laid-Open No. 52-30316. To summarize this imaging technology, a mirror is placed in front of the imaging camera to check the position of the subject, and the imaging control that rotates all or a part of the optical axis of the imaging device to guide the subject into the field of view of the imaging device. Equipment. This imaging technique is specifically used to image and record the freight car number and other symbols attached to the wagon while the wagon is running.

On the other hand, as another imaging technique using a rotating mirror, there is a technique disclosed in Japanese Patent Application Laid-Open No. 8-32863. In this imaging technique, the imaging field of view of the CCD imaging device is scanned by rotating a rotatable mirror, and each partial image based on the output of the CCD imaging device corresponding to each of the plurality of imaging fields related to this scanning is formed. Information representing one entire image is obtained by combining the information to be represented. Specific applications include very short range scanners, facsimile machines, and copiers.

[0006]

However, the above-described imaging technique does not scan a wide area several km or more in a short time. In addition, since the search for a target at night is not considered at all, it is not a technology that can be used as it is for a low-sensitivity camera such as an infrared camera targeted in the present invention. Moreover, no consideration is given to image blur caused by the rotation of the mirror.

An object of the present invention is to provide a wide-angle imaging method capable of obtaining an image of a distant and wide range in a short time and without blurring of the image.

Another object of the present invention is to provide a wide-angle imaging method capable of achieving the above object even at night.

A further object of the present invention is to provide a wide-angle imaging device suitable for the above-mentioned wide-angle imaging method.

[0010]

According to the present invention, a distant region is set as a subject region, the subject region is divided into a plurality of parts, and an image is taken. From the obtained divided image, an image of the whole subject region is obtained. A wide-angle imaging method in which a mirror for reflecting an image is installed in front of a TV camera having a predetermined imaging cycle, and the mirror is reflected in the mirror while rotating in a stepwise manner in synchronization with the imaging cycle. The captured image is captured by the TV camera, and at least one image is taken from the image of the TV camera during the stop time, with a stop time between the stepwise rotations being at least one cycle of the imaging cycle. A wide-angle imaging method is provided, which captures and outputs the captured image as a divided image.

According to the present invention, there is further provided a wide-angle imaging apparatus which obtains an image of the entire object region from an obtained divided image by dividing the object region into a plurality of images and taking an image of the object region. A TV camera that performs imaging at a predetermined cycle, a mirror that is rotatably arranged in front of a lens of the TV camera, a direct drive actuator that directly drives and rotates the mirror, Control means for controlling an actuator in synchronization with the imaging cycle to rotate the mirror, and then driving the mirror in a stepwise manner so as to stop the mirror for at least one period of the imaging cycle, There is provided a wide-angle imaging apparatus characterized in that an image while the mirror is stopped is captured from a TV camera and output as a divided image.

[0012] The actuator moves an image pickup area by the mirror in a lateral direction in the object area, and the TV camera and the mirror are mounted on a common support member. The apparatus further includes a drive source that is rotatably supported about an elevation axis and that rotates the support member, wherein the control unit also controls the elevation angle of the support member in synchronization with the imaging cycle. Thus, the imaging area by the mirror is also moved in the vertical direction in the object area.

In any of the inventions, an infrared camera is suitable for the TV camera.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of a wide-angle imaging device according to the present invention will be described with reference to FIG.
This wide-angle imaging apparatus captures a distant area, which is several kilometers or more ahead, in particular, an air space as an object area, divides the object area into a plurality of parts, and takes an image.
The obtained divided images are combined to obtain an image of the entire subject area. Such a wide-angle imaging device is suitable for application to a device that searches for a moving object such as an aircraft that enters a monitoring area at an extremely low altitude by image processing. That is, it is used as an image acquisition system of a system that determines whether or not there is a moving object in any of the obtained divided images by image processing. Note that the image processing is not the gist of the present invention, and thus the description is omitted.

The basic configuration of this wide-angle imaging device is a predetermined period, in other words, 30 (frames / second)
And a mirror 11 rotatably arranged in front of the lens of the TV camera 10,
An actuator 12 is provided by a direct drive type motor that directly drives and rotates the mirror 11. The wide-angle imaging apparatus also controls the actuator 12 in synchronization with the above-described imaging cycle to rotate the mirror 11, and then drives the mirror 11 in a stepwise manner so as to stop for at least one imaging cycle. The control device 13 is provided. The control device 13 also controls the TV camera 10 to capture an image while the mirror 11 is stopped as a divided image. TV camera 1
As 0, an infrared camera is used here.

As is apparent from FIG. 1, the TV camera 10, the mirror 11, and its actuator 12 are accommodated in a frame 14. This frame 14
Mounted on the camera mount 15,
Thus, the entire frame 14 can be rotated. As a result, the mirror 11 in the frame 14 is rotatable around an axis indicated by X (hereinafter, referred to as a scanning axis).
The V camera 10 and the mirror 11 are rotatable about an axis indicated by Y (hereinafter, referred to as an elevation axis).

Referring to FIG. 2, the control device 13 controls the actuator 12 in synchronization with the imaging cycle of the TV camera 10 so that the image capturing area by the mirror 11 is moved in the horizontal direction (scanning direction) in the object area. Move to
The control device 13 also moves the imaging area of the mirror 11 in the vertical direction (elevation direction) in the object area by controlling the elevation axis motor 16 in synchronization with the imaging cycle of the TV camera 10.

As an example, a TV camera having a viewing angle of 6 degrees × 5 degrees and an imaging cycle of 1/30 second is used, and the rotation time is 2/3.
A case will be described in which the subject area of FIG.

In this case, the rotation time is two cycles of the imaging cycle of the TV camera 10, and the imaging time is one cycle of the imaging cycle of the TV camera 10, so that it is necessary to obtain one divided image. The control time is three periods of the imaging cycle of the TV camera 10, that is, 3/30 seconds. Control device 13
First, in synchronization with the imaging cycle of the TV camera 10, first, the mirror 12 is rotated three times by controlling the actuator 12 in order to change the scanning azimuth by six degrees corresponding to the viewing angle between two periods. Next, the control device 13 controls the actuator 12 and the mirror 11 to stop for one cycle of the imaging cycle of the TV camera 10, and also controls to capture a shake-free image captured during this period.

Such an operation is repeated five times to obtain five divided images 20-1 to 20-5. Then, the control device 1
The control 3 controls the elevation axis motor 16 to increase the elevation angle by 5 degrees. This control operation is performed similarly to the rotation control operation in the scanning axis direction. Therefore, the raising shaft motor 16
Is also performed in synchronization with the imaging cycle of the TV camera 10. Then, the image captured during the stop obtained as a result is taken in to obtain a divided image 20-6. The control device 13 controls the actuator 12 to turn the mirror 11 in the opposite direction. Thereafter, by repeating the above operation, a twentieth divided image 20-20 is obtained. These 20 divided images are subjected to image processing in chronological order one by one to determine the presence or absence of a moving object. A composite image is obtained. As an example, the time required to obtain the first to twentieth divided images and combine the subject area with the twenty divided images as shown in FIG. 2 is about 3 seconds.

According to the embodiment described above, even if the image has low sensitivity obtained from the infrared camera, an image without blur can be obtained, so that the recognition accuracy of the moving object does not decrease.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiment, the mirror 11 is driven by the actuator 12 to control the scanning angle, and the TV camera 10 and the mirror 11 are driven by the elevation axis motor 16 to control the elevation angle. May be driven by an elevation angle motor together with the actuator 12 to control the elevation angle. Further, instead of the TV camera 10, another ITV camera can be used. In short, the present invention can be applied to any TV camera as long as the exposure time is 1/30 (second), and is not limited to an infrared camera, that is, imaging only at night.

[0023]

According to the present invention, it is possible to obtain an image of a distant and wide range in a short time and without blurring of the image. Moreover, by using an infrared camera, the above effects can be obtained even at night. Furthermore, since the movable portion can be made smaller and lighter than in the conventional configuration, measures against vibration of the entire device during the step operation can be reduced, and the entire device can be reduced in weight.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a basic configuration of a wide-angle imaging device according to the present invention.

FIG. 2 is a diagram for explaining a wide-angle image obtained by the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 TV camera 11 Mirror 12 Actuator 13 Control device 14 Frame 15 Camera mount 16 Elevation axis motor

Claims (5)

[Claims] 1. A wide-angle imaging method in which a distant region is set as an object region, the object region is divided into a plurality of images, and an image of the entire object region is obtained from the obtained divided images. A mirror for image reflection is set in front of a lens of a TV camera having an imaging cycle, and the mirror reflects the image from the mirror while rotating the mirror stepwise in synchronization with the imaging cycle. Then, at least one image is taken into the TV camera during the stop time, and the taken image is output as a divided image, with a stop time between the step-like rotations being at least one cycle of the imaging cycle. And a wide-angle imaging method. 2. The wide-angle imaging method according to claim 1, wherein
The wide-angle imaging method, wherein the TV camera is an infrared camera. 3. A wide-angle imaging apparatus which obtains an image of the entire object region from an obtained divided image by dividing the object region into a plurality of images and taking an image of the object region by dividing the object region into a plurality of regions. A TV camera that performs imaging with a camera, a mirror rotatably arranged in front of a lens of the TV camera, a direct drive type actuator that directly drives and rotates the mirror, and the imaging cycle of the actuator. Control means for rotating the mirror by controlling the mirror in synchronization with the mirror, and then driving the mirror in a stepwise manner so as to stop the mirror for at least one period of the imaging cycle. A wide-angle imaging apparatus, wherein an image is captured while the camera is stopped and output as a divided image. 4. The wide-angle imaging device according to claim 3,
A wide-angle imaging device, wherein the TV camera is an infrared camera. 5. The wide-angle imaging device according to claim 3, wherein the actuator moves an imaging area by the mirror in a lateral direction in the object area, and the TV camera and the mirror are common. The support member is mounted on a support member, the support member is rotatably supported about an elevation axis, and further includes a drive source for rotating the support member, and the control unit is configured to synchronize with the imaging cycle. A wide-angle imaging device, wherein the imaging area of the mirror is also moved in the vertical direction in the object area by controlling the elevation angle of the support member.