JPH109853A - Distance-measuring type omnibearing visual sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable measurement of the distance to a target in omnibearings by obtaining the distance to an object based on a predetermined corresponding relationship from photographing positions of two images of the object guided with two different optical paths. SOLUTION: Light from a target, for example, from a light source 50 is guided to a CCD (image pickup device using a solid image sensor) 6 with a first optical path through a cone mirror 8 and a fisheye lens 7 and directly with a second optical path through the fisheye lens 7. Then, a light source image 10 reflected by the cone mirror 8 is formed in a cone image 9 of the cone mirror 8. A light source image 11 guided through the fisheye lens 7 is formed outside the cone image 9. So, distances d1 and d2 of the two light source images 10 and 11 from the center 0 of the cone image 9 are obtained to determine the distance to the target (light source) 50 from a corresponding relationship of both the images (determined by optical characteristics of the cone mirror 8 and the fisheye lens 7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance-measuring omnidirectional visual sensor for measuring a distance to a target in all directions, and more particularly to a distance-measuring omnidirectional visual sensor suitable for a robot eye.

[0002]

2. Description of the Related Art When a mobile robot is guided by using a tobology map (spectacle map) composed of a series of images captured in a wide field of view of an environment, an obstacle is detected by an ultrasonic sensor or the like, and the scene map information is used. Proposals have been made for estimating global and local positions (position identification using moving images of mobile robots using continuous DP, IEICE, pp1
39-144, 1995 etc.).

[0003]

However, the range in which the ultrasonic sensor can capture the target is limited, and it is not always possible to capture the target in all directions.

As an apparatus for photographing a target in all directions, an omnidirectional visual sensor has been proposed in which an omnidirectional image is taken into an image pickup apparatus via a reflection mirror (Transactions of the Institute of Electronics, Information and Communication Engineers). D-11, Vol, J79d
-11 No. 5 pp698-707 1996
Mon), the method of measuring distance is not proposed.

Accordingly, an object of the present invention is to provide a distance-measuring omnidirectional vision sensor that can measure the distance of a specific target by using the omnidirectional vision sensor.

[0006]

In order to achieve the above object, according to a first aspect of the present invention, there is provided an image pickup apparatus comprising: a first optical path; and a second optical path different from the first optical path. An optical system that guides a subject image to the device and forms two subject images on the imaging device, and a subject based on a predetermined correspondence relationship from the imaging positions of the two subject images formed by the imaging device. And information processing means for acquiring a distance to the vehicle.

According to a second aspect of the present invention, in the distance measuring type omnidirectional vision sensor according to the first aspect, the optical system includes a mirror for reflecting the subject image, a subject image reflected by the mirror, A lens for directing a direct subject image to the imaging device is provided.

According to a third aspect of the present invention, in the distance measuring type omnidirectional vision sensor according to the second aspect, the mirror is arranged on an optical axis of the image pickup device, and the information processing means takes a picture of the mirror itself. Detecting the imaging position of the subject image reflected by the mirror in the image area, and forming the direct subject image on a straight line connecting the imaging position corresponding to the optical axis of the imaging device and the imaging position of the reflected subject image; Is characterized by detecting the imaging position of the image.

According to a fourth aspect of the present invention, in the distance measuring type omnidirectional vision sensor according to the first aspect, the optical system has a first mirror and a second mirror that reflect the subject image. The first optical path and the second optical path are formed by a first mirror and a second mirror.

According to a fifth aspect of the present invention, in the distance measuring type omnidirectional vision sensor according to the fourth aspect, the first mirror and the second mirror are arranged on an optical axis of the imaging device, and The second mirror is provided with an opening for guiding the subject image reflected by the mirror to the image pickup device.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a configuration of a distance measuring type omnidirectional sensor to which the present invention is applied. In FIG. 1, reference numeral 50 denotes a target, for example, a light source. The light from the light source 50 passes through the first direction, namely, through the conical mirror 8 and the fisheye lens 7,
It is guided to a CD (imaging device using an individual imaging device) 6. The light from the light source 50 is in the second direction,
The light is directly incident on the fisheye lens 7 from 0 and is guided to the CCD 50. The optical system is configured such that the center of the conical mirror 8 coincides with the center of the fisheye lens 7, that is, the optical axis of the CCD 6.

In this way, two images of the light source 50 taken at the positions indicated by reference numerals 10 and 11 in FIG. Reference numeral 10 denotes an image of the light source 50 due to the light reflected by the conical mirror 8. Reference numeral 11 denotes an image generated by light guided directly from the light source 50 via the fisheye lens 7.

The light source image 10 of the light reflected by the conical mirror 8 is generated in the conical image 9 of the conical mirror 8 and the light source 5
The light source image 11 generated by the light guided directly from 0 through the fisheye lens 7 exists outside the cone image 9. Further, there is a feature that a straight line connecting the light source image 10 and the light source image 11 always passes through the center O (corresponding to the optical axis center) of the cone image.

In this embodiment, focusing on such features,
Distance d between two light source images 10 and 11 from cone image 10
By calculating 1, d2, the distance to the target is obtained.

If the optical characteristics of the conical mirror 8 and the fisheye lens 7 are determined, the correspondence between the distance L and the distances d1 and d2 in the screen can be expressed by a mathematical formula using a triangulation technique. Further, the light source position 50 is moved to a plurality of positions where the distance in the three-dimensional space is known, and the light source position 1 at that time is moved.
0 and 11 are obtained, and the actual distance L and the in-screen distances 10 and 1 are obtained.
One correspondence may be stored in the apparatus in the form of a table.

FIG. 3 shows a circuit configuration of a control system of such a distance measuring type omnidirectional vision sensor. In FIG. 3, image data for one screen of an image captured by the CCD 6 is converted from an analog signal to a digital signal by an analog / digital signal by a converter 6A. Image data in the form of digital signals, more specifically, luminance data for each pixel, is transferred to a CPU (Central Processing Unit) 1 via an input / output interface (I / O) 5 and then to a RAM (random access memory). 3) is stored. CPU1 is ROM
According to the program shown in FIG. 4 stored in the (read only memory) 2, the distance is calculated using the image data in the RAM 3. The calculation result is displayed on the display 4 under the control of the CPU 1.

The operation of such a system will be described with reference to the flowchart of FIG. When the power is turned on, C
PU1 performs an initialization process in distance calculation (step S10). Next, the CPU 1 captures image data for one screen via the I / O 5 (step S20). The CPU 1 checks the image data on the RAM 3 and first detects image data on an image (hereinafter, referred to as a first image) generated by the light reflected by the conical mirror 8. More specifically, since the position and size of the photographed image area of the outer peripheral circle of the conical mirror 8 are given in advance as initial values, image data having a luminance equal to or higher than a threshold value within this area and its pixel Detect the position. The detected pixel position is R
It is stored in AM3 (step S40).

Next, the CPU 1 directly moves the CCD 6 from the subject.
The position of the light image (hereinafter, referred to as a second image) captured in the RAM 3 is detected based on the image data in the RAM 3. As described above, the second image is characterized by being on a straight line connecting the first image and the image center of the conical mirror 8 and in an area outside the image of the conical mirror 8 itself. CPU1 is RA
It is determined whether or not the image data of each pixel on M3 matches the above characteristics. Thereby, the image data of the first and second images satisfying the above characteristics and the pixel positions thereof are detected.

The CPU 1 calculates distances d1 and d2 (see FIG. 2) between the pixel position and the center position of the image of the conical mirror 8. The distances d1 and d2 are calculated using a predetermined distance calculation formula or a conversion table.
Is obtained (step S50). The calculation result is displayed on the display 4 (step S60).

Hereinafter, the processing procedures of steps S20 to S60 are repeated until a termination instruction is given.

As described above, in this embodiment, the distance can be measured by using the omnidirectional vision sensor. Therefore, when this embodiment is mounted on a robot, not only the detection of an obstacle but also the detection of an obstacle can be performed. And the collision time to an obstacle can be obtained. Also, since it is not necessary to mount a conventionally known distance measuring device separately from the omnidirectional vision sensor,
The robot can be downsized. The omnidirectional vision sensor is C
Since the CD 6 can be fixedly installed, the swinging operation of the robot is not required, and the mechanism of the robot body can be simplified.

The following example can be carried out in addition to this embodiment.

1) In this embodiment, a conical mirror is used as the reflecting member used in the omnidirectional vision sensor, but a mirror having another shape such as a spherical mirror may be used.

2) In this embodiment, light is guided to the CCD 6 through two optical paths for the same light source. For this purpose, the present embodiment uses the fisheye lens 7. The present invention is not limited to this example, and can be realized by an optical system as shown in FIG. In the example of FIG. 5, a curved mirror 20 is provided between the conical mirror 8 and the CCD 6. An opening 2 for guiding the reflected light of the conical mirror 8 to the CCD 6 is provided at the center of the curved mirror 20.
1 is provided. Light from the light source 50 is reflected by the outer surface of the curved mirror 20 and guided to the CCD 6. In this case, one of the image positions of the point light source 50 occurs in the image area of the opening 21 of the curved mirror 20, and the other occurs in the area of the curved mirror 21 except for the opening 21. There is an advantage that only the inside of these areas is a search area for the light source image.

3) In this embodiment, for explanation of the invention,
Although the subject has been described as a point light source, the subject is not limited to a point light source and can be applied to all objects having a certain shape. In this case, two images generated by two light paths may be detected by pattern matching. The feature of the position of the image is the same as that of the point light source described above.

[0026]

As described above, according to the first aspect of the present invention, by acquiring two images of a subject image in the imaging device, it is possible to measure the distance even with the omnidirectional vision sensor.

According to the second aspect of the present invention, the optical system can be constituted by one mirror and one lens, and the distance-measuring omnidirectional vision sensor can be incorporated in a device such as a robot having a limited installation place.

According to the third aspect of the present invention, the image pickup position is detected by utilizing the position characteristics of the two subject images.
The position detection accuracy is improved, and the detection time is shortened.

According to the fourth aspect of the present invention, the optical system can be constituted by only two mirrors, which can contribute to downsizing of the apparatus.

According to the fifth aspect of the present invention, the two mirrors can be arranged on the optical axis, which facilitates the mounting.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an optical system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a captured image.

FIG. 3 is a block diagram illustrating a configuration of a control system according to the embodiment of the present invention.

FIG. 4 is a flowchart showing processing contents of a CPU 1;

FIG. 5 is a configuration diagram showing another configuration of the optical system according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 CPU 2 ROM 3 RAM 4 Display 5 I / O 6 CCD 6A A / D 7 Fisheye lens 8 Conical mirror 50 Light source

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takuichi Nishimura 1-9-4 Otemachi, Chiyoda-ku, Tokyo Keidanren Kaikan The Iron and Steel Federation of Japan

Claims (5)

[Claims] An imaging device, a first optical path and a subject image guided to the imaging device via a second optical path different from the first optical path, and the imaging device forms two subject images on the imaging device. A distance measuring type comprising: an optical system; and information processing means for acquiring a distance to a subject based on a predetermined correspondence relationship from imaging positions of two subject images formed by the imaging device. Omnidirectional vision sensor. 2. The distance-measuring omnidirectional vision sensor according to claim 1, wherein the optical system includes a mirror for reflecting the subject image, a subject image reflected by the mirror, and a subject image directly from the subject. A distance-measuring omnidirectional visual sensor, comprising a lens for guiding the lens to the imaging device. 3. The distance-measuring omnidirectional vision sensor according to claim 2, wherein the mirror is arranged on an optical axis of the imaging device, and the information processing means is provided in a captured image area of the mirror itself. The imaging position of the subject image reflected by the mirror is detected, and the imaging position of the direct subject image is detected on a straight line connecting the imaging position corresponding to the optical axis of the imaging device and the imaging position of the reflected subject image. A distance-measuring omnidirectional vision sensor characterized in that: 4. The distance-measuring omnidirectional vision sensor according to claim 1, wherein the optical system has a first mirror and a second mirror that reflect the subject image, and the first mirror and the second mirror reflect the first and second mirrors. The first optical path and the second
A distance-measuring omnidirectional visual sensor characterized by forming an optical path. 5. The distance-measuring omnidirectional vision sensor according to claim 4, wherein the first mirror and the second mirror are arranged on an optical axis of the imaging device, and are reflected by the first mirror. A distance measuring type omnidirectional vision sensor, wherein an opening for guiding the subject image to the imaging device is provided in the second mirror.