JP3265549B2 - Distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional image measuring apparatus capable of obtaining a three-dimensional coordinate position of a measured object without using triangulation.

[0002]

2. Description of the Related Art As a distance measuring method, a method utilizing triangulation is generally used.

FIG. 5 shows a distance measuring method based on triangulation, which comprises a light projector 10, an imaging lens 20, and a photoelectric conversion element 30.

The object to be measured 40 has three different positions A,
Assuming that they are at B and C, their distances L1, L2 and L
Consider the case of measuring 3. The light beam L emitted from the light projector 10 enters the object 40 and is scattered on the surface of the object 40. This scattered light is imaged on the photoelectric conversion element 30 by the imaging lens 20. These imaging positions are determined by the object 40
When the object is at position A, an image is formed at position a, when the object is at position B, an image is formed at position b, and when the object is at position C, position c is obtained. Is imaged. Since the relationship between the x-coordinate of the imaging position and the z-direction position of the object 40 is uniquely determined by the geometric relationship, it is possible to measure the distances L1, L2, L3 using these relationships. it can.

[0005]

In the above-mentioned triangulation, the projector 10 and the photoelectric conversion element 30 are restricted due to the principle limitation.
Must be kept at a constant angle of 0 degree or more.
, Such as a shadow portion where the light from the projector 10 does not hit,
Alternatively, it has been impossible to measure the distance of a portion that cannot be seen from the photoelectric conversion element 30 side.

Therefore, in order to solve such a problem, as shown in FIG. 7A, the object to be measured 40 and the formed object image (real image) 40 'are arranged so as to be aligned. The photoelectric conversion element 30 has to be arranged in the direction of the object image 40 ', so that light cannot reach the photoelectric conversion element.

Therefore, other arrangements, for example, FIG.
If the arrangement shown in (b) is to be realized by a lens system, the design of the lens becomes very complicated and cannot be easily realized. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a distance measuring device capable of performing distance measurement with a simple configuration without an invisible portion.

[0008]

According to the present invention, a distance is measured using a hologram.

That is, according to the present invention, there is provided a light source for generating light, a hologram which functions to form a plurality of points arranged on the optical axis of the light generated from the light source on different points, and A plurality of light detecting means arranged at a plurality of positions to be imaged, and a distance measuring means for measuring a distance of an object to be measured arranged on the plurality of points based on outputs of the plurality of light detecting means. Be equipped.

According to the present invention, a plurality of points for measuring the distance of the object to be measured are provided on the optical axis of the light source. When the object to be measured is located at these points, light generated from the light source is scattered, and the scattered light is imaged by a hologram on any of the plurality of light detection means. Since the positional relationship between the plurality of light detection means and the plurality of points for measuring the distance of the measured object is known at the time of hologram exposure,
The distance to the object to be measured can be measured by determining which of the plurality of light detecting means has detected the brightest light.

Further, according to the present invention, a plurality of light sources for generating diffused light, a hologram acting to form a plurality of points arranged on a predetermined axis on different points, and a plurality of the holograms to be formed A plurality of light detecting means arranged at respective positions, and a distance measuring means for measuring a distance of an object to be measured arranged on the plurality of points based on outputs of the plurality of light detecting means. I do.

According to the invention, diffused light is emitted from a plurality of directions to a space near the plurality of points where the object to be measured is located. The light scattered on the surface of the object to be measured is imaged by a hologram on any of the plurality of light detecting means. Similarly to the above, since the positional relationship between the plurality of light detecting means and the plurality of points for measuring the distance to the measured object is known at the time of hologram exposure, which of the plurality of light detecting means detects the brightest light By determining whether the measurement has been performed, the distance of the measured object can be measured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.

This embodiment comprises a laser light source 1 for generating a light beam, a volume hologram 2, and a photodetector array 3.

The hologram 2 has an optical axis (z-axis) of a light beam.
It functions to image the plurality of points A, B, C, and D on the respective elements a, b, c, and d of the photodetector array 3 arranged in the x-axis direction.

The hologram 2 having such an operation is shown in FIG.
Is created as shown in FIG.

First, as shown in FIG. 1A, a point light source is arranged at a desired image forming point R1 to irradiate the hologram 2 with diffused light La, and one point is set at a distance measuring point S1 on the z-axis. Is irradiated on the hologram 2.

Further, as shown in FIG. 2B, an R2 point light source is arranged at an image forming point at a different position from the above position to irradiate the hologram 2 with the diffused light La and at another distance on the z axis. The hologram 2 is irradiated with light Lb converging at one point at the measurement point S2.

By repeating such a process a plurality of times, a hologram that forms n points on the optical axis at different positions can be subjected to multiple exposure.

Thus, as shown in FIG. 2C, if light is scattered at the measurement point S1, an image is formed at the image point R1. If light is scattered at the measurement point S2, the image is formed at the image point R2. A hologram 2 that forms an image can be created. Note that La may be converged light and Lb may be diffused light.

Each element of the photodetector array 3 is arranged so as to coincide with each image point of the hologram 2. In this case, since each imaging point is arranged on a straight line in the x direction, the photodetector array 3 is arranged on this straight line.

In such a configuration, when a light beam is generated from the laser light source 1 along the z-axis,
For example, if the measured object 4 is located at the position of the point A, the light beam is scattered on the surface of the measured object 4, and the scattered light is imaged by the hologram 2 at a predetermined imaging point a. Therefore, the light detecting element located at the image forming point a detects the brightest light as compared with the other light detecting elements.

The distance measuring section 5 includes the photodetector array 3
Is input, and the distance measuring unit 5 selects the light detection element that has detected the brightest light from the photoelectric conversion output of each light detection element, and measures the distance of the measured object 4 according to the selection result.

For example, the relationship between the x coordinate and the z coordinate can be arbitrarily determined at the time of hologram exposure. If the hologram exposure is performed so that the x coordinate value is proportional to the z coordinate value, the selected light detection can be performed. The distance to the object 4 can be calculated by multiplying the x coordinate value of the element (the photoelectric conversion element detecting the brightest light) by a certain constant.

As described above, in this embodiment, a plurality of measurement points are arranged on the optical axis of the light beam, and each scattered light is connected so that scattered light from each measurement point can be received by the photodetector by the hologram. Since the image position is set, the distance measurement without the invisible portion can be performed.

In the above embodiment, the image forming points are arranged on one straight line, but in principle, the image forming points can be arranged at arbitrary positions.

In the above embodiment, the light source 1 is arranged between the hologram 2 and the photodetector array 3, but the light source 1 is arranged between the hologram 2 and the object 4 to be measured. Is also good.

FIG. 3 shows another embodiment of the present invention.

In this embodiment, a diffused light source for generating diffused light is used as the light source 1. Measurement point A,
Arranging B, C, and D on the optical axis (z-axis) of the diffused light is the same as in the previous embodiment, thereby solving the problem of the conventional shadow position. The relationship between the measurement points A, B, C, and D and the imaging point, and the distance measurement method are the same as those in the previous embodiment.
FIG. 4 shows still another embodiment of the present invention.

In this embodiment, instead of making the optical axis of the diffused light coincide with the z-axis, the diffused light sources 1-1 to 1-n are arranged at a plurality of different positions, and the diffused light is transmitted to the distance measurement site from all directions. By irradiating, the problem of the invisible area by the conventional triangular method is solved. Also in this case, the relationship between the measurement points A, B, C, and D and the imaging points, the distance measurement method, and the like are the same as those in the previous embodiment.

[0032]

As described above, according to the present invention,
Multiple measurement points are arranged on the optical axis of the light beam, and each image forming position of the scattered light is set so that the hologram can receive the scattered light from each measurement point by the photodetector. With such a configuration, distance measurement without an invisible area can be performed.

In the present invention, the diffused light is illuminated from a plurality of positions to measure the distance by using the hologram so as to eliminate a portion where the light does not reach. It can measure the distance of a part or an invisible part.

[Brief description of the drawings]

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

FIG. 2 is a view showing a procedure of multiple exposure of a hologram.

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

FIG. 4 is a diagram showing still another embodiment of the present invention.

FIG. 5 is a diagram showing conventional triangulation.

FIG. 6 is a diagram illustrating a conventional problem.

FIG. 7 is a diagram illustrating a conventional problem.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 hologram 3 photodetector array 4 object to be measured 5 distance measuring unit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Moriya 1200 Manda, Hiratsuka-shi, Kanagawa Prefecture, Komatsu Ltd.Laboratory (72) Inventor Manabu Ando 1200, Manda, Hiratsuka-shi, Kanagawa Komatsu Ltd., Laboratory (56) References JP-A-58-102107 (JP, A) JP-A-4-356092 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01C 3/00-3/32

Claims (4)

(57) [Claims] A light source that generates light; a hologram that functions to form a plurality of points on the optical axis of light generated from the light source into different points; A plurality of light detecting means respectively arranged at a plurality of positions; and a distance measuring means for measuring a distance of an object to be measured arranged on the plurality of points based on outputs of the plurality of light detecting means. Distance measuring device. 2. A distance measuring apparatus according to claim 1, wherein said light source generates a light beam. 3. The distance measuring apparatus according to claim 1, wherein said light source generates diffused light. 4. A plurality of light sources for generating diffused light; a hologram acting to form a plurality of points arranged on a predetermined axis into different points; A distance measuring device, comprising: a plurality of light detecting means respectively arranged; and a distance measuring means for measuring a distance of an object to be measured arranged on the plurality of points based on outputs of the plurality of light detecting means.