JP3190365B2 - Underwater imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater imaging device.

[0002]

2. Description of the Related Art Conventionally, when photographing a subject in water where natural light does not reach, it has been practiced to irradiate the subject with an underwater illumination lamp and photograph it with an imaging device such as a TV camera. However, in water such as the sea and lakes, there are not only many suspended particles, but also TV
High-quality images could not be obtained when shooting a subject away from an imaging device such as a camera.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the influence of backscattered light from underwater floating particles.
It is an object of the present invention to provide an underwater imaging device capable of obtaining a high-quality image even when capturing an image of a distant subject.

[0004]

That is, the underwater imaging device of the present invention emits a light beam toward a subject underwater.
Underwater imaging comprising a light beam emitting device, a beam scanner that scans the light beam emitting device up, down, left and right within a predetermined solid angle range, and a reflected light detector that detects light reflected by the light beam hitting a subject. In the apparatus,
Maintain a predetermined distance between the light beam emitting device and the reflected light detector, and
The light beam radiated toward and reflected on the subject
The angle between the incident light incident on the reflected light detector and 15 °
The angle is set to 45 ° .

As described above, a beam scanner that scans a light beam emitted from a narrow beam light source up, down, left, and right within a predetermined solid angle range, and a reflected light detector that detects light reflected by the subject when the light hits a subject Is maintained at a predetermined interval, the intensity of the backscattered light of the suspended particles in the water incident on the reflected light detector becomes weak, and a high-quality image can be obtained even in a distant subject.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a laser oscillator, 2 is an optical fiber for guiding laser light, 3 is an optical collimator for emitting laser light as a narrow beam, and 4 is the direction of the optical collimator 3 within a solid angle θ. , A beam scanner that swings up, down, left and right, 5 is a subject, 6 is a TV camera as a reflected light detector having a viewing angle ω, and 7 is one of particles floating in water.

When the light beam emitted from the optical collimator 3 hits the floating particles 7, the floating particles 7 reflect the light and generate backscattered light. The scattered light has directivity. FIG. 2 shows this state. FIG.
Medium 8 indicates the directivity pattern of the backscattered light. In this way, the intensity of the backscattered light 8 is strong in the direction in which the light is incident,
The intensity is represented by Io in FIG. And the angle ρ
The scattering intensity Iρ in the direction shifted by only Io is smaller than Io.

Therefore, the intensity of the scattered light of the floating particles 7 entering the TV camera 6 as a reflected light detector can be reduced by maintaining the space between the optical collimator 3 and the TV camera 6 at a predetermined interval. it can. The angle ρ at which the light emitted from the optical collimator 3 and the light reflected by the light hitting the subject 5 are incident on the TV camera 6 is preferably in the range of about 15 ° to 45 °. If the angle ρ is smaller than 15 °, since the intensity of the backscattered light 8 does not decrease, a high-quality image cannot be obtained. Conversely, when the angle ρ exceeds 45 °,
The shaded portion of the subject 5 increases, and a high-quality image cannot be obtained.

On the other hand, in FIG. 1, the subject 5 has a sufficiently large size compared to the suspended particles 7, and generally,
Since the light is irregularly reflected, the intensity of the scattered light does not show strong directivity. Therefore, the TV camera 6 as the reflected light detector can detect the reflected light of the subject 5. At this time, the TV camera 6 also detects the reflected light from the floating particles 7, but the intensity is relatively small as described with reference to FIG. In addition, since the TV camera 6 is used as a reflected light detector, the position of the reflected light from the subject 5 and the position of the reflected light from the floating particles 7 formed on the imaging surface are far from each other. 5 does not hinder the image. Therefore, a high-quality image of the subject 5 can be obtained by extracting the imaging position of relatively strong light as a true signal.

[0010]

As described above, according to the present invention, the present invention provides the photographic in water
A light beam emitting device for emitting a light beam toward a body,
Consisting of a light beam emitting device and the beam scanner to scan horizontally and vertically within a predetermined solid angle, light beam and the reflected light detector for detecting light reflected against the object
In water imaging device, to maintain a between the reflected light detector and the light beam emitting device at predetermined intervals, and the light
Light beam emitted from the beam emitting device toward the subject
Is reflected on the subject and enters the reflected light detector
Since the angle between the incident light and the incident light is 15 ° to 45 °,
Such excellent effects can be obtained. That is, the light beam
The light beam emitted from the radiation device (optical collimator)
When hit by airborne particles, they will reflect light back
Although scattered light is generated, the back scattered light has directivity.
The intensity of the backscattered light is the intensity Io in the direction in which the light is incident.
And the scattering intensity Iρ in the direction shifted by an angle ρ from it.
Is smaller than the intensity Io, so that the reflected light detector
The intensity of the backscattered light incident on the
By maintaining a predetermined distance from the light detector,
Can be frustrated. Therefore, from the light beam emitting device
The light beam emitted toward the subject and the light
The angle between the reflected light and the incident light that enters the reflected light detector
By setting the angle to 15 ° to 45 °, back scattering of suspended particles
It is hardly affected by light, even for distant subjects
Excellent operation and effect that high quality images can be obtained
You.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an underwater imaging device according to the present invention.

FIG. 2 is an explanatory diagram of a directivity pattern of backscattered light intensity of suspended particles in water.

[Explanation of symbols]

 3 Optical collimator 4 Beam scanner 5 Subject 6 Reflected light detector

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04N 5/222-5/257 H01S 3/00

Claims (1)

(57) [Claims] A light beam is emitted underwater toward a subject.
Water consisting of a light beam emitting device for elevation, a beam scanner to scan horizontally and vertically the light beam emitting device within a predetermined solid angle, light beam and the reflected light detector for detecting light reflected against the object In the imaging device,
Maintaining a predetermined distance between the light beam emitting device and the reflected light detector, and capturing an image from the light beam emitting device.
Light beam emitted to the body and reflected upon the subject
And the angle between the reflected light and the incident light incident on the reflected light detector is 15
An underwater imaging device, characterized in that the angle is between 45 ° and 45 ° .