JP2013108835A - Monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring device that uses eye-safe light for monitoring.SOLUTION: The monitoring device includes: a light transmission part for emitting a laser beam of a wavelength of 1400 nm or more; an imaging part 12 for receiving the light reflected by an object that receives the laser beam emitted from the light transmission part, to convert it to an image signal for output; and an image processing device for generating a monitoring image using the image signal from the imaging part 12. The imaging part 12 includes: an image intensifier 123 having an amplifying function of amplifying incident light and a shutter function; a wavelength conversion device 122 arranged closer to the light incident side than the image intensifier 123 to convert the wavelength of the reflection light to a wavelength range applicable to the image intensifier 123; and a camera 124 for receiving the light passing through the image intensifier 123.

Description

  The present invention relates to a monitoring device that is installed in, for example, a ship and monitors surrounding obstacles.

Conventionally, a monitoring device using a laser radar is known as a monitoring device that is installed in a ship or the like and detects an object over a wide range (see, for example, Patent Document 1).
For example, as shown in FIG. 5, the monitoring device using the laser radar includes a laser radar 51, a laser radar control unit 52 that controls the laser radar 51, and a display unit that displays an image signal obtained by the laser radar 51. 53. The laser radar 51 is configured such that the angle of attack and the rotation angle thereof are controlled by the turntable 54.

  In such a configuration, at the time of monitoring, pulse laser light is emitted from the laser head in the laser radar 51 to the periphery of the ship, and this laser light reaches the monitoring target A and the reflected light is reflected by the laser radar 51. An image is captured by a camera provided inside, and the image signal is output to the display unit 53, whereby the object A existing around is displayed on the display unit 53.

  Conventionally, there has been proposed a monitoring apparatus provided with an image intensifier (Image Intensifier) which is a device having a shutter function and an optical amplification function in front of the camera. In such a monitoring apparatus, unnecessary reflected light from raindrops or the like is avoided by opening the shutter of the image intensifier at the timing when the reflected light from the monitoring target reaches the camera.

Japanese Patent Laid-Open No. 11-102001

  In the monitoring apparatus having the image intensifier as described above, the wavelength band of the laser light emitted from the laser head is a wavelength band suitable for the characteristics of the image intensifier, and is mainly a wavelength band of about 1100 nm or less. Are used. FIG. 7 shows the wavelength and quantum efficiency characteristics of image intensifiers that are currently commercially available. As shown in FIG. 7, the current application wavelength of the image intensifier is about 200 nm or more and about 1100 nm or less, and the laser used in the laser radar has a wavelength of 1100 nm or less according to this characteristic.

  In recent years, there has been a demand for a monitoring device that uses eye-safe light with high safety for eyes and skin, in other words, laser light having a wavelength of 1400 nm or more. For example, in the JIS standard (JIS C 6802), as shown in FIG. 6, the maximum permissible exposure (MPE) is defined as the maximum exposure that can be exposed to the eyes or skin without being damaged. As shown in FIG. 6, the eye-safe wavelength has an advantage that the output power can be increased relatively easily because the maximum allowable exposure amount is twice or more as compared with the near-infrared wavelength.

  However, as shown in FIG. 7, currently available image intensifiers have a maximum adaptable wavelength of about 1100 nm at most, and if eye-safe laser light is used as a light source, image intensifiers of It will be out of the applicable range, and it will be difficult to obtain a conventional monitoring image.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the monitoring apparatus which can implement | achieve monitoring using eye safe light.

In order to solve the above problems, the present invention employs the following means.
The present invention provides a light transmitting unit that emits laser light having a wavelength band of 1400 nm or more, and the laser light emitted from the light transmitting unit reaches an object, receives reflected light reflected by the object, and receives an image. Imaging means for converting to a signal and outputting; and monitoring image creation means for creating a monitoring image using an image signal from the imaging means, wherein the imaging means includes an amplification function and a shutter function for amplifying incident light; An image intensifier comprising: a wavelength conversion unit that is disposed closer to the light incident side than the image intensifier, and converts the wavelength of the reflected light to a wavelength range applicable to the image intensifier; There is provided a monitoring device including light receiving means for receiving light that has passed through an image intensifier.

According to such a configuration, the eye-safe laser light that is light having a wavelength band of 1400 nm or more emitted from the light transmitting means is reflected by reaching the object. The reflected wave is guided to a wavelength conversion unit in the imaging unit, and the wavelength is converted into a wavelength range suitable for an image intensifier. The reflected wave whose wavelength has been converted is guided to the image intensifier, is amplified by the amplification function, and is guided to the light receiving means through the shutter. The light guided to the light receiving means is converted into an image signal, and a monitoring image is created by the monitoring image creating means based on the image signal.
In this way, on the light incident side of the image intensifier having an amplification function for amplifying incident light and a shutter function, wavelength conversion for converting the wavelength of the reflected light from the object into the applicable range of the image intensifier Since the means is provided, the wavelength band of the reflected light incident on the image intensifier is applied to the image intensifier even when using eye-safe laser light that is outside the applicable range of the image intensifier. It can be made possible. Thereby, an eye safe laser beam and an image intensifier can be used together.

  In the monitoring apparatus, the imaging unit is disposed closer to the light incident side than the wavelength conversion unit, and is interposed between the first optical system that collects incident light, and the wavelength conversion unit and the image intensifier. And a second optical system that expands the diameter of incident light.

  According to such a configuration, since the first optical system for condensing light is provided on the light incident side with respect to the wavelength conversion unit, the diameter of the light guided to the wavelength conversion unit can be reduced. The power density of the incident light to the wavelength conversion means can be increased. As a result, it is possible to increase the power density of the light output from the wavelength conversion means. In addition, since the second optical system for expanding the light diameter is provided between the wavelength converting means and the image intensifier, it is possible to increase the diameter of the light incident on the image intensifier. Become.

  The monitoring apparatus may further include an adjusting unit that adjusts a position of at least one of the first optical system and the second optical system in the optical axis direction.

  By changing the position of the first optical system in the optical axis direction, the light collection rate to the wavelength conversion means can be changed, and by changing the position of the second optical system, the light to the image intensifier can be changed. It becomes possible to change the enlargement ratio of the diameter of the. By changing the light collection rate and the magnification rate, the quality of the finally obtained monitoring image can be changed. Therefore, by adjusting the positions of the first optical system and the second optical system according to the monitoring image, it is possible to customize the quality of the monitoring image (for example, luminance, resolution, etc.).

  According to the present invention, there is an effect that monitoring using eye-safe light can be realized.

1 is a block diagram schematically showing an overall configuration of a monitoring device according to a first embodiment of the present invention. It is the figure which showed schematically the internal structure of the imaging part shown in FIG. It is the figure which showed schematically the internal structure of the imaging part with which the monitoring apparatus which concerns on 2nd Embodiment of this invention is provided. It is the figure which showed the relationship between the input power density and output power density of IR converter. It is the figure which showed the whole structure of the conventional monitoring apparatus. It is the figure which showed the relationship between the wavelength defined by JIS specification (JIS C 6802), and the maximum permissible exposure amount. It is the figure which showed an example of the characteristic of an image intensifier.

[First Embodiment]
Hereinafter, a monitoring device according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing the overall configuration of the monitoring apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the monitoring device according to the present embodiment includes a laser radar 1, a laser radar control unit 2, a control device 3, and a display device (display means) 4.

The laser radar 1 includes a light transmission unit (light transmission unit) 11 and an imaging unit (imaging unit) 12.
The light transmission unit 11 includes, for example, a laser light source 111 that continuously emits pulsed laser light, a light transmission lens 112 that irradiates a target with the laser light emitted from the laser light source 111, and a light transmission lens 112. A light transmission lens actuator (not shown) for adjusting the angle is provided as a main component.
The laser light source 111 is supplied with power from a laser power source 26 in the laser radar control unit 2 described later, and continuously emits pulsed laser light. Laser light emitted from the laser light source 111 is, for example, eye-safe laser light belonging to a wavelength band of 1400 nm or more. Note that the user can arbitrarily select which wavelength of laser light to use in a wavelength band of 1400 nm or more.

  The light transmission lens actuator adjusts the position of the light transmission lens 112 based on a control signal supplied from a laser radar control unit 2 described later. Thereby, the angle of the laser beam incident on the light transmission lens 112 can be adjusted, and the laser beam can be emitted in a desired range.

As shown in FIG. 2, for example, the imaging unit 12 includes a zoom lens 121, a wavelength conversion device (wavelength conversion unit) 122, an image intensifier 123, and a camera (light reception unit) 124.
The zoom lens 121 collects the reflected light emitted from the light transmitting unit 11 and reflected by the target and guides it to the wavelength conversion device 122.

  The wavelength conversion device 122 converts the wavelength of the input light into the applicable wavelength range of the image intensifier 123 and outputs it. A specific example of the wavelength conversion device 122 is an IR converter (InfraRed Converter). In the present embodiment, an IR converter having the ability to convert incident light of about 1495 nm to 1540 nm into light having a wavelength between 950 nm and 1075 nm and output the light is employed.

The image intensifier 123 has an amplification function for amplifying incident light and a shutter function. The shutter of the image intensifier 123 is driven by a shutter control unit 24 provided in a laser radar control unit 2 described later.
The camera 124 takes in the light from the image intensifier 123, converts it into an electrical signal, generates an image signal, and this image signal is an image processing device (monitoring image creation means) 25 in the laser radar control unit 2 described later. Output to.
Further, the image intensifier 123 and the camera 124 may be provided individually, or an integrated ICCD camera may be used.
Such a laser radar 1 has a structure in which the rotation angle and the attack angle are adjusted to desired angles by the swivel base 5.

The laser radar control unit 2 includes a turntable 5 that adjusts the light transmission unit 11, the imaging unit 12, the rotation angle of the laser radar 1, and the like based on various control signals supplied from the control device 3. Control. The laser radar control unit 2 includes, for example, a turntable drive unit 21, a synchronization circuit 22, a control signal conversion device 23, a shutter control unit 24, an image processing device 25, a laser power source 26, and the like.
The control device 3 generates various control signals for controlling the laser radar 1, outputs the generated various control signals to the laser radar control unit 2, and displays a monitoring image supplied from the laser radar control unit 2 as a display device Output to 4.

The control device 3 controls the laser radar control unit 2 so that pulsed laser light is continuously emitted from the laser light source 111 at a predetermined pulse period.
In addition, the control device 3 matches the timing when the pulsed laser light continuously emitted from the laser light source 111 reaches an object existing at a desired monitoring distance and the reflected light reflected by the object arrives. Then, the laser radar control unit 2 is controlled so that the shutter of the image intensifier 123 is opened.

The image processing device 25 in the laser radar control unit 2 accumulates image signals output from the camera 124 (see FIG. 2) of the imaging unit 12 over a predetermined period, and superimposes the accumulated image signals. Create a surveillance image. The monitoring image created by the image processing device 25 is configured to be output to the display device 4 via the control device 3.
The display device 4 includes a display monitor (not shown) that displays a monitoring image or the like output from the control device 3.

Next, the operation of the monitoring apparatus according to this embodiment will be described.
First, at the time of monitoring, the control device 3 uses a synchronous control signal necessary for continuously emitting pulsed laser light at a predetermined pulse period, and a pulsed laser continuously emitted from the laser light source 111. The light reaches the object at the position of the monitoring distance, and generates a shutter drive signal and the like for the camera 124 to capture only the reflected light reflected, and outputs these to the laser radar control unit 2.

The synchronization control signal and the shutter drive signal output from the control device 3 are respectively supplied to the synchronization circuit 22 and the shutter control unit 24 via the control signal conversion device 23 in the laser radar control unit 2.
The synchronization circuit 22 generates a synchronization signal for synchronizing the transmission and reception of the laser beam based on the input synchronization control signal, and outputs this synchronization signal to the laser power source 26 and the shutter control unit 24.
The laser power source 26 generates an operation signal of the laser light source 111 in the light transmission unit 11 included in the laser radar 1 based on the synchronization signal supplied from the synchronization circuit 22, and drives the laser light source 111 based on the operation signal. To do.
On the other hand, the shutter control unit 24 controls the shutter in the image intensifier 123 of the imaging unit 12 included in the laser radar 1 based on the shutter drive signal input from the control device 3 and the synchronization signal input from the synchronization circuit 22. To drive.

  As a result, first, the semiconductor laser light source 111 is driven by the laser power source 26, whereby pulsed laser light is continuously emitted from the laser light source 111 at a predetermined pulse period. The laser light is expanded to an irradiation area having a predetermined range by the light transmission lens 112, is emitted to the outside, and the laser light reflected by an object existing in the irradiation area is guided to the imaging unit 12. It will be.

The reflected light guided to the imaging unit 12 enters the wavelength conversion device 122 through the light receiving lens 121 shown in FIG. The incident light is converted into a wavelength range suitable for the image intensifier 123 by the wavelength conversion device 122 and then guided to the image intensifier 123.
In the image intensifier 123, the shutter control unit 24 (see FIG. 1) drives the shutter based on the shutter drive signal from the control device 3, and is reflected by an object existing at a predetermined monitoring distance. Only the laser light is guided to the camera 124. At this time, the light guided to the camera 124 is amplified by the amplification function of the image intensifier 123.

Then, the reflected light information captured by the camera 124 is converted into an image signal that is an electrical signal and output to the image processing device 25 in the laser radar control unit 2. The image processing device 25 accumulates a plurality of image signals output from the camera 124 during a predetermined period, and creates a monitoring image with high brightness by integrating (superimposing) the accumulated plurality of images. Output.
The monitoring image created by the image processing device 25 is input to the control device 3 via the control signal conversion device 23. The control device 3 outputs the input monitoring image to the display device 4. Thereby, for example, the outline of the suspended matter at the position of the monitoring distance is clearly displayed (high brightness) on the display monitor of the display device 4 as visible information. As a result, it is possible for a crew member or the like to check the image displayed on the display monitor, thereby acquiring information such as the shape and size of the object existing in the irradiation area.

  As described above, according to the monitoring apparatus according to the present embodiment, the imaging unit 12 of the laser radar 1 includes the wavelength conversion device 122 that converts the wavelength of incident light on the light incident side of the image intensifier 123. Since it is provided, the wavelength of the light incident on the image intensifier 123 can be set to the wavelength range of the application range of the image intensifier 123. As a result, the eye-safe laser light having a wavelength of 1400 nm or more and the image intensifier 123 can be used in combination, and a monitoring image having the same quality as the conventional one can be obtained while improving safety.

  Table 1 below shows the performance (sensor sensitivity + camera gain) when only the camera 124 is used without using the IR converter and the image intensifier, and the IR converter and the image intensifier as the wavelength conversion device 122. The performance of the camera 124 when used together with 123 is shown in comparison. Here, the case where an InGaAs camera is used as the camera 124 is illustrated.

As shown in Table 1 above, when the combination of the IR converter and the image intensifier is used, the performance (sensor sensitivity + camera gain) can be increased by 10 ³ times compared to the case where only the camera is used.

[Second Embodiment]
Next, a monitoring device according to a second embodiment of the present invention will be described. As shown in FIG. 3, the monitoring device according to the present embodiment employs a first lens (first optical system) 130 instead of the light receiving lens 121 shown in FIG. 2 in the imaging unit 12 ′, and The point which arrange | positions the 2nd lens (2nd optical system) 132 which expands the diameter of incident light between the wavelength conversion device 122 and the image intensifier 123 differs from the monitoring apparatus which concerns on 1st Embodiment mentioned above.
The first lens 130 is provided for the purpose of focusing on the fluorescent surface 126 of the IR converter that is the wavelength conversion device 122, and the second lens 132 is used to image the diameter of the light collected by the first lens 130. It is provided for the purpose of enlarging the light receiving surface size of the tensiifier 123.

Here, when an IR converter is employed as the wavelength conversion device 122, the output power density of the IR converter depends on the input power density of the IR converter. FIG. 4 is a diagram showing the relationship between the input power density and the output power density of the IR converter, with the horizontal axis indicating the input power density and the vertical axis indicating the output power density.
Further, due to the characteristics of the image intensifier 123, the power density of light incident on the image intensifier 123 needs to be equal to or higher than the power density corresponding to the minimum sensitivity exposure amount of the image intensifier 123. Then, the output power density of the wavelength conversion device 122 needs to be equal to or higher than the power density corresponding to the minimum sensitivity exposure amount of the image intensifier 123 (for example, the value A in FIG. 4). The density needs to be greater than or equal to the value B in FIG.

  In order to increase the power density of the light incident on the IR converter, the output power density of the laser light emitted from the light transmitting unit 11 may be increased, but the output value is limited as shown in FIG. . Therefore, in the present embodiment, the first lens 130 that condenses incident light on the phosphor screen 126 of the IR converter is provided on the light incident side of the IR converter, and the input power density to the IR converter is increased by condensing the light. Trying to increase.

  Thereby, it is possible to easily increase the input power density at the phosphor screen 126 of the IR converter without adjusting the output in the light transmitter 11. In addition, since the resolution | decomposability of the image projected on the fluorescent screen 126 falls by condensing light, it is necessary to examine the condensing degree of the 1st lens 130 previously.

  In addition, since the second lens 132 for enlarging the diameter of the light is disposed between the wavelength conversion device 122 and the image intensifier 123, the light condensed on the phosphor screen of the wavelength conversion device 122 It is possible to guide the light to the light receiving surface of the image intensifier 123. Here, the magnification ratio of the light by the second lens 132 is preferably determined according to the size of the light receiving surface of the image intensifier 123.

As described above, according to the monitoring apparatus according to the present embodiment, since the first lens 130 is provided on the light input side of the wavelength conversion device 122, the input power density of light to the wavelength conversion device 122 is increased. Is possible. As a result, the output power density of the light of the wavelength conversion device 122 can be increased, and even if eye-safe laser light is used, the power density of the light guided to the image intensifier 123 can be increased, and the image is more clearly displayed. Can be expected.
In addition, since the second lens 132 is disposed between the wavelength conversion device 122 and the image intensifier 123, the diameter of the light reduced by being condensed can be expanded again and guided to the image intensifier 123. The size of the image can be made as usual.

  Further, the monitoring apparatus according to the present embodiment includes a lens position adjustment mechanism (adjustment unit) (not shown) that can change the position of at least one of the first lens 130 and the second lens 132 in the optical axis direction. Also good.

Thus, by having a mechanism for adjusting the lens position, for example, it is possible to adjust the lens position while confirming the monitoring image. For example, when the resolution is more worrisome than the luminance, the position of the first lens 130 may be adjusted so that the degree of light collection by the first lens 130 is reduced. Thus, the quality of the monitoring image displayed on the display device 4 can be customized by adjusting the positions of the first lens 130 and the second lens 132 according to the state of the monitoring image displayed on the display device 4. It becomes possible.
Further, a control unit that drives the lens position adjustment mechanism according to the quality of the monitoring image may be provided to automatically adjust the image quality.

DESCRIPTION OF SYMBOLS 1 Laser radar 2 Laser radar control part 3 Control apparatus 4 Display apparatus 5 Turntable 11 Light transmission part 12, 12 'Image pick-up part 21 Turntable drive part 22 Synchronous circuit 23 Control signal converter 24 Shutter control part 25 Image processing apparatus 26 Laser Power supply 111 Laser light source 112 Transmitting lens 121 Zoom lens 122 Wavelength conversion device 123 Image intensifier 124 Camera 130 First lens 132 Second lens

Claims (3)

Light transmitting means for emitting laser light having a wavelength band of 1400 nm or more;
Imaging means for receiving the reflected light reflected by the object when the laser light emitted from the light transmitting means reaches an object, and converting the image into an image signal and outputting the image signal;
A monitoring image creating means for creating a monitoring image using an image signal from the imaging means,
The imaging means includes
An image intensifier having an amplification function for amplifying incident light and a shutter function;
Wavelength converting means that is disposed on the light incident side of the image intensifier and converts the wavelength of the reflected light into a wavelength range applicable to the image intensifier;
And a light receiving means for receiving the light that has passed through the image intensifier. The imaging means includes
A first optical system that is disposed on the light incident side of the wavelength converting means and condenses incident light;
The monitoring apparatus according to claim 1, further comprising: a second optical system that is disposed between the wavelength conversion unit and the image intensifier and expands a diameter of incident light.   The monitoring apparatus according to claim 2, further comprising an adjusting unit that adjusts a position of at least one of the first optical system and the second optical system in the optical axis direction.

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