JPH01241274A - Image pickup device for object - Google Patents

Abstract

PURPOSE:To obtain an object image accurately without being affected by an external disturbance light by passing only the band component including a pulse oscillating frequency among received light signal component obtained through the same wavelength component as that of a laser light among the reflected laser beam. CONSTITUTION:A reflected laser beam from an induction line L and its circumferential part is made incident in an interference filter 16 and the same wavelength component as the wavelength of the pulse laser light is transmitted. A condenser lens 17 and a photodetector 18 are installed on an output optical path of the filter 16 to output a photodetection signal in response to the light intensity of the component of the reflected laser beam transmitted through the filter 18. An amplifier circuit 19 is connected to the detector 18 to be acted like a BPF function for the same frequency component as the pulse oscillation frequency of the pulse laser output device 10. The output is inputted to an image forming means 21 via the A/D conversion circuit 20 and stored as the picture data. The means 21 has X, Y direction address counters 23, 24 to store a digital photodetection signal onto a picture memory 22 corresponding to the radiation position of the pulse laser beam.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is applied to, for example, an unmanned vehicle that runs by detecting a guidance line and detects the position of the guidance line while driving. Subject W11 whose image is obtained! Regarding IV & placement.

(Prior Art) There are various driving methods for unmanned vehicles, and among these, in the method of driving along a guidance line, the position of this guidance line is detected. FIG. 11 is a configuration diagram of an unmanned vehicle using the Kakaru driving method, in which an unmanned regular vehicle 111 is equipped with a television camera 2, and the #il signal from the television camera 2 is digitized and subjected to image processing. The image is sent to the image memory of bag M3. Then, this image 1g1 processing device 3 recognizes the position of the guide line L from the image data,
The deviation between this position and the reference line position S is determined and sent to the travel control unit 4. Note that the image data stored in the image memory is displayed on the monitor television 5. The travel control device 4 determines the steering amount from the input deviation value and controls the unmanned vehicle 1 to travel along the guide line.

However, in the above configuration, since the guidance line L is imaged by the television camera 2, it is strongly influenced by ambient light, and the guidance line L cannot be clearly captured as shown on the television monitor 5 in the figure. I won't be able to do that. For example, when light from an indoor fluorescent lamp enters directly into the television camera 2, the image becomes a mixture of the image of the guide line L and the fluorescent lamp @G, as shown in Fig. 12(a). It becomes difficult to accurately recognize the guide line L. In addition, when water accumulates on the guide line L outdoors and sunlight is reflected on the water and enters the television camera 2, the image will appear on the guide line L as shown in FIG. 12(b). iK becomes completely difficult.

(Problems to be Solved by the Invention) Even when the guide line L is imaged as described above, it is not possible to accurately obtain an image of the guide line L due to the influence of ambient light.

Therefore, it is an object of the present invention to provide a subject I5@H''l that can accurately obtain a subject image without being affected by ambient light.

[Structure of the Invention] (Means for Solving the Problem A pulse laser output device that emits pulsed laser light, an interference filter that passes the wavelength component of the reflected laser light that is the same as the wavelength of the laser light, and a pulsed signal component that passes through the interference filter. A photographic exercise that attempts to achieve the above object by providing a bandpass filter circuit that passes only a band component containing the pulse oscillation frequency of a laser output device, and an image creation means that obtains a subject image from the filter output of this bandpass filter circuit. @It is a device.

(Function) By providing such a means, when a pulsed laser beam is irradiated onto a subject, a component of the same wavelength as the laser beam among the reflected laser beams passes through the interference filter,
Among the received light signal components obtained by passing through this interference filter, a band component including the pulse oscillation frequency of the pulse laser output device passes through a bandpass filter circuit, and an image forming means obtains a subject image from the output of this filter.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a subject imaging device, and shows a case where the subject imaging device is applied to a guide line L as a subject. In the figure, 10 is a pulse laser output Hffi, and this device 10 outputs laser light with two wavelengths at a pulse oscillation frequency ω0. Its composition is laser diode 11
and a laser diode drive device 12. Note that the pulsed laser output device 10 may have a configuration in which continuous output laser light is divided by a chopper and outputted as pulsed laser light. A collimator lens 13 is disposed on the laser optical path of the pulsed laser output device 1, and the pulsed laser is focused by the collimator lens 13 and sent to the XY scanner 14.
It is now sent to This XY scanner 14 is driven by an XY scanner drive circuit 15 and has a function of scanning the pulsed laser irradiation position in the X direction and the Y direction. To explain this scanning order, for example, the pulse laser irradiation position is first set to A (0,0), then moved in the X direction and scanned to A (256,0), then moved in the Y direction and scanned to A (256,0). (0,1), and from this position, it is moved again in the X direction and scanned to position A (256,1). In this way, one scan in the X direction and then movement in the Y direction are repeated sequentially until the pulse laser irradiation position reaches A (256, 256>) in terms of Rn.

On the other hand, reference numeral 16 denotes an interference filter, and this interference filter 16 receives the reflected laser light from the guiding line and the surrounding area, and among the reflected laser light, the wavelength of the pulsed laser light is λ0, as shown in FIG. It transmits the same wavelength λ0 component.

A condensing lens 17 and a photodetector 18 are arranged on the filter output optical path of this interference filter 16. Therefore, this photodetector 18 outputs a light reception signal corresponding to the light intensity of the component of the reflected laser light that has passed through the interference filter 16. An amplifier circuit is connected to the output end of the photodetector 18, and as shown in FIG. It has a function as a filter circuit. An image forming means 21 is connected to the output end of this amplifier circuit 19 via an A/D (analog/digital) conversion circuit 20.

This image forming means 21 receives the digital light reception signal from the A/D conversion circuit 20 and stores it as image data, and is composed of an image memory 22 and address counters 23 and 24 in each direction, that is, the X direction and the Y direction. has been done. The X-direction and Y-direction address counters 23 and 24 receive the X-direction and Y-direction scanning drive signals from the XY scanner drive circuit 15, respectively, and output digital light reception signals corresponding to the irradiation position of the pulsed laser beam to the image memory. 22 is to be memorized. Note that the digital light reception signal is input to the luminance input terminal (Z).

Next, the operation of the apparatus configured as described above will be explained.

When a pulsed laser is output from the laser diode 11 by driving the laser diode drive circuit 12, this pulsed laser is focused by the collimator lens 13 and
It is sent to the scanner 14.

This XY scanner 14 operates a pulse laser in the X direction and Y direction according to each scanning drive signal from the XY scanner drive circuit 15.
scan in the direction. In other words, the pulse laser is at the irradiation position A.
Move from (0,0) in the X direction to position A (256,
O>, and then moves in the X direction again from position @A (0, 1) to reach position fiA (256, 1). In this way, the pulse laser moves while moving in the Y direction every time it scans in the X direction. Note that in FIG. 1, a circular mark on the guide line L indicates irradiation with a single pulse laser.

When the pulse laser is irradiated in this manner, reflected laser light F from the guide line and the surrounding area enters the interference filter 16. As shown in Fig. 4, the intensity level of this reflected laser beam F fluctuates under the influence of external light, and a signal Q due to the reflected laser beam from this line L appears in a portion corresponding to the guiding line L. ing. However,
When this reflected laser light F enters the interference filter 16, only the wavelength λa is transmitted, and this transmitted laser light is sent to the photodetector 18. The photodetector 18 outputs a light reception signal Fa corresponding to the intensity of the received transmitted laser light. Incidentally, since this light reception signal Fa is obtained from the laser light transmitted through the interference filter 16, the influence of disturbance light has been removed, as shown in FIG. After this, the light reception signal Fa is transmitted to the amplifier circuit 1.
Sent to 9th. This amplifier circuit 19 passes only the same frequency as the pulse laser oscillation frequency ω0 of the pulse laser output device 10 out of the received light signal Fa by its bandpass filter circuit. Then, this passed signal is amplified and sent to the A/D conversion circuit 20. In other words, this amplifier circuit 19
As shown in FIG. 4, the output Fb is only the light reception signal from the laser reflected from the guide line. In other words, only the gray level of the guide line L portion is loud. Therefore, this light reception signal Fb is digitally converted by the A/D conversion circuit 20 and sent to the image forming means 21.

This image forming means 21 stores the received digital light reception signal at an address corresponding to the irradiation position of the pulse laser by each address counter 23, 24 in the X direction and the Y direction. For example, the pulse laser irradiation position A (0,0
) is stored at address B (0,0), and the digital light reception signal at pulse laser irradiation position A (256,0) is stored at address B (256,0).

When the digital light reception signal is stored in this way and the scanning of the pulsed laser is completed, one image data of the guide line L is stored in the image memory 22. Thereafter, the image data stored in the image memory 22 is read out and displayed on, for example, a monitor television, and the deviation between the position of the guidance line L and the reference line is determined and the driving control w is performed.
sent to in.

In this way, in the above embodiment, a pulsed laser beam is irradiated onto the guide line L, and among the received signal components obtained by the reflected laser beam, a band component including the pulse oscillation frequency of the pulsed laser is passed. Since the guide line L is obtained from the filter output, even if disturbance light from a fluorescent lamp or the sun hits the guide line, this disturbance light will pass through the band filter circuit at the pulse oscillation frequency ω of the pulse laser. It is possible to reliably capture only the reflected laser light from the guide line.

Therefore, the position of the guide line can be detected with high accuracy, and, for example, an unmanned vehicle can be accurately steered according to the guide line.

Furthermore, by combining the interference filter 16 with a band filter circuit, only the reflected laser beam is extracted, and only the pulse oscillation frequency component is extracted from this reflected laser beam, so it is possible to obtain an image of the guiding line L with higher accuracy. Accuracy.

Note that the guide line L may be formed into an uneven shape as shown in FIG. 5 to diffusely reflect the pulsed laser beam, or
Further, as shown in FIGS. 6 and 7, a device formed so as to reflect the irradiated pulsed laser beam in the same direction as the irradiation direction of the pulsed laser beam may be used. in this case,
FIG. 6 shows a combination of a glass bead 30 and a reflecting mirror 31, and FIG. 7 shows one whose surface is formed into a prism-cut shape. This guiding line L is written as 1-
If applied to the embodiment, the intensity of the reflected laser beam from the guide line L will be increased, and the position of the guide line L can be detected more reliably.

Next, an example of application of the device of the present invention will be explained. FIG. 8 is an overall configuration diagram when the Wi image is applied to a character 41 engraved on a steel plate 40 as a subject. The characters engraved on the steel plate 40 are formed by grooves as shown in FIG. 9(a). Therefore, when this groove is scanned with a pulsed laser beam, the reflected laser beam changes rapidly. Thus, when the reflected laser beam from the steel plate 40 is received, the image data of the character is stored in the image memory 22. In this case, if the incident angle of the pulsed laser beam is increased by tilting the steel plate 40, for example, as shown in FIG. 9(b), the intensity of the laser beam reflected from the groove of the steel plate 40 will increase. Characters can be detected more reliably.

Further, as another example of application, the present invention can be applied to detecting dust 43 on a silicon wafer 42 as shown in FIG. In this case, the change in the reflected laser beam on the dust 43 causes the dust 4
3 is detected.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, connect the XY scanner drive circuit 1 to the X-axis input terminal of the oscilloscope.
If you input the scanning drive signal in the X direction of 5 and the scanning drive signal in the Y direction to the Y-axis input terminal, and input the light reception signal to the luminance input terminal in this state, the guide line L will appear on the display screen of the oscilloscope. It is possible to display letters, letters, etc.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a subject transport device that can accurately obtain a subject image without being affected by ambient light.

[Brief explanation of the drawing]

1 to 7 are diagrams for explaining an embodiment of the object conveying device according to the present invention, in which FIG. 1 is an overall configuration diagram, FIG. 2 is a transmission characteristic diagram of an interference filter, and FIG. Figure 3 is a pass characteristic diagram of the bandpass filter circuit, Figure 4 is an operation timing diagram, Figures 5 to 7 are configuration diagrams of the guiding line, and Figure 8 is a diagram of the passage characteristics of the bandpass filter circuit.
FIGS. 10 to 10 are configuration diagrams showing application examples, and FIGS. 11 and 12 are diagrams for explaining the prior art. 10... Pulse laser output device, 11... Laser diode, 1.2... Laser diode drive circuit,
13... Collimator lens, 14... XY scanner, 15... XY scanner drive circuit, 16... Interference filter, 17... Condenser lens, 18... Photodetector, 19... Amplification circuit , 20...A/D'I!
L conversion circuit, 21... Image creation means, 22... Image memory, 23.24... Address counter, L... Guide line. Figure 1 22 Figure 3 0 Time "■ Figure 4 Figure 5 Figure 6 Figure 7 (a) (b) Figure 9 Figure 10 (a) (b) Figure 12

Claims (1)

[Claims] A subject imaging device that scans and irradiates a spot-shaped laser beam onto a subject and receives the reflected light to obtain an image of the subject, comprising: a pulse laser output device that irradiates the subject with pulse-shaped laser light; an interference filter that passes wavelength components that are the same as the wavelength of the laser beam, and a bandpass that passes only the band components that include the pulse oscillation frequency of the pulse laser output device among the received light signal components that pass through this interference filter. 1. A subject imaging device comprising: a filter circuit; and image creation means for obtaining the subject image from the filter output of the bandpass filter circuit.