JP2000196924A - Weld image pickup device using double laser illumination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weld image pickup device using such laser illumination that the period of a pulse laser is synchronized to the frame period of a CCD with a simple device and the number and arrangement of laser light irradiating devices which make the shadow smaller are made clear. SOLUTION: A weld image pickup device is provided with a CCD camera 2 which picks up the image of a weld 1, a frame signal extracting section 3 which extracts the frame signal of the camera 2, and a delay circuit 6 which delays the extracted frame signal. The image pickup device is also provided with a pulse laser light generator 7 which generates pulse laser light at the period of the delayed signal and two laser light irradiating devices 8 which irradiate the weld 1 and its vicinity with the pulse laser light generated from the generator 7. The planar arrangement of the CCD camera 2 and laser light irradiating devices 8 are adjusted in such a way that, when the welding direction is set at the position of 270 deg., the camera 2, first laser light irradiating device 8a, and second laser light irradiating device 8b are respectively arranged at the position of 0 deg., within the range of 20-45 deg., and within the range of 315-340 deg. in the clockwise direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welded image pickup device using laser illumination for imaging a welded portion with a significantly darker background.

[0002]

2. Description of the Related Art When an image of a weld that emits strong light is picked up by a CCD camera, halation occurs, and only a shining image of the weld is obtained. In order to observe the welding condition, the image of not only the strongly shining molten metal and high-temperature gas, but also the background of the welding rod, welding torch, weld metal already solidified, and the base metal are displayed on a single screen together with the welded part. Is required.

As a method of displaying such an extremely bright object and a dark object on the same screen, there is a composite image method. CC
D has the function of an electronic shutter by adjusting the charge storage time, and can adjust the shutter time. The high-speed shutter does not show dark parts, but bright parts are sharp.
With a low-speed shutter, a bright portion is saturated and flies, but a dark portion is sharp. A composite image can be created by cutting out only the good points from these two images. FIG. 6 is a diagram for explaining this principle, in which A shows a bright image and B shows a dark image. (A) is an image taken with a high-speed shutter, in which B is darkened and A is sharp.
(B) is an image taken with a low-speed shutter. A is saturated and flies, but B is clearly seen. (C) is an image obtained by extracting and combining the optimum images of the two.

Further, a high-intensity pulse laser is used as a light source,
There is a method of irradiating a dark background to simultaneously image the weld and the background. In this case, the pulse laser is irradiated in synchronization with the charge accumulation period of the CCD. FIG. 7 is a diagram showing this state.
In this case, if the charge storage time is that of a normal CCD, the image of the welded portion is too bright with respect to the background image by the pulse laser, causing halation, and neither the background nor the image of the welded portion can be obtained. Therefore, the charge storage time is shortened by using an electronic shutter. FIG. 8 shows a case where the amount of light received is reduced by an electronic shutter so that the amount of light is substantially equal to the amount of reflected light of the pulse laser.
In this way, a clear image of the weld and the background can be obtained on the same screen. When a high-speed shutter is used in this way, CCD
It is necessary to accurately synchronize the frame period of the pulse laser with the period of the pulse laser.

[0005]

The method of synthesizing the above-mentioned screens is complicated and time-consuming, and the apparatus is expensive. The method using a pulsed laser is pulse period and CC
In order to synchronize the frame period of D, a high-precision clock device is used in the pulse laser generator, and the device is expensive. In addition, there is also a problem in that simply illuminating the image causes a shadow and a clear image cannot be obtained.

The present invention has been made to solve such a problem. That is, an object of the present invention is to synchronize the cycle of the pulse laser with the frame cycle of the CCD with a simple device, and further clarify the number and arrangement of the laser irradiation devices for reducing shadows. It is to provide an imaging device.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a CCD camera for picking up an image of a welded portion, a frame signal extracting portion for extracting a frame signal from the CCD camera, and a frame signal extracting portion for extracting the frame signal. A delay circuit that delays a signal, a pulse laser generator that generates a pulse laser at the cycle of the delayed signal, and two laser irradiators that irradiate the pulse laser generated by the pulse laser generator to the vicinity of the weld. The CCD camera and the laser irradiator are arranged in a plane at a welding position of 270 degrees and the CCD camera is disposed at a position of 0 degrees clockwise, and the first laser irradiator is moved from 20 degrees to 45 degrees. The second laser irradiator is disposed in a range of 315 degrees to 340 degrees.

The frame signal of the CCD camera is taken out,
After delaying this frame signal by an integral multiple of the frame period,
A pulse laser is generated at the cycle of the delayed signal to irradiate the area around the weld. Since the period is the same as the frame period of the CCD even if the delay is an integer multiple, the period of the pulse laser is
Frame period. As shown in FIG. 8, the CCD charge accumulation time is shortened by the high-speed shutter, and the amount of light received from the reflected light of the pulse laser and the amount of light received from the welded portion are balanced so that the image in which the welded portion and the background are reflected can be obtained. Obtainable. Further, the planar arrangement of the CCD camera and the laser irradiator is set at 0 degrees clockwise with the welding direction set to 270 degrees.
By placing the CCD camera at the position of degrees, the first laser irradiator in the range of 20 to 45 degrees and the second laser irradiator in the range of 315 to 340 degrees, there is almost no shadow. A clear image can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a welding image pickup apparatus using dual laser illumination according to the embodiment. The welding portion 1 is an arc or plasma generated by welding, and the background is a torch 1a, a welding rod 1b, a deposited metal 1c, a base material 1d, and the like. The CCD camera 2 is arranged so as to project a background around the welded portion 1, and the frame signal extracting unit 3 extracts a frame signal from a video signal of the CCD camera 2. A video signal from the CCD camera 2 is recorded by a video deck 4a and displayed on a monitor 4b.

The 1 / n decounter 5 is a device for increasing the period by dividing the period of the frame signal by an integer. The frame cycle of the CCD camera 2 is 30 Hz, which is the same as the TV signal.
(Exactly 29.97 Hz) is used.
Usually, 30 Hz, 15 Hz, and 10 Hz of n = 1, 2, and 3 are used, and can be switched to any one by a switch. The delay circuit 6 outputs a signal having a cycle delayed by n (n is an integer and usually n = 1) cycles from the cycle output from the 1 / n decounter 5. Thereby, a delay period less than one period can be eliminated, and the frame period and the pulse laser period can be reliably synchronized. For example, in the case of an Nd-YAG laser, the pulse laser generator 7 discharges and excites a flash lamp in a pulsed manner to oscillate. By performing the cycle of the exciting pulse by the signal of the delay circuit 6, the pulse lasers of 30 Hz, 15 Hz, and 10 Hz are supplied to the first laser irradiator 8a and the second laser irradiator 8a.
b. The first and second laser irradiators 8a and 8b irradiate the welded portion 1 and the background by diffusing the pulse laser generated by the pulse laser generator 7,
A pulsed laser is diffused by irradiating a pulse lens at the tip.

FIG. 2 is a diagram showing the synchronization between the frame cycle of the CCD camera 2 and the cycle of the pulse laser. A shows a case where the CCD frame period during normal charge accumulation where the electronic shutter does not operate is 30 Hz. B shows a case where the charge accumulation time is greatly reduced at the time of a high-speed shutter, and an image of the welded portion 1 is taken.
The period remains unchanged at 30 Hz. C is pulsed laser 3
A cycle generated in synchronization with 0 Hz is shown. D shows a case where the pulse laser is generated at 15 Hz and is synchronized with the frame signal, and E shows a case where the pulse laser is generated at 10 Hz and is synchronized with the frame signal. If the frequency is reduced as in D and E, the pulse laser generator 7 is simplified and the cost is reduced. However, on the screen not irradiated with the laser, only the welded portion 1 is present, and the screen flickers and the sharpness is reduced. In this case, an image one cycle before the irradiation of the pulse laser is stored in the memory, and the stored image is displayed at a period when the pulse laser is not irradiated.
A clear image without flicker is obtained. And always one
Since the image before the cycle is used, it can almost follow the change of the welded portion 1, so that the use value is large.

Next, the CCD camera 2 and the first and second laser irradiators 8a and 8a for obtaining a clear whole image with little shadow are provided.
8b will be described. FIG. 3 shows a side view of the CCD camera 2 and the laser irradiator 8, and FIGS. 4 and 5 show plan views. FIG. 4 shows a case in which one laser irradiator 8 is used, in which a large shadow is formed as indicated by a hatched portion, and an image of the welding rod 1b or the like included in the shadow cannot be obtained. FIG. 5 shows a dual laser irradiation method of the present embodiment. As shown in FIG. 3, the CCD camera 2 is about 30 degrees with respect to the plane of the base material 1d, and the first and second laser irradiators 8a and 8b are 30 to 30 degrees.
A range of 45 degrees is appropriate. As shown in FIG. 5, the CCD camera 2 is arranged at a position of 0 degrees clockwise with a welding direction of 270 degrees, and the first laser irradiator 8a is set at 20 degrees.
The second laser irradiator 8b is arranged in a range from 315 degrees to 340 degrees. With this illumination arrangement, the shadow range indicated by the oblique line can be generated at a position where the shadow is the smallest and has no influence.

[0013]

As described above, according to the present invention, by generating a pulse laser using the frame period of the CCD camera, the frame period of the CCD camera and the pulse laser can be synchronized with a simple system. Also, C
By properly arranging the CD camera and the two laser irradiators, the shadow can be generated at a position where the shadow is small and unaffected.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating frequency synchronization according to the embodiment;

FIG. 3 is a diagram showing a side arrangement of a CCD camera and a laser irradiator.

FIG. 4 is a diagram showing a screen on which a large shadow appears when one laser irradiator is used.

FIG. 5 is a diagram showing a planar arrangement of a dual laser irradiator of the present embodiment.

FIG. 6 is an explanatory diagram of a conventional composite image method.

FIG. 7 is a diagram illustrating a normal CCD charge accumulation time.

FIG. 8 is a diagram showing synchronization between a CCD using a high-speed electronic shutter and a pulse laser.

[Explanation of symbols]

 Reference Signs List 1 welding part 1a torch 1b welding rod 1c welding metal 1d base material 2 CCD camera 3 frame signal extracting part 4a video deck 4b monitor 5 1 / n decounter 6 delay circuit 7 pulse laser generator 8 laser irradiator 8a first laser irradiation 8b Second laser irradiator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Kojima 1 Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishikawashima-Harima Heavy Industries, Ltd. Yokohama Engineering Center (72) Inventor Fumio Matsuzaka Toyosu 3, Koto-ku, Tokyo No. 1-115, Ishikawajima-Harima Heavy Industries, Ltd. Tojin Technical Center (72) Inventor Taketo Yagi 1 Shinnakaharacho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Ishikawajima-Harima Heavy Industries, Ltd. F-term (Reference) 5C022 AA01 AB12 AB15 AB17 AB51 AB64 AB68 AC01 AC42 CA00

Claims (1)

[Claims] 1. A CCD camera for picking up an image of a welded portion, a frame signal extracting unit for extracting a frame signal of the CCD camera, a delay circuit for delaying the extracted frame signal, and a pulse laser having a cycle of the delayed signal. And a pulse laser generated by the pulse laser generator, which irradiates the vicinity of the weld with a pulse laser generator.
Laser irradiators, the CCD camera and the laser irradiator are arranged in a plane, the welding direction is 270 degrees, the CCD camera is disposed at a position of 0 degrees clockwise, and the first laser irradiator is set at 20 degrees. A welding image apparatus using double laser illumination, wherein the welding device is arranged in a range of from 45 degrees to 45 degrees and the second laser irradiator is arranged in a range of from 315 degrees to 340 degrees.