JPH07159133A - Dimension measuring device - Google Patents

Abstract

PURPOSE:To measure the dimension of a moving body in a simple manner by installing a line sensor in the aslant direction of the moving body, taking a photograph of the moving body while controlling the scan speed of a camera in proportion to the moving speed, comparing the photographed image surface with a well known image surface, or counting the scanning lines. CONSTITUTION:A line sensor 1 is arranged so as to form an angle Q (0<Q<90 deg.) with respect to the moving direction of a slide plate 10, and the speed of an electric train 20 is measured in a car speed measuring part 21. In this method, the time for the traveling of the electric train 20 in a certain division may be measured, or a Doppler radar may be used. The car speed information is inputted into an image processing part 2, and the scan cycle of a line sensor camera 1 is set. The set scan cycle is the cycle for the scan free from the duplication of the slide plate 10 and slip-off. After the synthesis in the image processing part 2, a photographed image is sent into a dimension calculation part 6, and the photographed image and the reference image are compared, or the dimension is obtained by counting the quantity of the scanning lines, and the result is outputted.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used for measuring the size of an object. In particular, it relates to a non-contact dimension measurement technique for a moving object using a line sensor. The present invention was developed as an apparatus for measuring wear of a pick-up board of a pantograph of a train by photographing it with a television camera, but it can be widely used for measuring the size of a moving object.

[0002]

2. Description of the Related Art There are several known methods for measuring the size of a moving object. One of them is a method of photographing a moving object with a television camera and calculating its size from the relationship between a subject, a CCD and a lens. Is one. This method is widely used because its principle is simple and can be applied to various objects.

There is also a one-dimensional television camera called a line sensor camera. The line sensor has a plurality of photosensitive parts, which are pixels, arranged in a straight line on the order of several hundreds to several thousands. A line sensor camera is constructed by combining this with a lens. When shooting a subject with this
When the subject is stationary, the same signal is obtained each time it is scanned. As the subject moves, the signal changes accordingly.
An image of the subject can be obtained by recording the linear signals in the memory and sequentially arranging and displaying them on the CRT.

By using such a photographing method, continuous images can be obtained as long as the memory continues, and there is no concept of one or two images as in a general television. There is also no concept of screen aspect ratio.

[0005]

There is known a technique for photographing and measuring the wear condition of a pick-up plate of a pantograph mounted on a train by using a television camera. This is a pantograph of the train entering the room, taken with a television camera,
This is to identify whether the wear of the pick-up plate has reached the replacement threshold value. In such an apparatus, when a general television camera is used, the dimensions of the pick-up plate cannot be measured accurately.

For example, a general television camera has 50
~ 60 frames / sec. Therefore, there is no problem if the measured object is a low-speed object like the pantograph of a train entering the warehouse, but if the measured object is a pantograph of a train running at high speed, it may not be possible to follow the number of frames taken by the television camera. is there. Further, since the aspect ratio of the television screen is about 4: 3, it cannot be applied to the measured object that does not fit within this ratio.

The present invention has been made against such a background, and a line sensor camera capable of obtaining continuous images and not restricted by the number of frames has a wide range of measurable dimensions and can be applied to a moving object. It is an object of the present invention to provide a dimension measuring device having a simple and inexpensive structure that can be applied.

[0008]

The present invention comprises a television camera for photographing an object to be measured, and means for measuring a size of a portion of the object to be measured from a photographed image of the television camera. It is a dimension measuring device.

Here, a feature of the present invention is that the television camera is a line sensor camera, the object to be measured is a moving object, and the shooting direction of the line sensor camera and the moving direction of the object to be measured. Are arranged at an angle θ (where 0 <θ <90), and a means for measuring the moving speed of the object to be measured and a means for controlling the scanning speed of the line sensor camera so as to be proportional to the moving speed. There is a place to prepare.

The measuring means preferably includes means for comparing with a reference size.

The line sensor may be provided with a lens which is uniform in the longitudinal direction and which is a concave lens in the lateral direction.

It is desirable to use it for measuring the wear state of the pick plate of a pantograph installed in a train.

[0013]

Function: The line sensor camera captures an image of the portion to be measured while moving the moving object. The position of the line sensor camera is set at a position where the measured portion can be photographed obliquely, not in front of the moving direction. That is, the line sensor camera is installed at a position where the measured portion crosses the field of view of the line sensor camera as time passes.

The relationship between the moving speed and the scanning period of the line sensor camera is set so that the images of the same portion of the measured portion are not redundantly scanned and there is no unscanned portion in the measured portion. It

The dimensions of the portion to be measured can be measured from the image signal thus photographed. For example, by comparing the image of an object whose dimensions are already known and the image of the measured object, or by counting the number of scanning lines required for imaging from the end to the other end of the measured part Can be measured.

As a result, a size measuring device having a wide range of measurable sizes and having a simple and inexpensive structure applicable to a moving object can be realized.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of the first embodiment of the present invention. FIG. 2 is a block diagram of the image processing unit 2. Here, a method for measuring the wear of the pick-up plate of the pantograph of the train will be described.

The present invention is a television camera for photographing a pick-up board 10 which is an object to be measured, and a dimension calculator as means for measuring the dimension of a target portion of the object to be measured from an image taken by the television camera. 6 is a dimension measuring device.

Here, a feature of the present invention is that the television camera is a line sensor camera 1.
The pick-up board 10 as the object to be measured is a moving object, and the shooting direction of the line sensor camera 1 and the moving direction of the pick-up board 10 are arranged at an angle θ (where 0 <θ <90). A vehicle speed measuring unit 21 as a unit for measuring the moving speed and a control unit 3 as a unit for controlling the scanning speed of the line sensor camera 1 so as to be proportional to the moving speed.
And is equipped with. The size calculator 6 includes means for comparing with the reference size.

The pantograph 12 comes into contact with the overhead wire, which obtains electric power to power the train 20. Therefore, since it is always in contact with the overhead line, it is worn because it is made of a relatively soft metal. It is an important maintenance work to correctly grasp the state of this wear and take necessary measures. Pickpocket 10
Is about 1 m long, 10 mm thick, and about 25 mm wide.
This 10 mm portion comes into contact with the overhead wire and wears. It is desirable to measure this portion while the train 20 is running.
The conditions required for this are: contactless measurement with the pantograph 12 mounted on the train 20; no special device is required on the train 20 side; regular measurement is possible; Yes, it is possible to obtain sufficient accuracy required for maintenance, it is cheaper than the conventional system, and so on. These conditions can be satisfied by using the present invention.

Next, the operation of the first embodiment of the present invention will be described. The vehicle speed measuring unit 21 measures the speed of the train 20. The specific measurement method is that the train 20
May be measured, or a radar device using a Doppler effect such as used for controlling speeding of automobiles may be used. In any case, a vehicle speed measuring method that does not require a special device on the train 20 side can be realized by a known technique, and thus a detailed description thereof will be omitted. This vehicle speed information is input to the control unit 3 of the image processing unit 2. The control unit 3 sets the scanning cycle of the line sensor camera 1 from the vehicle speed information. The scan cycle to be set is a cycle in which the surface to be measured of the pick-up plate 10 can be scanned without overlapping and without missing. This image signal is stored in the image memory 4 and combined by the image combining unit 5. Further, the combined signal is input to the size calculator 6. Here, the image of the reference object whose dimensions are known in advance and the pick-up board 1
The size of the picking board 10 is measured by comparing with the size of 0. The image of the reference object is captured and stored in advance. Alternatively, the pick-up board 10 is photographed (or combined)
It is also possible to measure the size by counting the number of scanning lines required for.

The conditions for obtaining the required measurement accuracy will be described with reference to FIGS. 3 and 4. FIG. 3 is a front view of the surface to be measured of the pick-up board 10. FIG. 4 is a diagram for explaining the measurement accuracy. As shown in FIG. 3, when the line sensor camera 1 photographs the front surface of the pickpocket plate 10 in a substantially horizontal direction parallel to the pickpocket plate 10, as the pickpocket plate 10 moves toward the front as the train 20 progresses, an image is taken. The line moves upward. If the line sensor camera 1 is set to have an appropriate scanning cycle, the photographing position will move each time photographing is performed, so that the scanning is performed several tens to several hundreds of times as a whole, and necessary portions are photographed to form an image. It

In the line sensor 30, since the pixels of the photosensitive portion are arranged in a straight line, the size of one pixel is, for example, d × d.
(Mm ² ), assuming that the total number of pixels is n and the longitudinal direction L of the area to be photographed is determined, the width D of the photographing line is automatically determined as shown in FIG. The measurement accuracy is limited to D. Focal length:
f, the distance between the lens and the pick-up plate: M, and the width of the photosensitive portion of the line sensor: d, the imaging line width: D = d × (M / f) × (1 / cos θ) mm ² (1) L = Nd × (M / f) mm (2) If the picking plate 10 advances at a speed at which the position of the photographing line moves by D for each scanning, this is the limit of the moving speed of the picking plate 10. If the process proceeds faster than this, there is a portion of the pick-up board 10 that is not imaged, and the measurement accuracy cannot be maintained.

Travel speed of pick-up plate: X (mm / s),
Assuming that the moving speed of the position of the photographing line is x (mm / s) and the number of scans per second of the line sensor is z (Hz), X = (D · x · z) / sin θ (mm / s) (3) Become. By the way, when specifying the line sensor,
As shown in the equations (1) and (2), the longitudinal direction L of the photographing area and the photographing line width D are functions of the number of pixels n. This is D = (L / n) · (1 / cos θ) (4), which means that increasing L results in increasing D. Therefore, when L = 1 m as in the pantograph and n = 1000 and θ = 30 °, D = 1.15 mm. If this accuracy is insufficient, a method for improving the measurement accuracy without replacing the line sensor is the second embodiment of the present invention.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a conceptual diagram of the second embodiment of the present invention. As shown in FIG. 5, a semicircular lens 40 is arranged near the line sensor 30. The imaging line width D can be set to D / K by expanding the light entering the photosensitive portion of the line sensor 30 in the longitudinal direction only by magnifying only the component in the longitudinal direction by K times. The lens for this purpose is a semi-circular concave lens.

Further, considering the illumination method for photographing, as shown in FIG. 1, the boundary between the object to be photographed originally and the table supporting it may not be clear in some cases. The boundary line becomes clearer by arranging it in the middle and intentionally creating a shadow.

In the first and second embodiments of the present invention, the line sensor camera 1 is installed in front of the pick-up plate 10 in the moving direction, but the line sensor camera 1 is set in the back-moving direction of the pick-up plate 10 '. It is also possible to measure the dimensions of the pick-up plate 10 '.

[0028]

As described above, according to the present invention,
A dimension measuring device having a wide range of measurable dimensions and having a simple and inexpensive structure applicable to a moving object can be realized.

[Brief description of drawings]

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

FIG. 2 is a block configuration diagram of an image processing unit.

FIG. 3 is a view of the surface to be measured of the pick-up plate as seen from the front.

FIG. 4 is a diagram for explaining measurement accuracy.

FIG. 5 is a conceptual diagram of a second embodiment of the present invention.

[Explanation of symbols]

 1 line sensor camera 2 image processing unit 3 control unit 4 image memory 5 image compositing unit 6 size calculation unit 10, 10 'pick-up board 11, 11' panto stand 12 pantograph 20 train 21 vehicle speed measuring unit 30 line sensor 40 Kamaboko lens

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G06T 7/00

Claims (4)

[Claims] 1. A dimension measuring apparatus comprising: a television camera for photographing an object to be measured; and means for measuring the dimension of a portion of the object to be measured from a photographed image of the television camera. The camera is a line sensor camera,
The object to be measured is a moving object, and the shooting direction of this line sensor camera and the moving direction of the object to be measured are arranged at an angle θ (where 0 <θ <90), and the moving speed of the object to be measured is measured. A dimension measuring apparatus comprising: a means and a means for controlling a scanning speed of the line sensor camera so as to be proportional to a moving speed thereof. 2. The dimension measuring device according to claim 1, wherein the measuring means includes means for comparing with a reference dimension. 3. The dimension measuring device according to claim 1, wherein the line sensor is provided with a lens that is uniform in the longitudinal direction and is a concave lens in the lateral direction. 4. The dimension measuring device according to claim 1, which measures a wear state of a pick-up plate of a pantograph mounted on a train.