JPS61259108A - Apparatus for measuring dimension of matter - Google Patents

Abstract

PURPOSE:To perform dimensional measurement with high accuracy regardless of the moving speed of matter, by arranging two scanning type sensors synchronized so as to be capable of respectively and simultaneously detecting two points of the matter to drive both of them. CONSTITUTION:Objective matter 11 is moved to the direction by an arrow WW by a belt conveyor 12 and the ends W1, W2 of the matter are respectively imagewise projected on image sensors 4A, 4B through optical systems 2A, 2B by light sources 3A, 3B. Both sensors are scanned and driven by the common timing signal S of a control apparatus 13 and output signals S1, S2 are inputted to the control apparatus 13 to be operated. At this time, the reference positions K1, K2 of the sensors are taken at the end parts of a matter detection range. Whereupon, the dimension Rx between both ends of the objective matter 11 comes to formula Rx=Rk1+(Ra-Rb). The control apparatus 13 measures the time Ra1... corresponding to Ra and the times Rb1... corresponding to Rb at every scanning frame and the dimension Rx of the matter 11 is calculated accord ing to the above mentioned formula. Herein, because the dimension Rx measured at every frame is negated in the effect of the moving speed of the matter 11, the measured value at every frame becomes substantially the same.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an object dimension measuring device that measures the dimensions of an object using a scanning sensor such as an image sensor or a photodiode.

(Technical Background of the Invention and Problems Thereof) Conventionally, when measuring the dimension between two points on an object without contact, a device as shown in FIG. 4(A) has generally been used. This is because the target object 1 projects an image onto the image sensor 4 via the optical system 2 by the light source 3, and the dimension R1 of the target object l within the object detection @gIR2 of the image sensor 4 is measured. can. This image sensor 4 consists of a plurality of image sensor elements, and can measure the dimensions of an object by temporally scanning the outputs of these elements and sequentially extracting signals.
The principle is shown in the same figure (B).

In this figure, the horizontal axis shows time and the vertical axis shows the signal output of each element of the image sensor, and one hour t2 is the object detection range R2.
Since the time U corresponds to the dimension R1 of the target object 1, this dimension R1 can be found from this time tl.

The disadvantage of such a device is that there is a limit that the entire part of the target object l to be measured must be within the object detection range R2, and the image sensor element is limited depending on the size of the object. Since a large number of resolutions are required, the drawback of one resolution is often unsatisfactory.

Figure 5 shows how to improve resolution with fewer image sensor elements.
The image sensor 4J is connected to one end of the target object l^ through an optical system 2 using a light source 3.
: This device is used when the approximate dimensions of the target object 1^ are known in advance, and when the target object IA moves in the direction of the arrow QQ, the target object When one end Q2 is detected by the end detection stage f 5, the target object IA is stopped. Then, from the image projected on the image sensor 4 at this time, that is, the dimension R4, and the preset position of the edge detection means 5, that is, the dimension R3, the target object is determined! The dimension R5 of ^ can be obtained by using the following equation (1).

R5-R3◆R4・・・・・・・・・(1) However, even in this method, the detection error of the terminal film 5 directly becomes a cause of the error in dimension measurement, and also, when Q2 is detected at one end, It is necessary to stop the target object instantaneously, which is quite difficult. In addition, there are cases where it is necessary to measure the target object in a moving state rather than in a stationary state, but since the image sensor is a scanning type, there is a new error, that is, one frame scanning of the image sensor. Errors occur because it is difficult to accurately detect the speed of the target object.If the speed of the target object is known, it is possible in principle to correct the scanning speed, but
The process is complex and difficult to implement.

(Object of the invention) This invention was made under the above circumstances,
An object of the present invention is to provide an object dimension measuring device that can accurately measure the dimension between two points of an object, regardless of whether the object is stationary or moving.

(Summary of the Invention) The present invention relates to an object dimensioning device that measures the dimension between two points on an object using two synchronized scanning sensors. Two scanning sensors are installed and the first scanning sensor
and a second reference position, which is detected as a dimension between the position detected by the first scanning sensor and the first reference position with respect to the dimensions of the first and second reference positions. By adding the difference between the first detected dimension and the second detected dimension detected as the dimension between the position detected by the second scanning sensor and the second reference position, two points of the object can be detected. It is designed to measure the distance between the two.

(Embodiment of the invention) 1. This figure shows the case of measuring the dimension between both ends of a target object 11 carried by a belt conveyor 12 in the four directions of the arrows. . One end w1 of the target object 11 is configured to project an image onto the image sensor 4A via the optical system 2A by the light source 3A, and similarly, the other end w2 of the target object 11 is configured to project an image onto the image sensor 4A via the optical system 2A by the light source 3B. The calligraphy is projected onto the image sensor 4B via the image sensor 4B. The image sensors 4A and 4B are scanned and driven by a common timing signal S produced by the control device 2113, and the output signals S1 and S2 are inputted to the control device fi13 and calculated. Here, the scanning direction of the image sensors 4A and 4B is, for example, the same as the direction wv in which the belt conveyor 12 moves. And image sensors 4A and 4
The reference positions Kl and 2 of B are respectively taken at the ends of the object detection range, and the dimension between these reference positions IKI and 2 is R.
kl, and one end wl of the target object 11 and the reference position fi
Let Rh be the dimension between the other end l112 and the reference position 51, and Ra be the dimension between the other end l112 and the reference position 51, then the desired end-to-end dimension Rx of the target object 11 can be obtained by the following equation (2).

Rx = Rk+ + (Ra - Rh) --
-(2) In such a configuration, its operation is shown in Figure 1 (
The motion analysis diagrams B) and (C) will be explained.

In the same figure (B), the horizontal axis is time, and the vertical axis is the output signal Sl of the image sensor 4A, and in the same figure (B), the vertical axis is the output signal S2 of the image sensor 4B. These image sensors 4A and 4B are repeatedly scanned, and the n-th, (n+1)-th, (n
The output signals of the n-th frame, (total of 1) frame, and (total of 2) frames are shown corresponding to the +2)-th scan. Here, since the target object 11 is moving, the images projected on the image sensors 4A and 4B also move, and therefore the output signals S1 and S2 also differ every time scanning is performed, that is, every scanning frame. That is, the time corresponding to the dimension Ra gradually becomes smaller as Rat, Ra7, Ra3,
Conversely, the time corresponding to the dimension Rh is Rh+, Rh, 2.
It gradually increases like Rbz. Then, by measuring these times and performing calculations for each frame according to equation (2), the length dimension R8 of the target object 11 can be determined.

Here, since the influence of the moving speed of the target object 11 is canceled as shown in equation (2), the dimension R, determined in each frame is the same in terms of wood quality. becomes. However, the number of elements in the image sensor is not infinite, so resolution errors and optical system 2
This is because there will always be variations in the images projected onto the image sensors 4A and 4B by A and 2B.

If the obtained R is averaged, even more accurate dimensions can be obtained.

FIG. 2 shows an embodiment of the control device M13 used in the present invention, in which output signals S1 and S2 of two sets of image sensors 4A and 4B are sent to comparators 22A and 22B, respectively.
and is converted into a binary signal indicating the presence or absence of an object using an appropriate threshold level. These comparators 2
The signals output from 2A and 22B are input to AND gates 23A and 23B together with the clock signal GK output from the timing generation circuit 21, and these output clock signals are input to counters 24A and 24B.

The outputs of these counters 24A and 24B are digital signals proportional to the length of the object projected on each image sensor 4A and 4A, and are output by the reset signal R5 outputted from the timing generation circuit 21 for each frame. It is reset and the data is updated every frame. These digital signals are input to the latches 25A and 25B, and are latched by the latch signal RT output from the timing generation circuit at the end of each frame, after which the difference between the two latch output signals by the subtractor 26 is calculated. Calculated. After the output signal of the subtractor 28 is multiplied with the coefficient Kl(l) in the multiplier 27, the output signal of this multiplier and the coefficient Kll are added in the adder 28, and the output signal of the adder 28 is S× is target object 1
It is output as a signal corresponding to the dimension required by 1.

To explain the operation in detail in such a configuration,
When an object is projected onto the image sensors 4A and 4B, the AND gates 23A and 24A are opened, and the counters 24A and 24B count the number of clocks corresponding to the object.

Each frame is latched into latches 25A and 28A as a signal proportional to the length of the object. After the subtraction unit 28 subtracts (Ra−Rh) in equation (2), the multiplication unit 27 multiplies the coefficient KIO determined by the expansion or reduction by the optical systems 2A and 2B. After this correction, the adder 28 calculates Rkl◆(Ra-Rb) in the equation (2), and the object dimension RX is obtained as the signal Sx. Here, the digital calculation unit 20 can be replaced with a microprocessor to reduce the number of parts and facilitate the setting of each constant.

FIG. 3 shows another embodiment of the control device M13 used in the present invention, in which analog switches 32A and 32B are operated by the outputs of comparators 22A and 22B,
A reference voltage source 31 is input to an integrator 33. and,
The output signal of this integrator 33 is processed by a gain adjuster 34 with a coefficient K.
After IO is multiplied.

It is added together with the coefficient Kll set and outputted by the coefficient setter 35 in the adder 3B, and held in the hold circuit 37 by the hold signal HO outputted from the timing generation circuit 21 for each frame, and the output signal of this hold circuit 37 is 8 is output as a signal corresponding to the desired dimension of the target object 11. Further, the reset signal RS outputted from the timing generation circuit 21 is applied to the integrator 33 every frame, and the data of the output signal of the integrator 33 is updated every frame.

In such a 411 configuration, when an object is projected on the image sensors 4A and 4B, the analog switch 3
2A and 32B are closed and one or both of the positive voltage and negative voltage of the reference voltage source 31 is input to the integrator 33, so a voltage proportional to the time difference between the analog switches 32A and 32B being closed is input to the integrator 33. becomes the output signal.

Therefore, the calculation of (Ra - Rh) in equation (2) has been performed. The coefficient KIO has the same meaning as in the example of FIG. 2, and the object dimension R is obtained as the signal A8.

In addition, here we have shown the case of finding the length of an object when it is moving in the same direction as the scanning direction of the image sensor, but even if the object is moving in a direction perpendicular to the scanning direction, It is possible to measure as long as the image of is projected onto the image sensor. In this embodiment, the case where a bar-dimensional image sensor is used has been explained, but it is also possible to use an ITV camera, a two-dimensional image sensor, or various scanning sensors such as electrostatic, magnetic, acoustic, mechanical, etc. This is extremely easy.

(Effects of the Invention) As described above, according to the present invention, even when an object is not at rest but in motion, it can be measured irrespective of its moving speed and in a non-contact state, so it can be measured extremely accurately and at high speed. We can provide an object dimension measuring device that can easily measure dimensions with precision.

[Brief explanation of drawings]

Figures 1 (A) to CC) are diagrams for explaining an embodiment of the present invention and its operation, Figures 2 and 3 are diagrams each showing a specific example for carrying out the invention, and Figure 4 ( A), (B)
and FIG. 5 are diagrams each showing an artificial example. 1.11...Target object, 2.2A, 2B...Optical system, 3,3A, 3B...Light source, 4.4A, 4B...
Image sensor, 5... End detection means, 12... Belt conveyor, 13... Control device, 20... Digital calculation section, 21... Timing generation circuit, 22A, 2
2B... Comparator, 23A, 23B... AND gate, 24A, 24B... Counter, 25A, 2
5B... Latch, 26... Subtraction section, 27... Multiplication section, 28... Addition section, 31... Reference voltage section, 32A
, 32B...analog switch, 33...integrator,
34... Gain adjuster, 35... Coefficient setter, 36
...Addition section, 37...Hold circuit.ゐ l Figure 4 Hong Sokbe J Liu Tsui-y Masuru≦

Claims (1)

[Claims] In an object dimension measuring device that measures the dimension between two points on an object using two synchronized scanning sensors,
The two scanning sensors are installed so that points can be detected simultaneously, and the position detected by the first scanning sensor and the A first detected dimension detected as a dimension between a first reference position, and a second detected dimension detected as a dimension between a position detected by the second scanning sensor and the second reference position. An object dimension measuring device characterized in that the dimension between two points of the object can be measured by adding the difference between the dimensions.