JPS5988627A - Liquid level inspector for container - Google Patents

Abstract

PURPOSE:To inspect the level of a liquid in an container simply, inexpensively and quickly by a method wherein windows are generated to observe areas corresponding to the liquid level to compute the area value of an object image within the windows and the results are compared with specified reference values. CONSTITUTION:As a vessel 1 is placed intercepting light from a light source 3, a TV camera 5 takes a transmission light image, which is converted into an electrical signal to be sent out to a decision device 6. The decision device 6 processes a video signal of one frame immediately after the detection of a vessel to be inspected with a position sensor and determines the propriety of the liquid level to be outputted to the outside or the like. A transmission object image taken with the TV camera 5 is converted into an electrical signal and binary coded at a specified threshold level with a binary coding screen splitting circuit 61 while quantized or converted into pixels by a specified signal. A window generation circuit 62 generates windows for observing only a specified area within a taken effective picture with the TV camera 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid level inspection device for a liquid filled in a transparent or translucent container.

Conventionally, this type of device irradiates an object with, for example, soft X-rays with a relatively long wavelength, and measures the amount of transmitted soft X-rays using a one-dimensional sensor (for example, - It is known to measure using a dimensional diode array). However, a light source that generates such soft X-rays is generally expensive and has the disadvantage that there is little flexibility in the light source or sensor. Furthermore, since the sensors are arranged one-dimensionally, there is also the problem that measurement errors become significantly large when the liquid level constantly vibrates or tilts. Furthermore, in the case of foaming liquids, there is a foaming surface in addition to the liquid level, but in such cases, if a printed pattern etc. is formed on the container surface, the liquid level and foaming surface should be distinguished and measured. The disadvantage is that it becomes virtually impossible to do so.

The present invention has been made in view of the above, and it is an object of the present invention to provide a drop-in inspection device that can easily, inexpensively, and quickly inspect the level of liquid in a container.

The feature is that the transmitted light image from the container illuminated by a predetermined light source is captured by an imaging device such as a television camera, and predetermined image processing is performed, and the liquid level is adjusted to an appropriate level based on a predetermined position of one subject image. .

The liquid level can be determined by generating windows for observing each area corresponding to the insufficient liquid level and excessive liquid level, calculating the subject image area value within each window, and comparing this with a predetermined reference value. The main point is that the system is designed to check for adequacy or excess or deficiency.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. In the figure, 1 is a transparent or opaque container filled with a predetermined liquid, 2 is a conveyor that conveys the container 1, and 3 is a conveyor that conveys the container 1.
is a light source, 41 is a light emitting element, and 42 is a light receiving element (hereinafter referred to as 41
．． 42 is also called a position sensor. ), 5 is an imaging device such as an industrial television camera (ITV camera), and 6 is an imaging device such as an industrial television camera (ITV camera).
is a judgment device. Note that 7 is a vibrating device that vibrates the container 1, and this will be described later.

That is, when the container to be inspected 1 transported by the conveyor 2 reaches a predetermined position, the light receiving element 42 is activated.
Thereby, it is detected that the container 1 has reached the imaging field of view of the television (TV) camera 5.

Since the container 1 is placed so as to block the light from the light source 3, the TV camera 5 photographs the transmitted light image, converts it into an electric signal, and sends it to the determination device 6.In this case, the container 1
At the interface between the liquid and the air inside, the light does not pass through due to the phenomenon of critical refraction, so that the interface or liquid level can be detected. The determination device 6 processes the video signal of one frame immediately after the position sensor detects the container to be inspected as described below, determines whether the liquid level is appropriate or not, and outputs the result to the outside.

The determination device is further configured as follows. FIG. 2 is a block diagram showing details of the determination device. In the same figure, 6
1 is a binarization/screen division circuit, 62 is a window generation circuit, 63 is a logic circuit, 64 is a data memory, 65 is an arithmetic control unit such as a microprocessor, 66 is a read-only memory (ROM), and 67 is a random access memory. (R
AM).

68 is an input device such as a keyboard, 69 is a CRT (Cat
This is a display device such as a body ray tube (body ray tube). Note that 5 is a TV camera similar to that shown in FIG.

That is, the transmitted subject image captured by the TV camera 5 is converted into an electrical signal, and is binarized at a predetermined threshold level in the binarization/screen division circuit 61, and
It is quantized or pixelized by a predetermined signal. The window generation circuit 62 generates a window for observing only a predetermined area within the effective image capturing screen imaged by the TV camera 5, that is, a window. Therefore, only pixelated data within a predetermined area is taken out from the logic circuit 63 formed of, for example, an AND gate, and stored in the data memory 64. In addition, to generate the window, use the TV camera 5.
When scanning the imaging screen by
One method is to store the horizontal and vertical coordinate position information in a fixed memory (for example, the ROM 66 in FIG. 2), or to use an input device such as a key code and a monitor each time. It is conceivable to use this together to indicate typical points regarding the window, calculate each ζ ind from this by linear interpolation, and store it in a memory (for example, the RAM 67 in Figure 2), but in any case, It is also desirable to be able to generate multiple windows with predetermined areas at desired positions.The present applicant has already proposed this point, so if necessary, for example, Japanese Patent Application No. Please refer to No. 71496 etc.

Although circuits and the like for synchronizing the subject image and the TV camera 5 are omitted in FIG. 2, it is assumed that they are provided as appropriate.

FIG. 3 is an explanatory diagram for explaining the determination operation according to the present invention. The figure is an example of a monitor image when a transparent or translucent container filled with a predetermined liquid is imaged using the transmitted light illumination method as shown in Figure 1. 'Wo-W2 is a window, and T-Jl is a window. L2 is the image portion, e.g. black level, formed by the wall thickness of the container, L2 is the image portion, e.g. black level, formed by the cap of the container, L3 is the image portion, e.g. black level, formed by the liquid level boundary, and L4 is the white level image formed by the liquid phase, Pl
is the origin of the TV camera. 1) 2 is the reference point of the subject image. In this case, the light from the light source does not pass through the interface between the liquid juice and the air due to critical refraction, resulting in an image with a black level as shown by L3 in the figure. Also, each window W
o~w2 can be set using the tip of the container as a reference, for example P2, and therefore the reference point P2
It is assumed that a position correction circuit (not shown) is provided to change the window generation position accordingly when the window moves.

The determination device determines the area value Ai within the window wo-W2 set as shown in FIG. 3, and compares this with appropriate upper and lower thresholds to check whether the liquid level is appropriate or not. can do. As explained in Fig. 2, the tree image is divided into pixels of a predetermined size, and the area of each pixel is known in advance.
The area of the portion representing the boundary surface existing within each window can be easily determined by counting the number of pixels. Therefore, if each area in the window Wo-w2 is defined as Ao#A2, then Ao becomes a constant and A
If both A2 and A3 are approximately zero, the liquid level is normal, and if AD is smaller than the predetermined value and A2 is (zero) and A3 is greater than zero, it is excessive;
If the relationship with 3 is opposite to this, it can be determined that there is a shortage.

Figure 4 is a layout diagram showing another configuration of the window, taking into consideration the case where there is a considerable play or step in a conveyor such as a belt conveyor. In some cases, the liquid level is tilted, so the wind fy pair (W6 to W2'
) is provided at symmetrical positions across the longitudinal center line of the subject image, so that correct judgment can be made even when the liquid level is inclined. In this case, in addition to determining the area value of the liquid level image for each window and comparing it with a set value, it is also possible to make a determination by correlating the area values between two predetermined windows. If you do so, you can get even more accurate results. As the judgment condition, for example, the following cases can be considered.
indicates the area values of windows WO to W2.

b) A,)=o, A2! =i0, AI #0
, AO'=i0.

IAI-A21=o, A1#K (constant) ty)
A2 ”io, AI L=i0, A□+
AI L#K, AO + A2 object K zs) A, @ ζOt A1 ”; Op A2-
Og AO-OpIA2 At I”-0, A2
= Ni2) A2 ζ0 # Al ζOp Ao IAI
ζK v AO+A2- In other words, the above cases (a) and (a) are cases where the boundary surface image L3 is tilted to the left side of the figure, as shown in No. 4 @ (4), and in particular, this case is set as the limit of the slope. Anything that falls within the range is considered normal. Also, c).

Case 2) is the opposite case to the above, and therefore the fourth case
If you refer to Figure (l[3), the meaning of the conditional expression will be clear. In addition, AO−K w AO=KrAz
=Ot A, 1==Q, A2 =0, AI=
It goes without saying that if it is 0, then it is determined that it is in a horizontal state.

FIG. 5 is a layout diagram showing another aspect of the window. This is suitable for application when the liquid in the container generates foam, such as sparkling drinking water. That is, as shown by the dashed line in FIG.
When bubbles are forcibly generated inside the container, the time for the bubbles to disappear is proportional to the air density inside the container, so the state of the bubbles is monitored during the time from when the container starts vibrating until it reaches the determination device 6. This allows the airtightness to be checked. That is, if the degree of sealing of the container is good, the bubbles will be retained for a long time and the level will be high, and if the degree of sealing is poor, the opposite will be true, which is why this inspection is performed.

Therefore, the liquid level inspection windows Wo to W located at a predetermined distance from the reference point of the subject image as explained in Fig. f43.
In addition to window W3, a bubble level inspection window W3 is provided, and the bubble level is inspected from the area value within this window.0 In this case, if the area value of window Wo-w3 is AO to A3, the following conditional expression is obtained. The liquid level and foam level can be checked by

a) A, 0'5K (constant) e A2#O, A1
=0, A3"; Ka (constant) b) Ao=K p Az'i0 p A1=Oe A
3 < α to 3 (α is a constant smaller than 1) In other words, in a) above, both foam and liquid level are good, and in b) above, although the liquid level is good,
This is a case where the foam level is abnormal.

As described above, according to the present invention, windows are generated for observing each area corresponding to the appropriate liquid level, the insufficient liquid level, and the excessive liquid level based on a certain point, and each window in the window is It becomes possible to easily and accurately determine the liquid level from the correlation between two area values. Furthermore, by providing another window in addition to the above-mentioned windows, the bubble level can also be determined. Furthermore, since data is processed through a predetermined window, the number of pieces of data to be processed is reduced, resulting in an advantage that rapid processing can be performed using inexpensive equipment.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing details of the determination device in FIG. 1, and FIG.
The figure is an explanatory diagram showing the relationship between the subject image and the window.
Figures 5 and 5 are layout diagrams showing the other side of the window. Code explanation 1...container, 2...conveyor, 3...
...Light source, 41...Light emitting element, 42...
... Light receiving element, 5... Brevi camera, 6...
... Determination device, 7 ... Vibration device, 61 ...
... Binarization/screen division circuit, 62 ... Window generation circuit, 63 ... Logic circuit, 64 ...
... Data memory, 65 ... Arithmetic control unit (μ-CPU), 66 ... Read only memory (RQM), 67 ... Random access memory (RAM) , 68... input device, 69...
・・・C几'r、wo-W3・・・Window,
Pl...TV camera origin, Pl...
Subject Image Reference Point Agent Patent Attorney Kiyoshi Matsuzaki

Claims (1)

[Scope of Claims] 1) An apparatus for inspecting the liquid level in a container in which a predetermined liquid is sealed by utilizing the fact that irradiated light is refracted at the interface between the liquid and air. , an image dividing means for binarizing an image signal obtained by capturing a transmitted light image of the container using a two-dimensional successive scanning type imaging device at a predetermined logical value level and dividing it into pixels of a predetermined size; and an image capturing screen. window generation means for generating windows for observing respective regions corresponding to the appropriate liquid level, insufficient liquid level, and excessive liquid level based on a predetermined position of the liquid level; and a memory for storing imaged data for each of the windows. and calculating means for calculating the object image area in each window based on the stored data, and inspecting the liquid level in the container by comparing each of the calculated area values with a predetermined reference value. A liquid level inspection device in a container, characterized by: 2. In the liquid level inspection device according to claim 1, three types of window groups for observing respective areas corresponding to the appropriate liquid level, insufficient liquid level, and excess liquid level are arranged at the center of the container. They are generated in pairs at symmetrical positions with respect to the long axis passing through the window, and the area values of each window are compared with a predetermined setting value to make an individual judgment.
A liquid level inspection device in a container, characterized in that a correlation @product value of a pair of windows is determined by pairing a predetermined two of each window, and the correlation is determined by comparing the correlation with a predetermined set value. 3) In the liquid level inspection device according to claim 1, the window generating means detects an appropriate liquid level;
Inspection of liquid level in a container characterized by generating a window for observing bubbles generated by IM movement of liquid in addition to windows for observing areas corresponding to insufficient liquid level and excessive liquid level. Device.