JPS6017042B2 - Tilt detection automatic visual inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic appearance inspection device that inspects the appearance of an object to be inspected while it is being moved by a conveyance device by taking a television image, and in particular, the present invention relates to an automatic appearance inspection device that inspects the appearance of an object to be inspected while it is being moved by a conveyance device. The detection performance of the visual inspection is improved by limiting the visual inspection area.

In general, when automatically inspecting the appearance of products such as medicines and foods packaged with PTP (PressThro female hPack) using television imaging, it is necessary to inspect the packaged product itself and other parts, especially the seal. Since it is necessary to perform each inspection separately for the inspection of the condition of the Preferably, the defect image is removed from the field of view to improve the performance of the desired defect detection.

However, in conventional visual inspections of this type, for example, the medium sheet of a PTP packaged product to be visually inspected is transported in a state of being by a conveying device such as a belt conveyor, and then the television No consideration was given to the case where the object comes within the field of view of the image sensor that performs imaging. For example, a desired product, such as a tablet, is inserted into each product storage pocket 2 of a rectangular PTP sheet 1 as shown in FIG. Each product is divided into sections, where the dimensions of the PTP sheet 1 are width A = area ■, length B =
Conventional visual inspection will be explained by taking as an example a case in which the ship has 37 sides and the pocket 2 has a diameter of 9 mm and 1 side.

When the contour shape of the rectangular PTP sheet 1 enters the imaging screen of the image sensor with the neck angle 8 shown in FIG. 2, the neck amounts x and y in the horizontal x direction and the vertical y direction are as shown in FIG. As shown in, for example, a rectangular PTP
With respect to the angle formed by the contour line of the sheet 1 and the horizontal and vertical scanning directions of the television green screen, at any lateral distance a and longitudinal distance b of the sheet 1,
× Ni b average n 8 y n 8 becomes n 8 , and when a=A and b=B, the maximum amount of attachment × and Y become X; B ne na Y ni A ne na .

Here, the angle of inclination is usually small, and the amount of inclination ×, y
and X, Y have a nearly proportional relationship with the inclination angle 8 as shown in FIGS. 3 and 4 (here, A=94 objects, a=
83 ribs, B = 37 ribs, b = 33.5 willow. ). On the other hand, as shown in FIG. 5A, when the above-mentioned mask 4 is set such that there is a margin in the dimension of the product storage pocket 2, the mask margin ΔC of the dimension of the pocket 2 is
The above-mentioned tolerance of the inclination angle 0 relative to the angle of inclination also has a proportional relationship, as shown in FIG. 5B. However, for example, the slope of the contour line of the PTP sheet with respect to the imaging screen does not occur only in one direction, downward to the right as shown in Figure 2, but the opposite slope, upward to the right, must also be considered. Therefore, the tolerance of the inclination angle 8 for the same mask allowance of the PTP product storage pocket 2 needs to be set to 1'2, which is the value shown in FIG. 5B, taking into consideration the inclination in both directions. When performing an appearance inspection on the PTP sheet 2 having the shape and dimensions shown in FIG. 1, the dimensions of the mask 4 as shown in FIG. Considering the deviation in the transport direction of the transport device and the direction perpendicular to this, for example, when both the vertical and horizontal dimensions are set to the 11 side, the tolerance for the slope of the contour line is at most 0.5 degrees, and this With degree of tolerance,
In practice, this is the same as not allowing the nuisance of the contour line. On the other hand, in order to increase the tolerance for contour lines, the dimensions of the mask 4 described above are increased so that the inspection target area does not fall out of the field of view of the mask 4 even if there is some mirroring. However, in order to allow a mirror angle of, for example, ±2 degrees, the dimensions of the mask 4 must be increased to 16 ribs in both the vertical and horizontal directions.

If the dimensions of the mask 4 were increased to about 16 sides for the product storage pocket 2, which has a diameter of about 1 inch as shown in FIG. The purpose of using a mask for visual inspection will be lost. Furthermore, when the mask used for such visual inspection is electronically formed, especially when a monostable multipipelator and a counter are used to form a square waveform mask signal, for example, the PTP sheet is the field of view of the image sensor. If the number of strokes is not oblique at all, or if the forehead is tilted downward to the right, square waves in the vertical scanning direction and horizontal scanning direction are generated based on the rising edges of the top and left edges of the background separation signal, respectively. Even if PT is sequentially generated as a mask signal, there will be no problem in forming the required mask signal, but for example, PT
If the upper contour line of the PTP sheet is tilted upward to the right, which is a backward state in the vertical scanning direction, with respect to the upper left corner, which is the starting point of screen scanning for the contour of the P sheet, the rising edge of the background separation signal is used as the reference point. If a mask signal is formed using a square wave generated by a square wave, an area unrelated to the desired inspection target area will be masked. It was only possible to perform a satisfactory visual inspection.

It is an object of the present invention to eliminate the above-mentioned conventional drawbacks, and to improve the tolerance of the inclination of the outline of an object to be inspected, such as a PTP-wrapped product, for example, the outline of a PTP sheet, with respect to a television image screen. It is possible to make the inspection target area sufficiently large without removing the inspection target area in the appearance of the inspection object, and it is also possible to electronically generate effective and accurate mask signals regardless of the direction of inclination with respect to the horizontal scanning direction of the television imaging screen. An object of the present invention is to provide an automatic visual inspection device for detecting inclination, which can improve the performance of visual inspection of PTP packaging products, etc.

That is, the tilt detection automatic visual inspection apparatus of the present invention is an automatic visual inspection apparatus that detects the external appearance of an inspected object while it is being moved by a conveyance device using an image sensor, and performs an external appearance inspection of the inspected object. means for measuring the duration time in the image sensor scanning direction of a background separation signal representing the
means for measuring the length of time between the scanning reference signal of the image sensor and the background separation signal; vertical mask signal generating means for generating a vertical mask signal based on the background separation signal; A plurality of horizontal mask signal generating means generate horizontal mask signals respectively corresponding to the direction of inclination, and a plurality of horizontal mask signal generating means generate horizontal direction mask signals respectively corresponding to the direction of inclination, and detecting the direction of the detected object according to the direction of the oblique direction with respect to the horizontal scanning direction of the detected object detected by the inclination direction detecting means. A mask that limits an inspection area in the external appearance of an object to be inspected by combining a horizontal mask signal generated from a horizontal mask signal generating means corresponding to the direction of inclination and a vertical mask signal generated from a vertical mask signal generating means. The present invention is characterized by comprising a mask signal generating means for generating a signal.

The invention will be explained in detail below by way of example embodiments with reference to the drawings.

An example of the overall configuration of the automatic visual inspection device for detecting inclination according to the present invention is shown in FIG. 6, and signal waveforms of various parts thereof are shown in FIGS. 7A to 7L.

In the inspection apparatus of the present invention shown in FIG. 6, the background separation signal 5 (see FIG. (see C) directly to the vertical mask signal generation circuit 6, and also to other vertical mask signal generation circuits 8 via an appropriate delay circuit 7. A waveform vertical mask signal 9 (see FIG. 7D) and a rectangular waveform vertical mask signal 10 (see FIG. 7E) rising with an appropriate delay are generated.

The vertical mask signal 9 and the background separation signal 5 are added to the AND gate 11, the vertical mask signal 10 and the background separation signal 5 are added to the AND gate 12, and the AND gate 1
The output signals from AND gates 1 and 12 are applied to horizontal mask signal generation circuit 13, and the output from AND gate 11 is further supplied to horizontal mask signal generation circuits 14 and 15, respectively. Further, the background separation signal 5 is transmitted to the forehead direction detection circuit 16.
As will be described later, the direction of mirror inclination with respect to the horizontal scanning direction on the ray image screen of the outline of the object to be inspected is detected, and the detected output signal is sent to each horizontal direction mask signal generation circuit 1.
3, 14 and 15 and a mask signal generation circuit 17. The mask signal generation circuit 17 also combines the horizontal mask signals 18, 19 and 20 from the horizontal mask signal generation circuits 13, 14 and 15, and generates signals according to the results of the skew detection in the forehead direction detection circuit 16. When there is no cross slope, the horizontal direction mask signal 18 from the horizontal direction mask signal generation circuit 13 (see FIG. (the horizontal mask signal is missing), and in the case of a downward slope to the right, the horizontal mask signal 19 from the horizontal mask signal generation circuit 14 is
(see FIG. 7F), and in the case of an upward slope to the right, the horizontal direction mask signal 20 (see FIG. 71) from the horizontal direction mask signal generation circuit 15 is input vertically in the mask signal generation circuit 17. A mask signal 21 is generated by combining with the direction mask signal so as to form a mask having a shape that appropriately corresponds to the inspection area according to the direction of the outline of the object to be inspected and the amount of intrusion. FIG. 7 J, K, and L show the mask signal 21 in the case of downward slope to the right, no frame, and upward slope to the right, respectively. Note that FIGS. 7A and 7B are a vertical synchronization signal and a horizontal synchronization signal, respectively, which are not shown in FIG. The horizontal and vertical mask signal generation circuits add the background separation signal 5 to the cascade circuit of monostable multipipelators to appropriately mix the outputs of the monostable multipipers at positions corresponding to desired mask portions. Alternatively, the screen corresponding to the field of view of the image sensor may be divided into pixels, and the horizontal position of each pixel may be specified by a clock pulse with a higher frequency in synchronization with the horizontal scanning frequency, and the vertical position may be set by horizontal scanning. It may be configured with a counter to specify the position of the line, or the mask signal waveform may be stored in advance in a storage element such as random access memory (RAM) or read-only memory (ROM).
A desired mask signal can be read out based on the background separation signal and the screen division clock signal.

Examples of the state of the mask applied to the image obtained by reproducing the image pickup output of the object to be inspected using the mask signal 21 for visual inspection formed as described above are shown in FIGS. 8A, B, and C, respectively.

The mask 4 shown in the shaded area in FIG. 8 is used when five product storage pockets 2 are arranged in two rows, in the case where the PTP sheet 1 is not so large in appearance of the PTP packaging product. This shows a state in which the storage pockets are divided into two groups for each row to correct for the sagging.
Fig. 8A shows the state when there is no movement, Fig. 8B shows the state when the movement is downward to the right, and Fig. 8C shows the state when the movement is upward to the right. When using a normal conveying device such as a belt conveyor, if the nuisance is corrected to the extent shown in Figure 8, it is possible to perform a practically satisfactory appearance inspection of the product with the mask applied sufficiently accurately. . If the outline of the object to be inspected has a large slant, the detection circuit 16 detects not only the direction of the slant, but also the amount of slant, and outputs the detection output signal to the vertical and vertical directions separately provided. In addition to the horizontal mask signal generation circuit, a mask signal in the horizontal direction and vertical direction that is suitable for the detected head size is synthesized so as to form a necessary mask depending on the state of the forehead. Of course, any desired mask signal can be formed.

Next, an example of a specific configuration of the above-mentioned scratch direction detection circuit 16 is shown in FIG. 9, and signal waveforms representing its operating principle are shown in FIGS.
Shown in Figures A to E.

As described above, the principle of detecting the tilt direction in the device of the present invention is based on the starting edge in the horizontal scanning direction of a background separation signal representing the outline of a rectangle such as a PTP sheet, that is, the rise of a square waveform, and the horizontal synchronization on the scanning line. Measures the time interval that represents the distance between the signal and the background separation signal waveform itself, which represents the time period during which the same horizontal scanning line that measured the time interval crosses the outline of the rectangle. By doing so, it is determined whether the direction of inclination of the contour line of the object to be inspected is horizontal, downward to the right, or upward to the right, based on a combination of these measurement results. That is, in the circuit configuration shown in FIG. 9, the clock pulse generation circuit 31 generates a clock pulse train with a repetition period corresponding to the pixels of the television image taken of the object to be inspected.

This ku. A counter 32 that measures the duration of the background separation signal 5 described above, and a horizontal synchronization signal 33.
a counter 34 that measures the time interval between the signal 5 and the background separation signal 5;
A counter output 35 of the counted quantity Y, which is the result of counting the number of clock pulses corresponding to the duration thereof, and a counter output 36 of the counted quantity x, which is the result of counting the number of clock pulses corresponding to the above-mentioned time interval, are respectively output from the counter. 32 and 34. 10 A to E, 11 A to E, and 12 A to 12, respectively, when the counters 32 and 34 do not operate properly, when the forehead is downward to the right, and when the scale is upward to the right. Shown in E. In each of these figures, A shows the state of the sheet with respect to the horizontal scanning line, B shows the horizontal synchronizing signal 33, C shows the background separation signal 5 whose pulse width changes depending on the state of the spread, and D shows the counter output 36. (Count amount X) and E indicate the counter output 35 (Count amount Y), respectively, and the generation position and pulse width of the background separation signal 5 change depending on the slope state. Supplying the output 35 from the counter 32 and the set value C to a digital comparator 37 and comparing both values,
Take out the Y≦C output that produces an output when YSC and the C<Y output that produces an output when C<Y. counter 3
The output 36 from 4 and the set value A are supplied to a digital comparator 38, from which the XmiA output which produces an output when ×miA is taken out. The output 36 from the counter 34 and the set value B are supplied to the digital comparator 39, and similarly x≦B
Take out the output and B<x output. Y≦C of comparator 37
The output and C<Y output, the X≦A output of the comparator 38, and the ×miB output and B<× output of the comparator 39 are supplied to the familiarity determination circuit 40'. From this slope determination circuit 40,
When both of
When both of the outputs occur, the "falling to the right" output 42 is taken out, and when both the B < , an AND gate supplied with ×≦B output and C<Y output, an AND gate supplied with V and XSA output and Y≦C output, and an AND gate supplied with B<× and Y≦C output. , the above-mentioned outputs 41, 42 and 43 are taken out from the respective AND gates.
In addition, as the horizontal scanning line for measuring the above-mentioned duration and time interval, the horizontal scanning line that crosses the top end of the rectangle represented by the background separation signal formed when the image sensor captures the object to be inspected is used. Errors occur due to the resolution of the image sensor and the fact that, for example, the cutting line of the PTP sheet as the object to be inspected is not a perfect straight line. It is preferred to select horizontal scan lines that cross the avoided portion.

In addition, a mask signal waveform for setting the inspection target area in combination with a background separation signal representing the outline of the object to be inspected is set in advance and stored in a storage element such as ROM or RAM, and the mask signal is used for discussion. When using the mask signal, the waveform can be corrected by controlling the address of the mask signal depending on the direction and amount of the slope of the contour of the object to be inspected detected as described above. As is clear from the above description, according to the present invention, unnecessary signals from areas other than the inspection target area of the appearance of the object to be inspected are eliminated in an automatic appearance inspection apparatus that performs an appearance inspection of an object to be inspected such as a PTP packaged product. By adding a shift correction circuit to the mask signal generation circuit used for the inspection, it is possible to reliably mask unnecessary parts regardless of the tilt direction without reducing the inspection target area due to the shift of the inspected object. Therefore, the performance of detecting defects in the appearance of the object to be inspected can be improved.

In addition, in the present invention, since tilt detection and correction of the mask signal waveform based on the detection are all performed purely electronically, there is no need to provide a complicated mechanism for the inspection device, and in addition, the response speed for defect detection can be sped up. You can also do that. moreover,
The inspection device of the present invention can detect whether or not the object to be inspected is being conveyed at an angle with respect to the sensor field of view and its direction, and can also detect troublesome children if necessary.
It can be applied not only to the appearance inspection of TP packaging products, but also as a general sagging detection device, and can also be applied to correcting sagging using a sagging detection signal.

Furthermore, in a general pattern recognition device, it is possible to improve inspection accuracy by detecting deviations and excluding undesired areas that are not subject to inspection.

[Brief explanation of drawings]

Figure 1 is a diagram showing the shape of PTP packaging, Figure 2 is a diagram showing the shape of PTP packaging.
A line diagram showing the definition of the height and amount of inclination of the sheet, Figs. 3 and 4 are graphs showing an example of the relationship between the inclination angle and amount of inclination of the PTP sheet, and Fig. 5A shows the margin of the mask for visual inspection. FIG. 5B is a graph showing an example of the relationship between mask allowance and neck tolerance; FIG. 6 is a block diagram showing an example of the configuration of the inspection device of the present invention; FIG. Figures 7A to L are signal waveform diagrams showing the signal waveforms of each part, and Figure 8A
, B and C are diagrams each showing the tilted state of the PTP sheet, FIG. 9 is a block diagram showing an example of the configuration of a framing direction detection circuit used in the device of the present invention, FIGS. 10 to E, and FIG. A to E and FIGS. 12A to E are similarly explanatory diagrams of the inclination state and signal waveform diagrams showing the operating principle of forehead detection, respectively. 1... PTP sheet, 2... Product storage pocket, 3... Slipper (perforation), 4... Mask, 5... Background separation signal, 6, 8... ... Vertical direction mask signal generation circuit, 7 ... Delay circuit,
9, 10... Vertical mask signal, 11, 12...
...And gate, 13, 14, 15...Horizontal mask signal generation circuit, 16...Mirror direction detection circuit, 17...Mask signal generation circuit, 18, 19
, 20...Horizontal mask signal, 21...
Mask signal, 31...Clock signal generation circuit,
32, 34... Counter, 33... Horizontal synchronizing signal, 35... Counting amount Y, 36...... Counting amount X, 37, 38, 39...・Digital comparator,
40...Forehead determination circuit, 41...No bothersome output, 42...Output for falling to the right, 43...
... Nostalgic upward right output. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 A Figure 5 B Figure 6 Figure 7 Figure 9 Figure 8 Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] 1. In an automatic appearance inspection device that performs an appearance inspection of an object to be inspected by detecting the appearance of the object to be inspected while it is being moved by a conveyance device using an image sensor, an image sensor scanning direction of a background separation signal representing the outline of the object to be inspected is provided. means for measuring the duration of time between the scanning reference signal of the image sensor and the background separation signal; tilt direction detection means for detecting whether or not the background separation signal is inclined relative to the background and the direction of the inclination; vertical mask signal generation means for generating a vertical mask signal based on the background separation signal; a plurality of horizontal direction mask signal generating means for generating horizontal direction mask signals corresponding to the direction of inclination of the object to be inspected with respect to the horizontal scanning direction of the television image based on the separation signal; In accordance with the direction of inclination of the object to be inspected with respect to the horizontal scanning direction, a horizontal mask signal generated from the horizontal mask signal generation means and a vertical mask signal generated from the vertical mask signal generation means corresponding to the direction of the detected inclination are generated. 1. A tilt detection automatic visual inspection apparatus comprising mask signal generating means for generating a mask signal that limits an inspection area in the external appearance of the object to be inspected by combining the mask signal with a direction mask signal.