JPH0228438Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention uses an imaging device such as a television camera to detect dirt, foreign matter, etc. attached to the surface of an object such as a pharmaceutical capsule, or surface deformation. The present invention relates to a device for detecting the presence or absence of defects, and particularly to a device configuration that can reliably detect surface defects that exist on curved end surfaces such as those in the capsule.

[Prior art and its problems]

FIG. 4 is a block diagram of a conventionally used surface defect detection device for an object such as a pharmaceutical capsule. This is a binarization circuit that converts the image signal 1a into a binary signal 2a and outputs it as a threshold signal. In FIG. 4, if there is an abnormal condition such as dirt, foreign matter, etc., or deformation on the surface of the object imaged by the television camera 1 (hereinafter, such a condition may be referred to as a surface defect), a binary value will be generated. An abnormality such as an interruption occurs in the signal 2a. 4 is a signal processing device that detects such an abnormality in the binary signal 2a and performs a predetermined operation such as outputting an alarm, and 5 is a surface defect detection device comprising the above-mentioned parts.

FIG. 5 shows a defect detection device 5 for a cylindrical capsule 6 having a bottom curved at both ends as shown in FIG.
In FIG. 5, the vertical axis V represents the voltage level of the image signal 1a in FIG. This is the waveform of the image signal 1a corresponding to the axis XX of the capsule 6 when scanning is performed parallel to the axis XX. Hereinafter, the image signal 1a corresponding to one horizontal scan may be referred to as a 1H raster signal. In FIG. 5, Vs is the voltage level of the reference signal 3 input to the binarization circuit 2 in FIG.
Since the characteristic line A is binarized, the part between points B and C is binarized, and the defect detection device 5 corresponds to the binarized part of the characteristic line A. Defects are detected on the surface of the capsule 6. Therefore, the detection device 5 in FIG.
There is a problem in that defects cannot be detected for the portion of the capsule 6 that corresponds between and points C, so differential detection is performed on the characteristic line A between points B and D and between points C and E. A method for detecting defects has been proposed, but this method has problems such as difficulty in setting thresholds for detecting defects and a complicated equipment configuration. There was a problem in that even if differential detection was performed, it was not possible to detect all surface defects.

[Purpose of invention]

The present invention solves the problems with conventional surface defect detection devices as described above, and provides surface defect detection that can reliably detect surface defects that exist not only on flat surfaces but also on curved end surfaces such as those in the capsule. The purpose is to provide equipment.

[Key points of the idea]

In order to achieve the above object, the present invention provides an imaging device that outputs an image signal, and a first imaging device that binarizes the image signal based on a reference signal and outputs a first binary signal.
In an object surface defect detection device comprising a binarization circuit and a signal processing circuit that performs signal processing on the first binary signal, the image signal is further binarized with a predetermined threshold value and a first binary signal is output. a second binarization circuit that is driven by a second binary signal, integrates a constant voltage signal during a period when the second binarization signal is applied, and uses the integrated output as the reference signal; It is equipped with a reference signal generation circuit that generates
With this configuration, the reference signal changes over time in almost the same way as the image signal,
It is possible to obtain a surface defect detection device that can reliably detect surface defects present not only on a flat surface but also on a curved end surface such as in the capsule described above.

[Example of idea]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a waveform explanatory diagram of each part in FIG. 1. 1st
In the figure and FIG. 2, 7 is a constant voltage generated by the image signal 1a and a circuit not shown.
V ₁ is input, and a second binarization circuit outputs a second binary signal 7a obtained by binarizing the image signal 1a using the voltage V ₁ as a threshold; This is a reference signal generation circuit that is driven by the reference signal 3 and generates the reference signal 3. The reference signal generating circuit 8 is constructed as shown in FIG. That is, in Figure 3,
81 is an input terminal to which the second binary signal 7a is input;
82 is an input terminal to which a constant voltage Vs generated by a circuit not shown is input, 83 is an output terminal to which the reference signal 3 is output as explained below, and 84 is a binary signal 7a. It is an analog switch that is input through a terminal 81, and is turned on when the signal 7a is at L level, shorting the output terminal 83 to ground, and turned off when the signal 7a is at H level. 85 is a variable resistor, and 86 is a capacitor.

In FIG. 1, the binarization circuit 7 and the reference signal generation circuit 8 are configured as described above, so that while the level of the image signal 1a input to the binarization circuit 7 is lower than the constant voltage V ₁ . The binary signal 7a is at the L level, and as a result, the analog switch 84 is turned on and the reference signal 3 is at 0 volts. However, when the level of the image signal 1a exceeds the constant voltage _V1 , the binary signal 7a is turned on. 7a becomes H level, the analog switch 84 is turned off, and as a result, the voltage of the reference signal 3 is equal to the resistance value of the resistor 85 and the capacitor 86.
The capacitance increases according to a time constant determined by the capacitance. This voltage increase continues while signal 7a is in the H level state, so the voltage of signal 3 is a constant voltage.
Asymptotic to Vs. 9 in FIG. 1 is a first binary value that receives the image signal 1a and the reference signal 3, calculates the difference between the two signals, and becomes H level when this difference voltage becomes larger than the built-in constant voltage _V2 . The first binary circuit outputs the signal 9a, and in this case, the signal processing circuit 4 is configured to perform signal processing on the binary signal 9a.

In FIG. 1, since the binarization circuit 9 is configured as described above, when the image signal 1a is input to the binarization circuits 7 and 9, the binary signal 9a is inputted at the time of point F in FIG. becomes H level, and this H level is the second
It returns to the L level at the time of point G in the figure. Therefore, the first
According to the defect detection device shown in the figure, point F in Figure 2
Surface defects are detected for the portion of the capsule corresponding to the characteristic line A between
While it was not possible to detect defects in the capsule portion corresponding to characteristic line A on the left side of point B in Figure A, that is, in the curved end surface at the left end of capsule 6 shown in Figure 6, It is clear that the apparatus shown in the figure can detect defects even in such a capsule portion. According to the device shown in FIG. 1, as is clear from FIG. 2A, the defect detection range is reduced only in the capsule portion corresponding to the characteristic line A between points G and C compared to the conventional device. However, in the apparatus shown in FIG. 1, the main parts are constructed so that this reduction in the detection range is negligible.

[Effect of idea]

As described above, the present invention includes an imaging device that outputs an image signal, a first binarization circuit that binarizes the image signal based on a reference signal and outputs a first binary signal, and a first binary signal. A signal processing circuit that performs signal processing on the signal; and a second binarization circuit that binarizes the image signal using a predetermined threshold value and outputs a second binary signal; a reference signal generating circuit that is driven by the first binary signal, integrates the constant voltage signal during the period when the second binary signal is applied, and generates the integrated output as the reference signal. Therefore, by configuring it in this way, the reference signal changes over time in almost the same way as the image signal, so that it can be used not only on a flat surface but also on a curved end surface like the one in the capsule mentioned above. This has the effect of providing a surface defect detection device that can reliably detect existing surface defects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of waveforms of various parts in FIG. 1. FIG. 1A, FIG. 1B, and FIG. FIG. 3 is a configuration diagram of the reference signal generation circuit in FIG. 2, FIG. 4 is a configuration diagram of a conventional surface defect detection device,
FIG. 5 is an explanatory diagram of the operation of the apparatus shown in FIG. 4, and FIG. 6 is a plan view of a capsule as an object to be detected for defects. 1... Television camera as an imaging device, 1a...
...Image signal, 3...Reference signal, 4...Signal processing circuit, 7...Second binarization circuit, 7a...Second binary signal, 8...Reference signal generation circuit, 9...First and second Value conversion circuit, 9a...second binary signal.

Claims (1)

[Scope of utility model registration request] an imaging device that outputs an image signal; a first binarization circuit that binarizes the image signal based on a reference signal and outputs a first binary signal; and a signal processor that performs signal processing on the first binary signal. A second binarization circuit that binarizes the image signal at a predetermined threshold value and outputs a second binary signal; and a second binarization circuit that is driven by the second binary signal. and a reference signal generation circuit that integrates the constant voltage signal during the period in which the second binary signal is applied and generates the integrated output as the reference signal. Device.