JP2000214116A - Thermography device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately judge whether an object is appropriate or not regardless of the atmospheric temperature of the object. SOLUTION: An object is line-scanned by a detector 2. A control part 4 compares a signal at this time with a threshold VTH for judging to see if the object is appropriate or not and outputs an alarm signal when the signal strength is equal to or more than the threshold VTH. At this time, the control part 4 extracts a signal that is regarded as a signal from a normal object out of signals from the detector 2, obtains the average of their strength, and determines the new threshold VTH based on the average. The new threshold VTH is used for the line scanning of a next object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermographic apparatus.

[0002]

2. Description of the Related Art A thermographic apparatus is used not only for measuring the temperature of a subject but also for judging the quality of an article as a subject. As an example, a case where the quality of a heat-sealed portion in a heat-sealed package is determined with reference to FIG. 2 is as follows. In FIG. 2, 1
Denotes a thermographic device, 2 denotes an infrared detector (hereinafter simply referred to as a detector), 3 denotes a signal processing unit, 4 denotes a control unit, 10 denotes a conveyor, and 11 denotes a package.

Now, it is assumed that a predetermined article is stored, and a package 11 which is heat-sealed at an appropriate place is being conveyed by a conveyor 10. In FIG. 2, it is assumed that a hatched portion of the package 11 is heat-sealed.

The thermographic apparatus 1 includes a detector 2, a signal processing unit 3, and a control unit 4. The detector 2 performs line scanning at a predetermined timing. This timing is the timing at which the heat-sealed portion of the package 11 is line-scanned as indicated by the arrow in the figure. An output signal from the detector 2 is subjected to predetermined processing such as amplification and A / D conversion in a signal processing unit 3 and input to a control unit 4. Control unit 4
Compares the strength of the input signal with the threshold value V _TH and outputs an alarm signal if the signal strength is equal to or higher than the threshold value V _TH . Then, the package 11 from which the alarm signal has been output is:
It is removed as a defective product in a subsequent device (not shown).

The reason why the quality of the heat sealing portion of the package 11 can be determined in this manner is as follows. When the heat sealing is successfully performed, when the heat sealing portion is line-scanned, the obtained signal intensity is substantially constant as shown in FIG. When heat sealing is not performed satisfactorily due to, for example, mixing, it is known that a peak occurs as shown by P in FIG. ing. Therefore, the threshold V _TH as shown in FIG. 3C is determined in advance, and the quality of the heat sealing can be determined by comparing the signal intensity obtained by the line scanning with the threshold V _TH . The threshold value V _TH may be determined experimentally according to the site where the thermographic device 1 is used.

[0006]

However, in the above-mentioned conventional thermographic apparatus 1, the threshold value V _TH for determining the quality of heat sealing is a fixed value, but the conveyor 10
And the ambient temperature of the heat-sealed portion of the package 11, which is the subject, may fluctuate due to the operating conditions of various devices, including the ambient temperature, and the outside temperature. The signal intensity of the output signal of the detector 2 is increased as a whole, and an alarm signal is output even when the heat sealing is performed well, or the atmosphere of the heat sealed portion of the package 11 which is the subject. When the temperature decreases, the signal intensity of the output signal of the detector 2 decreases as a whole, and an alarm signal may not be output even when heat sealing is not performed well. That is, in the conventional apparatus, the accuracy of the pass / fail judgment may be reduced or the pass / fail judgment may not be performed due to a change in the ambient temperature of the subject.

The above description has been given of the case where the quality of the heat-sealed portion of the package is judged. However, the above-described problem is generally caused when the signal strength detected by the detector is compared with a threshold value to judge any quality. It is something that happens in nature.

Accordingly, the present invention provides a thermographic apparatus capable of accurately determining whether or not the quality is good regardless of the ambient temperature of the subject by changing a threshold value for performing the quality determination in accordance with a change in the ambient temperature of the subject. The purpose is to provide.

[0009]

In order to achieve the above object, a thermographic apparatus according to the present invention compares the signal intensity of a signal from a subject obtained by an infrared detector with a threshold value to determine whether the subject is good or bad. In the thermographic apparatus, the threshold value is changed based on a signal intensity of a signal from a subject.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Here, a case will be described in which the thermography apparatus according to the present invention is applied to the quality determination of a heat-sealed portion in a heat-sealed package.

The block configuration of the thermographic apparatus according to the present invention is the same as that shown in FIG. 2, but the operation of the control unit 4 is different. This will be described below.

In the control unit 4, three threshold values V _TU , V _TL and V _TH are set. V _TU is a threshold value indicating the upper limit intensity of a signal obtained from a subject which is well sealed with heat, and
_TL is a threshold value indicating the lower limit strength of a signal obtained from a subject that is well sealed with heat. These two thresholds V _TU , V _TL
Is a fixed value, and may be determined experimentally in consideration of the environment and the like in the vicinity of a place where a line scan of the heat sealing portion of the package 11 is performed by the thermographic device 1. And V _TH
Is a threshold for judging the quality of the heat sealing portion,
It is determined based on the signal strength of the signal obtained when performing the line scanning. These three thresholds V _TU , V _TL , V _TH
As shown in FIG. 1 (a), the magnitude relation of V _TH > V _TU > V
_TL .

The operation of the control unit 4 is as follows.
Now, assuming that the heat sealing portion of the package 11 is line-scanned, the control portion 4 takes in the output signal from the signal processing portion 3 and compares it with the threshold value V _TH, and the signal intensity becomes _{equal to} or higher than the threshold value V _TH . In this case, a process of outputting an alarm signal is performed, and the signal strength at each position of the acquired signal is calculated as V _TU ,
Compared with V _TL , those having a signal strength of V _TU or less and V _TL or more are extracted, an average of those signal intensities is obtained, and the obtained average value is multiplied by a predetermined coefficient k. _Is determined. This new threshold value V _TH will be used to determine the quality of the heat-sealed portion during the next line scan. Note that the value of the coefficient k may be determined based on various experiments.

In this process, the control unit 4
As indicated by A in (b), which signal intensity exceeds the threshold V _TU, about what the signal strength is less than the threshold V _TL, in order to determine the next new threshold V _TH is not used. That the signal strength exceeds the threshold V _TU, and for those signal strength is less than the threshold V _TL is because not be regarded the signal from a normal subject. Therefore, in the case shown in FIG.
The signal strength in the range indicated by B in the figure and the signal strength in the range indicated by C will be used to determine the next new threshold V _TH .

As described above, according to the thermographic apparatus, when the ambient temperature of the subject changes, the threshold value V _TH is changed accordingly, so that the quality judgment is always performed with high accuracy. be able to.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above description, 1
And it shall determine a new threshold V _TH of the following for each round of line scanning, but those may be determined a new threshold V _TH of the following for each line scan of a predetermined number of times.

Further, in the above embodiment, the case where the thermography apparatus is applied for judging the quality of the heat-sealed portion in the heat-sealed package has been described. The method can be generally applied to a case where the signal strength detected by the above is compared with a threshold value to determine any quality.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an operation of a control unit of a thermographic apparatus according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a thermography apparatus when applied to the quality determination of a heat-sealed portion in a heat-sealed package.

FIG. 3 is a diagram for explaining a method of determining the quality of a heat-sealed portion in a heat-sealed package.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thermography apparatus, 2 ... Infrared detector, 3 ... Signal processing part, 4 ... Control part, 10 ... Conveyor, 11 ... Package.

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Claims (1)

[Claims] 1. A thermography apparatus for judging the quality of a subject by comparing the signal strength of a signal from the subject obtained by an infrared detector with a threshold, wherein the threshold is changed based on the signal strength of a signal from the subject. A thermographic apparatus characterized in that: