Real-Time Terahertz Diagnostics for Detecting Microleak Defects in the Seals of Flexible Plastic Packaging

Morita, Yasuyuki; Dobroiu, Adrian; Otani, Chiko; Kawase, Kodo

doi:10.1299/jamdsm.1.338

Cited by 7 publications

(3 citation statements)

References 12 publications

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“…However, liquid contamination is difficult to detect with this method. Morita et al (2007) explored the potential of terahertz radiation for detecting microleaks in seals [12]. Although the technique is able to detect both air-and water-filled channels, it is not an imaging technique, and therefore, the data are not straightforwardly interpreted.…”

Section: Related Workmentioning

confidence: 99%

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

D'huys¹,

Saeys²,

Ketelaere³

2016

J. Imaging

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Packaging protects food products from environmental influences, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the quality of the packaging material and of the closure or seal. A common problem possibly jeopardizing seal quality is the presence of seal contamination, which can cause a decreased seal strength, an increased packaging failure risk and leak formation. Therefore, early detection and removal of seal contaminated packages from the production chain is crucial. In this work, a pulsed-type active thermography method using the heated seal bars as an excitation source was studied for detecting seal contamination. Thermal image sequences of contaminated seals were recorded shortly after sealing. The detection performances of six thermal image processing methods, based on a single frame, a fit of the cooling profiles, thermal signal reconstruction, pulsed phase thermography, principal component thermography and a matched filter, were compared. High resolution digital images served as a reference to quantify seal contamination, and processed thermal images were mapped to these references. The lowest detection limit (equivalent diameter 0.60 mm) was obtained for the method based on a fit of the cooling profiles. Moreover, the detection performance of this method did not depend strongly on the time after sealing at which recording of the thermal images was started, making it a robust and generally applicable method.

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Section: Related Workmentioning

confidence: 99%

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

D'huys¹,

Saeys²,

Ketelaere³

2016

J. Imaging

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“…Adams (2000) describes a method for ultrasound scanning of medical packaging, resulting in a similar difference which he explains as being due to the inability of ultrasound to travel through air, meaning that the ultrasound transmitted into air-filled faults only passes through the first layer before bouncing back. Morita et al (2007) used terahertz radiation to scan package seals. Terahertz radiation, located between infrared and millimeter radiation, has advantages over light in that many materials which are opaque to the visible spectrum are only translucent with regards to the terahertz band, allowing a terahertz sensor to inspect the seals of opaque packages as though they were translucent.…”

Section: Introductionmentioning

confidence: 99%

Polarised light stress analysis and laser scatter imaging for non-contact inspection of heat seals in food trays

Barnes¹,

Dudbridge²,

Duckett³

2012

Journal of Food Engineering

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This paper introduces novel non-contact methods for detecting faults in heat seals of food packages. Two alternative imaging technologies are investigated; laser scatter imaging and polarised light stress images. After segmenting the seal area from the rest of the respective image, a classifier is trained to detect faults in different regions of the seal area using features extracted from the pixels in the respective region. A very large set of candidate features, based on statistical information relating to the colour and texture of each region, is first extracted. Then an adaptive boosting algorithm (AdaBoost) is used to automatically select the best features for discriminating faults from non-faults. With this approach, different features can be selected and optimised for the different imaging methods. In experiments we compare the performance of classifiers trained using features extracted from laser scatter images only, polarised light stress images only, and a combination of both image types. The results show that the polarised light and laser scatter classifiers achieved accuracies of 96% and 90%, respectively, while the combination of both sensors achieved an accuracy of 95%. These figures suggest that both systems have potential for commercial development.

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“…Defective seals were identified by Ostyn et al (2007) due to the abnormal vibration of the sealing bars during their production 2 . Morita et al (2007) explored the potential of terahertz radiation for detecting micro leak defects in the seals of flexible plastic packaging 9 . Shuangyang (2010) studied the inspection of seal quality using machine vision 10 .…”

mentioning

confidence: 99%

Detection of seal contamination in heat sealed food packaging based on active infrared thermography

2015

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In the food industry packaging is often applied to protect the product from the environment, assuring quality and safety throughout shelf life if properly performed. Packaging quality depends on the material used and the closure (seal). The material is selected based on the specific needs of the food product to be wrapped. However, proper closure of the package is often harder to achieve. One problem possibly jeopardizing seal quality is the presence of food particles between the seal. Seal contamination can cause a decreased seal strength and thus an increased packaging failure risk. It can also trigger the formation of microchannels through which air and microorganisms can enter and spoil the enclosed food. Therefore, early detection and removal of seal-contaminated packages from the production chain is essential. In this work, a pulsed-type active thermography method using the heat of the sealing bars as an excitation source was studied for detecting seal contamination. The cooling profile of contaminated seals was recorded. The detection performance of four processing methods (based on a single frame, a fit of the cooling profile, pulsed phase thermography and a matched filter) was compared. High resolution digital images served as a reference to quantify contamination. The lowest detection limit (equivalent diameter of 0.63 mm) and the lowest processing time (0.42 s per sample) were obtained for the method based on a single frame. Presumably, practical limitations in the recording stage prevented the added value of active thermography to be fully reflected in this application.

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Real-Time Terahertz Diagnostics for Detecting Microleak Defects in the Seals of Flexible Plastic Packaging

Cited by 7 publications

References 12 publications

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

Active Infrared Thermography for Seal Contamination Detection in Heat-Sealed Food Packaging

Polarised light stress analysis and laser scatter imaging for non-contact inspection of heat seals in food trays

Detection of seal contamination in heat sealed food packaging based on active infrared thermography

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