international patent application w0/2011/121346 confidential overview of nir defect detection system

International Patent Application W0/2011/121346 CONFIDENTIAL

Overview of NIRDefect Detection System


Background


For the detection of plastics and other materials in foodstuffs, it is not always possible to use traditional methods such as x-ray and metal detectors as these materials often cannot be detected via these approaches. Often x-ray or metal detectors detection apparatus are not easily deployed at strategic points in the production process due to restricted access or radiation hazard concerns etc.

ITL’s near-infrared (NIR) imaging technique uses NIR beams of light—around the wavelengths found in ordinary domestic remote controls—and signal recovery techniques commonly used in astronomy.

Work in the area of industrial application of NIR in NDE was reported initially at the annual QNDE conference in 2008 [1,2] and has enjoyed considerable success since in various deployments. It is a zero-radiation technique

Technical Overview


• Originally developed for security applications, this technique has also had commercial application for in-line food inspection and has now been applied to HB Fuller products .

• Unlike x-rays this apparatus is low-voltage and low powered and is completely free of non-ionising radiation.

• The technique of NIR imaging can detect things which are detectable by x-rays and metal detectors but also many things which often are not, such as rubber, paper, wood and plastics .

• Also provide simultaneous in situ chemical analysis by transmission spectroscopy and detection of chemical signatures.


The figure opposite shows a cardboard box that contains several specimens made of wood and cotton (Q-tip), plastic (pen lid) and metal (tack and paper clip).

Note that it shows several materials in shot at the same time, three of which are normally highly radiolucent (plastic, cotton and wood are not well imaged by x-rays).


•In-line inspection of moving objects requires a compromise or “trade-off” in clarity and sharpness of imaging in return for real-time detection at practical belt speeds.

•This often means that an image will become less recognisable - but this does not necessarily mean that that detection is still not possible

•The main approach is to use “blob” extraction and histogram distribution analysis to distinguish between product and contaminant. The software may not know what the defect actually is but it knows that it is not product and hence activates a reject mechanism

Real-Time Industrial Application


The image is blurred - but there is no doubt that an object is being detected.

Real-Time Industrial Application: Detectivity Vs. Image Distortion


3D Surface

The photograph of the black rubber, o-ring and the pen top

The image scan of the black rubber, o-ring and the pen top.

Example - Plastic and Rubber in CheeseDetection of plastic contaminants at realistic production rates involved a deal of distortion of the NIR image but did not compromise the detection of the presence of these materials in cheese, as illustrated below


Moisture Detection using 980 nm Wavelength

3D Surface3D Surface3D Surface

850 nm 980 nm 1064 nm

•The NIR of 980 nanometres is strongly absorbed by free water and moisture and appears to be darker.

•Below, a water bearing sample with two defects, illuminated at various NIR wavelengths, illustrates this.

•If two wavelengths were used the simultaneous imaging/defect detection and moisture content determination is possible .


Initial In-Situ NIR Defect Detector Results from HB Fuller Plant in 6th

October City, Egypt

17th January 2011


1. Recorded NIR Image of Single Bag on Belt

NO CONTAMINANT


•Click on image to Start REPLAY


Bagged product containing no defect and its equivalent NIR Image


2. Recorded Image of Single Bag on Belt Containing

Contaminants


PAPERYellow paper underneath yellow product

(Defect in bottom of bag as it rests on belt and hidden from sight)


•Click on picture

opposite to Start REPLAY


Bagged product containing paper contaminant and its equivalent NIR Image


Other Contaminants


(Both Contaminants laying in bottom of bag as they rest on the belt and thus hidden from sight)

Wood Washer


Bagged product containing washer and equivalent NIR Image

(NB: Similar results obtained with both metal and nylon washers)


Bagged product containing wood contaminant and its equivalent NIR Image


3. Next stage of installation and proposed validation

procedure.


October 2011

First stage of installation was in October 2011 and was for the purpose of data-collection and characterisation trials in order to tune the operational parameters of the machine (illumination intensity, gain settings etc.) and train the software to be able to distinguish between product and contaminant for a range of different glues.

Although this was a successful installation it was not without problems: fortunately was memorialised and fully documented with a photographic record by Chris Blears how after delivery of the working machine to Duckinfield in the UK, Egyptians Customs officials had prised opened the machine and caused extensive damage to fittings and internal components which required an extended stay of an extra two days by ITL staff to affect a field-repair. Joe Kijowski later instigated a complaint with the Egyptian Customs regarding this. The machine ran continuously and trouble free from thereon.

Timeline


January 2012

Following the successful characterisation trials, and based on the data gathered , ITL decided to provide HB Fuller with an upgraded-specification detector beyond that originally contracted for. ITL staff took another visit to the site in Egypt to implement the next stage and also be on hand to assist with the P&G Audit.

Based on the previous experience with Egyptian Customs, the new detector unit and illumination modules were carried as hand luggage to ensure their safe delivery. Other specialised test equipment such as oscilloscopes, and general tools were shipped as checked-in luggage due to airport security regulations. Unfortunately, on the outbound journey luggage with all the test equipment, tools and personal effects were permanently lost by Air France

.....Egypt can be a very arduous environment in which to conduct business where basic things which are often simple to source in the USA or Europe such as fully-threaded 3 mm stainless screws with slotted cheese or hex heads (also lost in the luggage) can be difficult to get. This was compounded by the fact that the first two days of the visit were public holidays. Most crucial though, was the lack of test equipment such as oscilloscopes. This was a major impediment as the installation and setting-up process depends upon such specialised tools.

Trying to make-do with out the proper equipment was unfortunately not successful and resulted in the illumination module being damaged and an incomplete installation and the electronics being returned to the UK for diagnosis and repair.

Timeline


February 2012

ITL diagnosed and replaced the lighting module and delivered it to Duckinfield along with the upgraded detection unit. HB staff watched a successful demonstration of the upgraded unit’s performance and were briefed regarding its installation. However, it proved technically too difficult to assist the installation process via remote tele-conferencing and the installation remains to be completed.

Timeline


Immediate problems and proposed actionIssue Proposed Action

Installation of second stage behind schedule Deliver and demonstrate working machine in the UK and then two ITL engineers , one hardware and one software, accompany HB personnel to Egypt plant to oversee installation. Suggested date: 18th March onwards

Tools and Equipment To ensure adequate resources in terms of fittings and equipment are available , suggest despatch via courier of these items to Egypt beforehand.

Other issues These would be such things as full connectivity with the machine at the plant to maximise performance by remote continuous monitoring and providing software upgrades – but are of secondary importance at this time.

international patent application w0/2011/121346 confidential overview of nir defect detection system

Documents

commercial application

contaminant slide

equivalent nir image

replay slide

image distortion slide

sight slide

realtime detection

technique of nir imaging