Machine Vision Applications: Labeling and Coding

NOVEMBER 28, 2009 (ASIA PACIFIC) - Recent economic recession has changed consumer's behaviors where they are forced to reduce their spending while trying to maintain pre-recession lifestyle. This is apparent even while purchasing food & drink. In addition to it, food safety awareness is increasing due to media reports on recent food scandals. Three forces are acting towards food labeling and coding. These are consumers, regulators and food manufacturers, each protecting their own interest. The proposed article will examine each of these forces and discuss some of the available technologies that food manufacturers can utilize to inspect labels and read codes in their product lines using Machine Vision System.

Recent economic recession has changed consumer's behaviors. They are forced to reduce their spending while trying to maintain pre-recession lifestyle. This is apparent even while purchasing food & drink. In addition to it, food safety awareness is increasing due to recent food scandals on global level. Government and industry regulators are acting to protect consumer's interest. They are enforcing stricter regulations to ensure food manufacturers provide appropriate labels and legible manufacturing & expiry code on food packaging. Almost all the food manufacturers that we have met so far understand their responsibility to provide safe food to their customers, but find it hard to balance among cost, quality & safety in a highly competitive consumer market.

Food labeling in packaged food industry is important for several reasons. Most importantly, a food label and date code provides useful information to consumers about the product, its origin and safety when designed according to the right rules and regulations.
Thus the three driving force to labeling and coding are (a) consumers, (b) regulators, and (c) food manufactures. (See the pic. 1). This article will gather some of the insights from these driving forces. It will then discuss some of the technologies that food manufacturers can adopt in their production lines.

Picture 1: Three driving force to labeling and coding
 

Consumers

As per September 2008, “Consumers and Nutritional labeling”, a global Nielsen report published on internet www.sg.nielsen.com. Two-thirds of global consumers are reading nutritional panels more than two years ago. Nielsen's survey has found that 25% of Asia Pacific shoppers always check the nutritional information on the package. “As obesity rates continue to rise globally and with lifestyle-related heart disease the number one killer worldwide today, there is increasing pressure on governments and the food industry to play a greater role in educating people about what they're eating. Shoppers, when surveyed, consistently ask for more information about exactly what food labels mean. They like to know how to make informed choices about healthier eating from reading nutrition information and claims such as ‘low fat’ and ‘reduced salt’, What is in the ingredients list, percentage labeling of the key ingredient and the country of origin of that food. Next big question is how we ensure that food is safe; this is about food recalls, storage requirements and allergens.

 

Regulators

Despite the growing proliferation of products claiming to help manage weight gain, waistlines are growing to epic proportion globally. In a bid to mitigate this impending crisis, policy-makers across the globe have turned to labeling packaged goods with nutritional information to help consumers become savvier in managing their energy intake. Besides the weight gain, another driving force for food labeling is the food safety that includes allergy and contamination. FDA estimates that approximately 2% of adults and about 5% of infants and young children in the United States suffer from food allergies. Each year, roughly 30,000 individuals require emergency room treatment and 150 individuals die because of allergic reactions to food. Eight major foods – milk, eggs, fish, Crustacean shellfish, tree nuts, peanuts, wheat, and soybeans – amount for 90% of these food allergies.

In spite of having Food Allergen Labeling and Consumer Protection Act of 2004, Incorrect Labeling is one of the top reasons a product is detained in USA, explained Laura Dougherty, Registrar Corp. in a recent workshop in Singapore on Key Labeling Regulations Affecting Exports to the USA. The correct label should include common name of the product, Net Weight, Ingredient & Allergen, Name/Address of Manufacturer, Country of Origin & Lot or Tracking Number. There are guidelines for fonts and layout. More information on key labeling regulations for food exports to USA can be found at www.registrarcorp.com. Registrar Corp. assists with Food and Beverage, Medical Device, Drug, and Cosmetics compliance for exports to the U.S.

Surprisingly FDA does not require bar code and lot numbers, but several other countries do require. For example, Gulf Cooperation Council that is covering Saudi Arabia, UAE, Bahrain, Qatar, Kuwait and Oman clearly specifies requirement for lot and producing factory identification, production and expiry dates on most products. (www.esma.ae). Closer to home, Food Regulations under Agri-food and Veterinary Authority of Singapore (AVA) requires pre-packed food products listed in the regulations to bear a date-mark to indicate the food content's expiry date and food label in English with essential information.
 

Manufacturers

Imagine a formula milk powder container for baby is actually carrying milk powder for adult. Unwary consumers will end up feeding adult milk formula to their baby without suspecting. This can happen if the maker for milk powder has products ranging from baby to adult, and wrong label is applied accidentally due to human error. This is not an imagination to scare you but rather a real case. A quick check on internet can reveal that several food & beverage manufacturers, including top brands have history of recalled products. The four common causes are:

1. Labeling defect whereby allergen is not declared on a product label. For example, bottles of Honey Dijon Peppercorn dressing mistakenly have the back label for French dressing. The peppercorn product contains eggs, which is not declared as an ingredient on the French dressing label. People who have allergies to egg run the risk of serious allergic reaction if they consume this product.

2. Labeling detect whereby manufacturers forget to declare allergen. For example, chocolate containing nuts.

3. Foreign matter in packaging. Example, rubber pieces in a can of soup or glass shards in juice bottle.

4. Contamination of product by microbial, salmonella, melamine etc.

Picture 2: Machine Vision System inspects date code like a human eye

Another leading company in Japan does not want to take any chance. The company is a leader in beverage market. Its product variety ranges in hundreds. It was looking for a solution that ensures correct labels are applied on each of its product before shipment. Besides mixing up of label, it is also highly concern about its appearance. The top management in this company is strong believers in technology. One of the scenarios that they considered during risk assessment was – “what if, wrong label is applied due to human error; it goes undetected and exported to overseas market?” The answer is obvious. It would be hard to win the confidence of overseas clients and regulators. Immediately after that the top management approved budget for having suitable machine vision system in their production line. The Machine Vision System with multiple cameras are inspecting and verifying if correct labels are applied and are not defective.

Picture 3: Machine Vision System Confirming Correctness of Label

 

What is a Machine Vision System and What It Can Do?

Machine Vision Systems like Omron's ZFX uses CCD color camera to capture image label, date code. At first, OK object is taught to the controller. The controller divides the entire model into several small models automatically (Pic. 4) and memorizes them.

Picture 4: ZFX Machine Vision System memorizing OK object

During production run, camera captures each label and processor compares it against the pre-registered OK model. If there is any difference (Pic. 5), such as missing print, wrong print then NG outputs are send to activate an alarm to alert or a corresponding rejection mechanism.

Picture 5 : ZFX Machine Vision System capturing NG parts

 

Recent Innovation in Sensing Technology

So far food manufacturers had to use different process steps, one for code reading using a bar code or a 2D code reader and second for Machine Vision Systems for label inspections or date code inspection. But, Omron has combined barcode/2D code and powerful inspection items into ZFX-CD to create two-in-one process. It is easy; it saves time, money and reduces complexity for mechanical integration.


Picture 6: ZFX-CD inspects code and label at the same time

But, just detecting wrong label or date code is not enough. The most important point is to retrieve saves images to investigate cause of the production defects. This is a big advantage of using a two-in-one Vision Sensor plus code reader build on sensing technology. Machine Vision Systems have capability to save past NG images that can be recalled and analyzed. The result of this analysis helps to understand cause of the defect.


Picture 7: ZFX-CD sending inspection data to external PC for SPC and logging

Finally, whatever may be the driving force the awareness and importance for food safety and labeling will keep on increase. Each involved party i.e. Regulators, Consumers and Manufacturers have an important role to play because it matters to all of us.
 

For more information, please refer to:

ZFX Machine Vision System