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Industrialized Vision Inspection Systems

Automated quality control of print, labels and packaging

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FAQs

What is a Vision Inspection System?

Machine Vision, or Vision Inspection Systems encompass automated machinery with cameras designed to visually inspect food, beverage or pharmaceutical packages for defects, and errors. Visions systems have been programed to take a photo of a package on the production line and compare specific inspections against an "ideal" image stored in its memory. This provides a manufacturer the capability to:

  • Compare packaging on the production line to ideal images and reject mismatches
  • Measure product dimensions and reject out-of-tolerance product
  • Read data on products to verify that correct data is shown and is printed to acceptable quality standards.
  • Count the number of products in a case or package and reject it if there is too few or too many items
What are the components of a Vision Inspection System?

There are a number of components available to choose from when specifying a vision inspection solution. These components are the fundamental building blocks of a solution and are critical to the effectiveness of the inspections the final solution performs. For an industrialized Vision Inspection System, typical components are as follows:

  • Cameras - PC-based or Smart Cameras
  • Lights – used to illuminate the product packaging to achieve the best image
  • Framing & Brackets – used to hold the lights and camera in place to ensure accurate imaging
  • HMI (Human Machine Interface) – a touch screen monitor and computer enclosure containing software tools to enable the user to fine-tune the inspection for each product inspected.
  • Enclosure (depending upon the model) – used to minimize outside light or for harsh wash-down environments
  • Addition equipment (conveyor, side grips, tracking modules) - integrated into the system depending upon the production line setup
What is the difference between a PC Based and Smart Camera vision system?

Smart Cameras are completely self-contained systems which perform all the image processing and analysis work using an on-board CPU. Smart Cameras often feature integrated lighting as well, making them ideal for simple applications such as code reading. Unfortunately, this simplicity is not without its drawbacks – on-board memory is naturally limited, meaning that a comprehensive record of all products inspected may not be feasible. A PC based vision system uses cameras which transmit images to a control PC which coordinates image capturing and processing. PC-controlled systems generally deliver faster processing times – which can be important for more complex applications – and carry the advantage of having far more memory to store different inspection profiles and inspection images.

Why do you need a Vision Inspection System?

Inspection of product packaging is critical to ensure products are safely packaged for end consumers. Using a machine vision system you can achieve 24/7 operation and track and record every product inspected. With a Vision Inspection System you can achieve the following:

  • Minimize quality defects
  • Protect the customer and consumer
  • Protect your company brand and reputation
  • Offer a return on investment (ROI)
  • Support adherence to industry best practice guidelines and industry standards
  • Mitigate the risk and impact of product recalls and returns


Investment of a vision inspection system will pay off over time, by eliminating mislabeled products, label mix-ups and the associated costs resulting from mistakes, you can avoid costs from product recalls, fines and production rework. Learn more from our ROI Calculator, by customizing your production data to see how much you can save.

How does mislabelling happen?

There are a few causes of product mislabelling, although the most common cause is operator error. This refers to any issue caused by human interaction with the production line – forgetting to load a different label type during a product changeover, for example. There is also equipment malfunction – which can be a defect in the printing process caused by wear and tear. This can result in anything from a shift in coloration to missing lines of important text. It occurs less often, but can still result in significant problems.

What are the consequences of a labelling error?

The consequences for poor print or label quality can vary depending on the severity of the problem. A printing defect such as faded coloration does not place any consumers at risk, or expose manufacturers to any potential legal threat, but it does potentially damage the brand's image. In more extreme cases, such as an error that results in missing information, a product recall is usually necessary.

How does a label vision system graphical identification work?

Graphical identification is a fairly straightforward process. When the lable inspection system is set up, the user selects a graphical element on the label which is unique to that particular label – this can be anything from a photo of the product in question, or a symbol – it can even be a particular phrase. Once the vision system knows what to look for, it will search for that graphical element on each label it inspects. Should that element be missing or incomplete, the system flags it for removal from the production line or alerts operators.

What's the difference between OCR and OCV?

Optical Character Recognition (or OCR) is a method for identifying printed characters on a package surface. OCR is ideal for variable text fields, where it may not be possible to know what text string will be on the production line. The system compares a given character image against all the characters in a pre-defined font to find the closest match. Optical Character Verification, on the other hand, is looking for a pre-defined value – it is used to check for the accuracy of a code rather than determine what a code is. More information on the way that OCR and OCV work can be found in our white paper Making Codes Readable.

How are 1D and 2D barcodes read by cameras?

Cameras read barcodes in the same way that any barcode reader functions: the software analyses the contrast between filled and empty spaces in order to understand the shape of the code, and then decodes the pattern into an alphanumeric string. Depending on the code type, this either means analysing a simple horizontal line (as in a 1D barcode) or analysing a square (in the case of a 2D barcode). Either way, the basic principle of reading in a pattern of light and dark is the same. The advantage of using a camera instead of a more traditional barcode reader is that camera systems are better-suited to gauging barcode quality – a more traditional barcode reader can only really return a readable or undreadable result.

How does a missing cap actually happen?

There are plenty of reasons something can go wrong, particularly in a high-speed production environment. It could be an insufficient number of caps loaded into the filler, or an unexpected problem with the feed, or some other mechanical issue. It happens more often than you might think, and it is inevitably a headache for operators when it happens. Being able to instantly alert operators when caps start going missing is critical.

Do I need a stand-alone system to check for caps?

No, you really do not need a stand-alone system to check for caps. There are a couple ways to go about this, depending on what your priorities are. If you are only concerned with cap and fill level, you can integrate a smart camera (or a PC-controlled camera) into your existing filling equipment. We have experience with producing integrated solutions, and are happy to lend our expertise and equipment in setting something up. You can find out more about our custom solutions by contacting us or visiting our custom solutions page.

What else can I do while I'm inspecting caps?

The most convenient part of a vision inspection system is its ability to carry out simultaneous inspections of other package elements. A single shot of the package can be used to perform multiple inspections – most simply, a picture used for cap inspection can also ensure the presence of a tamper evident band (if one is used) and verify the fill level. Calibrated correctly, the same image can be used to perform inspections on the package label, although depending on the package shape it may be necessary to use a multi-camera configuration.

Can I inspect the fill level of opaque packages?

A vision-based system will not be able to perform such an inspection with any sort of reliability, although it can be possible depending on the level of opacity. Adding an x-ray element to the system makes such an inspection possible. This is an easy solution to the problem, particularly when dealing with a supplier that can provide both technologies in a way that ensures the software and hardware do not run into any compatibility issues.

What defects are common in packaging seals?

Common seal defects include holes in the seal itself, product caught in the seal, and (more simply) improperly-applied seals. Another common defect is marring or unevenness in the sealing surface itself, which prevents a good seal.

How does seal inspection work?

Depending on a few factors – the seal type, the location, and the material the seal is made from – it is often enough for a camera to look for the presence of the seal material and identify any unusual markings. For clear seals, UV ink is often used to mark the seals, which cameras are able to spot by using specialized lights.

How reliably can a vision system spot flaws in a package seal?

Completely clear seals are difficult to inspect, as the system may not be able to reliably spot holes or gaps. Foil or colored seals are far easier to spot flaws in, although depending on how reflective the surface is it may be necessary to utilize specialized lighting in order to provide a clear image.

Can a Smart Camera Perform Seal Inspection?

Package seal inspection applications can vary immensely in terms of complexity, depending on the packaging material and the container shape. Simple presence inspections (that is to say, the presence or absence of a tamper evident band), can be easily accomplished using a smart camera. Detecting flaws in a seal is also frequently possible, although a more complex solution may necessitate the use of a PC based vision system.

What is a custom vision inspection system?

While most of our vision inspection systems are designed to be highly flexible in terms of available configurations, occasionally the situation calls for a more unique touch. This may be down to size concerns, or it may just make sense to have cameras integrated into existing hardware. In this case, our engineers work to design a system that fits your specific line layout to provide a vision solution that works.

What is the difference between a custom vision inspection system and an OEM-produced vision inspection system?

With an OEM system, we are brought on to help an equipment manufacturer (the OEM) create equipment that includes a vision inspection component. We do not provide a system to an end user – that's the OEM's job – but we do provide the necessary support not just to develop and install the system, but further maintenance and support during the life of the system, if desired.

What other inspection applications can I do with a custom system?

While most of our standard inspection systems are able to perform a variety of inspection applications, there are a few applications in particular that require specialized equipment or product handling. This is particularly the case when conducting quality inspection on rigid plastic containers. In order to perform these inspections with the highest levels of precision, we rely on specialized lenses and lighting, along with sidegrip conveyors and other product handling solutions.

Where do your Smart Cameras come from?

We manufacture our own smart cameras in house, making them in our Germany facility and sending them across the globe, wherever they are required. Building our own cameras has given us considerable flexibility in our offerings, and we are constantly developing them to be faster and more accurate.

How do I know whether or not I need a custom solution?

The best way to figure out what you need is to contact a METTLER TOLEDO representative. We will take a look at your product and the inspections you need performed, and determine whether or not one of our standard offerings work or if we will need to put a custom solution together. Regardless of the result, you will get an effective, fast, and fully-supported vision inspection system from us.

I'm an OEM in need of vision system components. How do I contact you?

Simply contact us and let us know in your message what you need. A METTLER TOLEDO representative will be in touch to discuss the details of your planned project. Once we have the particulars, we will work with you to design the vision inspection elements of your planned system.

What do you mean by 'integrated vision system?

When we talk about an integrated vision system, we specifically mean a piece of production equipment that includes a vision inspection component along with whatever other capabilities it may have. An example would be a filling and capping station with an included camera to check fill levels or cap presence, but it could be in any number of other applications as well.

Why would I want an integrated vision system?

Perhaps the greatest and most noticeable advantage to an integrated solution is the reduction in system footprint. It is ideal for adding vision inspection to an existing production line without requiring a significant overhaul of the line layout. It is also useful when planning a new production line, as vision can be placed where it is most effective.

Do integrated systems only use smart cameras?

Smart cameras are commonly used in the creation of integrated systems, but they are not the only option. PC-controlled cameras might make more sense depending on space, processing power required, and type of inspection control point you have in mind. We also offer other METTLER TOLEDO Product Inspection systems developed from the ground-up to include a vision component.

How will a vision system fit into my production process?

Positioning a vision system depends on what precisely you are hoping to inspect and where space exists on the production line. The advantage of going with an integrated system is that it can be easy to add the necessary equipment to the production line without having to redesign the line's layout. While there is no way to avoid some changes to layout (cameras are small, but they still take up space), the impact can be significantly reduced with proper planning.

What about new production lines?

When planning a new production line, space is still going to be a factor – and combining product inspection systems into a single unit helps to establish a firm quality control point on the production line. Similarly, a new production system with integrated vision components allow for more efficient detection and removal of defective products.

What kind of smart cameras do you use?

We manufacture our own smart cameras, like we've been doing for the last 30 years. We are pretty good at it.

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