What Machine Vision Tool is Right for Your Application?

Machine vision is an inherent terminology in factory automation but selecting the most efficient and cost-effective vision product for your project or application can be tricky.

We can see machine vision from many angles of view, for example market segment and application or image processing deliver different perspectives. In this article I will focus on the “sensing element” itself, which scan your application.

The sensing element is a product which observes the application, analyzes it and forwards an evaluation. PC is a part of machine vision that can be embedded with the imager or separated like the controller. We could take many different approaches, but let’s look at the project according to the complexity of the application. The basic machine vision hardware comparison is

  1. smart sensors
  2. smart cameras
  3. vision systems

Each of these products are used in a different way and they fit different applications, but what do they all have in common? They must have components like an imager, lens, lighting, SW, processor and output HW. All major manufacturing companies, regardless of their focus or market segment, use these products, but what purpose and under what circumstances are they used?

Smart Sensors

Smart sensors are dedicated to detecting basic machine vision applications. There are hundreds of different types on the market and they must quickly provide standard performance in machine vision. Don’t make me wrong, this is not necessarily a negative. These sensors are used for simple applications. You do not want to wait seconds to detect QR code; you need a response time in milliseconds. Smart sensors typically include basic functions like:

  • data matrix, barcode and 2D code reading
  • presence of the object,
  • shape, color, thickness, distance

They are typically used in single purpose process and you cannot combine all the features.

Smart Cameras

Smart cameras are used in more complex projects. They provide all the function of smart sensors, but with more complex functions like:

  • find and check object
  • blob detection
  • edge detection
  • metrology
  • robot navigation
  • sorting
  • pattern recognition
  • complex optical character recognition

Due to their complexity, you can use them to find products with higher resolution , however it is not a requirement. Smart cameras can combine more programs and can do parallel several functions together. Image processing is more sophisticated, and limits may occur in processing speed, because of embedded PC.

Vision Systems

Typically, machine vision systems are used in applications where a smart camera is not enough.

Vision system consists of industrial cameras, controller, separated lighting and lens system, and it is therefore important to have knowledge of different types of lighting and lenses. Industrial cameras provide resolution from VGA up to 30Mpxl and they are easy connected to controller.

Vision systems are highly flexible systems. They provide all the functions from smart sensors and cameras. They bring complexity as well as flexibility. With a vision system, you are not limited by resolution or speed. Thanks to the controller, you have dedicated and incomparable processing power which provides multi-speed acceleration.

And the most important information at the end. How does it look with pricing?

You can be sure that smart sensor is the most inexpensive solution. Basic pricing is in the range of $500 – $1500. Smart cameras can cost $2000 – $5000, while a vision system cost would start closer to $6000. It may look like an easy calculation, but you need to take into consideration the complexity of your project to determine which is best for you.

Pros Cons Cost
Smart sensor
    • Easy integration
    • Simple configuration
    • Included lightning and lenses
    • Limited functions
    • Closed SW
    • Limited programs/memory
$
Smart camera
    • Combine more programs together
    • Available functions
    • Limited resolution
    • Slower speed due to embedded PC
$$
Vision system
    • Connect more cameras(up to 8)
    • Open SW
    • Different resolution options
    • Requires skilled machine vision specialist
    • Requires knowledge of lightning and lenses
    • Increased integration time
$$$

Capture

Increase Competitiveness with RFID in the Intralogistics Industry

In times of globalization and high labor costs it is a challenge to increase competitiveness in the fashion industry. Within a warehouse, an RFID system supports a high degree of automation as well as short transport distances. To supply dealers and to keep their facility profitable, one of the most successful fashion companies in the world has built a highly modern hanging garment distribution center. Let’s take a look at how they successfully implemented RFID technology to improve their processes.

Separate and sort clothes with just one hybrid module (2D code + RFID)

Within this distribution center 45,000 of these innovative clothes hanger adapters (L-VIS) are used. They replace the previous trolley-based logistics approach by allowing the transportation of a number of different garments that have the same destination.

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L-VIS, clothes hanging adapter made by P.E.P. Fördertechnik

With the investment in some additional space in the so-called buffer or storage zone, and by providing empty trolleys at various locations to keep the product flow moving, this project is successfully accomplished. A major advantage of this system, is the usability over the entire intralogistics chain. From receiving, to the hanging storage, to the sorter for single item identification, and from there as a transport unit to shipping.

The clothes hanger contains an RFID chip, that is automatically read by the conveying technology, and the 2D-code. This code is read manually by employees with a portable acquisition unit. The code can be DMC (Data Matrix Code), QR-Code, or any other optical code standard.

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HUGO BOSS garment distribution center (Metzingen, Germany)

Information exchange without visual contact

A high frequency RFID chip is installed. With this identification system, neither direct alignment nor contact is needed to enable data exchange via nearfield communication. Non-contact identification is extremely reliable and wear-free. The identification system consists of a rugged data carrier, a read/write head and an RFID processor unit. The processor unit communicates to the control system via Profibus, but could be accomplished with ProfiNet or EtherNet/IP as well.

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BIS-M RFID processor unit

The following table gives you an overview of types of Radio Frequency Identification solutions that are available on the market:

Common Types Low Frequency Low Frequency High Frequency Ultra High Frequency
Frequency 70/455 kHz 125 kHz 13.56 MHz 860 … 960 MHz
Short description Dedicated solution to tool identification in Metal-Working industry. Standard solutions for simple Track & Trace applications. Fast & reliable – even with high volumes of data in medium distances in assembly, production and intralogistics. Identification at large distances and bunching capability for current material flow concept.

For the customer, the decision to choose this particular system among others was the separation between the processor and read/write head. In a widespread facility it would not make sense to have a decoder with 30 read/write heads attached. By interfacing two read/write heads per processor, it is possible to track the travel of a transport unit over the entire conveyor line as well as track within the aisles between the individual shelves.

An additional advantage of the system implemented is the housing options. The L-VIS carrier and the 30 mm read/write head are an ideal match. The simple mounting of the processors and ready-to-use connection were of high value to the system integrators. In the sorting area, a 2D code was supplemented by the RFID tags to reach speeds of up to 0.6 and 0.7 m/s. This would probably not have been possible with the installation of a corresponding camera technology.

Experiences have shown, that RFID projects need a lot of support. Consultation and assistance from true experts can be provided by our team. Learn more about RFID technology here.