Why and how to choose the right machine vision system

Machine vision encompasses all sorts of industrial and non-industrial applications, starting from operational guidance to executing critical functions based on the captured and processed images.

Perhaps, the human vision is best for qualitative interpretation of a complex and unstructured scene. Still, machine vision excels at the quantitative measurement of a structured scene because of its speed, accuracy, and repeatability.

Using the right camera resolution and optics, a machine vision system can quickly inspect hundreds or even thousands of parts on a production line per minute. It can also examine object details too small to be seen by the human eye.

Machine vision is critical for achieving strategic goals such as higher quality, increased productivity, production flexibility, less machine downtime and reduced setup time, tighter process control, lower production costs, scrap rate reduction, minimized the risk of recalls, lesser human contamination, and safety of workers from hazardous environments.

The machine vision applications are generally divided into four major categories: guidance, identification, gauging, and inspection (GIGI).

  • Guidance – Locates the position and orientation of a component, compare it to a specified tolerance, and ensure it is at the correct angle for proper assembly.
  • Identification – Reads barcodes (1-D), data matrix codes (2-D), direct part marks (DPM), and characters printed on parts, labels, and packages.
  • Gauging – Calculates the distances between two or more points or geometrical locations on an object and determines whether these measurements meet specifications.
  • Inspection – Detects defects, contaminants, functional flaws, and other irregularities in manufactured products.

A machine vision system consists of many vital components, including the lighting, lens, image sensor, vision processing, and communications. The lighting illuminates an area or part to be inspected, allowing the features to stand out for the camera to clearly see. The lens captures the image to be presented to the sensor in the machine vision camera that converts the light into a digital image and then sends it to the analysis processor.

Here are the key reasons why you should use machine vision:

  • High savings potential that often pays off your investment in about a few months.
  • 100% quality check and maximum product quality.
  • Reduced expensive product recalls, product liability claims, and image loss.
  • Safe production and reliable end products.
  • Smooth, stable, and optimized processes
  • Flexibility and user-friendliness.
  • Seamless and ease-of-use integration into the production process.
  • Higher productivity and competitiveness.
  • Perfect human-machine interaction that results in a more advanced and safe workplace.

Broadly speaking, there are three kinds of machine vision systems available in the market today: 1D, 2D, and 3D. With machine vision becoming three-dimensional, the technology is developing rapidly, creating ever greater opportunities for users to accomplice many tasks in the production cycle in a cost-effective way. The increase in demand for vision-guided robotics system is one of the critical factors that drive the global growth of the machine vision system market.

Other growth drivers are as follows:

  • Demand for vision technology is increasing due to the trend towards industrial automation and robotics needs.
  • Continued increased demand for more productivity and improvement of quality of products and manufacturing processes.
  • Vision technology is a superior alternative for controlling production systems and detection, inspection, and identification that cannot be seen by the human eye.
  • Substantial increase in new applications where vision technology will be applied and adopted.
  • Data from the camera can be decentral stored and computed in real-time through embedded technology.
  • Because of strict regulations on the quality of food and medicines, vision technology offers the solution because of the 100% traceability and ‘fail/pass’ application.

Now, let’s discuss how to choose the right machine vision system. There are several key factors to take into account when selecting a machine vision system. Your choice depends on the objects you want to inspect, the necessary speed, lighting and temperature, and available space.

  • Make sure that the system is suitable for the application you are looking for. Whether it is a line scan or area scan camera, the type of camera you need depends on the application. A machine vision system designed for one task may not be well suited for the other.
  • Determine the critical visual performance criteria for ensuring the right level of performance of the camera and lens. Consider the factors such as object size, required measurement accuracy, image size, image capture and processing speed, and the need for color.
  • Resolution is vital since it is one of the main elements driving camera costs. Calculate the resolution requirement based on the size of the field of view. Get as much resolution as needed, but do not overdo it. Determine the budget because that will set the bar for resolution.
  • Choose a camera system with an imaging rate slightly higher than the actual requirement.
  • Consider the environmental factors since some cameras suit stationary views while others are more suitable for handling linear object motion. Temperature, humidity, and vibration can impose a need for specific system fabrication and assembly practices. Besides, the physical space for installing the system can restrict camera and lens choices.
  • Give enough attention to choosing the right communication interface from available interfaces out there: USB 2.0, USB 3.0, GigE, Camera Link, PoE, and VGA.
    Make sure the camera adequately functions in the lighting and environmental conditions. Check out if the manufacturer is willing to customize the camera.

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