It is impossible to tell what can be going wrong in a production process that is churning out thousands of faulty products by the second or a production line that is making hundreds of good ones and erroneously throwing most of them out. At such speeds, you cannot notice the obvious. The answer is to slow things down? How do you slow things down without compromising output speed? Machine vision is the answer.
For decades, businesses have used high-speed machine vision to ensure product quality and inspect for any defects before goods are supplied to the market. Machine vision has integrated itself within critical business processes more than ever.
As technology advances, new sensor technologies enable machine vision cameras to produce clear, more stunning results at lower operational costs. This creates the need to upgrade, but how do you pick what camera sensor is right for you?
Line scan vs. area scan cameras
One of the most important questions you need to ask before you buy the next camera sensor is whether your environment needs line scan or area scan machine vision. Area scan machine vision cameras, as the name suggests, takes an image of an area and inspects for any defects. This is great for environments having lots of similar objects in a practical-size field of view, such as water bottles or soda cans.
Line scan machine vision enables scanning and inspecting high-speed moving objects that cannot be captured in a practical-size FOV. For example, you might have a 10,000-ft. aluminum roll that needs constant inspection. You cannot take a still area image scan and pass the entire roll on quality checks. Line scan allows for moving parts to be scanned continuously.
While most machine vision applications and systems are built to satisfy area scan needs for production processes and micro-inspection, line scan machine vision is difficult to set up and needs high-performance sensors producing clear and crisp details for all moving parts on a production line.
Different imaging sensors have different frames per second. In high-speed environments, imaging rates are important. How many units move through a practical-size field of view in a second in your production/live environment? How many components would you like inspected per minute?
If for example, you have 25 bottles moving per second, you would want a machine vision camera that inspects at 30 fps. The extra bit of cushion is to account for errors in imaging and processing.
Conditions and special requirements
Often at times, machine vision systems are needed in extreme conditions. While some environments are functional under extreme heat, others work under extreme cold temperatures. This impacts the sensitive electronic equipment present in machine vision systems.
If you have a production environment that requires all technology to be functional at unusual temperatures, it is important you check for temperature bearing metrics and ask the vendor for solutions they can provide to keep your camera functioning under such conditions.
CCD vs. CMOS image sensors
Another important component is the technology behind the camera’s imaging sensor. A CCD imaging sensor will take photos with lesser noise under less light, however a CMOS imaging sensor will provide greater flexibility as the transistors treat each pixel individually on the sensor. CCD image sensors are also not 10 GigE Vision compliant, which is the latest and most advanced standard in machine vision image processing.
Budget for the new camera
Last but not the least, your budget also defines what camera you are going to purchase next. After thorough research based on what specifications you want in your machine vision system, it is always advisable to narrow your results down on the basis of price.
Operational cost is of importance too. A camera that might sound economical for its purchase price might hurt in terms of power consumption and processing when it is being operated. Operational expenditure is long-term and builds up over time to become a big amount. Always consider investing more initially so you can enjoy cost saving with your new camera when it is being operated.