An optical sorter is a device that automatically sorts objects based on visual criteria. Also known as sorting machines, optical sorters are often found in manufacturing and food processing facilities. They are used to find defects and separate different types of items. There are several different types of sorters including some that make use of light sensors while others use infrared light.
One of the primary uses of an optical sorter is to find blemishes in products, and remove unsatisfactory items from the manufacturing process. These flaws may be merely superficial, or they might indicate that a product is defective or unsafe. In a factory that produces a specific size item, for example, a defect or size variation with one of the products could cause significant problems. An optical sorter can detect the defect, and remove the improperly sized part before it is released from the factory.
In addition to controlling the quality of manufactured products, optical sorters are also used to keep different types of items separate. This capability is particularly important for food processing applications. In facilities where consumable products are being packaged, optical sorters are able to identify and prevent foreign objects from accidentally being processed. This helps keep packaged food pure, and prevents dangerous and inedible items from being introduced into the food supply.
There are several different types of optical sorters. The most basic design uses a simple light sensor, called a photodetector. These are able to sense the amount of light reflected by an object. Because dark objects absorb light, an optical sorter with a photodetector can categorize items based on color contrast.
Optical sorters are not limited to the capabilities of the human eye. Some sorting machines use infrared light sensors to sort objects with optical differences that are unnoticeable to human workers. These machines project infrared light onto objects, and detect the level of reflection of this invisible light. Other optical sorting machines combine laser beams with high-sensitivity detectors to detect very small variations or cracks in a product too small for the human eye to see.
In addition to categorizing items based on color and light absorption, some optical sorters are also able to tell the shape of an object. These advanced versions use digital cameras to capture high-resolution optical data, which is loaded into a computer. Using image processing software, the computer can identify lines on the image and determine its general shape. This advanced type of optical technology is very useful for sorting items that are made from the same material but have different outlines.