Vision Sensors
Visions sensors are commonly employed for the rapid and accurate inspection, recognition and evaluation of parts and products throughout the manufacturing process. In some instances this evaluation is the end goal while other
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systems go further and use the interpretation of this information to determine proper action. In this way vision sensors aid in the automated visual inspection, sorting, flaw detection, orientation, measurement, verification, code reading and gauging processes of several industries. These industries vary considerably and include pharmaceutical, food processing, electronics, textile, medical, automotive and automation among others. In each of these applications the vision sensor is the first component of machine vision in that it initiates further action and extrapolation of data. The device achieves this by detecting the presence or absence of product and engaging or disengaging image capturing devices as needed in accordance with pre-programmed system criteria.
There are two main areas of consideration when selecting a vision sensor for a given application. The hardware encompasses all of the physical components. A camera or other image capture device is necessary as well as a controller such as a computer. Additional hardware may include lighting or lens holders to optimize visibility and highlight important features within the frame. The collection and interpretation of the data in each frame, however, necessitates the second element of vision sensors, the software.
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software varies widely and is programmed into the computer processor. A control system, user and developer interfaces and image processing algorithms are essential components while additional memory is a common add on to customized vision sensor systems. In addition to these two broad areas of concern, specific capabilities should be considered with regards for the intended use or uses of the vision sensor before purchasing. The number of images that may be stored and the rate of inspection should meet the expectations of production rates in any industry as well as archiving needs. Shutter control and speed, mounting, dimensions, frame rate, sensitivity, adjustability, and signal to noise ratio are also important concerns. The latter is related to the resolution of the image capture device or camera and can often be compensated for with additional software. Vision sensor manufactures and engineers can provide helpful insight when selecting a sensor or other machine vision technology.
