Machine Vision

Imaging-based applications

Machine Vision, in simplistic terms, is a computer’s ability to see. It includes analog to digital conversion (ADC), digital signal processing (DSP), and video devices. These optics are categorised as imaging optics (for more information on imaging optics, click here).

Machine vision technologies require a complex combination of cameras and sensors. These cameras essentially give industrial machinery the ability to see and sort information, speeding up production and logistics dramatically. Both these cameras and sensors require high grade optical lenses and mirrors, and many require highly complex visual elements.

Optics in Machine Vision

There are three variables for selecting the right lens design for machine vision applications. The first being the sensor size; the lens must be large enough to illuminate the complete sensor in order to avoid shading. The pixel size also needs to be determined and the lens must have the appropriate optical resolution in order to resolve the pixel size. The final variable is the required magnification of the lens in order to resolve the details of an object; the required magnification is based on the needed resolution of the object and the pixel size. 

Fixed focal lenses and macro lenses are used for close range applications where high precision is required. Since machine vision technology has advanced, many different imaging optic designs have been developed in order to limit the amount of singular components needed within the system. Because of these developments cameras are able to send high-megapixel images at incredibly quick frame rates.

An example of the use of optical lenses in machine vision systems is within the CMOS image sensors. A key part of these sensors are the micro lenses used to help focus and steer incoming photons into the photosensitive region, and doubling the photodiode sensitivity. This all depends on the wavelength and incident angle of the microlens. Many manufacturers of these sensors chose to use polymer optics in this application due to the cheaper cost, easier manufacturability and the flexibility of the material. 

Optical Coating 101

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