Sensors in Machine Vision

The heart of a camera lies in its image sensor. These sensors are responsible for capturing light across various wavelengths and converting it into digital signals. Subsequently, image processing systems scrutinize and interpret this data, serving a multitude of purposes such as machine control, quality inspection, security, and traffic monitoring. The compatibility between the lens and the image sensor plays a pivotal role in determining image quality, impacting the precision and reliability of the overall image processing.

When selecting a lens, several criteria come into play:

• Spectral Sensitivity: Choosing the appropriate lens involves considering the spectral sensitivity. Optical lenses employ different materials with distinct properties depending on the wavelength of light rays. For instance, glass can appear opaque at certain infrared wavelengths, necessitating the use of an infrared-optimized lens for processing infrared images. Additionally, whether the image sensor is monochrome or color-sensitive within the visible spectrum may influence the lens choice as well.
• Sensor Size: The physical dimensions of a sensor chip, referred to as sensor size, are decisive for the angle of view and, consequently, the focal length of the lens. Typically expressed as the optical format in inches (e.g., 1″, 3/4″), the sensor size directly impacts the overall composition of the image.
• Resolution: Measured in megapixels, the sensor’s resolution determines the level of detail in an image. Higher resolution sensors may demand high-grade lenses to fully exploit their capabilities. Specialized applications include line scan cameras with sensors consisting of a single line of pixels, specifically designed for continuous scanning of products like paper or textile webs.
• Pixel Size: The pixels size is another critical aspect, as smaller pixels can capture less light, affecting performance in low-light conditions. In these cases, preference is given to faster lenses with larger apertures (lower f-numbers) to enable more light to reach the sensor.
  
  

When choosing the right lens for your imaging needs, it is imperative to consider these sensor properties and their interaction with the lens. Our experts are ready to provide guidance, or you can utilize our Online Lens Selector here to find the right lens for your application.