Rochester Imaging Technology Corporation

A Leading Provider of Components and Turnkey Solutions for the Industrial Imaging Market

 

 

ENTOCENTRIC LENSES

ENTOCENTRIC LENS: def. In machine vision a "normal" or "entocentric"" lens is a lens that generates images that have a "natural" perspective, as compared to lenses with longer or shorter focal lengths. Lenses of shorter focal length are called wide-angle lenses, while longer focal length lenses are called telephoto lenses.

Typical C-mount lenses have a minimum working distance of approximately 10 centimters.

 

To capture a high resolution image of a small object, it is advantageous to place the lens closer than 10 centimeters from the object.

 

A common techniquue used in machine vision to enable close-up, small Field of View images of small objects, is to place spacer rings behind the C-mount lens.  C-mount lens spacer kings are available in legneths from 0.5 mm to 40 mm. The spacer rings increase the distance between the lens and the image sensor, which enables close-up focus.

 

Using C-mount spacers with a C-mount lens has two issues:

     1) Poor light transmission - resulting in poor sensitivity

     2) Optical Sharpness (MTF) Degradation

 

ENTOCENTRIC lenses provide an optimal solution for close-up imaging of small objects, as they are designed from the ground up for this purpose,

 

Using an Entocentric lens will result in significant image quality improvement, as compared to the C-mount spacer technique.

 

Entocentric lenses provide the optimal solutionh for high-resolution imaging, small Field of View imaging applications.

 

Rochester Imaging Technology Corporation

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