Explain the selection method and calculation formula of industrial lens

Date:2018-09-25 Author:admin Click:

For industrial lens selection, it is a very important and critical link. Because the industrial lens selection is suitable and good or bad directly affects the quality of machine vision imaging. The following POMEAS engineers will combine the actual case after many years to share the industrial lens selection method and calculation formula, for your reference only.

Method / step

First, determine the interface, target size and resolution of the industrial camera. For example, a 2/3 "industrial camera with a C-mount and 5 megapixels; then we can first determine that the required industrial lens is a C-mount with a minimum support of 2/3", 5 megapixels or more, or a line pair at 160LP.

Second, determine the field of view (FOV) and working distance (WD) to be achieved, and then calculate the focal length (f) of the industrial lens based on these two requirements and the known target surface size. The calculation formula is:

Focal length f = WD × target size (H or V) / FOV (H or V)

Field of view FOV (H or V) = WD × target surface size (H or V) / focal length f

Field of View FOV (H or V) = target surface size (H or V) / optical magnification

Working distance WD = f (focal distance) × target surface size / FOV (H or V)

Optical magnification = target surface size (H or V) / FOV (H or V)

Selection method and calculation formula of industrial lens

For example, the field of view is 100 * 100mm, WD. Is 500mm; then we first determine from the working distance that the focal length of the industrial lens must be less than 50mm (the naming method of the industrial lens is PMS-5018M, the front letter indicates the POMEAS brand, 50 indicates the focal length 50mm, 18 Indicates the maximum aperture value), the focal length of industrial lenses on the market is generally 12mm, 16mm, 20mm, 25mm, 35mm, 50mm, 75mm. Combined with the size of the camera's target surface to determine which model, the smaller the focal length of the industrial lens, the larger the angle of view and the correspondingly larger field of view.

If the target surface is 2/3 ", you can choose an industrial lens with a focal length of 35mm; if the target surface is 1/2", you need an industrial lens with a focal length of 25mm, or smaller ... and so on.

In the process of industrial lens selection, in order to facilitate the calculation of industrial lens parameters, a target surface size table is provided for reference.

英寸 1.1 inch-target surface size is 12mm wide * 12mm high, 17mm diagonal

英寸 1 inch —— target surface size is 12.7mm wide * 9.6mm high, 16mm diagonal

2/3 inches-target surface size is 8.8mm wide * 6.6mm high, 11mm diagonal

1 / 1.8 inch——The target surface size is 7.2mm wide * 5.4mm high, 9mm diagonal

1/2 inch-target surface size is 6.4mm wide * 4.8mm high, 8mm diagonal

1/3 inch-target surface size is 4.8mm wide * 3.6mm high, 6mm diagonal

1/4 inch-target surface size is 3.2mm wide * 2.4mm high, 4mm diagonal