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### Selection Examples of Industrial Camera and Industrial Lens

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2021/05/01

Matching relationship between industrial camera and lens resolution

The image quality of the lens has its own series of measurement indicators. Generally speaking, the image quality of the camera should correspond to the image quality of the lens, and the difference can not be too big. If the lens is good enough, the resolution of the fuselage sensor will not go up, and the quality of the viewfinder can not be displayed. The frame size and resolution of the fuselage are higher, and the quality of the lens is not strong enough to catch the excellent picture quality.

Generally, in the selection of industrial camera and lens, in the aspect of resolution matching, in order to facilitate the memory of the matching relationship between the lens and the camera, people often use the resolution of the corresponding camera to name the lens. This naming method is not scientific, but it also brings many misunderstandings to people who are new to the visual system. Megapixel resolution cameras are often applied mechanically to megapixel lenses, 2 megapixel resolution cameras to 2 megapixel lenses, and 5 megapixel resolution cameras to 5 megapixel lenses. Head. In fact, the lens and the camera do not correspond to the pixel resolution (the number of pixels) of the camera itself, but the limit spatial resolution (that is, the space cut-off frequency corresponding to the transfer function MTF).

Note: The resolution of the lens refers to the logarithm of black and white that can be distinguished within 1mm. The performance of the lens is mainly judged by MTF curve. The smoother the curve is, the better the performance is.

Examples of Lens Selection (Selected Lens for Defined Cameras)

1. Known customer observation range is 30mm*30mm, working distance is 100mm, CCD size is 1/3', then how many focal lenses are needed?

Computing method:

1/3'= 3.6mm (vertical) chip size in the vertical direction

F=(100*3.6)/30

2. The system resolution required by known customers is 0.06mm, the pixel size is 4.7um, the working distance is more than 100mm, and the light source is white LED lamp, then how many focal lenses are needed.

Computing method:

1) If the customer does not have zoom requirement, the fixed-focus lens can be selected.

2) If you have measurement function, use small distortion lens or telecentric lens as far as possible.

3) Focal length calculation

Imaging magnification M = 4.7/(0.06*1000)

F = L*M/(M+1)

Note: The image plane of the lens should be larger than or equal to the size of the CCD, and the interface of the lens and the camera should match.

Examples of Camera Selection (Selected Camera with Defined Lens)

Known customer lens size is 1/3, interface is CS interface, field of view size is 12*10 mm requires accuracy of 0.02 mm, then what resolution camera should be selected?

Computing method:

(12/0.02)* (10/0.02) = 300,000 pixels, but if defect detection does not usually use only one pixel to represent accuracy, it multiplies by 3-4 times, that is, 30*4 = 1.2 million pixels. Minimum not less than 1.2 million pixels.

Size of sensor for industrial camera

1/4: (3.2mm x 2.4mm);

1/3: (4.8mm x 3.6mm);

1/2: (6.4mm x 4.8mm);

2/3: (8.8 x 6.6 mm);

1: (12.8mm x 9.6mm)

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