Posted March 8, 2019 at 7:05 am by by56014904

Factors to consider when choosing an optical camera

A good optical camera should have high precision, high definition, good color reproduction, low noise, etc., and can be programmed to control the exposure time, brightness, gain and other parameters through the computer, and the image window is steplessly scaled with an external trigger input. Features such as flash control output. Microvision, a well-known BIBO nonlinear crystal manufacturer and seller in China, combines years of R&D and production experience with customer needs, and carefully selects the precautions and necessary parameters when selecting an optical camera, so that general customers can make reasonable choices.

Image processing, the object of processing is the image from the optical camera, so the choice of optical camera, industrial camera, industrial camera is an indispensable and very important step.
When choosing an optical camera, the first thing to understand is your own detection task, whether it is static or dynamic, how often is the photo, whether it is defect detection or size measurement or positioning, the size of the product (field of view), and the need How much accuracy is achieved, the performance of the software used, the on-site environmental conditions, and other special requirements. If it is a dynamic photo, what is the speed of the movement, choose a small exposure time according to the speed of movement and whether the camera needs to be scanned progressively; and the camera’s rate (high camera frequency) is related to the pixel, usually the higher the resolution, the lower the rate. The optical frequencies of different brands of optical cameras are slightly different; the resolution of the customizable large size optical prism can be calculated according to the different inspection tasks, the size of the product, the resolution required, and the performance of the software used; the temperature of the field environment is to be considered. Choose a different optical camera for humidity, interference, and lighting conditions.

Optical camera / line camera

For stationary detection or general low-speed detection, optical cameras are preferred, and linear array cameras are considered for special applications such as large-format high-speed motion or roller motion;

Resolution

The resolution actually refers to the number of camera pixels, which is usually tens of thousands of pixels, but in the detection, it is not necessary to pursue too high pixels, the pixel height will bring the frame rate down, the image processing is slow When selecting, it can be selected according to the accuracy requirements of the project. The accuracy of the project occupies 1 pixel in the image as the basic requirement. The engineer with weaker software level can choose 3 pixels or more.

Frame rate

Select the static detection as much as possible, so the cost of the whole project will be reduced a lot, but it will bring about a decline in detection efficiency. For those who have motion, use a frame exposure camera, and the line exposure camera will cause the image to be distorted. For the specific frame rate selection, High-speed cameras should be chosen blindly. Although high-speed cameras have high frame rates, they generally require externally enhanced light illumination. The high cost and image processing speed are also very stressful. It needs to be determined according to the relative motion speed, as long as it is within the detection area. The object to be measured can be captured, for example, the field of view with a length of 1 meter is observed, and the object to be measured passes through the field of view at a speed of 10 m/s, and the object to be measured can be completely captured at a speed of 10-12 frames per second. However, the same speed through the 0.1 meter field of view, you need a camera 100-120 frames / sec.

color

In the industrial visual inspection, we generally recommend the use of black and white cameras, because software processing is generally converted to grayscale data for processing, and industrial color cameras are converted by Bayer algorithm, and there are certain colors with real colors. gap;

Chip type, size and pixel size

As far as the current industry status is concerned, for the case of high image quality requirements or poor ambient illumination, it is recommended to use a CCD sensor and select an customized large size and special shape CaF2 optics with a larger pixel size. Of course, as the industry develops, the gap between CCD and CMOS is also In the gradual reduction, CMOS changes the resolution (ROI) more flexible, the same resolution, and higher speed.

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