How to choose industrial cameras

In the application of machine vision systems, there are many problems in the selection process of industrial cameras, industrial lenses, image capture cards, machine vision light sources, and machine vision system platform software. So today I will introduce you to some experiences in the selection of industrial cameras and industrial CCD cameras.

1. 1. Select the signal type of the industrial camera

   Industrial cameras are broadly divided into two types: analog signals and digital signals. Analog cameras must have image capture cards. The resolution of standard analog cameras is very low, usually 768*576. In addition, the frame rate is also fixed, 25 frames per second. For example, standard signals simulate industrial cameras, and there are also some non-standard signals. Most of them are imported products, so the cost is relatively high and the price/performance ratio is very low. So this should be chosen based on actual needs. In addition, the analog signals collected by the analog cameras are converted into digital signals by the digital acquisition card for transmission and storage. Analog signals can be distorted by electromagnetic interference from other equipment in the factory, such as electric motors or high-voltage cables. As noise levels increase, the dynamic range (ratio of raw signal to noise) of the analog camera decreases. Dynamic range determines how much information can be transferred from the camera to the computer. Industrial digital cameras collect digital signals, which are not affected by electrical noise. Therefore, digital cameras have a higher dynamic range and can transmit more accurate signals to computers, such as the MV-VD078SC\VEM200SC\VS120FC series industrial digital cameras on the market.

2. 2. What is the resolution of the industrial camera? Select the camera resolution according to the needs of the system. An application case is used to analyze it below.
   Application case:

   Suppose that the surface scratches of an object are detected, the size of the object to be photographed is required to be 10*8mm, and the required detection accuracy is 0.01mm. First, assuming that the field of view we want to shoot is 12*10mm, then the minimum resolution of the camera should be:. In other words, we are only using it for measurement, so using sub-pixel algorithm, a 1.3-megapixel camera can basically meet the needs. However, sometimes due to the influence of edge sharpness, when extracting edges, if we randomly shift one pixel, the accuracy will be greatly affected. Therefore, if we choose a 3-megapixel camera, we can also allow the extracted edge to deviate by about 3 pixels, which ensures the accuracy of the measurement.