The entire machine vision system is divided into two main sections: image acquisition and image processing. In image acquisition systems using analog industrial cameras, the image acquisition card is a crucial component connecting these two sections. The image acquisition card acts as a connector between the image acquisition and processing sections; it's a hardware device capable of acquiring, storing, or outputting digital image information. The object being measured is captured by the camera, and the photoelectric conversion by its image sensor converts the target into analog image signals. These signals are then converted into digital image signals by the image acquisition card and output to the image processing software for a series of operations.
Throughout its operation, there are still many fundamental concepts that we need to understand.
A/D conversion
We've learned that image acquisition cards can convert analog signals to digital signals, which plays a crucial role in the image acquisition process of a machine vision system. This analog-to-digital conversion performed by the image acquisition card in a machine vision system is called A/D conversion, and the component that performs this conversion is called an A/D converter. There's also the term D/A conversion, which, obviously, refers to the conversion from digital signals to analog signals.
Number of transmission channels
In industrial production inspection processes, multiple vision systems often need to operate simultaneously to ensure a certain level of efficiency. Therefore, to meet the needs of system operation, machine vision system image acquisition cards typically perform A/D conversion on multiple cameras simultaneously. The number of transmission channels refers to the number of conversions that can be performed simultaneously using the same image acquisition card. Langrui Intelligent Technology's series of image acquisition cards are designed with users in mind, fully considering their needs, and offering single-channel, dual-channel, and quad-channel transmission options.
sampling frequency
Sampling frequency is a key technical specification of image acquisition cards in machine vision systems. It refers to the frequency at which the image acquisition card acquires image information, reflecting the card's image processing speed and capability. Especially when performing high-speed image acquisition, sampling frequency is a crucial parameter in determining the type of image acquisition card to choose.
Frames and Fields
A video signal can be progressively sampled over a series of frames, or it can be interlaced sampled over a sequence of interlaced fields. In this interlaced video sequence, half of the data in a frame is sampled at each time sampling interval.
Features:
A video capture card on a computer can receive analog video signals from a video input terminal, acquire and quantize these signals into digital signals, and then compress and encode them into digital video. Most video capture cards have hardware compression capabilities; they first compress the video signal on the card during acquisition, and then transmit the compressed video data to the host computer via the PCI interface. Typical PC video capture cards use intra-frame compression algorithms to store digitized video as AVI files, while more advanced cards can directly compress the acquired digital video data into MPEG-1 format files in real time.
