图像采集卡 区别比较： Comparison between video capture card and image capture card :
The concept and principle of frame grabber:
Frame grabber concept:
Image capture card (Image Capture Card), also known as image capture card, is a hardware device that can obtain digital video image information, and store and play it. The function of the image acquisition card is to collect the image signal into the computer and save it on the hard disk as a data file.
The principle of frame grabber:
Acquisition, the process of sampling the video / image after being sampled, quantized, converted into a digital image, and input and stored in the frame memory. Because the transmission of image signals requires a high transmission speed, the universal transmission interface cannot meet the requirements, so an image acquisition card is required.
The signal obtained from the video source is sent to the video capture card through the video interface. The signal is first subjected to analog-to-digital conversion and then sent to a digital decoder for decoding. The analog-to-digital converter ADC is actually a video decoder. It can be seen that it decodes and digitizes video signals from video sources. In addition, different color space can be used to select different video input decoder chips.
When the signal input rate of the frame grabber is high, the bandwidth between the frame grabber and the image processing system needs to be considered. When using a PC, the peak theoretical bandwidth of the frame grabber using the PCI interface is 132MB / S.
1. The field of view (FOV) or scene is a specific part of the real world that the camera and optical system "see".
2. The CCD chip converts light energy into electricity.
3. The camera outputs this information to the frame grabber in the format of an analog signal.
4. AD-converter converts analog signals into 8-bit (or multi-bit) digital signals. Each pixel independently expresses the light intensity in the form of a gray level.
5. These light intensity values are stored in the matrix data structure of the memory from the matrix of the CCD chip.
Video capture card concept and principle:
Video capture card concept:
Video capture card (Video Capture card) is also called video card. It is to input video data or mixed data of video and audio output from analog video cameras, video recorders, LD video players, televisions and other video signals into a computer and convert it into a computer-readable Digital data is stored in the computer and becomes editable video data files. According to its use, it can be divided into broadcast-level video capture cards, professional-grade HD video capture cards, and civilian-level video capture cards.
Video capture card principle:
High-definition video capture card, "Video Capture Card", its function is to capture video signals to a computer and save them on the hard disk in the form of data files. It is an indispensable hardware device for our video processing. It is used for post-editing digital video signals, such as cutting pictures, adding filters, subtitles and sound effects, setting transition effects, adding various video effects, and so on. Finally, the edited video signal is converted into standard VCD, DVD, and online streaming media formats for easy dissemination.
Video (Video) is a mixed media in which multiple still images (image frames) and continuous audio information move synchronously on the time axis. Multi-frame images change over time to create a sense of motion, so video is also called moving image. According to the different storage and processing methods of video, it can be divided into analog video and digital video.
Video acquisition is the process of converting the analog signal of a video source into a digital signal (that is, 0 and 1) and storing these digital information on the computer's hard disk. This analog / digital conversion is performed by a capture chip on a video capture card.