Will USB cameras lose data as rumored?
Generally, camera data loss has nothing to do with the interface used by the camera. Whether it is USB/1394/PCI/GbE, poorly designed drivers or cameras are the real cause of data loss.
There are many network cameras on the market that use USB as the transmission interface, but the problem of data loss is often caused by the poor design of the driver and the camera buffer. This does not mean that there is a problem with the USB interface, but the network camera manufacturer's driver Caused by poor programming or camera design, this also creates a false perception that USB will lose data.
The USB interface is a standard specification jointly formulated by many international manufacturers such as Intel/Microsoft/HP/NEC/Philips. The compatibility and stability are absolutely beyond doubt. Since 2000, Intel has fully and exclusively supported the USB interface in its entire series of CPU chipsets (this is why computers using Intel chipsets can use USB directly on the motherboard, while 1394 must insert a PCI interface)
AISYS Vision full range industrial cameras use self-developed high-performance drivers, combined with the large-capacity buffer memory installed on the camera, to fully and smoothly use the USB bandwidth and transmit real-time image data accurately and without errors. Among the more than 2500 sets of vision systems sold, no users have reported the problem of data loss.
Refer to the following [Details of how the data channel works]
The reason why a poorly designed camera will lose data is the congestion of the data channel, which cannot be processed in time. So when a new image comes in, the previous one may be forced to be discarded, or the new image may be forced to be discarded. To solve this problem, designers need to carefully design every link between the driver and the camera hardware data transfer.
There are two places where the video data will be congested, one is the camera, and the other is the PC
The image sensor transmits image data to the USB chip on the camera, Then the USB chip sent to the PC. If the PC system is too busy to process the received job, the sensor keeps throwing out new image data, at this time, the camera must have enough memory buffer. otherwise, the data will be lost.
1. Whether the user's program has a buffering mechanism for the image space waiting for calculation, in order to increase the buffer of the image to gain buffering time so that the program's operation can be processed in time.
However, if the operation is stable, the overall processing speed of the CPU is slower than the incoming speed of the image.
Then the buffer will always overflow, and data will be lost.
2. The efficiency of the hardware driver is the key to the reception of the PC, and how many THREADs of KERNEL MODE in WINDOWS operating system are dividing up the time of the CPU system.
The receiving efficiency is poor, and the camera does not have enough buffer memory, which will cause data loss.
The camera works very fast, the Buffer of the camera will not increase unlimitedly like the PC program. In practice, As long as there is enough capacity to accommodate the temporary busyness of the system.
Drivers for our USB cameras are self-developed and optimized. The data is transmitted by DMA, and the SDK on the PC side is designed with a QUEUE mechanism in the form of software. All cameras have been calculated and measured to be equipped with sufficient buffer memory.
In transmission and buffering, we have in-depth research and solutions. Our long-term repeated actual measurement, the image data transmission has excellent performance and stability.
There is only one situation in which the data will be lost by using the AISYS camera. That is, the speed of the user program operation is slower than that of the camera image input. After a long time, the software queue is full and can no longer store new images.
But this is the system losing data, not the camera losing data. No matter the camera using 1394/ USB/ PCI/ GbE... any transmission interface will get the same result.