What are Frame Grabbers?
Your image processor or integrator may have mentioned this component on his bill of materials, which may have been the first time you had heard of a frame grabber. Or maybe the phrase was spoken during the earlier conversation regarding your new machine vision solution. In any case, more information on the purpose of a frame grabber is required.
In this essay, we make the topic more understandable. In doing so, we respond to the following queries:
- What exactly are frame grabbers?
- What are they used for?
- When and why ought one to use them?
Why frame grabbers?
The initial purpose of frame or video grabbers was to transform analog pictures into digital signals. Due to the prevalence of digital-only image processing technologies nowadays, this usage has mostly disappeared.
Today, digital cameras are connected to devices that do not have the same data interface (such as USB) using frame grabbers instead. Frame grabbers can also be used to deliver triggers to a linked PLC or robot controller that contain information about the progress of picture processing. Through their interface, they may also announce and communicate information regarding the precise timing of the incoming picture data.
Function
An analog-to-digital converter comes after a sample-and-hold amplifier in most analog frame grabbers. This gives each incoming voltage a number. The analog picture is converted to a digital numeric representation, allowing for the digital transmission of the image capture.
This translation is no longer required thanks to digital frame grabbers. Instead, a PCI or PCI Express card in the computer is typically used here to acquire data in a defined picture format. If necessary, additional features and programmable parameters can be utilized to change the data conversion’s format. Thus, digital frame grabbers serve as interpreters for various picture formats.
Picture data transmission is simply one aspect
Frame grabbers enable exact data speed and transmission predictions since this image capture to machine vision translation service always operates across a cable. This is especially important for time-sensitive operations like identifying a damaged item. Data transmission can reach up to 25 GB/s since frame grabbers are typically used with Gigabit Ethernet (although USB and FireWire are other options). This indicates that latencies of under 1 are attained. As a result, latencies of less than 1 s are now feasible. This is a significant improvement for large picture data.
A data check is also done by more advanced frame grabbers. As a result, they are able to make accurate claims about whether all data was transported as intended or, more importantly, if and where it was lost. This greatly simplifies troubleshooting.
Frame grabbers’ ability to combine the complete picture acquisition process onto a single device is unquestionably its biggest benefit. Today’s image processing systems are typically multi-layered and occasionally sophisticated. The administration of this procedure is greatly facilitated by the use of a frame grabber.
Grabbing capabilities provide quicker processing
All triggering and synchronization of the different picture capture devices may be managed via frame grabbers. Particularly when several cameras and flashes are employed. An further benefit is the ability to integrate image processing right away. For instance, color adjustments fall within this category.
Simple image processing duties may already be handled by the frame grabber, freeing up the linked PC’s CPU. This is made feasible by the computer’s built-in Direct Memory Access (DMA). In this manner, the frame grabber may immediately process the incoming data without losing any time. The amount of time saved is huge.
Frame grabbers demand attention.
Frame grabbers are by no means a minor part of industrial machine vision, despite all these capabilities, linkages, and interactions. In order to handle the occasionally difficult operation, its implementation and proper use need extensive user expertise.
In the processing PC, the frame grabber also has to be connected. A bigger PC casing could be required if a PCI bus grabber is employed. It might get rather crowded in certain control cabinets.
Use it when and why?
When a quick and dependable solution is needed for image processing, frame grabbers are always employed. This holds true for both the actual picture capture and early processing as well as synchronizing multi-part setups. Frame grabbers truly shine in situations like these. In addition to capturing athletic events, typical uses in industry focus mostly on time-sensitive quality checks on production lines.
