The market share of USB3 Vision interface as common digital interface keeps growing as it replaces analog and CameraLink. The rate of growth is higher than the speed when GigE Vision interface product was first launched.

About USB3 Vision Interface

USB3.0 was launched in 2008 as a new standard replacing USB2.0. Today, it is a widely used standard used in PC’s peripheral devices, and it is increasingly used as a new interface for industrial cameras. However, USB3.0 was developed as a common interface and thus it was not intended to be used in industrial applications. Automated Imaging Association (AIA), an organization for international standardization, is leading the development of new industrial standard that takes advantages of USB3.0, which resulted in USB3 Vision, a new standard that includes communication specifications required in industrial applications. The standard is built on GenICam standard and took 14 months to develop since the process started in September 2011.

The advantage of USB3 Vision compared with other interface is its speed. USB3 Vision can execute high-speed data transfer at 5Gbit/sec in theory and at about 350MB/sec in practice. This is 3.5 times faster than GigE Vision and as shown below, greater than CameraLink Base. In addition, its CPU load is quite low because of DMA transfer. USB3 Vision is excel in signal stability, and thus it is more stable in terms of electronic and standard points of view.

Comparison of Camera Interface

USB3 Vision camera is excel in real-time performance and its response time to trigger input is as good as CameraLink as shown below. In the meantime, USB3 Vision can be adopted at a much lower cost compared with CameraLink because it does not need a dedicated image input board.

Real-time response speed of USB3 Vision and CameraLink

Mega trend of the Market

The use of USB3 Vision interface has been accelerated partly because of the major trend shift in the market of industrial camera. As the figure shows, the market for the past decade has been shaped by three mega trends, namely a shift from analog to digital, CCD to CMOS, and PC to embedded.

Three Mega trends of the Market

From Analog to Digital

Analog interface had long been the dominant format of main interface, especially in Japanese market. Thanks to the arrival of common digital interface and cost cutting, the situation has changed dramatically in the past decade. USB3 Vision and GigE Vision played a major role in this trend. In particular, GigE Vision became readily available thanks to the mass production and significant cost reduction by its producer, BASLER of Germany. This made significant contribution in the acceleration of this trend. USB3 Vision, which followed the success of GigE Vision, further promoted the replacement of analog and CameraLink interface thanks to its advantages such as wide band width and plug & play (the ease of connection) and became a major interface that competes with GigE Vision in the market.

From CCD to CMOS

The shift from CCD sensor to CMOS sensor is another factor that explains why USB3 Vision becomes very popular. The shift to CMOS sensor, which is more high-resolution and high-speed, makes USB3 Vision interface more advantageous because it has wider band width among common digital interface. Traditionally, CCD sensor enjoyed the dominant market share in industrial camera market thanks to image quality. However, it cannot execute high-speed data readout. Even VGA class, it stands at 120fps. GigE Vision interface can comfortably manage data transfer at 120fps in VGA class and 17fps in 5Mpix. But the arrival of more high-speed and high-resolution CMOS sensor created the demand for interface with wider band width. USB3 Vision is a perfect choice for this need and becomes popular very quickly.

These developments further accelerate the improvement in sensor technology and its product development cycle. Today, CMOS sensor manufactures offer a wide range of products, and cameras with high-speed and high-resolution sensor seem to be a recent trend.

From PC to Embedded

Following the shift from analog to digital and from CCD to CMOS, the third major transition appears to be beginning in the market of industrial camera. The emergence of single board computer such as Raspberry Pi lowers the barriers in developing an embedded system. Therefore, it is expected that embedded system, rather than large PC-based system, will be a new standard for image processing in the future. USB and GigE interfaces are normally built-in in these single board computers and thus the use of USB3 Vision camera and GigE Vision camera is likely to accelerate. The combination of embedded system and USB3 Vision or GigE Vision can reduce the total cost of the system because it not only eliminates the need of dedicated board but reduces the cost of computer itself. This opens up the new market where cost is the major barrier in introduction of image processing system, especially in non-FA market.

BASLER’s FPGA design and development based on the concept of “minimizing total cost of ownership”

With its high technical capabilities, BASLER manufactures a wide range of interfaces and sensors. The widespread use of USB3 Vision interface and the arrival of high-performance sensor require the camera manufacture to produce high-quality camera at low cost.

In this context, the design concept of FPGA which affects the image quality and the quality of camera driver and SDK for which compatibility and usability with PC becomes ever more important are major factors in differentiating industrial cameras. Digital cameras with the same CMOS sensor do not necessarily produce the same quality image. Likewise, the development of ISP (Image Signal Process) for industrial cameras has become the core technology of camera manufactures.

Along with an increase in the product lineups and precision of sensors, there are a number of cases in which the replacement purchase of camera-related optical equipment results in an increase in the total cost of vision system. Based on the concept of “minimizing total cost of ownership”, BASLER develops unique functions with the latest FPGA technologies and differentiates its products with other manufactures. A new function called vignetting adjustment.

Vignetting adjustment controls the reduction of an image’s brightness or saturation toward the periphery compared to the image center which is caused by the gap in camera sensor size and lens image circle. In this function, calibration is conducted once and the adjustment value saved at the time of taking a picture is automatically applied. By doing so, it can control vignette effect without using the larger lens. There is no impact on frame rate by using this function.

Image without (left) and with (right) vignetting adjustment

Large, over 1-inch sensors such as recently launched SONY IMX series are high performance and more cost-effective compare with conventional high-end high-resolution cameras. Thanks to this function, the cost of lens can be minimized too.

The market of industrial camera undergoes the period of major change, and USB3 Vision is set to become more and more common digital interface. It is necessary to create additional value added by combining latest sensor technologies and unique FPGA technologies.

* This text is prepared based on “Reading I/F trend from the market and FPGA solution of BASLER”, a series that were published in March and April editions of Eizo Joho Industrial.