Lumenera’s Lt225 and Lt425 USB 3.0 Cameras provide superior quality high-speed imaging for a myriad of applications. This article discusses these USB 3.0 cameras and their technical specifications in detail.
The comparison of CMOS and CCD sensors is the subject of intense debate over the selection of suitable image sensor technology. However, a majority of the camera end-users is really concerned about the image being captured by the imager rather than the underlying technology. Although the image sensor technology will influence the fidelity of the image to some extent, expertise of the camera designer and manufacturer are also equally important.
Moreover, the continuing developments in sensor technology result in overlapping of the operational characteristics that is achievable with either technology. Hence, selecting a camera based solely on its sensor technology is often meaningless. The selection of a camera should be based on the combination of performance characteristics, price and customer support.
High-speed imaging enables an application to run rapidly and facilitates users to achieve the resolution they are looking for, irrespective of barriers such as lighting conditions. Most cameras, including Lumenera’s systems, take into account sub-windowing of the image where a smaller frame portion is output, leading to higher frame rates but with a much lower resolution. This makes the image practically useless as it is not possible to distinguish the details of an object except its presence with such low resolution.
However, Lumenera’s Lt225 and Lt445 cameras provide high-speed imaging with a high resolution. With a resolution of 2048 x 1024, the Lt225 outputs 170fps. Halving the resolution to 1024 x 1024 increases the frame rate by two folds (340fps). With a starting frame size of 2048 x 2048, the Lt425 outputs 90fps at full resolution with the same proportional increase in frame rate when sub-windowed. These high frame rates are realized utilizing an on-board memory buffer in conjunction with adaptive data flow management logic in a high-speed FPGA, thereby offering the reliable delivery of images without lost frames in any environment.
Advantages of USB 3.0 High-Speed Interface
In machine vision, USB 3.0 offers a high-speed data interface (even super speed), with a user-friendly consumer oriented technology. It does not require exotic cabling, specialized frame-grabbers or tedious software installation. The high bandwidth of USB 3.0 delivers a transfer speed of roughly 5Gb/s, which is five folds faster than the widely used GigE interface and 10 folds faster than USB 2.0.
Not all of this is usable speed because USB 3.0 depends upon 8b/10b data encoding to embed bus timing information within the data. Nevertheless, the effective payload data rate of USB 3.0 still stands at 4Gb/s. The data transfer speed of USB 3.0 becomes closer to the speed of specialized machine vision interfaces such as CameraLink and CoaXPress. USB 3.0 provides a true plug-and-play experience as all major software operating systems have built-in support for it.
Being compatible with many different computer platforms and operating systems, USB 3.0 provides system designers with a wide choice of options to facilitate the configuration of complex machine vision systems. Lumenera is the pioneer of USB 2.0 megapixel industrial imaging, introducing the technology over a decade ago. The company now fully supports USB 3.0 with the launch of the Lt series of cameras. The high resolutions and frame rates of the Lt225 and Lt425 meet the requirement for a high-speed interface such as USB 3.0. These high-speed cameras deliver image data at rates higher than 3Gb/s.
Lumenera’s New USB 3.0 Cameras
Figure 1. The Lt series of cameras.
Lumenera selected a sensor with global shutter that has appropriate frame rate and resolution to develop a camera for high-speed imaging. The company then chose the CMOS imager technology, especially the sensors designed by CMOSIS, to make a reasonably priced camera.
The data interface selected was USB 3.0 to meet the image data rates, for ease of operation, and to reduce costs of end-user’s system by eliminating the requirement for sophisticated software or a framegrabber. Together with these technologies, the combination of Lumenera’s design expertise, production capabilities and proprietary processing algorithms yielded the Lt series of cameras (Figure 1).
The Lt225 and Lt425 high-speed cameras are specially designed for applications, including motion analysis and control, high-speed inspection, automatic license plate recognition, and traffic monitoring. It is possible to customize these cameras to fit into OEM designs with given form factor or enclosure requirements. Models available include color, monochrome, or enhanced near IR sensitivity versions. Color quantum efficiency curve and monochrome quantum efficiency curve of these cameras are illustrated in Figures 2 and 3.
Figure 2. Color Quantum Efficiency Curve.
Figure 3. Monochrome Quantum Efficiency Curve.
Lumenera also offers research-grade models for life science applications, including slide scanning and digital pathology. With high resolution and relative low noise, these cameras are ideally suited for acquiring the finest details to perform all kinds of data analysis. It is also possible to synchronize image capture utilizing using either a hardware or software trigger. The 128MB onboard memory performs frame buffering to ascertain full image delivery without losing any data.
The Lt225 and Lt425 cameras are lightweight and compact with dimensions of 40 x 40 x 53mm. They can be easily integrated into tight spaces and enclosures, thanks to the multitude of threaded mounting holes. The fully locking USB 3.0 connector enables a simple but secure single cable plug-and-play installation. Additional functionality is provided through the connection of simplified I/O cabling to the locking Hirose connector to support external power input. Moreover, 1 optically isolated input, 1 optically isolated output, and 2 configurable I/Os are also available. The characteristics of the camera are listed in the following table:
Table 1. Camera Characteristics.
||2048 x 1024 or 2048 x 2048
|Full Well Capacity
||45% peak color,
64% peak monochrome
|Dark Current Noise
||125 e-/s (at 25 °C die temp)
Lumenera’s Camera Software Development Kit
The Lumenera camera Software Development Kit (SDK) offers a complete range of functions, features and source code samples that enable users to optimize the performance of the camera within their own vision applications. The SDK can be used with all of Lumenera’s USB and GigE-based cameras. The availability of Windows API, Microsoft DirectX/DirectShow, and .NET API interfaces provides users the choice of application development environments from C/ C++ to VB.NET or C#.NET.
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This information has been sourced, reviewed and adapted from materials provided by Lumenera Corporation.
For more information on this source, please visit Lumenera Corporation.