Camera options for the biomedical instrument builder. There are many considerations when selecting an imaging system for quantitative, low-light imaging. Our support goes beyond camera options to include advice on mounting and placement, thermal management, optical design and image related software.
We'll work with you to educate your team and ensure the best selections are made to meet performance and cost targets. When your instrument needs to fit a tight budget, we can help you get the most from routine cameras, ensuring you are not paying for capabilities that are not needed.
Sensor cooling is used to eliminate noise resulting from thermal background signal, known as dark current, an intrinsic property of semiconductor detectors. The amount of thermal noise that can be tolerated depends on the application requirements and image sensor. In camera selection, the actual dark current per exposure time is far more important than the specified temperature, as the true sensor temperature can vary widely. In nearly all cases, camera sensitivity and measurement precision can be improved by reducing thermal noise through use of well regulated, Thermo-Electric Cooling (TEC), typically resulting in a thermal noise of few electrons per pixel or less for a given exposure time.
TEC coolers offer a simple, compact solution, but are electrically inefficient, generating far more heat then they remove. For this reason, cameras offer several choices for removing heat from the TEC. Our OEM products offer a selection of passive air (limited heat removal but highly reliable, convenient and without vibration), forced air using low vibration fans (increased heat removal, convenient, but reduced long-term reliability) and liquid cooling (powerful, low vibration, but adds cost and maintenance).
In all cases, the amount of heat to remove is reduced by thermally isolating the sensor. This can be as simple as mechanical isolation with the sensor in an inert gas with reduced thermal conductivity, to as complex as a permanently sealed, high vacuum environment that eliminates convective heat loads all together.
Photometrics offers a wide range of sensor technologies, sensor areas and pixel sizes. We are always evaluating innovative sensors to bring the best products to our OEM partners.
Current sensor technologies are highlighted by 95% QE back-illuminated Scientific CMOS. We also have standard CMOS, CCD and EMCCD (Electron Multiplying CCD) available to deliver just the right balance of price vs. performance for any application. Sensor manufacturers frequently used by Photometrics include GPixel, Sony, e2v, BAE/ Fairchild, OnSemi (formerly Kodak) and others.
Recent advances in FPGA and GPU signal processing have enabled a significant increase in the real-time processing power of Photometrics cameras. Recent cameras, including the new QI OEM series, perform defective pixel correction, removal of dark current background and implement HDR algorithms, all on cameras using an FPGA (field programmable gate arrays with specialized signal processing capabilities). This processing power can also be extended to embedding OEM’s own algorithms inside the camera, in an IP protected environment. In addition, instrumentation builders can leverage in-line parallel processing on the host PC using CUDA and OpenCL based GPU processing. To simplify the integration of streaming pixel data and GPU processing, the PVCAMSPLICE library is available to instrument builders.
Photometrics’ experience in building digital cameras predates PC technology. This deep experience has provided lasting insights on how to maximize performance across variable PC architectures without increasing cost.
PVCAM cameras support USB2, USB3, IEEE1394, and PCIe host computer interfaces, under Windows 7 (32 bit and 64 bit), Windows 8 (64 bit), Linux (32 bit and 64 bit) on Intel processors, and Linux (32 bit) on ARM processors. The host computer is chosen based on the applications and markets served by the camera, and in some cases the camera offers the choice of interface depending on performance.
PVCAM (Photometrics Virtual Camera Access Method) is a standard API across Photometrics cameras. PVCAM uses a smart camera philosophy, where the API queries the camera for its capabilities. This not only simplifies the library, it allows the software architect to write general interfaces, and still easily switch between camera models without rewriting applications, even across different technologies like CCD and sCMOS. The benefit is that instrument builders can start development well before a particular camera is available, or quickly switch camera models when markets shift, without significant rework. This approach has been so successful that it is now widely mimicked across the industry, but it seldom achieved without a true intelligent camera approach.
The speed of current design requires full attention to 3D design practices. The process starts with sharing 3D models (STEP files are available on the product pages in this site) to optimize camera location and mounting points. Advanced CFD modeling is used not only for sensor cooling design, but also to assist OEMs to ensure camera operation is maintained inside their instrument enclosure.