HIGH DYNAMIC RANGE IMAGING WITH sCMOS (SCIENTIFIC CMOS)
Andor Technology, Fairchild Imaging and PCO adapt CMOS technology specially for the needs of scientific imaging
Belfast (Northern Ireland), Milpitas (USA), Kelheim (Germany), 23 July 2009 - Scientists are reporting that the new sCMOS technology is proving essential for scientific imaging applications because, for the first time, it is allowing for the accurate measurement of structures that are very dim as well as structures that are very bright in the same field of view. Having a camera system with a large dynamic range is therefore important for scientific imaging applications such as fluorescence microscopy.
In addition to this intra-scenic variation, inter-scenic variations in intensity also require a camera with a large dynamic range. An example of this is calcium ratiometric imaging where signals can vary greatly in intensity on a frame to frame basis.
The dynamic range in image sensors is defined as the pixel full well capacity divided by the smallest signal level that can be measured, which equals the readout noise. Therefore to improve the dynamic range both a large pixel full well and a small readout noise are beneficial. In order to utilize the full well of a CMOS pixel, the amplifier gain must be kept low. For example, given a 1.5V swing on the output of the amplifier, a 30,000 electron signal will require a gain of 1.5V/30,000e- = 50uV/e-.
This will allow measurement of the full well signal but will not allow for the lowest possible read noise. In order to get a very low readout noise and the resulting superior sensitivity, a value of 1500uV/e- would be ideal but this would mean that the largest signal would be limited to 1000e- maximum which is only 1/30th of the total well size. This leaves us with a quandary of whether to choose maximal sensitivity or good dynamic range imaging.
Andor Technology, Fairchild Imaging and PCO have taken together a novel design approach in sCMOS technology by using both approaches simultaneously. sCMOS technology has a high gain, high sensitivity amplifier to get the lowest possible noise on one output and a low gain amplifier for the largest possible signal on another output which are simultaneously read out and converted into digital values allowing both signals to be combined for a higher dynamic range signal.
As shown in the sCMOS White Paper released on June 16th at the Laser World of Photonics show, both circuits incorporate high performance 11 bit ADCs to produce 2048 gray levels of significant data. Both outputs are sent to the camera which could either combine the data into one 16 bit image or leave it in two high quality data streams. This means, depending on the camera system, that a user could select high sensitivity data for one application, high signal data for another application or a combined high dynamic range data that maintains a good SNR for the low and the high end of the data range.
This approach allows the scientific user to get high quality linear data for both dim and bright targets within the field of view while getting unparalleled sensitivity due to the ultra-low noise of the readout. This combination makes the sCMOS technology a compelling solution for many scientific imaging applications.
TRANSATLANTIC CO-OPERATION LEADS TO MAJOR SCIENTIFIC CMOS (sCMOS) TECHNOLOGY BREAKTHROUGH
Andor Technology, Fairchild Imaging and PCO combine resources to give CMOS technology long heralded world lead position
Laser World of Photonics - Munich, Germany, 16 June 2009 - CMOS image sensor (CIS) technology today stands on the brink of fulfilling its potential to become the global detector platform of choice for scientific photonics applications that require world class performance in the fields of sensitivity, speed, dynamic range, resolution, and field of view.
The results of pioneering work, pooled resources and shared expertise by scientists from Andor Technology (Northern Ireland), Fairchild Imaging (United States) and PCO (Germany) will be revealed with the publication of a ground-breaking white paper at the Laser Conference and Exhibition in Munich (15 - 18 June 2009).
The document presents sCMOS, a breakthrough technology based on next-generation CIS design and fabrication techniques. sCMOS is poised for widespread recognition as a true scientific grade CIS, capable of out-performing most scientific imaging devices on the market today. Unlike previous generations of CMOS and CCD-based sensors, sCMOS is uniquely capable of simultaneously offering: extremely low noise, rapid frame rates, wide dynamic range, high quantum efficiency (QE), high resolution, and a large field of view.
"Today's announcement is a great moment for all three companies, who have come together in a true spirit of commitment to reach a shared goal," said Fairchild Imaging's Colin Earle.
"We have reached a 'leap forward' point, where we can confidently claim that the next significant wave of advancement in high-performance scientific imaging capability has come from the CIS technology stable" added Dr. Colin Coates, Andor Technology.
Dr. Gerhard Holst, PCO, said "Scientific CMOS (sCMOS) technology stands to gain widespread recognition across a broad gamut of demanding imaging applications, carrying an advanced set of performance features that renders it entirely suitable to high fidelity, quantitative scientific measurement."
Current scientific imaging technology standards suffer limitations in relation to a strong element of 'mutual exclusivity' between performance parameters, i.e. one can be optimized at the expense of others. sCMOS can be considered unique in its ability to concurrently deliver on many key parameters, whilst eradicating the performance drawbacks that have traditionally been associated with conventional CMOS imagers.
Performance highlights of the first sCMOS technology sensor include:
- Sensor format: 5.5 megapixels (2560(h) x 2160(v))- Read noise: < 2 e- rms @ 30 frames/s; < 3 e- rms @ 100 frames/s
- Maximum frame rate: 100 frames/s
- Pixel size: 6.5 μm
- Dynamic range: > 16,000:1 (@ 30 frames/s)
- QEmax.: 60%
- Read out modes: Rolling and Global shutter (user selectable)
Press and Corporate Information
All news related to the launch of Scientific CMOS will be posted here.
Laser & Photonics - Issue 2009/05
Article Download - Dr Gerhard Holst (PCO) considers the validity of the claims made during the launch of sCMOS.
High Dynamic Range Imaging with Scientific CMOS - July 23 2009
Press Release - sCMOS technology allowing scientists, for the first time, to accurately measure both dim and bright structures in the same field of view.
Press Conference - June 16 2009
Andor, Fairchild and PCO hosted a joint press conference at LASER World of Photonics 2009 in Munich to formally announce the launch of sCMOS.
Read the associated Press Release.
White Paper Release - June 16 2009
Access the complete sCMOS story, including comparative technology measurements, by downloading the comprehensive sCMOS White Paper.