Cropped Sensor mode
Andor Technology, a provider of scientific imaging and spectroscopy solutions, has implemented the Cropped Sensor mode as a standard, user-selectable feature with its iXon+, Newton and iKon range of high-performance EMCCD (Electron Multiplying CCD) and CCD cameras. This flexible and specialised readout mode is capable of achieving extremely fast continuous frame rates (typically sub-millisecond exposures) of either images or spectra.
In this mode, the user defines through software a sub-array from within the full sensor area, such that it encompasses the region of the image where light is actually falling and change is rapidly occurring, e.g. a calcium spark within a living cell, or a dispersed spectral signature. The sensor subsequently imagines that it is of this smaller defined array size, achieved through specially optimised readout patterns, and reads out at a proportionally faster frame rate. The smaller the defined array size, the faster the frame rate achievable.
Cropped Sensor mode has the end result of achieving much faster sustainable speeds than that obtainable in a conventional sub-array/ROI readout mode. Combined with EMCCDs, this mode also offers potential for replacement of PMT or APD detectors with a higher sensitivity alternative.