By incorporating on-chip multiplication gain, the electron multiplying CCD achieves, in an all solid-state sensor, the single-photon detection sensitivity typical of intensified or electron-bombarded CCDs at much lower cost and without compromising the quantum efficiency and resolution characteristics of the conventional CCD structure.
The Time Delay Integration (TDI) CCD system is an ideal tool for capturing images of rotating objects or rapidly moving specimens, and is thus widely utilized in line scan cameras for industrial robots and similar applications. This interactive tutorial explores capturing images of rapidly moving objects using characters printed on a virtual drum by a CCD operating in a combination of frame and TDI mode.
The tutorial initializes with the image of a drum scanner on the left-hand side of the window, flanked on the right by the TDI detector readout array and the final displayed image. To operate the tutorial, use the blue scan button to initiate rotation of the drum and subsequent scanning of the characters by the TDI sensor. The speed of the TDI-based system can be adjusted with the Scan Speed slider and the individual scanned lanes can be highlighted by activating the Show Lanes checkbox. Note that by decreasing the scanning speed, the sensor is able to integrate more photoelectrons, thus increasing image brightness. After all of the characters on the drum have been read (four rotations), the tutorial halts with the final image being displayed in the Display Image window.