| 摘要 |
A charge-transfer device (CTD) 10 for use in particular in high speed imaging apparatus comprises a matrix 12 of pixels, the matrix 12 being divided into a number of 'super pixels' 15. Each super pixel 15 is in the form of a sub-array and is further divided into a plurality of pixels 16. One of the pixels 16 in each sub-array 15 is active, i.e.photo-sensitve, and the remaining pixels (storage pixels) are masked off or non-photo sensitive. In operation, light from the image to be recorded falls on the device 10 and produces in the active pixel 18 of each sub-array 15 a charge packet which is characteristic of the incident light. The charge packets formed in all of the active pixels 18 at a particular instant form a pattern which represents a single frame of the image to be recorded. Clock signals are provided, in response to which the charge packet stored in each of the active pixels 18 is shifted into an adjacent storage pixel, leaving the active pixels free to record another frame. This process is repeated in response to each clock signal, each charge packet being shifted through the sub-array in, for example, a spiral configuration until it reaches the final storage pixel. At this point, the occurrence of another clock signal causes the charge packet to either be read-out or dumped. Thus, a plurality of frames can be stored within the CTD of the present invention, and the readout analogue electronic circuitry required for the present invention is relatively simple, i.e slow scan technology optimised for dynamic range and noise performance. The CTD may be a charge-coupled device (CCD). |
