Patent ID: 6263095
Filing Date: 2001-07-17
Classification: G01N

Abstract:
A method of interrogating a charge pattern on a CCD array arising from the emission of photons of light by labeled material in a sample during an exposure period comprising the steps of:(1) organizing the addressing of the CCD so as to define sub-regions which make up the sensitive area of the array, the quantity of charge found in each sub-region at the end of the said exposure period being proportional to the photon energy incident thereon during the said period;(2) storing for each sub-region an electrical signal having a value indicative of the said charge for reading out as data signals;(3) reading out the stored electrical signals as date signals;(4) performing measurements of each individual data signal so as to identify and isolate from adjoining data signals any clusters of data signals of unlimited size and shape and which by their magnitude and adjacency are attributable to one or more photons of light impinging on a region of the array;(5) comparing the measurements with at least one threshold so as to distinguish clusters of data signal values attributable to photon emitting regions labeled material from the remaining regions of the sample;(6) computing the coordinates of the centroid of each cluster of data signal values which satisfies the thresholding criteria with reference to the sub-regions of the camera array, and(7) storing the centroid coordinates in a memory together with the centroid coordinates of any other threshold satisfying clusters of data signals identified during the same interrogation.