Patent ID: 8363042

Claim:
A method for photon transfer curve (PTC) testing to determine pixel reliability in an image sensor device, comprising: (a) providing a sensor array having a plurality of pixel rows and columns formed thereon wherein each pixel is in a charged state; (b) illuminating the sensor array with a uniform light source such that a first plurality of x 1 pixels in a first region are illuminated at a first light intensity level m 1 in a first step, a second plurality of x 2 pixels in a second region are illuminated at a second light intensity level m 2 in a second step, and so forth up to an nth plurality of x n pixels in an nth region illuminated at a light intensity level m n in an nth step wherein x 1 , x 2 , . . . x n are integers, m n >m 2 >m 1 , and the length of each step is a constant time “t”, said illuminating the sensor array produces a result comprising: (1) an intensity level m 1 in a first plurality of pixel rows, an intensity m 2 in a second plurality of pixel rows, and so forth up to an intensity level m n in an nth plurality of pixel rows; and (2) a first transition pixel region with a variable intensity between the first plurality of pixel rows and the second plurality of pixel rows, a second transition pixel region with a variable intensity between the second plurality of pixel rows and a third plurality of pixel rows up to an (n−1)th transition pixel region with a variable intensity between an (n−1)th plurality of pixel rows and the nth plurality of pixel rows; (c) sending residual charge information for each pixel in the “n” plurality of pixel rows to an image processor where an image for a first frame (F 1 ) is generated, said image has a top and bottom and two sides; (d) resetting the plurality of pixel rows and columns to the same charged state as in step (a); and (e) repeating steps (b)-(c) in succession to form an image having a top and bottom and two sides for a second frame (F 2 ) in said image processor wherein illumination values for F 1 , F 2 , and (F 2 -F 1 ) may be calculated and a difference frame (F 2 -F 1 ) determined.