Patent ID: 7714903

Claim:
A method of operating an image sensor array having one or more photo sensitive pixels that can be non-destructively interrogated for a parameter value indicative of the cumulative amount of light to which individual ones of said pixels have been exposed, the sensor being continuously exposed to said light during a known time interval, the method comprising: interrogating a first pixel for a parameter value at a first time value during the interval; recording the value of the parameter at the first time value; at a second time value during the time interval, interrogating the first pixel to obtain a second parameter value; determining whether the parameter value at the second time value exceeds a limit value; substituting the second parameter value for the first parameter value if the limit value is not exceeded, otherwise maintaining the first parameter value; and determining the value of the parameter corresponding to the cumulative amount of exposure to light for the entire time interval based on the recorded value of the parameter and the time value to which the recorded value of the parameter corresponds.