Patent ID: 7545949

Claim:
A method for setting a shutter time parameter and a gain parameter of an imager, the gain parameter having a minimum allowable gain value and a maximum allowable gain value, comprising: configuring the imager to capture images of a field of view of a production line in relative motion with respect to the field of view in a direction and at a nominal line speed, the field of view having a size in the direction of motion of the production line; choosing a motion parameter that specifies a desired relative motion of the production line, in units related to pixels, during an interval specified by the shutter time parameter; estimating, responsive to the nominal line speed, an apparent line speed in units related to pixels per unit of time; computing, responsive to the apparent line speed and the motion parameter, a motion shutter time; inputting a desired image brightness parameter; computing, responsive to the desired image brightness parameter, a brightness shutter time; computing a desired shutter time and a desired gain, such that the brightness shutter time is approximately equal to the product of the desired shutter time and the desired gain, the desired gain is not less than the minimum allowable gain value and not greater than the maximum allowable gain value, and at least one of a first condition, a second condition, and a third condition hold, wherein the first condition holds when the desired shutter time is approximately equal to the motion shutter time, the second condition holds when the desired shutter time is less than the motion shutter time and the desired gain is approximately equal to the minimum allowable gain value, and the third condition holds when the desired shutter time is greater than the motion shutter time and the desired gain is approximately equal to the maximum allowable gain value; and setting the shutter time parameter of the imager to the desired shutter time, and the gain parameter of the imager to the desired gain.