Method for automatic prevention of vertical streaks by selectively applying gains to the output signals of optical sensor elements

A method for automatic prevention of vertical streaks, the method comprising the steps of:

• processing output signals from an optical sensor;
• and
• selectively applying gains to the output signals depending upon differences between each output signal and its respective neighbor output signals;
• wherein the step of selectively applying gains includes
• identifying an output signal for which the difference between the output signal and its neighbor output signals indicates that an optical obstruction is not likely to be present in an optical path associated with the output signal, and
• applying a proportionate gain to the output signal;
• wherein the identifying step includes
• determining a normalized difference between the output signal and its neighbor output signals.

A method for automatic prevention of vertical streaks, the method comprising the steps of:

• processing output signals from an optical sensor;
• and
• selectively applying gains to the output signals depending upon differences between each output signal and its respective neighbor output signals;
• wherein the step of selectively applying gains includes
• identifying an output signal for which the difference between the output signal and its neighbor output signals indicates that an optical obstruction is likely to be positioned in an optical path associated with the output signal between the optical sensor and a scan area surface over which an object to be imaged by the optical sensor is positioned, and
• applying a proportionate gain to the output signal;
• wherein the identifying step includes
• determining a normalized difference between the output signal and its neighbor output signals.

A method for automatic prevention of vertical streaks, the method comprising the steps of:

• processing output signals from an optical sensor;
• and
• selectively applying gains to the output signals depending upon differences between each output signal and its respective neighbor output signals;
• wherein the step of selectively applying gains includes
• identifying an output signal for which the difference between the output signal and its neighbor output signals indicates that an optical obstruction is likely to be positioned in an optical path associated with the output signal on or between a scan surface area over which an object to be imaged by the optical sensor is positioned and a calibration strip facing the scan area surface, and
• applying a gain to the output signal, the gain being determined from a gain which is appropriate for at least one of the neighbor output signals;
• wherein the identifying step includes
• determining a normalized difference between the output signal and its neighbor output signals.

A method for automatic prevention of vertical streaks, the method comprising the steps of:

• receiving output signals from a plurality of optical sensor elements configured in an array;
• for each of the sensor elements, comparing the value of the output signal with the values of the output signals of neighbor sensor elements to determine whether an optical obstruction appears to be present in an optical path associated with any of the sensor elements;
• distinguishing between narrow dips and wide dips in magnitudes of the output signals moving linearly across the array;
• and
• applying gains to the output signals depending upon whether the dips are narrow or wide.

A method for automatic prevention of vertical streaks, the method comprising the steps of:

• receiving output signals from a plurality of optical sensor elements configured in an array;
• for each of the sensor elements, comparing the value of the output signal with the values of the output signals of neighbor sensor elements to determine whether an optical obstruction appears to be present in an optical path associated with any of the sensor elements;
• and
• determining whether changes in the output signals, moving spatially across the array, are greater for a sensor element than for its neighbor sensor elements.