One aspect of the present invention is a system for estimating sensor and illumination non-uniformities. The system comprises a first light source, and a first sensor operable to capture light reflected from a first side of film illuminated by the light source while the film has a developer chemical applied thereto and processing circuitry coupled to the first sensor. The processing circuitry is operable to capture a first plurality of readings from the sensor responsive to light reflected from an unexposed region of film to determine a first set of non-uniformity data and adjust image data obtained from the film in response to the first set of non-uniformity data. In a further embodiment, the processing circuitry is further operable to dim the first light source for at least a portion of the time that the sensor is being used to sense the unexposed region of the film. The processing circuitry may also capture a second plurality of readings from the sensor while the first light source is dimmed to determine a second set of non-uniformity data and adjust image data obtained from the film in response to the second set of non-uniformity data.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims benefit under 35 U.S.C. .sctn. 119(e) of U.S. Provisional Application Serial No. 60/173780, entitled Method and System for Estimating Sensor and Illumination Non-Uniformities, which was filed on Dec. 30, 1999 and U.S. Provisional Application Serial No. 60/174074, entitled Method and System for Estimating Sensor Dark Current Drift which was filed on Dec. 30,1999.
This application is related to the following co-pending applications all filed on Dec. 30, 1999: Serial No.60/173,781, entitled Pulsed Illumination Signal Modulation Control and Adjustment; Serial No. 60/173,787, entitled Digital Film Processing Method and System; and Serial No. 60/174,073, entitled Digital Film Processing Feature Location Method and System.
Fast, under-sampled raster scans are created and measured in order to automatically determine appropriate settings for the adjustable gain detector that is employed in the device. The non-linear nature of the detector response to gain settings, and the characteristics of the raster scan are modeled to create an overall transfer function that is used to calculate the correct settings of the detector for a full-resolution image. Multiple samples are introduced to the scanning device under computer control, and the auto-exposure device is employed for each sample without user intervention.
