| 摘要 |
A photographic printer includes large area transmission density (LATD) sensors and a digital processor, such as a microprocessor, which calculates red, green and blue exposure times based upon the LATD sensor values. Prior to an exposure cycle, the LATD sensors are initialized, and LATD sensor readings are taken. From these initial sensor readings red, green, and blue initial exposure times are calculated, and an exposure cycle is initiated based upon these initial exposure times. During the exposure cycle, additional sensor readings continue to be taken on an asynchronous basis, and red, green, and blue exposure times are recalculated each time a reading is taken. The exposure times used during the exposure cycle are continuously modified and updated as a function of the recalculated exposure times. A running average of the sensor readings is maintained, and the modified exposure times are based upon a weighted average of the most recent sensor reading and the running average. In addition, individual bad readings are sorted out and are not included in the running average. The occurrence of greater than a predetermined number of bad readings or data points causes termination of the exposure.
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