Patent ID: 6259540
Filing Date: 2001-07-10
Classification: H04N

Abstract:
A method for distinguishing an object to be scanned by a transmissive/reflective dual-mode image scanner as a transmissive object or a reflective object, said transmissive/reflective dual-mode image scanner having a transmitting light source and reflecting light source, and said method comprising:(a) turning on one of said transmitting and reflecting light sources to serve as a first light source;(b) pre-scanning a first portion of said object by using said first light source to obtain a first pre-scan image signal;(c) calculating a first scanning value of said first pre-scan image signal;(d) turning off said first light source and turning on the other of said transmitting and reflecting light sources to serve as a second light source;(e) pre-scanning a second portion of said object by using said second light source to obtain a second pre-scan image signal;(f) calculating a second scanning value of said second pre-scan image signal; and(g) distinguishing said object to be said transmissive object or said reflective object according to said first scanning value and said second scanning value so as to determine which one of said transmitting light source and said reflecting light source will be used for a subsequent scanning operation.