Patent ID: 6873728

Claim:
A vertical black line removal system in a document scanner which includes a binarization system comprising: a. processing means that defines a difference value indicative of either a potential vertical black line defect or no vertical black line defect and defines a histogram value for each corresponding cross track sensor pixel; b. first storage means for storing each histogram value from the processing means wherein a cross track sensor pixel address for each pixel relates to a histogram value address; c. vertical black line search processing means which compares each stored histogram value with a predetermined threshold value to define a defect list of cross track sensor pixel addresses corresponding to a vertical black line defect; and d. output means operating only after the vertical black line search processing means has compared all stored histogram values to complete the defect list of addresses wherein the output means would output either a first normal binary image value or a second low contrast binary image value depending on whether a vertical black line defect exists at that particular pixel location.