Control system for digital de-screening of documents
First Claim
1. A method for controlling de-screening operation in a de-screening system, the de-screening system including a bank of filters, the bank of filters receiving an image signal and producing a set of filter output signals, the method comprising the operations of:
- (1) receiving, via a contrast module, a filter output signal from a first filter in a bank of filters and producing a contrast signal, the first filter being one of the filters having larger filter spans in the bank of filters;
(2) receiving, via a halftone estimate module, the image signal and a second filter output signal from a second filter in the bank of filters, the second filter being one of the filters-having smaller filter spans in the bank of filters, and producing an estimated frequency signal and a halftone weight signal; and
(3) receiving, via a pixel control module, the contrast signal from the contrast module and the estimated frequency signal and the halftone weight signal from the halftone estimate module, and producing the first control signal, the first control signal including information regarding which of the filter output signals are to be blended and the proportion of blending.
4 Assignments
0 Petitions
Accused Products
Abstract
A method and a system for controlling de-screening of documents. The control system is included in a de-screening system including a bank of filters. The filter bank receives an image signal and produces a set of filter output signals. The control system comprises a contrast module, a halftone estimate module and a pixel control module. The contrast module receives a filter output signal from a filter having a large filter span and produces a contrast signal. The halftone estimate module receives the image signal and a filter output signal from a filter having a small filter span and produces an estimated frequency signal and a halftone weight signal. Based on the contrast signal, the estimated frequency signal and the halftone weight signal, the pixel control module produces a control signal which includes information regarding which of the filter output signals are to be blended and the proportion of blending.
37 Citations
23 Claims
-
1. A method for controlling de-screening operation in a de-screening system, the de-screening system including a bank of filters, the bank of filters receiving an image signal and producing a set of filter output signals, the method comprising the operations of:
-
(1) receiving, via a contrast module, a filter output signal from a first filter in a bank of filters and producing a contrast signal, the first filter being one of the filters having larger filter spans in the bank of filters; (2) receiving, via a halftone estimate module, the image signal and a second filter output signal from a second filter in the bank of filters, the second filter being one of the filters-having smaller filter spans in the bank of filters, and producing an estimated frequency signal and a halftone weight signal; and (3) receiving, via a pixel control module, the contrast signal from the contrast module and the estimated frequency signal and the halftone weight signal from the halftone estimate module, and producing the first control signal, the first control signal including information regarding which of the filter output signals are to be blended and the proportion of blending. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A control system included in a de-screening system, the de-screening system including a bank of filters, the bank of filters receiving an image signal and producing a set of filter output signals, the control system comprising:
-
a contrast module receiving a filter output signal from a first filter in a bank of filters, the first filter being one of the filters having larger filter spans in the bank of filters, and producing a contrast signal; a halftone estimate module receiving the image signal and a filter output signal from a second filter in the bank of filters, the second filter being one of the filters having smaller filter spans in the bank of filters, and producing an estimated frequency signal and a halftone weight signal; and a pixel control module receiving the contrast signal from the contrast module and the estimated frequency signal and the halftone weight signal from the halftone estimate module, and producing the first control signal, the first control signal including information regarding which of the filter output signals are to be blended and the proportion of blending. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
-
23. An article of manufacture comprising:
a machine usable medium having program code embedded therein, the program code is used for controlling de-screening operation in a de-screening system, the de-screening system including a bank of filters, the bank of filters receiving an image signal and producing a set of filter output signals, the program code comprising; machine readable code to process a filter output signal received from a first filter in a bank of filters and produce a contrast signal, the first filter being one of the filters having larger filter spans in the bank of filters; machine readable code to process the image signal and a second filter output signal received from a second filter in the bank of filters, the second filter being one of the filters having smaller filter spans in the bank of filters, and produce an estimated frequency signal and a halftone weight signal; and machine readable code to process the contrast signal and the estimated frequency signal and the halftone weight signal, and produce the first control signal, the first control signal including information regarding which of the filter output signals are to be blended and the proportion of blending.
Specification