Method for reconstructing a dithered image
First Claim
1. A method for reconstructing a dithered image, comprising the steps of:
- selecting a first filter from a set of filters, the selected first filter having a first filter coefficient and the selected first filter operable on a first region of support;
determining that an image edge exists within the first region of support;
responsive to determining that an image edge exists within the first region of support, selecting a second filter from the set of filters, the selected second filter having a second filter coefficient and the selected second filter operable on a second region of support, the second region of support being smaller than the first region of support;
determining if an image edge exists within the second region of support; and
responsive to determining that no image edge exists within the second region of support, reconstructing the dithered image using the second filter coefficient.
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Accused Products
Abstract
A method of reconstructing an image from a dithered image. A predefined set of filters having different regions of support is established. Each filter is defined by a number of filter coefficients and an impulse response function which defines the filter response for a region of support outside of which the impulse response is zero. Filters are organized according to indexes and this organization represents the order in which the filters are considered during a filter selection process. The filter selection process selects a filter constrained by the rule that the filter selected must only perform low-pass filtering on a region of support that does not contain edges of an image. Due to the organization of the filter set, the filter selection process first selects the largest filter from the filter set that fits within the region about the current processed pixel. If there is an edge of an image within the support region of the first selected filter, the next smaller filter is selected. If there is no edge in the selected smaller filter, the dithered image is reconstructed using the selected smaller filter.
14 Citations
12 Claims
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1. A method for reconstructing a dithered image, comprising the steps of:
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selecting a first filter from a set of filters, the selected first filter having a first filter coefficient and the selected first filter operable on a first region of support;
determining that an image edge exists within the first region of support;
responsive to determining that an image edge exists within the first region of support, selecting a second filter from the set of filters, the selected second filter having a second filter coefficient and the selected second filter operable on a second region of support, the second region of support being smaller than the first region of support;
determining if an image edge exists within the second region of support; and
responsive to determining that no image edge exists within the second region of support, reconstructing the dithered image using the second filter coefficient. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An article of manufacture for processing a dithered image, comprising:
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computer readable storage medium; and
a computer program stored on said storage medium;
wherein said computer program is configured to be readable from said computer readable storage medium by a processor and thereby causing said processor to operate so as to;
select a first filter from a set of filters, the selected first filter having a first filter coefficient and the selected first filter operable on a first region of support;
determine that an image edge exists within the first region of support;
responsive to determining that an image edge exists within the first region of support, select a second filter from the set of filters, the selected second filter having a second filter coefficient and the selected second filter operable on a second region of support, the second region of support being smaller that the first region of support;
determine if an image edge exists within the second region of support; and
responsive to determining that no image edge exists within the second region of support, reconstruct the dithered image using the second filter coefficient.- View Dependent Claims (8, 9, 10, 11, 12)
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Specification