Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
59 words
A method for creating a continuous tone image(Figs. 23 and 24) from a halftone
image (Figs. 1 and 2), comprising: decomposing (S110) the halftone image into a plurality of subband images; selectively removing (S130) at least one of noise and patterns from the plurality of subband
images; and recomposing the plurality of subband images into the continuous tone image.
Claim 2
Dependent Claim
37 words
A method for creating the continuous tone image from the halftone image as claimed
in claim 1, further comprising filtering (S160) the continuous tone image using a non-linear, edge-preserving
filter to form an enhanced continuous tone image.
Claim 3
Dependent Claim
54 words
A method for creating the continuous tone image from the halftone image as claimed
in claim 2, wherein the continuous tone image filtering step comprises non-linearly filtering the
continuous tone image using spatial smoothness constraints modeled using a Huber Markov random
field; or comprises non-linearly filtering the continuous tone image using an edge-preserving filter.
Claim 4
Independent Claim
98 words
A method for creating the continuous tone image from the halftone image as claimed
in any of claims 1 to 3, wherein the halftone decomposing step comprises decomposing the halftone
image into a plurality of different frequency subband images based on a discrete wavelet transform; or
comprises: decomposing the halftone image into a plurality of different first level frequency subband
images; decomposing one of the plurality of first level subband images into a plurality of second level
different frequency subband images; and repeating the subband image decomposing step for at least the plurality of second level
subband images.
Claim 5
Independent Claim
52 words
A method for creating the continuous tone image from the halftone image as claimed
in any of claims 1 to 4, wherein the selectively removing step comprises: attenuating noise from non-edge areas of each of the plurality of subband images; and oriented filtering of each of the plurality of noise-attenuated subband images.
Claim 6
Dependent Claim
80 words
A method for creating the continuous tone image from the halftone image as claimed
in claim 5, wherein the noise-attenuating step comprises clipping the magnitudes of the pixels of high
frequency subband images; or wherein the noise-attenuating step comprises: weighting magnitudes of coefficients for a parent subband image for each high frequency
subband image; and clipping magnitudes of coefficients of the high frequency subband images to at most the
weighted magnitudes of the coefficients of the corresponding parent subband image.
Claim 7
Dependent Claim
147 words
A method for creating the continuous tone image from the halftone image as claimed
in claim 5 or 6, wherein the oriented filtering step comprises applying a one-dimensional low-pass filter
along an orientation of each subband image; or wherein oriented filtering step comprises applying one
of a plurality of oriented filters to each of the subband images, the plurality of oriented filters comprising
a horizontal low-pass filter, a vertical low-pass filter and a X-shaped low-pass filter; or wherein the
oriented filtering step comprises: applying a horizontal low-pass filter to vertical subband images; applying a vertical low-pass filter to horizontal subband images; and applying a X-shaped low-pass filter to diagonal subband images; or wherein the oriented
filtering step comprises adapting the oriented filtering to a resolution of the subband images; or wherein
the oriented filtering step further comprises selecting appropriate filters based on estimates of the
screen parameters.
Claim 8
Independent Claim
66 words
An apparatus for converting a halftone image (Figs. 1,2) into a continuous tone image
(Figs. 2, 3, 24), comprising: decomposing means (140) for decomposing the halftone image into a plurality of subband
images; means for selectively removing at least one of noise and patterns from the plurality of
subband images; and recomposing means (160) for recomposing the plurality of subband images into the
continuous tone image.
Claim 9
Independent Claim
29 words
An apparatus for converting a halftone image into a continuous tone image,
comprising: an N-stage halftone image decomposer; a subband noise/pattern filter system; and an N-stage subband image recomposer.
Claim 10
Dependent Claim
88 words
An apparatus for converting a halftone image into a continuous tone image as claimed
in claim 9, wherein the N-stage halftone image decomposer comprises: a halftone image to subband image decomposer; and at least one subband image to subband image decomposer; and/or wherein the N-stage
subband image recomposer comprises: at least one subband image to subband image recomposer; and a subband image to continuous tone image recomposer; and/or wherein the subband
noise/pattern filter system comprises: a non-edge area noise attenuating filter; and a subband image oriented filter system.