Enhancing the quality of decoded quantized images
A system for image enhancement and, more particularly, a system for enhancing the quality of a quantized image.
1. A method for modifying an image comprising:
(a) receiving an image having a first bit depth wherein modifying said image to a second bit depth would result in artifacts, wherein said first bit depth is less than said second bit depth;
(b) modifying said image to another bit depth different than said first bit depth in such a manner that the lower amplitude higher frequency content with respect to the higher amplitude lower frequency content of said image is attenuated to reduce said artifacts that would have otherwise occurred;
(c) wherein said modifying includes a filter that is based upon a selection of pixels of said image wherein at least of one said pixels is selectively not considered; and
(d) wherein said modifying said image to another bit depth is performed using a Sieve filter that is applied only in the horizontal direction after averaging pixels vertically spaced apart from each other.
2. The method of claim 1 wherein said filter is represented by
I
LP
(
x
,
y
)
=
∑
(
i
,
j
)
∈
E
&
l
(
i
,
j
)
-
l
(
x
,
y
)
<
T
I
(
i
,
j
)
N
(
x
,
y
)
.
3. The method of claim 1 wherein said artifacts are contouring artifacts.
4. The method of claim 1 wherein said filter is a 1-dimensional rectangle.
5. The method of claim 1 wherein said filter is a 2-dimensional rectangle.
6. A method for modifying an image comprising:
(a) receiving an image having a first bit depth wherein modifying said image to a second bit depth would result in contouring artifacts;
(b) modifying said image to another bit depth different than said first bit depth in such a manner that the lower amplitude higher frequency content with respect to the higher amplitude lower frequency content of said image is attenuated to reduce said contouring artifacts that would have otherwise occurred;
(c) wherein said modifying includes a sieve filter represented by
I
LP
(
x
,
y
)
=
∑
(
i
,
j
)
∈
E
&
I
(
i
,
j
)
-
I
(
x
,
y
)
<
T
I
(
i
,
j
)
×
(
N
total
N
(
x
,
y
)
)
×
I
(
x
,
y
)
N
total
.
7. The method of claim 6 wherein said filter is a 1-dimensional rectangle.
8. The method of claim 6 wherein said filter is a 2-dimensional rectangle.