US5363213A — Unquantized resolution conversion of bitmap image…

Claim 1

Independent Claim 251 words

A method of image conversion, for converting an original bitmap image having a bitmap of pixels defined along x- and y-axes and at a resolution of I pixels per unit length along the x-axis×J pixels per unit length along the y-axis (I×J) and pixel depth a, to an output image having M pixels per unit length along the x-axis x, N pixels per unit length along the y-axis (M×N) and pixel depth d, comprising the steps of: directing the original bitmap image including a number of input pixels defined at resolution I×J×a through a filter to produce a second bitmap image including a number of output pixels defined at a resolution of K pixels per unit length along the x-axis×L pixels per unit length along the y-axis (K×L) and pixel depth b; determining, for each pixel in the output image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and nonoverlapped input pixels about each output pixel, each input pixel, defined by the second bitmap image at resolution K×L×b, in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel; and quantizing the gray level value of each pixel of the output image having pixel depth c to depth d, while retaining local area density and sharpness over the image at resolution M×N.

Claim 2

Independent Claim 251 words

A method of image conversion, for converting an original bitmap image having a bitmap of pixels defined along x- and y-axes and at a resolution of I pixels per unit length along the x-axis×J pixels per unit length along the y-axis (I×J) and pixel depth a, to an output image having M pixels per unit length along the x-axis x, N pixels per unit length along the y-axis (M×N) and pixel depth d, comprising the steps of: directing the original bitmap image including a number of input pixels defined at resolution I×J×a through a filter to produce a second bitmap image including a number of output pixels defined at a resolution of K pixels per unit length along the x-axis×L pixels per unit length along the y-axis (K×L) and pixel depth b; determining, for each pixel in the output image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and nonoverlapped input pixels about each output pixel, each input pixel, defined by the second bitmap image at resolution K×L×b, in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel; and quantizing the gray level value of each pixel of the output image having pixel depth c to depth d, while retaining local area density and sharpness over the image at resolution M×N.

Claim 3

Dependent Claim 22 words

The method as defined in claim 1, wherein the filter is selected in accordance with input image characteristics and output image specifications.

Claim 4

Dependent Claim 22 words

The method as defined in claim 2 wherein said input image characteristic is an output type for which the image is optimized.

Claim 5

Dependent Claim 23 words

The method as defined in claim 3 wherein said output image characteristic is an output type for which the image is not optimized.

Claim 6

Dependent Claim 27 words

The method as defined in claim 1 wherein the predefined neighborhood of overlapped and non-overlapped input pixels includes the neighboring input pixels nearest to the output pixel.

Claim 7

Dependent Claim 32 words

The method as defined in claim 1 wherein the precalculated filter weight is a function of the distance from the center of the input pixel to the center of the output pixel.

Claim 8

Dependent Claim 51 words

The method as defined in claim 1 wherein the quantization of the gray level value of each output pixel having pixel depth c to a depth d suitable for output is at least partially a function of quantization of previously processed output pixels, within a predetermined distance from the output pixel.

Claim 9

Independent Claim 155 words

A method of image conversion, for converting an original image having a bitmap of pixels defined along x- and y-axes and at a resolution of K pixels per unit length along the x-axis×L pixels per unit length along the y-axis (K×L) and pixel depth b, to an output image having M pixels per unit length along the x-axis×N pixels per unit length along the y-axis (M×N) and pixel depth c, comprising the steps of: determining, for each pixel in the output image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and non-overlapped input pixels about each output pixel defined at resolution K×L, each input pixel in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel.

Claim 10

Independent Claim 155 words

A method of image conversion, for converting an original image having a bitmap of pixels defined along x- and y-axes and at a resolution of K pixels per unit length along the x-axis×L pixels per unit length along the y-axis (K×L) and pixel depth b, to an output image having M pixels per unit length along the x-axis×N pixels per unit length along the y-axis (M×N) and pixel depth c, comprising the steps of: determining, for each pixel in the output image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and non-overlapped input pixels about each output pixel defined at resolution K×L, each input pixel in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel.

Claim 11

Dependent Claim 27 words

The method as defined in claim 8 wherein the predefined neighborhood of overlapped and non-overlapped input pixels includes the neighboring input pixels nearest to the output pixel.

Claim 12

Dependent Claim 32 words

The method as defined in claim 8 wherein the precalculated weight based is a function of the distance from the center of the input pixel to the center of the output pixel.

Claim 13

Dependent Claim 51 words

The method as defined in claim 8 wherein the quantization of the gray level value of each output pixel having pixel depth n to a depth m suitable for output is at least partially a function of quantization of previously processed output pixels, within a predetermined distance from the output pixel.

Claim 14

Independent Claim 221 words

An apparatus for converting an original image at a first resolution and pixel depth to a second resolution and pixel depth, distinct from the first, comprising: an image input receiving a bitmap of pixels defined along x- and y-axes at a resolution of I pixels per unit length along the x-axis×J pixels per unit length along the y-axis (l×j) and pixel depth a; filter means for processing the image to produce a number of output pixels defined at K pixels per unit length along the x-axis s L pixels per unit length along the y-axis (K×L) and pixel depth b; interpolation means, for determining, for each output pixel in the image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and non-overlapped input pixels defined at resolution K×L×b about the output pixel, each input pixel in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on a position in the neighborhood of the input pixel with respect to the output pixel; quantizing means for quantizing the gray level value of each output pixel having pixel depth c to a depth d suitable for output, while retaining local area density over the image at resolution M×N; and an image output.

Claim 15

Independent Claim 221 words

An apparatus for converting an original image at a first resolution and pixel depth to a second resolution and pixel depth, distinct from the first, comprising: an image input receiving a bitmap of pixels defined along x- and y-axes at a resolution of I pixels per unit length along the x-axis×J pixels per unit length along the y-axis (l×j) and pixel depth a; filter means for processing the image to produce a number of output pixels defined at K pixels per unit length along the x-axis s L pixels per unit length along the y-axis (K×L) and pixel depth b; interpolation means, for determining, for each output pixel in the image defined at resolution M×N, a gray level value having pixel depth c as a function of a predefined periodically repeating neighborhood of overlapped and non-overlapped input pixels defined at resolution K×L×b about the output pixel, each input pixel in the periodically repeating neighborhood contributing to the gray level determination in accordance with a precalculated weight based on a position in the neighborhood of the input pixel with respect to the output pixel; quantizing means for quantizing the gray level value of each output pixel having pixel depth c to a depth d suitable for output, while retaining local area density over the image at resolution M×N; and an image output.

Claim 16

Dependent Claim 26 words

The apparatus of claim 12, wherein the predefined periodically repeating neighborhood of overlapped and non-overlapped input pixels includes neighboring input pixels nearest to the output pixel.

Claim 17

Dependent Claim 23 words

The apparatus of claim 12, wherein the precalculated weight is a function of the distance from an input pixel to an output pixel.

Claim 18

Dependent Claim 12 words

The apparatus of claim 12, wherein said quantizing means performs error diffusion.

Claim 19

Independent Claim 261 words

A method for converting an input image including a number of input pixels defined at resolution K×L to an output image including a number of output pixels defined at resolution M×N, comprising the steps of: calculating an input tile size in accordance with the input image resolution and an output tile size in accordance with the output image resolution, the input tile size defining an input tile and output tile size defining an output tile, both the input tile and the output tile being dimensionally equal and being dimensionally smaller than the input image and output image; overlaying the input tile with the output tile to define an input output grid having a plurality of phases, each phase of the input-output grid defining a periodically repeating neighborhood of overlapped and nonoverlapped input pixels about each output pixel, said overlaying step identifying a position for each output pixel in the input-output grid of the periodically repeating neighborhood of overlapped and non-overlapped input pixels; determining a gray level value having depth c for each output pixel defined at resolution M×N, each input pixel defined at resolution K×L and depth b in the periodically repeating neighborhood contributing to a gray level determination of each output pixel in the output image in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel; and quantizing the gray level value of each output pixel having pixel depth c to depth d, while retaining local area density and sharpness over the image at resolution M×N.

Claim 20

Independent Claim 261 words

A method for converting an input image including a number of input pixels defined at resolution K×L to an output image including a number of output pixels defined at resolution M×N, comprising the steps of: calculating an input tile size in accordance with the input image resolution and an output tile size in accordance with the output image resolution, the input tile size defining an input tile and output tile size defining an output tile, both the input tile and the output tile being dimensionally equal and being dimensionally smaller than the input image and output image; overlaying the input tile with the output tile to define an input output grid having a plurality of phases, each phase of the input-output grid defining a periodically repeating neighborhood of overlapped and nonoverlapped input pixels about each output pixel, said overlaying step identifying a position for each output pixel in the input-output grid of the periodically repeating neighborhood of overlapped and non-overlapped input pixels; determining a gray level value having depth c for each output pixel defined at resolution M×N, each input pixel defined at resolution K×L and depth b in the periodically repeating neighborhood contributing to a gray level determination of each output pixel in the output image in accordance with a precalculated weight based on position in the periodically repeating neighborhood of each input pixel with respect to each output pixel; and quantizing the gray level value of each output pixel having pixel depth c to depth d, while retaining local area density and sharpness over the image at resolution M×N.

Claim 21

Dependent Claim 35 words

The method of claim 16, wherein said calculating step calculates the input tile size and the output tile size in accordance with the following equations: C=Greatest Common Divisor(K,M); input tile size=(k/c+2)×(l/c+2); and output tile size=(M/c)×(N/c).

Claim 22

Dependent Claim 36 words

The method of claim 16, wherein said determining step includes the step of defining a weight as proportional to the inverse of the distance between an output pixel and each input pixel surrounding the output pixel.

Claim 23

Dependent Claim 23 words

The method of claim 18, wherein said determining step includes the step of precalculating a weight in accordance with the following equation: ##EQU4##

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-11-07	1998-05-09	1998-11-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-11-07	2002-05-09	2002-11-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-11-07	2006-05-09	2006-11-08	$7700.00	Window Closed / Lapsed

Unquantized resolution conversion of bitmap images using error diffusion

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