Method and apparatus for combining multiple image scans for enhanced resolution

Claim 1

A system for producing an enhanced resolution image from a set of lower resolution raster scanned images of an original image, the system comprising: (a) a scanner with a point-spread-function (PSF) represented by a two-dimensional set of known values for raster scanning the original image subject and for producing as an output a multiplicity of signals, one for each raster scanned representation of the original image and having means for introducing tracking errors to ensure adequate variety in each raster scan of the original image for efficient reconstruction of an enhanced resolution raster scan image; (b) converter means for uniformly sampling and quantizing the scanner output signal for producing a multiplicity of pixel value sets, one pixel value set for each scanner output signal; (c) a memory for temporary storage of the multiplicity of pixel value sets produced by the converter means; and (d) a numerical processor coupled to the memory for access to the stored pixel value sets, for storing of processed pixel value sets, and for executing a stored image resolution enhancement program, the numerical processor including means for, (i) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (ii) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (iii) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (iv) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means known PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, and (v) repeating the use of the means for aligning the interpolated prototype scan and the means for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 2

A system for producing an enhanced resolution image from a set of lower resolution raster scanned images of an original image, the system comprising: (a) a scanner with a point-spread-function (PSF) represented by a two-dimensional set of known values for raster scanning the original image subject and for producing as an output a multiplicity of signals, one for each raster scanned representation of the original image and having means for introducing tracking errors to ensure adequate variety in each raster scan of the original image for efficient reconstruction of an enhanced resolution raster scan image; (b) converter means for uniformly sampling and quantizing the scanner output signal for producing a multiplicity of pixel value sets, one pixel value set for each scanner output signal; (c) a memory for temporary storage of the multiplicity of pixel value sets produced by the converter means; and (d) a numerical processor coupled to the memory for access to the stored pixel value sets, for storing of processed pixel value sets, and for executing a stored image resolution enhancement program, the numerical processor including means for, (i) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (ii) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (iii) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (iv) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means known PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, and (v) repeating the use of the means for aligning the interpolated prototype scan and the means for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 11

A system for producing an enhanced resolution image from a set of lower resolution raster scanned images of an original image, the system comprising: (a) a scanner with a point-spread-function (PSF) represented by a set of known values for raster scanning the original image subject and for producing as an output a multiplicity of signals, one for each raster scanned representation of the original image and having means for introducing tracking errors to ensure adequate variety in each raster scan of the original image for efficient reconstruction of an enhanced resolution raster scan image; (b) converter means for uniformly sampling and quantizing the scanner output signal for producing a multiplicity of pixel value sets, one pixel value set for each scanner output signal; (c) a memory for temporary storage of the multiplicity of pixel value sets produced by the converter means; and (d) a numerical processor coupled to the memory for access to the stored pixel value sets, for storing of processed pixel value sets, and for executing a stored image resolution enhancement program, the numerical processor including means for, (i) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (ii) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (iii) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (iv) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means known PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, the means for adjusting the aligned interpolated prototype scan mixel values including means for (aa) forming overlapping cluster zones from contiguous prototype mixel elements contained within a rectangular array, (bb) forming an associated mixel zone vector, one vector associated with each overlapping cluster zone, having elements corresponding to the prototype scan mixel values included within the associated overlapping cluster zone, (cc) forming a zone matrix, each row having elements representative of known PSF values, which when multiplied by the associated mixel zone vector produces a vector of pixel value representative of the pixel elements included within the associated overlapping cluster zone, and (dd) sequentially solving for each associated mixel zone vector using any overlapping elements of the associated mixel zone vector, as obtained, for updating the prototype scan mixel values, and (v) repeating the use of the means for aligning the interpolated prototype scan and the means for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 12

A system for producing an enhanced resolution image from a set of lower resolution raster scanned images of an original image, the system comprising: (a) a scanner with a point-spread-function (PSF) represented by a set of known values for raster scanning the original image subject and for producing as an output a multiplicity of signals, one for each raster scanned representation of the original image and having means for introducing tracking errors to ensure adequate variety in each raster scan of the original image for efficient reconstruction of an enhanced resolution raster scan image; (b) converter means for uniformly sampling and quantizing the scanner output signal for producing a multiplicity of pixel value sets, one pixel value set for each scanner output signal; (c) a memory for temporary storage of the multiplicity of pixel value sets produced by the converter means; and (d) a numerical processor coupled to the memory for access to the stored pixel value sets, for storing of processed pixel value sets, and for executing a stored image resolution enhancement program, the numerical processor including means for, (i) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (ii) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (iii) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (iv) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means known PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, the means for adjusting the aligned interpolated prototype scan mixel values including means for (aa) forming overlapping cluster zones from contiguous prototype mixel elements contained within a rectangular array, (bb) forming an associated mixel zone vector, one vector associated with each overlapping cluster zone, having elements corresponding to the prototype scan mixel values included within the associated overlapping cluster zone, (cc) forming a zone matrix, each row having elements representative of known PSF values, which when multiplied by the associated mixel zone vector produces a vector of pixel value representative of the pixel elements included within the associated overlapping cluster zone, and (dd) sequentially solving for each associated mixel zone vector using any overlapping elements of the associated mixel zone vector, as obtained, for updating the prototype scan mixel values, and (v) repeating the use of the means for aligning the interpolated prototype scan and the means for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 31

A method for producing an enhanced resolution image from a multiplicity of lower resolution raster scan images produced by a scanner with known point-spread-function (PSF), each represented by a set of uniformly sampled and quantized pixel values, the method comprising the following steps: (a) storing the multiplicity of lower resolution raster scan images; (b) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (c) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (d) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (e) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, the steps of adjusting the aligned interpolated prototype scan mixel values including (i) forming overlapping cluster zones from contiguous prototype mixel elements contained within a rectangular array, (ii) forming an associated mixel zone vector, one vector associated with each overlapping cluster zone, having elements corresponding to the prototype scan mixel values included within the associated overlapping cluster zone, (iii) forming a zone matrix, each row having elements representative of known PSF values, which when multiplied by the associated mixel zone vector produces a vector of pixel values representative of the pixel elements included within the associated overlapping cluster zone, and (iv) sequentially solving for each associated mixel zone vector using any overlapping elements of the associated mixel zone vector, as obtained, for updating the prototype scan mixel values; and (f) repeating the use of the step for aligning the interpolated prototype scan and the step for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 32

A method for producing an enhanced resolution image from a multiplicity of lower resolution raster scan images produced by a scanner with known point-spread-function (PSF), each represented by a set of uniformly sampled and quantized pixel values, the method comprising the following steps: (a) storing the multiplicity of lower resolution raster scan images; (b) selecting one of the multiplicity of pixel value sets as a prototype scan from memory, the non-selected pixel value sets referred to as remaining pixel scans, (c) interpolating the prototype scan pixel values to produce an interpolated prototype scan with a higher density of sampled and quantized pixel values, the higher density of pixel values referred to as mixels, (d) aligning the interpolated prototype scan with a selected pixel scan of the remaining pixel scans, (e) adjusting the aligned interpolated prototype scan mixel values by minimizing an error cost function representative of a difference measure between a selected pixel of the selected pixel scan and a pixel value computed from the mixel values of the interpolated prototype scan using the scanner means PSF to produce a computed pixel value from the interpolated prototype scan mixel values, for producing a modified prototype scan, the steps of adjusting the aligned interpolated prototype scan mixel values including (i) forming overlapping cluster zones from contiguous prototype mixel elements contained within a rectangular array, (ii) forming an associated mixel zone vector, one vector associated with each overlapping cluster zone, having elements corresponding to the prototype scan mixel values included within the associated overlapping cluster zone, (iii) forming a zone matrix, each row having elements representative of known PSF values, which when multiplied by the associated mixel zone vector produces a vector of pixel values representative of the pixel elements included within the associated overlapping cluster zone, and (iv) sequentially solving for each associated mixel zone vector using any overlapping elements of the associated mixel zone vector, as obtained, for updating the prototype scan mixel values; and (f) repeating the use of the step for aligning the interpolated prototype scan and the step for adjusting the aligned prototype scan for each of the non-selected remaining pixel scans using the modified prototype scan as the interpolated prototype scan so that after all remaining pixel scans are processed, the modified prototype scan is an enhanced resolution raster scan image of the original image.

Claim 40

A method for reconstructing often used characters from raster scanned documents containing multiple examples of the often used characters, the method comprising the following steps: (a) raster scanning at least one document containing multiple examples of each character to be reconstructed using a scanner with known point-spread-function (PSF) and producing a uniformly sampled and quantized pixel raster scan; (b) storing each scanned pixel raster scan; (c) selecting a set of scanned exemplars of a given character from one or more pixel raster scan; (d) selecting one of the set of scanned exemplars as a prototype of the given character; (e) interpolating the prototype of a given character to produce a high resolution mixel image of the prototype; (f) aligning the interpolated prototype with a remaining scanned example of selected set of scanned exemplars of the given character; (g) adjusting the aligned interpolated prototype mixel values by computing a pixel value using the known PSF as a convolution kernel and comparing the computed pixel value with the corresponding pixel value of the scanned example of the given character for producing an updated prototype character with improved resolution; (h) repeating steps (f) and (g) for all secured examples selected in step (c); and (i) using the updated prototype character, after all scanned exemplars selected in step (c) are processed in steps (f) and (g) as the reconstructed given character.

Claim 41

A method for reconstructing often used characters from raster scanned documents containing multiple examples of the often used characters, the method comprising the following steps: (a) raster scanning at least one document containing multiple examples of each character to be reconstructed using a scanner with known point-spread-function (PSF) and producing a uniformly sampled and quantized pixel raster scan; (b) storing each scanned pixel raster scan; (c) selecting a set of scanned exemplars of a given character from one or more pixel raster scan; (d) selecting one of the set of scanned exemplars as a prototype of the given character; (e) interpolating the prototype of a given character to produce a high resolution mixel image of the prototype; (f) aligning the interpolated prototype with a remaining scanned example of selected set of scanned exemplars of the given character; (g) adjusting the aligned interpolated prototype mixel values by computing a pixel value using the known PSF as a convolution kernel and comparing the computed pixel value with the corresponding pixel value of the scanned example of the given character for producing an updated prototype character with improved resolution; (h) repeating steps (f) and (g) for all secured examples selected in step (c); and (i) using the updated prototype character, after all scanned exemplars selected in step (c) are processed in steps (f) and (g) as the reconstructed given character.