Resolution reduction technique for displaying documents on a monitor

Abstract

A method of generating an output image having a lower resolution than that of a source image is provided. A thinned image is generated by discarding outer pixels of the source image. In parallel with generation of the thinned image, an averaged image is generated, such that each pixel of the averaged image represents an average of a subset of pixels in the source image. A first output image is then generated by subsampling the pixels of the thinned image. A final output image is generated as a function of both the first output image and the averaged image.

What is claimed is:  
     
         1 . A method of generating an output image from a source image, the output image having a lower resolution than that of the source image, the method comprising: 
 performing a first process on the source image to generate a first image, the first image having a resolution lower than that of the source image;    performing a second process on the source image in parallel with the first process-to generate a second image, the second image having a resolution lower than that of the source image; and    generating the output image as a function of the first image and the second image.    
     
     
         2 . A method according to  claim 1 , wherein the first process comprises thinning the source image to generate the first image.  
     
     
         3 . A method according to  claim 2 , wherein the second process comprises windowed sampling of the source image to generate the second image.  
     
     
         4 . A method according to  claim 3 , wherein the second process comprises averaging values of pixels of the source image to generate pixels of the second image.  
     
     
         5 . A method according to  claim 1 , wherein the second process comprises windowed sampling of the source image to generate the second image.  
     
     
         6 . A method according to  claim 5 , wherein the first process comprises thinning the source image to generate the first image.  
     
     
         7 . A method according to  claim 6 , wherein the windowed sampling comprise averaging of values of pixels of the source image.  
     
     
         8 . A method according to  claim 5 , wherein the first process comprises: 
 generating an intermediate image; and    subsampling the intermediate image to produce the first image.    
     
     
         9 . A method according to  claim 1 , wherein the source image consists of binary pixels, and wherein the step of generating the output image as a function of the first image and the second image comprises the step of generating the output image as a plurality of gray-scale pixels.  
     
     
         10 . A method of enabling a target computer to generate an output image from a source image, the method comprising the step of transmitting sequences of instructions from a host computer to a target computer, the sequences of instructions including instructions which, when executed on the target computer, cause the target computer to perform the method recited in  claim 1 .  
     
     
         11 . A method of generating an output image based on a source image, the source image having a plurality of binary pixels, the method comprising the steps of: 
 averaging values of pixels of the source image to produce a first image having a plurality of gray-scale pixels, the first image having a resolution lower than that of the source image;    processing the source image in parallel with the averaging step to generate a second image having a plurality of gray-scale pixels, the second image having a resolution lower than the resolution of the source image; and    generating the output image based on the first image and the second image.    
     
     
         12 . A method of enabling a target computer to generate an output image from a source image, the method comprising the step of transmitting sequences of instructions from a host computer to a target computer, the sequences of instructions including instructions which, when executed on the target computer, cause the target computer to perform the method recited in  claim 11 .  
     
     
         13 . A method of generating an output image based on a source image, the source image having a plurality of binary pixels, the method comprising the steps of: 
 thinning the source image to produce a first image;    performing windowed sampling of values of the pixels of the source image to produce a second image, such that the second image has a plurality of gray-scale pixels; and    generating the output image based on the first image and the second image, such that the output image has a plurality of gray-scale pixels, and such that the output image has a resolution lower than that of the source image.    
     
     
         14 . A method according to  claim 13 , wherein the step of performing windowed sampling comprises generating each pixel of the second image as an average of a plurality of pixels of a predefined region of the source image.  
     
     
         15 . A method according to  claim 13 , further comprising the step of subsampling the first image to produce a subsampled image, wherein the step of generating the output image comprises generating the output image based on the subsampled image and the second image.  
     
     
         16 . A method of enabling a target computer to generate an output image from a source image, the method comprising the step of transmitting sequences of instructions from a host computer to a target computer, the sequences of instructions including instructions which, when executed on the target computer, cause the target computer to perform the method recited in  claim 13 .  
     
     
         17 . A method of generating an output image from a source image, the output image having a lower resolution than that of the source image, the source image and the output image each having a plurality of pixels, the method comprising the steps of: 
 generating a thinned image having a plurality of pixels by discarding outer pixels of the source image;    generating a first output image having a plurality of pixels by subsampling the pixels of the thinned image;    generating an averaged image having a plurality of pixels, wherein each pixel of the averaged image is generated as an average of a subset of the pixels in the source image; and    generating a final output image based on the first output image and the averaged image.    
     
     
         18 . A method according to  claim 17 , further comprising the step of generating a second output image from the averaged image by increasing the intensity of the pixels of the averaged image, wherein the step of generating a final output image comprises generating the final output image as a function of the first output image and the second output image.  
     
     
         19 . A method according to  claim 17 , wherein the step of generating the final output image comprises the step of generating each pixel of the final output image as the darker of the corresponding pixels in the first output image and the second output image.  
     
     
         20 . A method of enabling a target computer to generate an output image from a source image, the method comprising the step of transmitting sequences of instructions from a host computer to a target computer, the sequences of instructions including instructions which, when executed on the target computer, cause the target computer to perform the method recited in  claim 17 .  
     
     
         21 . A method of generating an output image from a source image, the output image having a different resolution than that of the source image, the method comprising: 
 providing a first image at a first resolution;    providing a second image at a second resolution, wherein the second resolution is different from the first resolution;    identifying a pattern in the source image; and    assigning a value to a subset of the output image based on a relationship between the first image and the second image with respect to the pattern.    
     
     
         22 . A method according to  claim 21 , wherein the step of identifying a pattern in the source image comprises the step of identifying a pattern of pixels within a region of the source image having a predetermined size and shape.  
     
     
         23 . A method according to  claim 21 , wherein the step of assigning a value to a subset of the output image comprises the step of assigning an intensity value to a subset of the output image, wherein the subset of the output image corresponds to the pattern in the source image.  
     
     
         24 . A method according to  claim 22 , wherein the subset of the output image is a pixel.  
     
     
         25 . A method according to  claim 22 , wherein the step of assigning a value to a subset of the output image comprises the step of assigning a gray-scale value to a pixel of the output image.  
     
     
         26 . A method according to  claim 22 , wherein the step of assigning a value to a subset of the output image comprises the step of assigning a value to the subset of the output image based on a relationship between: 
 at least one subset of the first image which represents the pattern; and    at least one subset of the second image corresponding to said at least one subset of the first image.    
     
     
         27 . A method of generating an output image based on a source image, the source image and the output image each including a plurality of pixels, the method comprising: 
 providing a first image at a first resolution and at a second resolution, wherein the second resolution is lower than the first resolution;    identifying a pattern formed in each of a plurality of subsets of the first image at the first resolution, wherein each of the subsets of the first image at the first resolution corresponds to a particular subset of the first image at the second resolution;    for each pattern, computing a value based on the subsets of the first image at the second resolution which correspond to said pattern;    storing each of the computed values in a storage device in association with a corresponding one of the patterns;    identifying a pattern in each of a plurality of subsets of the source image; and    for each of the subsets of the source image: 
 retrieving from the storage device the value corresponding to the pattern of said subset of the source image; and  
 assigning an intensity value to a subset of the output image based on the expected value retrieved from the storage device.  
   
     
     
         28 . A method according to  claim 27 , wherein each subset of the image at the first resolution includes a greater number of pixels than each corresponding subset of the image at the second resolution.  
     
     
         29 . A method according to  claim 27 , wherein each of the subsets of the source image corresponds in size and shape to each of the subsets of the image at the first resolution.  
     
     
         30 . A method according to  claim 27 , wherein the step of assigning an intensity value to a subset of the output image comprises the step of assigning a gray-scale intensity value to a subset of the output image based on the expected value retrieved from the storage device.  
     
     
         31 . A method of generating an output image based on a source image, such that the output image has a lower resolution than that of the source image, the source image and the output image each including a plurality of pixels, the method comprising: 
 providing a first set of pixels representing an image at a first resolution;    providing a second set of pixels representing the image at a second resolution, wherein the second resolution is lower than the first resolution;    identifying a pattern formed by the pixels in each of a plurality of subsets of the first set of pixels, wherein each of the subsets of the first set of pixels corresponds to a particular subset of the second set of pixels;    for each pattern identified in the identifying step, computing an expected value of the subsets of the second set of pixels which correspond to said pattern;    storing each of the expected values in a storage device in association with a corresponding one of the patterns;    identifying a pattern formed by the pixels in each of a plurality of subsets of the source image;    for each of the subsets of the source image, retrieving from the storage device the expected value corresponding to the pattern of said subset of the source image; and    for each of the subsets of the source image, assigning a gray-scale value to a subset of the output image based on the expected value retrieved from the storage device.    
     
     
         32 . A method according to  claim 31 , wherein the subset of the output image in the assigning step is a pixel of the output image.  
     
     
         33 . A method of removing blank space from an input page including a plurality of images, the method comprising the steps of: 
 representing the images as a plurality of objects; and    locating each of the objects on an output page to cause a spacing between the objects in the output page to be smaller than a spacing of the objects in the input page.    
     
     
         34 . A method according to  claim 33 , wherein the images comprise text.  
     
     
         35 . A method according to  claim 34 , wherein the step of representing comprises the step of representing a complete line of text as one object.  
     
     
         36 . A method according to  claim 34 , wherein the step of representing comprises the step of representing less than a complete line of text as one object.  
     
     
         37 . A method according to  claim 36 , wherein the step of representing comprises the step of representing a word as one object.  
     
     
         38 . A method according to  claim 33 , wherein the images comprise a plurality of lines of text, and wherein the step of representing comprises the step of representing each of the lines of text as an object.  
     
     
         39 . A method according to  claim 33 , further comprising the step of providing an output page that is smaller than the input page.  
     
     
         40 . A method according to  claim 33 , wherein the locating step comprises the step of rearranging the objects such that the relative positions of the objects in the output page are different from the relative positions of the objects in the input page.  
     
     
         41 . A method according to  claim 33 , wherein the step of locating the objects on the output page comprises the step of increasing the size of the output page until all of the objects fit on the output page.  
     
     
         42 . A method of removing blank space from an input page, the input page including a plurality of lines of text, the method comprising the steps of: 
 (a) representing the lines of text as a plurality of objects;    (b) determining a size for an output page, such that the output page is smaller than the input page;    (c) determining whether all of the objects can fit on the output page; and    (d) if not all of the objects can fit on the output page, then: 
 (d)(1) increasing the size of the output page; and  
 (d)(2) repeating step (c).  
   (e) if all of the objects can fit on the output page, then locating each of the objects on the output page.    
     
     
         43 . A method according to  claim 42 , further comprising the step of identifying a position on the input page of each of the objects.  
     
     
         44 . A method according to  claim 42 , wherein the step (a) of representing the lines of text as a plurality of objects comprises the step of representing at least one of the lines of text as more than one object.  
     
     
         45 . A method according to  claim 42 , wherein the step (a) of representing the lines of text as a plurality of objects comprises the step of representing each of the lines of text as one object.  
     
     
         46 . A method according to  claim 33 , wherein the step (e) of locating each of the objects comprises the step of rearranging the objects such that the relative positions of the objects in the output page are different from the relative positions of the objects in the input page.  
     
     
         47 . In a system including a processor coupled to a display device, a method of displaying a document on the display device, the method comprising the steps of: 
 (a) parsing the document into a plurality of portions, the plurality of portions including a first portion and a second portion;    (b) causing the first portion and the second portion to be simultaneously displayed on the display device, such that the first portion is displayed at a first resolution and the second portion is displayed at a second resolution different from the first resolution.    
     
     
         48 . A method according to  claim 47 , wherein the causing step (b) comprises the step of causing the second portion to be displayed on the display device such that the document is displayed on the display device in its entirety.  
     
     
         49 . A method according to  claim 47 , wherein the document has a resolution, and wherein the first resolution and the second resolution are different from the resolution of the document.  
     
     
         50 . A method according to  claim 49 , wherein at least one of the first resolution and the second resolution is lower than the resolution of the document.  
     
     
         51 . A method according to  claim 47 , wherein the parsing step (a) comprises the step of parsing the document into a plurality of portions in response to a user input, the user input for defining the first portion and the second portion.  
     
     
         52 . In a local computer system coupled to a plurality of remote computer systems over a network, each of the remote computer systems having a display device, a method of selecting a computer-implemented operation from a plurality of possible computer-implemented operations, the method comprising the steps of: 
 transmitting image data to each of the remote computer systems, the image data for use by each of the remote computer systems for displaying a plurality of images on the display device of each of the remote computer systems;    receiving a user input from each of the remote computer systems, each of the user inputs designating at least one of the images displayed on each of the remote computer systems; and    selecting the computer-implemented operation based on the user inputs.    
     
     
         53 . A method according to  claim 52 , wherein each of the images displayed by particular one of the remote computer systems corresponds to one of the possible computer-implemented operations.  
     
     
         54 . A method according to  claim 52 , wherein the computer-implemented operation comprises an operation for affecting the display of images on a monitor.  
     
     
         55 . A method according to  claim 52 , wherein the computer-implemented operation comprises an operation for displaying a digitized image on a monitor.  
     
     
         56 . A method according to  claim 52 , wherein the computer-implemented operation comprises an operation for altering a resolution of a digitized image for displaying the digitized image on a computer monitor.  
     
     
         57 . A method according to  claim 52 , wherein the computer-implemented operation comprises an operation for correcting a gamma of a monitor.  
     
     
         58 . A method according to  claim 52 , wherein the computer-implemented operation comprises an operation for adjusting a contrast of a digitized image for display on a monitor.