Methods, apparatus, and devices for noise reduction

Abstract

Embodiments include applying a compensation to an image signal based on nonuniformity of a display device. The compensation is based on information about variations in light-output response among elements of the display device. The compensation is also modified based on a characteristic of a desired use of the display.

1. A method of image processing, said method comprising:
 for each of a plurality of pixels of a display, obtaining a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels; 
 to increase a visibility of a characteristic of a displayed image during a use of the display, modifying a map that is based on the obtained measures; and 
 based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object. 
 
     
     
       2. The method of image processing according to  claim 1 , wherein the map comprises at least one of a luminance map of the display and a chrominance map of the display. 
     
     
       3. The method of image processing according to  claim 1 , wherein said modifying a map is based on a characteristic of a feature to be detected during display of an image. 
     
     
       4. The method of image processing according to  claim 1 , wherein said modifying a map is based on a characteristic of a class of images to be displayed. 
     
     
       5. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes:
 obtaining a characteristic of an image to be displayed; and 
 modifying the map according to the obtained characteristic. 
 
     
     
       6. The method of image processing according to  claim 1 , wherein said modifying a map includes modifying the map according to a desired frequency response of the display. 
     
     
       7. The method of image processing according to  claim 1 , wherein said modifying a map includes modifying the map according to a desired response of the display to a predetermined image characteristic. 
     
     
       8. The method of image processing according to  claim 1 , wherein said modifying a map includes attenuating a magnitude of a first component of the map relative to a magnitude of a second component of the map, wherein the second component has a higher spatial frequency than the first component. 
     
     
       9. The method of image processing according to  claim 8 , wherein said modifying a map includes attenuating a magnitude of a third component of the map relative to the magnitude of the second component of the map, wherein the third component has a higher spatial frequency than the second component. 
     
     
       10. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of an image area having a spatial frequency greater than 0.1 cycles per degree. 
     
     
       11. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a perceptibility of features of a displayed image that are mutually separated by more than one arc-minute. 
     
     
       12. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of an area in accordance with a contrast of the area. 
     
     
       13. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a contrast sensitivity function. 
     
     
       14. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a predetermined feature of interest. 
     
     
       15. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of a clinically relevant feature. 
     
     
       16. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a shape and size of a clinically relevant feature. 
     
     
       17. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map to increase a visibility of rounded shapes. 
     
     
       18. The method of image processing according to  claim 1 , wherein the image signal is derived from a photographic representation of living tissue obtained using at least one among a penetrating radiation and a penetrating emission. 
     
     
       19. The method of image processing according to  claim 1 , wherein the image signal is derived from an X-ray photograph. 
     
     
       20. The method of image processing according to  claim 1 , said method comprising verifying that a desired structure was not removed from the map during said modifying. 
     
     
       21. The method of image processing according to  claim 20 , wherein said verifying includes calculating a difference between the map and the modified map. 
     
     
       22. The method of image processing according to  claim 1 , wherein said modifying a map to increase a visibility of a characteristic of a displayed image includes modifying the map according to a first selected characteristic in a first region of the display, and modifying the map according to a second selected characteristic in a second region of the display,
 wherein the first characteristic is different than the second characteristic, and wherein the first region is separate from the second region. 
 
     
     
       23. The method of image processing according to  claim 1 , said method comprising calculating a plurality of correction functions based on the modified map. 
     
     
       24. The method of image processing according to  claim 23 , wherein said obtaining a display signal comprises applying, to a value of the image signal that corresponds to a pixel of the display, a correction function that corresponds to the pixel from among the plurality of correction functions. 
     
     
       25. The method of image processing according to  claim 1 , wherein the map comprises a plurality of correction functions, each of the plurality of correction functions corresponding to at least one of the plurality of pixels. 
     
     
       26. The method of image processing according to  claim 25 , wherein said obtaining a display signal comprises applying, to a value of the image signal that corresponds to a pixel of the display, a correction function that corresponds to the pixel from among the plurality of correction functions. 
     
     
       27. The method of image processing according to  claim 1 , wherein the luminance resolution of the display signal is greater than the luminance resolution of the image signal. 
     
     
       28. The method of image processing according to  claim 1 , wherein the luminance resolution of the display signal is greater than the luminance resolution of the display. 
     
     
       29. The method of image processing according to  claim 28 , said method comprising displaying the display signal on the display, said displaying including performing an error diffusion technique based on the display signal. 
     
     
       30. The method of image processing according to  claim 1 , said method comprising attenuating a component of the image signal according to a characterization of noise of an image detector. 
     
     
       31. The method of image processing according to  claim 1 , wherein said modifying a map includes modifying the map to reduce a visibility of a defective pixel of the display. 
     
     
       32. A data storage medium having machine-readable instructions describing the method of image processing according to  claim 1 . 
     
     
       33. The method of image processing according to  claim 1 , wherein said method comprises using a correction circuit to perform said obtaining a display signal. 
     
     
       34. An image processing apparatus comprising:
 an array of storage elements configured to store, for each of a plurality of pixels of a display, a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels; and 
 an array of logic elements configured to modify a map based on the stored measures and to obtain, based on the modified map and an image signal that represents at least one physical and tangible object, a display signal that is configured to cause the display to depict the at least one physical and tangible object, 
 wherein the array of logic elements is configured to modify the map to increase a visibility of a characteristic of a displayed image during a use of the display. 
 
     
     
       35. The image processing apparatus according to  claim 34 , wherein said array of logic elements is configured to attenuate a magnitude of a first component of the map relative to a magnitude of a second component of the map, wherein the second component has a higher spatial frequency than the first component. 
     
     
       36. A method of image processing, said method comprising:
 for each of a plurality of pixels of a display, obtaining a measure of a light-output response of at least a portion of the pixel at each of a plurality of driving levels; 
 modifying a map of the display that is based on the obtained measures, said modifying including, with respect to a magnitude of a component having a spatial period between one and fifty millimeters, decreasing a magnitude of a component having a spatial period less than one millimeter and decreasing a magnitude of a component having a spatial period greater than fifty millimeters; and 
 based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object. 
 
     
     
       37. A method of image processing, said method comprising:
 for each of a plurality of pixels of a display, obtaining a measure of a luminance of at least a portion of the pixel in response to each of a plurality of different electrical driving levels; 
 to increase a visibility of a characteristic of a displayed image during a use of the display, modifying a map that is based on the obtained measures; and 
 based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object. 
 
     
     
       38. The method of image processing of claim 1, wherein the plurality of pixels excludes a second plurality of pixels of the display.  
     
     
       39. The image processing apparatus of claim 34, wherein the plurality of pixels excludes a second plurality of pixels of the display. 
     
     
       40. The method of image processing of claim 1, wherein said obtaining a measure of a light-output response comprises retrieving the measure from storage. 
     
     
       41. A method of image processing, the method comprising:
 for each of a plurality of groups of pixels of a display, obtaining corresponding data representative of a light-output response of the group of pixels at each of a plurality of driving levels;   to increase a visibility of a characteristic of a displayed image during use of the display, modifying a map that is based on the obtained corresponding data for each of the plurality of groups; and   based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object.    
     
     
       42. The method of image processing according to claim 41, wherein the plurality of driving levels is less than a number of driving levels of the display. 
     
     
       43. The method of image processing according to claim 41, wherein the plurality of groups of pixels excludes at least one other pixel of the display. 
     
     
       44. The method of image processing according to claim 41, wherein at least one of the plurality of groups comprises a plurality of portions of pixels. 
     
     
       45. The method of image processing according to claim 41, wherein, for at least one of the plurality of groups, each pixel of the group comprises a plurality of portions, and the corresponding data comprises data representative of a light-output response of the group of pixels for each of the plurality of portions. 
     
     
       46. The method of image processing according to claim 41, wherein the modifying includes, with respect to a magnitude of a component having a spatial period between one and fifty millimeters, decreasing a magnitude of a component having a spatial period less than one millimeter and decreasing a magnitude of a component having a spatial period greater than fifty millimeters. 
     
     
       47. The method of image processing according to claim 41, wherein the light-output response comprises luminance. 
     
     
       48. The method of image processing according to claim 41, wherein the light-output response comprises chromaticity. 
     
     
       49. The method of image processing according to claim 41, wherein the modified map comprises correction data configured to produce a desired non-uniform light-output response. 
     
     
       50. An image processing apparatus comprising:
 an array of storage elements configured to store, for each of a plurality of groups of pixels of a display, corresponding data representative of a light-output response of the group of pixels at each of a plurality of driving levels; and   an array of logic elements configured to modify a map based on the stored corresponding data for each of the plurality of groups and to obtain, based on the modified map and an image signal that represents at least one physical and tangible object, a display signal that is configured to cause the display to depict the at least one physical and tangible object,   wherein the array of logic elements is configured to modify the map to increase a visibility of a characteristic of a displayed image during use of the display.   
     
     
       51. The image processing apparatus of claim 50, wherein at least one of the plurality of groups comprises a plurality of portions of pixels. 
     
     
       52. The image processing apparatus of claim 50, wherein the modified map comprises correction data configured to produce a desired non-uniform light-output response. 
     
     
       53. A method of processing an image for a display, the display comprising a plurality of pixels, said method comprising:
 modifying a map to increase a visibility of a characteristic of a displayed image, wherein the map is based on a measure of a light-output response of at least a portion of each pixel in at least a portion of the plurality of pixels at each of a plurality of driving levels; and   based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object.   
     
     
       54. The method of processing an image for a display of claim 53, wherein the modifying includes, with respect to a magnitude of a component having a spatial period between one and fifty millimeters, decreasing a magnitude of a component having a spatial period less than one millimeter and decreasing a magnitude of a component having a spatial period greater than fifty millimeters. 
     
     
       55. The method of processing an image for a display of claim 53, wherein the light-output response comprises luminance. 
     
     
       56. The method of processing an image for a display of claim 53, wherein the light-output response comprises chromaticity. 
     
     
       57. The method of processing an image for a display of claim 53, wherein the modified map comprises correction data configured to produce a desired non-uniform light-output response. 
     
     
       58. A method of processing an image for a display, the display comprising a plurality of pixels, said method comprising:
 based on a modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object,   wherein the modified map is based on a measure of a light-output response of at least a portion of each pixel in at least a portion of the plurality of pixels at a plurality of driving levels.   
     
     
       59. The method of processing an image for a display of claim 58, wherein the modified map comprises correction data configured to produce a desired non-uniform light-output response. 
     
     
       60. An image processing apparatus comprising:
 an array of storage elements configured to store, for each pixel in at least a portion of a plurality of pixels of a display, data representative of a light-output response of at least a portion of the pixel at a plurality of driving levels; and   an array of logic elements configured to obtain, based on a modified map and an image signal that represents at least one physical and tangible object, a display signal that is configured to cause the display to depict the at least one physical and tangible object,   wherein the modified map increases a visibility of a characteristic of a displayed image during use of the display.   
     
     
       61. The method of processing an image for a display of claim 60, wherein the modified map comprises correction data configured to produce a desired non-uniform light-output response. 
     
     
       62. An image processing apparatus comprising:
 an array of logic elements configured to generate a display signal based on a map and an image signal that represents at least one physical and tangible object,   wherein the display signal is configured to cause a display to depict a display image of the at least one physical and tangible object, and   wherein the map comprises correction data configured to produce a desired non-uniform light-output response.   
     
     
       63. The image processing apparatus according to claim 62, wherein said desired non-uniform light-output response is a desired spatially non-uniform light-output response of the display. 
     
     
       64. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a lower degree of non-uniformity for pixels substantially at a center of the display than for pixels substantially at edges of the display. 
     
     
       65. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises lower display noise for pixels substantially at a center of the display than for pixels substantially at edges of the display. 
     
     
       66. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a constant contrast for a majority of the display. 
     
     
       67. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a lower degree of non-uniformity for luminance than for color. 
     
     
       68. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a lower degree of non-uniformity for driving levels in a first range of driving levels than for driving levels outside the first range of driving levels. 
     
     
       69. The image processing apparatus of 68, wherein the first range of driving levels comprises a plurality of driving levels between a minimum driving level of the display and a maximum driving level of the display. 
     
     
       70. The image processing apparatus of claim 68, wherein the first range of driving levels comprises less than a total number of driving levels of the display. 
     
     
       71. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises:
 a first degree of non-uniformity at a first range of driving levels; and   a second degree of non-uniformity at a second range of driving levels.   
     
     
       72. The image processing apparatus of claim 71, wherein a value of the image signal corresponding to a maximum driving level is substantially uncorrected. 
     
     
       73. The image processing apparatus of claim 71, wherein a value of the image signal corresponding to a minimum driving level is substantially uncorrected. 
     
     
       74. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises:
 a first degree of non-uniformity for driving levels within a first range of driving levels; and   a second degree of non-uniformity for driving levels outside the first range of driving levels.   
     
     
       75. The image processing apparatus of claim 74, wherein the first degree of non-uniformity is less than twenty percent and the second degree of non-uniformity is greater than twenty percent. 
     
     
       76. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a contrast that is at least ninety percent of an uncorrected display contrast. 
     
     
       77. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a first contrast substantially at a center of the display and a second contrast substantially at edges of the display. 
     
     
       78. The image processing apparatus of claim 77, wherein the first contrast is greater than the second contrast. 
     
     
       79. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises contrasts substantially at a center of the display that are greater than contrasts substantially at edges of the display. 
     
     
       80. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises a lower degree of non-uniformity within a first range of spatial frequencies than outside the first range of spatial frequencies. 
     
     
       81. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises less correction for a defective pixel than for a non-defective pixel. 
     
     
       82. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response comprises less correction for pixels having a degree of non-uniformity greater than or equal to a first threshold than for pixels having a degree of non-uniformity less than the first threshold. 
     
     
       83. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response is based in part on a type of image being displayed. 
     
     
       84. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response is based in part on a physical characteristic of an image being displayed. 
     
     
       85. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response is based in part on an effect of a post-processing system. 
     
     
       86. The image processing apparatus of claim 85, wherein a resulting light-output that includes post processing is substantially uniform. 
     
     
       87. The image processing apparatus of claim 85, wherein the post-processing system comprises a projection system. 
     
     
       88. The image processing apparatus of claim 85, wherein the post-processing system comprises a lens. 
     
     
       89. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response is based in part on a desired frequency response. 
     
     
       90. The image processing apparatus of claim 62, wherein the desired non-uniform light-output response increases the visibility of a feature of the at least one physical and tangible object. 
     
     
       91. The image processing apparatus of claim 62, wherein the map includes at least one lookup table. 
     
     
       92. The image processing apparatus of claim 62, wherein the map is implemented in a compressed form. 
     
     
       93. The image processing apparatus of claim 62, wherein the map includes a plurality of coefficients of a polynomial description. 
     
     
       94. The image processing apparatus of claim 62, wherein the map has a lower resolution than a resolution of the display. 
     
     
       95. The image processing apparatus according to claim 62, wherein the correction data is based on at least one characteristic of an image represented in the image signal. 
     
     
       96. A method of image processing comprising:
 receiving an image signal representative of at least one physical and tangible object;   obtaining correction data configured to produce a desired non-uniform light-output response; and   generating a display signal based on the image signal and the correction data,   wherein the display signal is configured to cause the display to depict a display image of the at least one physical and tangible object.   
     
     
       97. The method of image processing according to claim 96, wherein said desired non-uniform light-output response is a desired spatially non-uniform light-output response of the display. 
     
     
       98. An image processing apparatus comprising:
 an array of logic elements configured to generate a display signal based on a map and an image signal that represents at least one physical and tangible object,   wherein the display signal is configured to cause a display to depict a display image of the at least one physical and tangible object,   wherein the map comprises correction data configured to produce a light-output response with a lower degree of non-uniformity for driving levels within a first range of driving levels than for driving levels outside the first range of driving levels.   
     
     
       99. The image processing apparatus of claim 98, wherein a degree of non-uniformity gradually increases from a driving level within the first range of driving levels to a driving level outside the first range of driving levels. 
     
     
       100. An image processing apparatus comprising:
 an array of logic elements configured to generate a display signal based on a map and an image signal that represents at least one physical and tangible object,   wherein the display signal is configured to cause a display to depict a display image of the at least one physical and tangible object,   wherein the map comprises correction data configured to correct for pixel non-uniformity only when the pixel non-uniformity is outside of a tolerance level.   
     
     
       101. The image processing apparatus of claim 100, wherein the tolerance level varies among pixels of the display. 
     
     
       102. The image processing apparatus of claim 101, wherein at least one pixel of the display has a plurality of portions and wherein the tolerance level varies among portions of the pixel. 
     
     
       103. The image processing apparatus of claim 101, wherein the tolerance level varies among pixels of the display based in part on a position of a pixel on the display. 
     
     
       104. The image processing apparatus of claim 103, wherein the tolerance level is greater for pixels substantially at edges of the display than for pixels substantially at a center of the display. 
     
     
       105. An image processing apparatus comprising:
 an array of logic elements configured to generate a display signal based on a map and an image signal that represents at least one physical and tangible object,   wherein the display signal is configured to cause a display to depict a display image of the at least one physical and tangible object,   wherein the map comprises correction data calculated based on whether at least a portion of a pixel is defective.   
     
     
       106. The image processing apparatus according to claim 105, wherein the map comprises correction data for a first pixel in the display based in part on a light-output response of at least one defective pixel in the display adjacent to the first pixel. 
     
     
       107. The image processing apparatus according to claim 105, wherein the map comprises correction data for a first pixel in the display based in part on a light-output response of at least one pixel in the display adjacent to the first pixel that has a degree of non-uniformity greater than a predetermined threshold. 
     
     
       108. A method of processing an image for a display, the method comprising:
 obtaining first data representative of a light-output response of a first group of pixels of the display at a first plurality of driving levels;   obtaining second data representative of a light-output response of a second group of pixels of the display at a second plurality of driving levels;   to increase a visibility of a characteristic of a displayed image during use of the display, modifying a map that is based on the obtained first and second data; and   based on the modified map and an image signal that represents at least one physical and tangible object, obtaining a display signal that is configured to cause the display to depict the at least one physical and tangible object.   
     
     
       109. The method of processing according to claim 108, wherein said display includes a third group of pixels. 
     
     
       110. The method of processing according to claim 108, wherein said first group of pixels includes at least one pixel that is excluded from said second group of pixels. 
     
     
       111. The method of processing according to claim 108, wherein said first plurality of driving levels is the same as said second plurality of driving levels. 
     
     
       112. The method of processing according to claim 108, wherein said first group of pixels comprises at least one pixel of the display, and wherein said second group of pixels comprises at least one pixel of the display. 
     
     
       113. The method of processing according to claim 108, wherein said first group of pixels comprises at least one portion of a pixel of the display, and wherein said second group of pixels comprises at least one portion of a pixel of the display. 
     
     
       114. An image processing apparatus comprising:
 an array of storage elements configured to store first data representative of a light-output response of a first group of pixels of a display and second data representative of a light-output response of a second group of pixels of the display; and   an array of logic elements configured to modify a map based on the stored first and second data and to obtain, based on the modified map and an image signal that represents at least one physical and tangible object, a display signal that is configured to cause the display to depict the at least one physical and tangible object,   wherein the array of logic elements is configured to modify the map to increase a visibility of a characteristic of a displayed image during use of the display.   
     
     
       115. The image processing apparatus according to claim 114, wherein said first data is representative of a light-output response of the first group at a first plurality of driving levels, and wherein said second data is representative of a light-output response of the second group at a second plurality of driving levels.