Apparatus and method for defect channel nulling
First Claim
1. A method for correcting defects in an image comprising:
- applying light to an image storing medium;
receiving from the image storing medium an image signal indicating an image deteriorated by defects;
applying a defect distinguishing radiation to the image storing medium;
receiving from the image storing medium a defect signal, in register with the image signal, indicating the defects in the image;
applying a gain to the defect signal to generate a normalized defect signal;
differencing the image signal and normalized defect signal to generate a recovered image signal; and
adjusting the gain to minimize the defects in the recovered image signal.
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Accused Products
Abstract
A method of and apparatus for removing the effects of surface and near surface image storage media defects from a scanned image using an infrared record as a norming control. Each pixel in a visible channel of the scanned images is divided by the corresponding pixel in the associated infrared control channel after it has been altered in gain to match the degree of defect in the visible channel. By appropriately altering the gain prior to dividing the pixel information, imbalances between the visible and infrared records which would leave defect residue after the division are reduced or eliminated. To remove defect residue, a degree of nulling is established for each defect region based on the visible and infrared content in that region. In one embodiment, the articulation gain is multiplicatively applied to the logarithm of the visible and infrared records. To prevent variations in articulation gain from mottling brightness, the articulation gain is applied to details extracted through a high pass filter. In this embodiment, the image is divided into frequency bands in a pyramid structure, and separate articulation gain is applied to each band. The articulation gains are calculated using the crosscorrelation between the visible and infrared images within a region to null the component of the visible channel matching the defect detected by the infrared channel. Gain limits are set based on correlations measured over the entire image.
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Citations
44 Claims
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1. A method for correcting defects in an image comprising:
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applying light to an image storing medium;
receiving from the image storing medium an image signal indicating an image deteriorated by defects;
applying a defect distinguishing radiation to the image storing medium;
receiving from the image storing medium a defect signal, in register with the image signal, indicating the defects in the image;
applying a gain to the defect signal to generate a normalized defect signal;
differencing the image signal and normalized defect signal to generate a recovered image signal; and
adjusting the gain to minimize the defects in the recovered image signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for correcting the effect of defects in an image comprising:
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means for applying light to the image storage medium;
means for receiving from the image storing medium an image signal indicating an image deteriorated by defects in the image storage medium;
means for applying a defect distinguishing radiation to the image storage medium;
means for receiving from the image storage medium a defect signal, in register with the image signal, indicating the defects in the image;
means for applying a gain to the defect signal to generate a normalized defect signal;
means for differencing the image signal and normalized defect signal to generate a recovered image signal; and
means for adjusting the gain to minimize the defects in the recovered image signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method of processing visual image data with non-image defect data to remove non-image defect information from the visual image data, the non-image defect data being registered with the visual image data, comprising:
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creating, from the visual image data, a plurality of visual image data sets for respective spatial frequency bands;
creating from the visual image data a plurality of non-image defect data sets for respective spatial frequency bands substantially similar to the spatial frequency bands for the visual imaging data;
cross correlating the visual image data set and the non-image defect data sets for respective spatial frequency bands to obtain crosscorrelation variables for each of the spatial frequency bands;
autocorrelating the non-image defect data set for each of the spatial frequency bands to obtain autocorrelation variables for each of the spatial frequency bands;
processing the crosscorrelation variables over a plurality of spatial regions to obtain spatially defined crosscorrelation variables for each of the spatial frequency bands;
processing the autocorrelation variables over a plurality of spatial regions substantially similar to the spatial regions of the crosscorrelation variables to obtain spatially defined autocorrelation variables for each of the spatial frequency bands;
processing the spatially defined crosscorrelation variables with the spatially defined autocorrelation variables to obtain spatially defined nulling gains for each of the spatial frequency bands;
applying the spatially defined nulling gains to the respective non-image defect data sets to obtain nulling data sets for the respective spatial frequency bands;
applying the nulling data sets to the visual image data sets for the respective spatial frequency bands to obtain corrected visual image data sets for the respective spatial frequency bands; and
merging the corrected visual image data sets for the respective spatial frequency bands to obtain corrected visual image data. - View Dependent Claims (44)
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Specification