Method for recognizing abnormal image
First Claim
1. A method comprising:
- selecting two adjacent image line, using a processor, each line representing a plurality of pixels, the image lines having respective level values Pi and Pi−
1, the values Pi and Pi−
1 each representing the brightness level of the pixels represented by a corresponding one of the image lines;
calculating an absolute value of a difference between said values Pi and P1−
1;
comparing said absolute value of the difference between said values Pi and Pi−
1 to a value X, wherein if said absolute value of the difference between said values Pi and Pi−
1 is smaller than said value X, said two adjacent image lines are determined as normal, and wherein if said absolute value of the difference between said values Pi and Pi−
1 is larger than said value X, said two adjacent image lines are determined as abnormal;
if said absolute value of the difference between said values Pi and Pi−
1 is larger than said value X, selecting an image line having a level value Pi+1 adjacent to said image line having the level value Pi and further selecting an image line having a level value Pi−
2 adjacent to said image line having the level value Pi−
1, each of the newly selected image lines representing a plurality of pixels, the values Pi+1 and Pi−
2 of the newly selected image lines each representing the brightness level of the pixels represented by a corresponding one of the newly selected image lines;
calculating an absolute value of a difference between said values Pi+1 and Pi−
2; and
comparing said absolute value of the difference between said values Pi+1 and Pi−
2 to said value X.
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Abstract
A method for recognizing abnormal image is disclosed. The invention utilizes level comparisons of adjacent image lines to determine if there is any abnormal image amid an image picture and whether the abnormal image belongs to shading or LBB. The method comprises the following steps. First of all, two adjacent image lines having level values Pi and Pi−1 are selected. Then an absolute value of the Pi and the Pi−1 is calculated. Next the absolute value is compared with a value X. When the absolute value is smaller than X, then the image lines are determined as normal. On the contrary, when the absolute value is larger than X, then at least one of the image lines is determined as abnormal. Moreover, another two image lines having level values Pi+1 and Pi−2 separately adjacent the image lines having level values Pi and the Pi−1 are selected. An absolute value of the Pi+1 and the Pi−2 is calculated and the absolute value of the Pi+1 and the Pi−2 is compared to the value X. When the absolute value of the Pi+1 and the Pi−2 is smaller than X, then the image lines having level values Pi and Pi−1 are determined as shading. However, when the absolute value of the Pi+1 and the Pi−2 is larger than X, then the image lines having level values Pi, Pi−1, Pi+1 and Pi−2 are determined as LBB.
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Citations
32 Claims
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1. A method comprising:
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selecting two adjacent image line, using a processor, each line representing a plurality of pixels, the image lines having respective level values Pi and Pi−
1, the values Pi and Pi−
1 each representing the brightness level of the pixels represented by a corresponding one of the image lines;calculating an absolute value of a difference between said values Pi and P1−
1;comparing said absolute value of the difference between said values Pi and Pi−
1 to a value X, wherein if said absolute value of the difference between said values Pi and Pi−
1 is smaller than said value X, said two adjacent image lines are determined as normal, and wherein if said absolute value of the difference between said values Pi and Pi−
1 is larger than said value X, said two adjacent image lines are determined as abnormal;if said absolute value of the difference between said values Pi and Pi−
1 is larger than said value X, selecting an image line having a level value Pi+1 adjacent to said image line having the level value Pi and further selecting an image line having a level value Pi−
2 adjacent to said image line having the level value Pi−
1, each of the newly selected image lines representing a plurality of pixels, the values Pi+1 and Pi−
2 of the newly selected image lines each representing the brightness level of the pixels represented by a corresponding one of the newly selected image lines;calculating an absolute value of a difference between said values Pi+1 and Pi−
2; andcomparing said absolute value of the difference between said values Pi+1 and Pi−
2 to said value X. - View Dependent Claims (2, 3)
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4. An apparatus, comprising:
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a light source to illuminate an object to be scanned with light; a component to convert at least a portion of light reflected from the object into a plurality of scan lines; and circuitry configured to; select two adjacent image lines having respective level values Pi and Pi−
1, each of the values Pi, and Pi−
1 representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;determine a difference between said values Pi and Pi−
1;compare said difference between said values Pi and Pi−
1 to a first threshold value;according to whether said difference exceeds the first threshold value, select an image line having a level value Pi+1 adjacent to said image line having the level value Pi and further select an image line having a level value Pi−
2 adjacent to said image line having the level value Pi−
1, each of the values Pi+1 and Pi−
2 representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;determine a difference between said values Pi+1 and Pi−
2; andcompare said difference between said values Pi+1 and Pi−
2 to a second threshold value. - View Dependent Claims (5, 6, 7, 8, 16, 17)
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9. A method comprising:
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selecting two adjacent image lines having respective level values Pi and Pi−
1, using a processor, the values Pi and Pi−
1 each representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;calculating a difference between said values Pi and Pi−
1;comparing said difference between said values Pi and Pi−
1 to a first threshold value;if said difference between said values Pi and Pi−
1 is larger than said first threshold value, selecting an image line having a level value Pi+1 adjacent to said image line having the level value Pi and further selecting an image line having a level value Pi−
2 adjacent to said image line having the level value Pi−
1, each of the values Pi+1 and Pi+2 representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;calculating a difference between said values Pi+1 and Pi−
2; andcomparing said difference between said values Pi+1 and Pi−
2 to a second threshold value. - View Dependent Claims (10, 11, 12, 18, 19, 20)
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13. An article comprising:
- a storage medium having stored thereon instructions, that, if executed, result in;
selecting two adjacent image lines having level values Pi and Pi−
1, the level values each representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;determining a difference between said values Pi and Pi−
1;comparing said difference between said values Pi and Pi−
1 to a first threshold value, wherein if said difference between said values Pi and Pi−
1 does not exceed said first threshold value, said two adjacent image lines are determined as normal, and wherein if said difference between said values Pi and Pi−
1 exceeds said first threshold value, said two adjacent image lines are determined as abnormal; andif said difference between said values Pi and Pi−
1 exceeds said first threshold value, selecting an image line having a level value Pi+1 adjacent to said image line having the level value Pi and further selecting an image line having a level value Pi−
2 adjacent to said image line having the level value Pi−
1, each of the values Pi+1 and Pi−
2 representing the brightness of a plurality of pixels represented by a corresponding one of the image lines;determining a difference between said values Pi+1 and Pi−
2; andcomparing said difference between said values Pi+1 and Pi−
2 to a second threshold value. - View Dependent Claims (14, 15, 21)
- a storage medium having stored thereon instructions, that, if executed, result in;
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22. A system, comprising:
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means for comparing first brightness indications of first adjacent image lines to determine a first variance in brightness, each first brightness indication representing a plurality of pixels associated with a corresponding one of the first image lines; means for determining whether the first variance exceeds a threshold value; according to whether the first variance exceeds the threshold value, means for selecting second image lines that are adjacent to the first adjacent image lines; means for comparing second brightness indications of the second image lines to determine a second variance in brightness, each second brightness indication representing a plurality of pixels associated with a corresponding one of the second image lines; means for determining whether a scanning abnormality has occurred according to the comparisons; and means for identifying a shading abnormality if the first variance exceeds the threshold value and the second variance does not exceed the threshold value. - View Dependent Claims (23, 24, 25, 26, 27)
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28. An apparatus comprising:
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a light source to illuminate an object to be scanned with light; a component to convert at least a portion of the light representing the object into a plurality of scan lines; and circuitry configured to; analyze first brightness indications of first adjacent image lines to determine a first variance in brightness, each first brightness indication representing a plurality of pixels associated with a corresponding one of the first image lines; according to a magnitude of the first variance, select second image lines that are adjacent to the first adjacent image lines; analyze second brightness indications of the second image lines to determine a second variance in brightness, each second brightness indication representing a plurality of pixels associated with a corresponding one of the second image lines; and determine whether a scanning abnormality has occurred according to the comparisons, and identify a dark band abnormality if the magnitudes exceed threshold values. - View Dependent Claims (29, 30, 31, 32)
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Specification