Method and apparatus for processing or resizing digital images, such as images of bar code symbols
First Claim
1. Bar code reading apparatus for imaging a data collection symbol representing encoded information, the apparatus comprising:
- a sensor that receives light reflected from the symbol and produces an output signal therefrom that represents the reflectance of the bars and spaces of the symbol;
a memory for storing at least a portion of an image of the symbol, the stored image being comprised of pixels in at least one dimension, each pixel having an intensity value; and
image processing circuitry that retrieves a set of M pixels from the memory and applies an M-pixel sized window to the set of M pixels, replicates a first pixel in the set of M pixels in the window j times and replicates at least a second pixel in the set of M pixels in the window k times, sorts the M set of pixels and replicated pixels, selects an n-th largest pixel in the sorted pixels where the n-th largest pixel is not a largest pixel in the sorted pixels, stores the selected pixel in the memory, and repeatedly retrieves another set of M pixels and again replicates, sorts, selects and stores for the another set of M pixels to generate a reduced size image based on the stored image, and wherein j is greater than k, and j and k are greater than one.
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Accused Products
Abstract
A method and apparatus for resizing or processing images initially retrieves a one-dimensional sample of the image, such as a line of pixels. The image can be of a machine-readable symbol, or other data. A moving window having, for example, five pixels, includes a center "hard core" and four surrounding pixels. Two or more structural sets or multisets are applied to the window to produce a set of pixels greater than the set of pixels in the original image. For example, the center pixel is repeated three times, while immediately adjacent left and right pixels are repeated twice. Thus, a series of nine pixels results. The resulting nine pixels are then sorted based on descending gray scale levels. The n-th largest pixels is selected, such as the third largest. The image is updated, the window moved, and the method repeats again. Pyramid filtering, cubic convolution interpolation, or other techniques can be used to reduce the size of an image, and more complex windows and structural sets can be employed.
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Citations
34 Claims
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1. Bar code reading apparatus for imaging a data collection symbol representing encoded information, the apparatus comprising:
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a sensor that receives light reflected from the symbol and produces an output signal therefrom that represents the reflectance of the bars and spaces of the symbol; a memory for storing at least a portion of an image of the symbol, the stored image being comprised of pixels in at least one dimension, each pixel having an intensity value; and image processing circuitry that retrieves a set of M pixels from the memory and applies an M-pixel sized window to the set of M pixels, replicates a first pixel in the set of M pixels in the window j times and replicates at least a second pixel in the set of M pixels in the window k times, sorts the M set of pixels and replicated pixels, selects an n-th largest pixel in the sorted pixels where the n-th largest pixel is not a largest pixel in the sorted pixels, stores the selected pixel in the memory, and repeatedly retrieves another set of M pixels and again replicates, sorts, selects and stores for the another set of M pixels to generate a reduced size image based on the stored image, and wherein j is greater than k, and j and k are greater than one. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. An apparatus for processing a stored image, the stored image being comprised of a plurality of pixels and at least a portion of the image being stored in a memory, the apparatus comprising pixel analysis circuitry that retrieves a set of M pixels from the stored image and applies an M-pixel sized window to the set of M pixels, replicates a first pixel in the set of M pixels in the window j times and replicates at least a second pixel in the set of M pixels in the window k times, sorts the M set of pixels and replicated pixels, selects an n-th largest pixel in the sorted pixels where the n-th largest pixel is not a largest pixel in the sorted pixels, stores the selected pixel in the memory, and retrieves another set of M pixels and again replicates, sorts, selects and stores for the another set of M pixels to generate a reduced size image based on the stored image, and wherein j is greater than k, and j and k are greater than one.
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16. A method of reducing the size of a stored image comprising:
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storing an image, the image being comprised of a plurality of pixels; retrieving a set of M pixels from the memory and applying an M-pixel sized window to the M set of pixels; replicating a first pixel in the set of M pixels in the window j times and replicating at least a second pixel in the set of M pixels in the window k times; sorting the M set of pixels and replicated pixels; selecting an n-th largest pixel in the sorted pixels, wherein the n-th largest pixel is not a largest pixel in the sorted pixels; storing the selected pixel in the memory; repeatedly retrieving another set of M pixels and again performing the replicating, sorting, selecting and storing for the another set of M pixels, and wherein j is greater than k, and j and k are greater than one; and generating a reduced size image based on the stored image and the acts of retrieving, replicating, sorting, selecting, storing and repeatedly retrieving the selected pixel. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A computer implemented method of processing a stored image, the stored image being comprised of a plurality of pixels, the method comprising:
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choosing a set of M pixels from the memory and applying an M-pixel sized window to the M set of pixels; replicating a first pixel in the set of M pixels in the window j times and replicating at least a second pixel in the set of M pixels in the window k times; sorting the M set of pixels and replicated pixels; selecting an n-th largest pixel in the sorted pixels, wherein the n-th largest pixel is not a largest pixel in the sorted pixels; storing the selected pixel in the memory; repeatedly choosing another set of M pixels and again performing the replicating, sorting, selecting and storing for the another set of M pixels, and wherein j is greater than k, and j and k are greater than one, and generating a reduced size image based on the stored image and the acts of choosing, replicating, sorting, selecting, storing and repeatedly choosing. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A computer-readable medium containing instructions for causing a computer system to resize a stored image, the stored image being comprised of a plurality of pixels, the instructions causing the computer to perform a method comprising:
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choosing a set of M pixels from the memory and applying an M-pixel sized window to the M set of pixels; replicating a first pixel in the set of M pixels in the window j times and replicating at least a second pixel in the set of M pixels in the window k times; sorting the M set of pixels and replicated pixels; selecting an n-th largest pixel in the sorted pixels, wherein the n-th largest pixel is not a largest pixel in the sorted pixels; storing the selected pixel in the memory; repeatedly choosing another set of M pixels and again performing the replicating, sorting, selecting and storing for the another set of M pixels, and wherein j is greater than k, and j and k arc greater than one; and generating a reduced size image based on the stored image and the acts of choosing, replicating, sorting, selecting, storing and repeatedly choosing.
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Specification