EP0153167A2
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EP
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Method of image enhancement by raster scanning
Assignee: 3M Co
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Filing: 1985-02-15
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Granted: —
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Expires: 2005-02-15
Abstract
Abstract A method of image enhancement is disclosed in which a raster scan of an original image is made and the electrical signals so generated are processed on line to give an enhanced image.The adaptive image filtering scheme used gives edge and contrast enhancement. The technique is based on a sliding window, which moves across the image both in vertical and horizontal directions. At each step the center pixel density D<sub>c</sub> of this window is transformed to a new value D<sub>c</sub>', upon the following mathematical equationwhere D represents the mean level of the window. The parameters a and β are identified and adjusted on line.Since the parameters a and are adaptively adjusted according to the statistics of a given window size, there are no user interactions required. Unlike earlier techniques, high frequency noise components are not uniformly enhanced. The technique is particularly valuable in the treatment of medical radiographic images.
Inventors
- 👤 Abolghassem R. C/O Minnesota Mining And Mahmoodi
- 👤 Owen L. C/O Minnesota Mining And Nelson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 14:49
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/73; G06T5/75; G06T5/20; H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092; Y; Y10; Y10S; Y10S250/00; Y10S250/909
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
196 words
A method of displaying or recording an image showing enhanced detail relative to an original image or record comprising: a) making a point by point record of the original image by scanning it in a manner to select successive pixels in a logical array, b) storing the pixel values in such a way and for such a period that a window comprising a sub-array of adjacent pixels can be selected and analysed statistically said window comprising between 5 and 225 pixels, c) analyse the pixel values of the window surrounding each pixel in turn to give the average value D and the standard deviation δ. d) processing the central fixed value D c to give an improved value D' c such that D' C - kD c + (1-k)D wherein k is a variable having a value between 0 and 0.99 which varies from pixel to pixel based on the value of δ, said value of k being related monotonically to δ in such a way as to have an upper and lower bound within the said range 0 to 0.99. e) displaying or recording the enhanced image based on the derived values D' C .
Claim 2
Independent Claim
196 words
A method of displaying or recording an image showing enhanced detail relative to an original image or record comprising: a) making a point by point record of the original image by scanning it in a manner to select successive pixels in a logical array, b) storing the pixel values in such a way and for such a period that a window comprising a sub-array of adjacent pixels can be selected and analysed statistically said window comprising between 5 and 225 pixels, c) analyse the pixel values of the window surrounding each pixel in turn to give the average value D and the standard deviation δ. d) processing the central fixed value D c to give an improved value D' c such that D' C - kD c + (1-k)D wherein k is a variable having a value between 0 and 0.99 which varies from pixel to pixel based on the value of δ, said value of k being related monotonically to δ in such a way as to have an upper and lower bound within the said range 0 to 0.99. e) displaying or recording the enhanced image based on the derived values D' C .
Claim 3
Dependent Claim
21 words
The method of Claim 1 in which k increases monotonically with δ. and the window comprises between 5 and 100 pixels.
Claim 4
Dependent Claim
20 words
The method ot Claim 1 in which k decreases monotonically with δ, arid the window comprises between 5 100 pixels.
Claim 5
Dependent Claim
31 words
The method as in Claim 1 in which k is an increase exponential function of with an upper bound and a lower bound both lying in the range 0 to 0.99.
Claim 6
Dependent Claim
59 words
A method as in Claim 3 in which the relation ship of k with δ is which had an upper bound k u and a lower bound k 1 such that k u >k 1 the parameters r and S being chosen such that and and the value of the parameter t is in the range 0 to 2000.
Claim 7
Dependent Claim
26 words
The method of Claim 1 in which the original image is or the record represents a radiograph, and the window comprises between 5 and 81 pixels.
Claim 8
Dependent Claim
17 words
The method of Claim 5 in which the original image is ur the record represents a radiograph.
Claim 9
Dependent Claim
27 words
The method of Claim 1 or 5 in which the original image is or the original record represents one of the color separations of a color picture.
Claim 10
Dependent Claim
19 words
The method of Claim 1 in which the original image is or the original record represents a monochrome picture.
Claim 11
Dependent Claim
86 words
The method of Claim 1, 5, 8 or 10 in which the original record comprises an electric signal time sequence obtained by: a) exposing stimulable phosphor to radiation which will cause an imagewise storage of energy by the phosphors, b) scanning said stimulable phosphor with radiation that will cause said imagewise storage of energy to be released in a different form of energy or at a different wavelength than tile exposing energy, c) reading out said released energy and converting it into an original electric signal.
Claim 12
Dependent Claim
88 words
The method of Claim 1. 5 or 7 in which the original record comprises an electric signal time sequence obtained by: a) providing an imaging system in which a multilayered device having a photoconductive insulative layer is used to provide an electrostatic charge image at a layer of the device in response to imaging radiation directed onto the device, b) scanning the imaged device with readout radiation synchronized with readout electronics connected to the said multilayered device so as to convert the electrostatic charge image to electrical signals.
Claim 13
Independent Claim
185 words
A method of displaying or recording an enhanced radiation image comprising: a) exposing stimulable phosphor to radiation which will cause an imagewise storage of energy by the phosphors, b) scanning said stimulable phosphor with radiation that will cause said imagewise storage of energy to be released in a different form of energy or at a different wavelength than the exposing energy, c) reading out said released energy and converting it into an original electric signal, d) processing said original signal to produce an output signal in accordance with D c ' = kD c + D-(l-k) wherein D' c is the strength of the enhanced image of a pixel, D c is the strength of image at the center pixel of a scanning window, D is the mean level of the strength of the image of the pixels in the window, k is a variable present during the process and having a value between 0 and 0.99 and which is related monotonically to the standard deviation of the fixed values within the window and, e) displaying a visual image in resonse to said output signal.
Claim 14
Independent Claim
185 words
A method of displaying or recording an enhanced radiation image comprising: a) exposing stimulable phosphor to radiation which will cause an imagewise storage of energy by the phosphors, b) scanning said stimulable phosphor with radiation that will cause said imagewise storage of energy to be released in a different form of energy or at a different wavelength than the exposing energy, c) reading out said released energy and converting it into an original electric signal, d) processing said original signal to produce an output signal in accordance with D c ' = kD c + D-(l-k) wherein D' c is the strength of the enhanced image of a pixel, D c is the strength of image at the center pixel of a scanning window, D is the mean level of the strength of the image of the pixels in the window, k is a variable present during the process and having a value between 0 and 0.99 and which is related monotonically to the standard deviation of the fixed values within the window and, e) displaying a visual image in resonse to said output signal.
Claim 15
Independent Claim
212 words
An apparatus for displaying or recording an image showing enhanced detail relative to an original image or record comprising: a) means for making a point by point record of the original image by scanning it in a manner to select successive pixels in a logical array, b) a means for storing the pixel values in such a way and for such a period that a window comprising a sub-array of adjacent pixels can be selected and analysed statistically said window comprising between 5 and 225 pixels, c) a means for analysing the pixel values of the window surrounding each pixel in turn to give the average value D and the standard deviation δ , d) a means for processing the central fixed value D c to give an improved value D' c such that D' c = kD c + (1-k)D wherein k is a variable having a value between 0 and 0.99 which varies from pixel to pixel based on the value of δ, said value of k being related monotunically to δ in such a way as to have an upper and lower bound within the said range 0 to 0.99, and e) a means for displaying or recording the enhanced image based on the derived values D' c .
Claim 16
Independent Claim
212 words
An apparatus for displaying or recording an image showing enhanced detail relative to an original image or record comprising: a) means for making a point by point record of the original image by scanning it in a manner to select successive pixels in a logical array, b) a means for storing the pixel values in such a way and for such a period that a window comprising a sub-array of adjacent pixels can be selected and analysed statistically said window comprising between 5 and 225 pixels, c) a means for analysing the pixel values of the window surrounding each pixel in turn to give the average value D and the standard deviation δ , d) a means for processing the central fixed value D c to give an improved value D' c such that D' c = kD c + (1-k)D wherein k is a variable having a value between 0 and 0.99 which varies from pixel to pixel based on the value of δ, said value of k being related monotunically to δ in such a way as to have an upper and lower bound within the said range 0 to 0.99, and e) a means for displaying or recording the enhanced image based on the derived values D' c .
References Cited (Backward Citations)
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