Patent US4939645A successfully refreshed from Google Patents.
US4939645A
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Method and apparatus to reduce transform compression visual artifacts in medical images
Assignee: Toshiba Corp
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Filing: 1988-09-09
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Granted: 1990-07-03
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Expires: 2008-09-09
Abstract
Abstract A method and apparatus for reducing visual artifacts in medical images reconstructed from compressed imaging data by the approximation of image data rejected during compression. Rejected data is modeled by a statistical distribution such as the Gaussian distribution. The standard deviation of the rejected data is stored with the not-rejected, compressed data. During image reconstruction, the standard deviation is used to approximate the data rejected during compression, and thus to approximate the original image with substantial reduction of visual artifacts.
Inventors
- 👤 James F. Hopkinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:27
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G06; G06T; G06T12/00; G06T12/30; G06T5/00; G06T5/70; G06T2207/00; G06T2207/10; G06T2207/10072; G06T2207/10081; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
113 words
A method for substantially reducing visual artifacts resulting from transform compression of image data, comprising the steps of: transforming spatial image data into spectral image data representing the frequency content and amplitude of said spatial image data; rejecting those of said spectral image data having selected frequency and amplitude characteristics; computing at least one parameter which characterizes said rejected spectral image data in terms of a selected mathematical model; encoding not-rejected spectral image data for data compression; storing on a data storage device said encoded data and said parameter; decoding said encoded spectral image data; and generating an approximation of said rejected spectral image data by application of said parameter to said model.
Claim 2
Independent Claim
113 words
A method for substantially reducing visual artifacts resulting from transform compression of image data, comprising the steps of: transforming spatial image data into spectral image data representing the frequency content and amplitude of said spatial image data; rejecting those of said spectral image data having selected frequency and amplitude characteristics; computing at least one parameter which characterizes said rejected spectral image data in terms of a selected mathematical model; encoding not-rejected spectral image data for data compression; storing on a data storage device said encoded data and said parameter; decoding said encoded spectral image data; and generating an approximation of said rejected spectral image data by application of said parameter to said model.
Claim 3
Dependent Claim
29 words
The method of claim 1 wherein said step of computing includes computing at least one parameter which characterizes said rejected spectral image data in terms of a Gaussian distribution.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein said step of computing includes computing a standard deviation of said rejected spectral image data.
Claim 5
Dependent Claim
31 words
The method of claim 1 wherein said step of generating includes randomly selecting numbers from a number table, said numbers in said table having a distribution conforming to said mathematical model.
Claim 6
Dependent Claim
25 words
The method of claim 4 wherein said mathematical model is a Gaussian distribution and said numbers in said table have a standard deviation of one.
Claim 7
Dependent Claim
42 words
The method of claim 1 further comprising the steps of: transforming said decoded spectral image data and said approximated rejected spectral image data into an approximation of said spatial image data; and displaying an image derived from said approximated spatial image data.
Claim 8
Independent Claim
129 words
A method for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising the steps of: partitioning the image data into a plurality of spatial subimages having spatial subimage data; transforming said spatial subimage data into spectral subimage data representing the frequency content and amplitude of said spatial subimage data; rejecting those of said spectral subimage data having selected frequency and amplitude characteristics; computing at least one parameter which characterizes said rejected spectral subimage data in terms of a selected mathematical model. encoding not-rejected spectral subimage data for data compression; storing on a data storage device said encoded data and said parameter; decoding said encoded spectral subimage data; and generating an approximation of said rejected spectral subimage data by application of said parameter to said model.
Claim 9
Independent Claim
129 words
A method for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising the steps of: partitioning the image data into a plurality of spatial subimages having spatial subimage data; transforming said spatial subimage data into spectral subimage data representing the frequency content and amplitude of said spatial subimage data; rejecting those of said spectral subimage data having selected frequency and amplitude characteristics; computing at least one parameter which characterizes said rejected spectral subimage data in terms of a selected mathematical model. encoding not-rejected spectral subimage data for data compression; storing on a data storage device said encoded data and said parameter; decoding said encoded spectral subimage data; and generating an approximation of said rejected spectral subimage data by application of said parameter to said model.
Claim 10
Dependent Claim
29 words
The method of claim 7 wherein said step of computing includes computing at least one parameter which characterizes said rejected spectral subimage data in terms of a Gaussian distribution.
Claim 11
Dependent Claim
25 words
The method of claim 7 wherein said step of computing includes computing a standard deviation for the rejected data of each of said spectral subimages.
Claim 12
Dependent Claim
22 words
The method of claim 7 wherein said step of computing includes computing a standard deviation for all said rejected spectral image data.
Claim 13
Dependent Claim
30 words
The method of claim 7 wherein said step of generating includes randomly selecting numbers from a table, said numbers in said table having a distribution conforming to said mathematical model.
Claim 14
Dependent Claim
25 words
The method of claim 11 wherein said mathematical model is a Gaussian distribution and said numbers in said table have a standard deviation of one.
Claim 15
Dependent Claim
42 words
The method of claim 7 further comprising the steps of: transforming said decoded spectral subimage data and said approximated rejected spectral subimage data into an approximation of said spatial subimage data; and displaying an image derived from said approximated spatial image data.
Claim 16
Independent Claim
123 words
An apparatus for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising: means for transforming spatial image data into spectral image data representing the frequency content and amplitude of said spatial image data; means for rejecting those of said spectral image data having selected frequency and amplitude characteristics; means for computing at least one parameter which characterizes said rejected spectral image data in terms of a selected mathematical model. means for encoding not-rejected spectral image data for data compression; a data storage device for storing said encoded data and said parameter; means for decoding said encoded spectral image data; and means for generating an approximation of said rejected spectral image data by application of said parameter to said model.
Claim 17
Independent Claim
123 words
An apparatus for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising: means for transforming spatial image data into spectral image data representing the frequency content and amplitude of said spatial image data; means for rejecting those of said spectral image data having selected frequency and amplitude characteristics; means for computing at least one parameter which characterizes said rejected spectral image data in terms of a selected mathematical model. means for encoding not-rejected spectral image data for data compression; a data storage device for storing said encoded data and said parameter; means for decoding said encoded spectral image data; and means for generating an approximation of said rejected spectral image data by application of said parameter to said model.
Claim 18
Dependent Claim
31 words
The apparatus of claim 14 wherein said means for computing includes means for computing at least one parameter which characterizes said rejected spectral image data in terms of a Gaussian distribution.
Claim 19
Dependent Claim
23 words
The apparatus of claim 14 wherein said means for computing includes means for computing a standard deviation for said rejected spectral image data.
Claim 20
Dependent Claim
32 words
The apparatus of claim 14 wherein said means for generating includes means for randomly selecting numbers from a table, said numbers in said table having a distribution conforming to said mathematical model.
Claim 21
Dependent Claim
25 words
The apparatus of claim 17 wherein said mathematical model is a Gaussian distribution and said numbers in said table have a standard deviation of one.
Claim 22
Dependent Claim
43 words
The apparatus of claim 14 further comprising: means for transforming said decoded spectral image data and said approximated rejected spectral image data into an approximation of said spatial image data; and means for displaying an image derived from said approximated spatial image data.
Claim 23
Independent Claim
140 words
An apparatus for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising: means for partitioning the image data into a plurality of spatial subimages having spatial subimage data; means for transforming said spatial subimage data into spectral subimage data representing the frequency content and amplitude of said spatial subimage data; means for rejecting those of said spectral subimage data having selected frequency and amplitude characteristics; means for computing at least one parameter which characterizes said rejected spectral subimage data in terms of a selected mathematical model; means for encoding not-rejected spectral subimage data for data compression; a data storage device for storing said encoded data and said parameter; means for decoding said encoded spectral subimage data; and means for generating an approximation of said rejected spectral subimage data by application of said parameter to said model.
Claim 24
Independent Claim
140 words
An apparatus for substantially reducing visual artifacts resulting from transform compression of medical image data, comprising: means for partitioning the image data into a plurality of spatial subimages having spatial subimage data; means for transforming said spatial subimage data into spectral subimage data representing the frequency content and amplitude of said spatial subimage data; means for rejecting those of said spectral subimage data having selected frequency and amplitude characteristics; means for computing at least one parameter which characterizes said rejected spectral subimage data in terms of a selected mathematical model; means for encoding not-rejected spectral subimage data for data compression; a data storage device for storing said encoded data and said parameter; means for decoding said encoded spectral subimage data; and means for generating an approximation of said rejected spectral subimage data by application of said parameter to said model.
Claim 25
Dependent Claim
31 words
The apparatus of claim 20 wherein said means for computing includes means for computing at least one parameter which characterizes said rejected spatial subimage data in terms of a Gaussian distribution.
Claim 26
Dependent Claim
27 words
The apparatus of claim 20 wherein said means for computing includes means for computing a standard deviation for the rejected data of each of said spectral subimages.
Claim 27
Dependent Claim
24 words
The apparatus of claim 20 wherein said means for computing includes means for computing a standard deviation for all said rejected spectral subimage data.
Claim 28
Dependent Claim
32 words
The apparatus of claim 20 wherein said means for generating includes means for randomly selecting numbers from a table, the numbers in said table having a distribution conforming to said mathematical model.
Claim 29
Dependent Claim
25 words
The apparatus of claim 24 wherein said mathematical model is a Gaussian distribution and said numbers in said table have a standard deviation of one.
Claim 30
Dependent Claim
43 words
The apparatus of claim 20 further comprising: means for transforming said decoded spectral subimage data and said approximated rejected spectral subimage data into an approximation of said spatial subimage data; and means for displaying a subimage derived from said approximated spatial subimage data.
References Cited (Backward Citations)
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