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EP0449259A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method and apparatus for emphasizing sharpness of image

Assignee: Fujifilm Holdings Corp
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Filing: 1991-03-27
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Granted: —
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Expires: 2011-03-27
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Abstract

Abstract According to this invention, a sharpness emphasis is carried out by multiplying a sharpness emphasis signal of an original image by a function of a look-up table which is accessed based on an output from an edge detecting filter performing detections in accordance with only the edge portions of the original image. Since the edge detecting filter for detecting edges of the image is equipped in order to emphasize the sharpness only in the edge portions of the image, it is possible to prevent the image grains from being sharpness-emphasized. In addition, although the edge detecting filter may have a same size of a mask with that of the unsharpness mask, it is possible, if required, to modify freely both sizes of the masks, in order to perform a proper process in accordance with each image variation.

Inventors

  • 👤 Fumito Takemoto
  • 👤 Osamu Shimazaki

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 14:08
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092; G; G06; G06T; G06T5/00; G06T5/73; G06T5/75; G06T7/00; G06T7/10; G06T7/12; G06T2207/00; G06T2207/10; G06T2207/10004; G06T2207/10008; G06T2207/20; G06T2207/20172; G06T2207/20192

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 43 words
An image sharpness emphasis method which is characterized in that; when a sharpness emphasis signal of an image is formed, sharpness of said image is emphasized based on an output of an edge detecting filter for detecting only edge portions of said image.
Claim 2
Dependent Claim 63 words
An image sharpness emphasis method which is characteriszed in that; in a sharpness emphasis signal of an image being multiplied by sharpness coefficients, the sharpness of said image is emphasized by multiplying said sharpness coefficients by a function value which is outputted from a look-up table based on an output of an edge detecting filter for detecting only edge portions of said image.
Claim 3
Dependent Claim 28 words
An image sharpness emphasis method as claimed in Claim 2, wherein mask size of said edge detecting filter corresponds to the same mask size of an unsharp signal.
Claim 4
Dependent Claim 18 words
An image sharpness emphasis method as claimed in Claim 3, wherein said mask size is weighted by coefficients.
Claim 5
Dependent Claim 20 words
An image sharpness emphasis method as claimed in Claim 2, wherein said function value is defined by a non-linear function.
Claim 6
Dependent Claim 132 words
An image sharpness emphasis apparatus comprising; a line memory which receives a sharp signal of an image to output an unsharp signal and a matrix signal, an edge detecting filter for detecting edges on said image, a multiplication accumulating means which multiplies said matrix signal by the output of said edge detecting filter so as to be accumulated, a subtracting means which calculates a difference signal between said sharp signal and said unsharp signal, a look-up table to be accessed based on the output value of said multiplication accumulating means, a multiplication means for effecting multiplications between said difference signal, said sharpness coefficients and a function output of said look-up table, and an adder for adding up said sharp signal and the output of said multiplication means so as to be outputted.
Claim 7
Dependent Claim 51 words
An image sharpness emphasis apparatus as claimed in Claim 6, wherein there are provided a plurality of said edge detecting filters and said multiplication accumulating means for the plural directions, and said look-up table is to be accessed by adding up the resultants of the multiplicated accumulation of said each direction.

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