EP0505999A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Outline enhancing device

Assignee: Panasonic Holdings Corp

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Filing: 1992-03-25

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Granted: —

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Expires: 2012-03-25

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Abstract

Abstract An outline enhancing device (OC) for enhancing an outline of an image formed by a video signal (S1) having a rising and falling slope portions (A and C) and a flat portion (B) includes an enhancing signal producing circuit (1, 2, 3, 4, 5, 6, 7, and 8) for producing an enhancing signal (S9) having a first, a second, and a third enhancing wave forms (Fp, Sp, and Tp) which wave lengths are the same as those of three portions (A, C, and B) of the video signal (S1), respectively. A delay circuit (9) is provided for delaying the video signal (S1) to be synchronized with the enhancing signal (S9). A subtracter (10) is further provided for subtracting the enhancing signal (S9) from the synchronized video signal (9) such that three enhancing waves forms (Fp, Sp, and Tp) are exactly superimposed on the rising slope (A), the falling slope (C) and the flat portions (B), respectively, without any interference to the neighboring slopes or portion. As a result of such subtraction, the gradients of the rising and falling slopes (A and C) are made large while the flat portion (B) is extended. Thus, the outline in the video signal (S1) is enhanced without preshoots or overshoots around the outline.

Inventors

👤 Yosuke Izawa
👤 Naoji Okumura

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-09 11:35

CPC Classifications

H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208

Claims Analysis

Total Claims: 4

Claim 1

Independent Claim 258 words

An outline enhancing device (OC) for enhancing an outline of an image formed by a video signal (S1) having a first and second slopes (A and C) and a flat portion (B) between said first and second slope portions (A and C), said first and second slope portions (A and C) and said flat portion (B) having a first and second wave lengths (Fa and Tc) and a third wave length (Tb), comprising: an enhancing signal producing means (1, 2, 3, 4, 5, 6, 7, and 8) for producing an enhancing signal (S9) having a first and second enhancing portions (Fp and Tp) and a plain portion (Sp) between said first and second enhancing portions (Fp and Tp) such that said first and second enhancing portions (Fp and Tp) and plain portion (Sp) have the same wave lengths (Ta, Tc and Tb) as those of said first and second slope portions (A and C) and said flat portion (B), respectively; a synchronizing means (9) for synchronizing said video signal (S1) with said enhancing signal (S9); and an enhancing means (10) for enhancing an outline of said video signal (S1) by subtracting said enhancing signal (S9) from said video signal (9), whereby said first and second enhancing portions (Fp and Tp) and said plain portion (Sp) are exactly superimposed on said first and second slope portions (A and C) said first and said flat portion (C), respectively, without interference to either of neighboring portions thereof and used for making said first and second slope portions (A and C) steep.

Claim 2

Dependent Claim 326 words

An outline enhancing device as claimed in Claim 1, wherein said enhancing signal producing means (1, 2, 3, 4, 5, 6, 7, and 8) comprising: a first delaying means (1) for delaying said video signal (S1) by a first predetermined period (t1) to produce a first delayed signal (S2), said first predetermined period (t1) being predetermined based on said first and second wave lengths (Ta and Tc); a first subtracting means (2) for subtracting said first delayed signal (S2) from said video signal (S1) to produce a primary differentiated signal (S3) representing a differentiation of said video signal (S1); a second delaying means (3) for delaying said primary differentiated signal (S3) by said first predetermined period (t1) to produce a delayed primary differentiated signal (S4); a first minimum means (4) for combining either part of said primary differentiated signal (S3) and said delayed primary differentiated signal (S4) which is smaller than the other to produce a minimum primary differentiated signal (S5); a third delaying means (5) for delaying said minimum primary differentiated signal (S5) by a second predetermined period (t2) to produce a first delayed minimum primary differentiated signal (S6), said second predetermined period (t2) being predetermined based on said first and second wave lengths (Ta and Tc); a second subtracting means (6) for subtracting said first delayed minimum primary differentiated signal (S6) from said minimum primary differentiated signal (S5) to produce a second differentiated signal (S7) representing a differentiation of said minimum primary differentiated signal (S5); a forth delaying means (7) for delaying said minimum primary differentiated signal (S5) by a third predetermined period (t2/2) to produce a second delayed minimum primary differentiated signal (S8), said third predetermined period (t2/2) being a half of said second predetermined period (t2); and a second minimum means (8) for combining either part of said second differentiated signal (S7) and second delayed minimum primary differentiated signal (S8) which is smaller than the other to produce said enhancing signal (S9).

Claim 3

Dependent Claim 44 words

An outline enhancing device (OC) as claimed in Claim 2, wherein said synchronizing means (9) is a delay circuit (9) for delaying said video signal (S1) by a total of said first and third predetermined period (t1+t2/2) to produce a delayed video signal (S10).

Claim 4

Dependent Claim 31 words

An outline enhancing means (OC) as claimed in Claim 4, wherein said enhancing means (10) is a subtracter (10) for subtracting said enhancing signal (S9) from said delayed video signal (S10).

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