# US 6,295,096 B1 · Edge key generating method and edge key generating apparatus

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- Number: US 6,295,096 B1
- Document ID: US6295096B1
- Status: Granted
- Kind: B1
- Application number: 09/108,182
- Filed: 1998-07-01
- Granted: 2001-09-25
- Earliest claimed: 1997-07-03
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Nobukatsu Okuda; Yoshiki Yamada
- Web page: https://patentgrep.com/patent/US6295096B1

## CPC

- H04N 5/278: Subtitling
- H04N 5/275: Generation of keying signals
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

To enable interlacing edge-generating means to be used for a progressive image signal that is separated into lines as two sequences of signals, the present invention comprises a pre-edge processing circuit (11) that executes appropriate pre-edge processing on the progressive image signal separated into lines depending on the condition of each of the two signals, and an edge generating circuit (18, 19) that executes on the two signals after pre-edge processing pre-edge generation processing similar to that for interlacing.

## Claims

### Claim 1

An edge key generating method for progressive image signals, comprising
executing pre-edge processing that generates on a horizontal scanning line above or below a key signal a key signal equivalent to said key signal;
executing edge addition processing on the output from said pre-edge processing which output includes two sequences of signals each appearing on every other horizontal scanning line; and
line multiplexing to obtain a progressive image signal to which edges have been added.

### Claim 2

An edge key generating method, comprising
executing pre-edge processing that generates on a horizontal scanning line above or below a key signal a key signal equivalent to said key signal; and
executing edge addition processing on the output from said pre-edge processing which output includes two sequences of signals each appearing on every other horizontal scanning line; wherein
the method synthesizes the key signal prior to the pre-edge processing and the key signal after the edge addition processing.

### Claim 3

An edge key generating apparatus comprising:
a pre-edge processing circuit that generates on a horizontal scanning line above or below a key signal a key signal equivalent to said key signal to output two sequences of signals each appearing on every other horizontal scanning line;
a first edge generating circuit that executes edge addition processing on one of the signals in the output from said pre-edge processing circuit; and
a second edge generating circuit that executes edge addition processing on the other signal in the output from the pre-edge processing circuit.

### Claim 4 (depends on 3)

An edge key generating apparatus for progressive image signals according to claim 3, further comprising a line multiplexing circuit that line-multiplexes the output from the first edge generating circuit and the output from the second edge generating circuit to obtain a progressive image signal to which edges have been added.

### Claim 5 (depends on 3)

An edge key gene rating apparatus According to claim 3, further comprising a synthesis circuit that synthesizes a key signal that is an input signal to the pre-edge processing circuit and the outputs from the first and second edge generating circuits after edge addition processing.