SCENE CHANGE DETECTION DEVICE, CODING DEVICE, AND SCENE CHANGE DETECTION METHOD

1 . A scene change detection device comprising:

an audio information determination part detecting silent state of audio signal to output silence detection time information;

an image information determination part detecting brightness change or decreased level of brightness of an image in image signal to store scene change time information indicating time detecting the brightness change or decreased level of the brightness;

a scene change candidate point detector outputting scene change candidate time based on the silence detection time information and the scene change time information; and

an output determination part outputting scene change detection information based on time difference between successive first scene change candidate time and second scene change candidate time and a detection maximum value.

2 . The scene change detection device according to claim 1 , wherein the scene change candidate point detector sets predetermined period including the silence detection time information to silence period and outputs the scene change candidate time when the scene change time information is included in the silence detection period.

3 . The scene change detection device according to claim 2 , wherein the scene change candidate point detector outputs the scene change time information indicating earliest time as the scene change candidate time when a plurality of scene change time information are included in the silence period.

4 . The scene change detection device according to claim 1 , wherein the output determination part performs following steps of:

calculating a length of a first detection section based on time difference between current time of the scene change candidate time and time of one time before the current time of the scene change candidate time;

calculating a length of a second detection section based on time difference between time of one time before the current time of the scene change candidate time and time of two time before the current time of the scene change candidate time;

outputting the scene change candidate time of one time before as start time of the scene change detection information when the length of the first detection section is equal to or below the detection maximum value and the length of the second detection section is larger than the detection maximum value; and

outputting the scene change candidate time of one time before as end time of the scene change detection information when the length of the first detection section is below the detection maximum value and the length of the second detection section is below the detection maximum value.

5 . The scene change detection device according to claim 1 further comprising a storage storing the detection maximum value.

6 . The scene change detection device according to claim 1 , wherein the image information determination part further comprises a scene change detector detecting brightness change of the image in the image signal, a black image detector detecting decreased level of brightness in the image signal, and an OR circuit implementing the logical OR operation between output of the scene change detector and output of the black image detector.

7 . A coding device comprising:

a scene change detection device;

an analog/digital converter converting analog audio signal and analog image signal into digital audio signal and digital image signal;

a delay circuit delaying the digital image signal; and

a coding device including an encoder coding the digital image signal input through the delay circuit and the digital audio signal,

wherein the audio information determination part of the scene change detection device outputs the silence detection time information based on the digital audio signal, and the image information determination part of the scene change detection device outputs the scene change time information based on the digital image signal input to the encoder.

8 . A scene change detection method in a scene change detection device to which video composed of audio signal and image signal is input, the scene change detection method comprising:

detecting silent state of the audio signal to generate silence detection time information;

detecting brightness change or decreased level of brightness of the image in image signal to generate scene change time information indicating time detecting the brightness change or decreased level of brightness;

generating scene change candidate time based on the silence detection time information and the scene change time information; and

outputting scene change detection information when time difference between successive first scene change candidate time and second scene change candidate time is below detection maximum time.