Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1999-03-24
2003-11-04
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C380S201000
Reexamination Certificate
active
06643451
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image data alteration preventing apparatus, an image data alteration preventing method, a scrambled image producing method, an image reproducing apparatus, and a digital VTR.
2. Description of the Prior Art
[1] A recording apparatus for continuously or intermittently recording an image picked up by a monitoring camera on a video tape by a video tape recorder (VTR) has already been developed.
The contents recorded on the video tape by such a recording apparatus maybe altered. In a case where the contents recorded on the video tape are altered, examination is performed with the truth distorted unless it is recognized that the contents are altered, which may cause social confusion.
An object of the present invention is to provide an alteration preventing apparatus and an alteration preventing method in which it is possible to judge whether or not image data recorded on a recording medium is altered, and prevent the image data from being altered.
[2] A digital VTR for continuously or intermittently recording on a video tape an image picked up by a monitoring camera after coding the image has already been developed.
It is not preferable that the image recorded on the video tape by such a digital VTR is freely reproduced by a person other than a particular person because it is deeply related to privacy.
An object of the present invention is to provide a scrambled image producing method in which a scrambled image can be produced when image coding data obtained by image coding is decoded.
An object of the present invention is to provide an image reproducing apparatus capable of reproducing, when an image is reproduced from a recording medium having image coding data obtained by image coding recorded thereon, a scrambled image.
An object of the present invention is to provide an image reproducing apparatus and a digital VTR which reproduce, when an attempt to reproduce an image is made by a person other than a particular person, a scrambled image.
SUMMARY OF THE INVENTION
An image data alteration preventing apparatus according to the present invention is characterized by comprising recording means for producing first alteration detecting data on the basis of image data, to record the produced first alteration detecting data, together with the image data, on a recording medium, and examining means for producing second alteration detecting data on the basis of the image data read out of the recording medium, and collating the produced second alteration detecting data and the first alteration detecting data read out of the recording medium, to judge whether or not the image data read out of the recording medium is altered. The image data may be digital image data or compressed coding data.
An example of the recording means is one comprising means for blocking in field units the image data such that the width thereof is previously determined n bytes long, means for subjecting image data for each block to a predetermined first operation in the longitudinal direction, to obtain first alteration detecting data which is n bytes long, and means for recording the first alteration detecting data, together with the image data, on the recording medium, and an example of the examining means is one comprising means for blocking in field units the image data read out of the recording medium such that the width thereof is previously determined n bytes long, means for subjecting image data for each block to the first operation in the longitudinal direction, to obtain second alteration detecting data which is n bytes long, and means for collating the obtained second alteration detecting data and the first alteration detecting data read out of the recording medium, to judge whether or not the image data read out of the recording medium is altered.
An example of the recording means is one comprising means for blocking in field units the image data such that the width thereof is previously determined n bytes long, means for subjecting image data for each block to a predetermined first operation in the longitudinal direction, to obtain the result of the operation which is n bytes long, means for subjecting the obtained result of the operation to a predetermined second operation, to obtain first alteration detecting data which is n bytes long, and means for recording the first alteration detecting data, together with the image data, on the recording medium, and an example of the examining means is one comprising means for blocking in field units the image data read out of the recording medium such that the width thereof is previously determined n bytes long, means for subjecting image data for each block to the first operation in the longitudinal direction, to obtain the result of the operation which is n bytes long, means for subjecting the obtained result of the operation to the second operation, to obtain second alteration detecting data which is n bytes long, and means for collating the obtained second alteration detecting data and the first alteration detecting data read out of the recording medium, to judge whether or not the image data read out of the recording medium is altered.
An image data alteration preventing method according to the present invention is characterized by comprising the recording step of producing first alteration detecting data on the basis of image data, to record the produced first alteration detecting data, together with the image data, on a recording medium, and the examining step of producing second alteration detecting data on the basis of the image data read out of the recording medium, and collating the produced second alteration detecting data and the first alteration detecting data read out of the recording medium, to judge whether or not the image data read out of the recording medium is altered. The image data may be digital image data or compressed coding data.
An example of the recording step is one comprising the steps of blocking in field units the image data such that the width thereof is previously determined n bytes long, subjecting image data for each block to a predetermined first operation in the longitudinal direction, to obtain the first alteration detecting data which is n bytes long, and recording the first alteration detecting data, together with the image data, on the recording medium, and an example of the examining step comprises the steps of blocking in field units the image data read out of the recording medium such that the width thereof is previously determined n bytes long, subjecting image data for each block to the first operation in the longitudinal direction, to obtain the second alteration detecting data which is n bytes long, and collating the obtained second alteration detecting data and the first alteration detecting data read out of the recording medium, to judge whether or not the image data read out of the recording medium is altered.
An example of the recording step is one comprising the steps of blocking in field units the image data such that the width thereof is previously determined n bytes long, subjecting image data for each block to a predetermined first operation in the longitudinal direction, to obtain the result of the operation which is n bytes long, subjecting the obtained result of the operation to a predetermined second operation, to obtain first alteration detecting data which is n bytes long, and recording the first alteration detecting data, together with the image data, on the recording medium, and an example of the examining step is one comprising the steps of blocking in field units the image data read out of the recording medium such that the width thereof is previously determined n bytes long, subjecting image data for each block to the first operation in the longitudinal direction, to obtain the result of the operation which is n bytes long, subjecting the obtained result of the operation to the second operation, to obtain second alteration detecting data which is n bytes long, and collating the obtaine
Suzuki Shiro
Tokura Masanori
Armstrong Westerman & Hattori, LLP
Chieu Po-lin
Sanyo Electric Co., LTD
Tran Thai
LandOfFree
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