US 5,208,857 A · Method and device for scrambling-unscrambling digital image data

Abstract

A method and device are disclosed for scrambling-unscrambling digital image data. The data is subjected to processing for extracting the colorimetric components of the pixels forming the image, the components being formed into blocks b(I,J) of N.times.N pixels x(i,j) so as to generate corresponding spatial chopping of the image where I designates a line index and J a column index of arrangement of the blocks in the image, i and j designating a line index and a column index of arrangement of the pixels in each block. The pixels and/or blocks are subjected to an intra-block and/or inter-block mixing procedure. The inter-block mixing consists of an arbitrary re-arrangement of said blocks of pixels and the intra-block mixing mixing consists of an arbitrary re-arrangement of the pixels os each block so as to obtain a scrambled arrangement of blocks and/or pixels.

Claims22

Dependent claims

Method for scrambling-descrambling digital image data, the method for scrambling-descrambling comprising:

a) subjecting said data to processing for extracting the colorimetric components of the pixels forming the image,
b) forming said components into blocks b(I, J) of N.times.N pixels x(i,j) so as to generate corresponding spatial chopping of the image, where I designates a left to right line index and J a top to bottom column index of arrangement of the blocks in the image and i designates a line index and j column index of arrangement of the pixels in each block,
c) then subjecting said blocks pixels to a mixing procedure so as to obtain a scrambled arrangement of blocks.

A device for scrambling-descrambling multiplexed digital television image data, said digital image data comprising video data that undergo a scrambling-descrambling operation together with auxiliary data that are not subjected to said scrambling-descrambling operation, this video data being subjected to compression to enable transmission thereof, said device comprising:

demultiplexing means for extracting the luminance and chrominance components of the pixels forming the image and the data not subjected to the scrambling-unscrambling operation,
first and second means for storing in blocks pixels of the luminance and chrominance components so as to generate corresponding spatial chopping of the image, said blocks b(I,J) of pixels being stored at corresponding addresses I, J where I designates a line index and J a column index of arrangement of the blocks of the image,
third means for storing said data not subjected to the scrambling-unscrambling operation, and
mixing means for mixing said pixels x(i,j) of each block b(I,J) so as to obtain a scrambled arrangement of blocks of pixels.

1 more element

Dependencies are inferred from the claim text.

Method and device for scrambling-unscrambling digital image data

Life of this patent

Method and device for scrambling-unscrambling digital image data

Life of this patent

Abstract

Claims22