Method for embedding watermark into an image and digital video recorder using said method

A method for embedding watermark into an image simultaneously with MPEG compression for the image, comprising:

• inputting quantized discrete cosine transformation (DCT) coefficient of a corresponding macro block in said image;
• dividing each DCT block of said corresponding macro block into a signature extracting region and a watermark embedding region;
• combining said quantized DCT coefficient in said signature extracting region with user information;
• obtaining a hash value by regarding said combined value as an input value of the hash function;
• and
• embedding said hash value into a least significant bit (LSB) of the quantized DCT coefficient in said watermark embedding region.

A method for embedding watermark into an image simultaneously with MPEG compression for image, comprising:

• inputting quantized discrete cosine transformation (DCT) coefficients of all macro blocks in corresponding slice in said image;
• dividing each DCT block of said macro blocks into the signature extracting region and the watermark embedding region;
• combining said quantized DCT coefficients in said signature extracting region with user information;
• obtaining hash value by regarding said combined value as an input value of hash function;
• and
• embedding said hash value into a least significant bit (LSB) of quantized DCT coefficient in watermark embedding region in next slice of said corresponding slice.

A digital video recorder for embedding watermark into an image which is shot in real time and for recording the image, wherein embedding watermark into an image shot in real time comprises:

• inputting quantized discrete cosine transformation (DCT) coefficient of a corresponding macro block in said image;
• dividing each DCT block of said corresponding macro block into a signature extracting region and a watermark embedding region;
• combining said quantized DCT coefficient in said signature extracting region with user information;
• obtaining a hash value by regarding said combined value as an input value of the hash function;
• and
• embedding said hash value into a least significant bit (LSB) of the quantized DCT coefficient in said watermark embedding region.