Method for identifying marked images based at least in part on frequency domain coefficient differences

An article of manufacture including a computer-readable medium having computer-executable instructions stored thereon, the instructions comprising:

• instructions for forming at least one coefficient difference array including a plurality of elements based at least in part on a frequency domain representation of at least one training image;
• instructions for thresholding the elements of the at least one coefficient difference array to obtain at least one thresholded coefficient difference array, wherein each of the elements of the at least one coefficient difference array is compared to a threshold value, and wherein each element larger than the threshold value is assigned the threshold value;
• and
• instructions for training an image classifier using the at least one thresholded coefficient difference array to obtain a trained hidden data image classifier for determining whether hidden data is present in at least one other image.

An apparatus comprising:

• means for forming at least one coefficient difference array including a plurality of elements based at least in part on a frequency domain representation of at least one training image;
• means for thresholding the elements of the at least one coefficient difference array to obtain at least one thresholded coefficient difference array, wherein each of the elements of the at least one coefficient difference array is compared to a threshold value, and wherein each element larger than the threshold value is assigned the threshold value;
• and
• means for training an image classifier using the at least one thresholded coefficient difference array to obtain a trained hidden data image classifier for determining whether hidden data is present in at least one other image.

An electronic computing device, comprising:

• at least one processor configured to obtain a trained hidden data image classifier, wherein said obtaining comprises:
• forming at least one coefficient difference array including a plurality of elements based at least in part on a frequency domain representation of at least one training image;
• thresholding the elements of the at least one coefficient difference array to obtain at least one thresholded coefficient difference array, wherein each of the elements of the at least one coefficient difference array is compared to a threshold value, and wherein each element larger than the threshold value is assigned the threshold value;
• and
• training an image classifier using the at least one thresholded coefficient difference array.

A method comprising:

• using at least one processor to form at least one coefficient difference array including a plurality of elements based at least in part on a frequency domain representation of at least one training image;
• using the at least one processor to threshold the elements of the at least one coefficient difference array to obtain at least one thresholded coefficient difference array, wherein each of the elements of the at least one coefficient difference array is compared to a threshold value, and wherein each element larger than the threshold value is assigned the threshold value;
• and
• using the at least one processor to train an image classifier using the at least one thresholded coefficient difference array to obtain a trained hidden data image classifier for determining whether hidden data is present in at least one other image.