Method and device for identifying whether standard picture contains watermark

A device for identifying whether a standard picture contains a watermark, comprising:

• one or more processors;
• and
• memory storing instructions, the instructions, when executed by the one or more processors, cause the processors to perform:
• obtaining a set of sample standard pictures;
• adjusting sample standard pictures in the set of sample standard pictures to a preset size, the sample pictures in the set of sample standard pictures not containing watermark information;
• calculating an average of pixel attribute values of the sample pictures in the set of sample standard pictures at pixel positions of the preset size;
• normalizing the average of the pixel attribute values at the pixel positions of the preset size;
• obtaining watermark-presence probabilities of the pixel positions of the preset size, wherein the watermark-presence probability of the pixel positions of the preset size is defined as a complementary event probability of a probability expressed by the average of the pixel attribute values at the pixel positions of the preset size;
• obtaining a target picture that is adjusted to the preset size;
• and
• calculating a sum of products of pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size;
• in accordance with a determination that the sum of products of the pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size is greater than a predefined threshold value, determining that the target picture contains a watermark, and providing a predefine output prompt indicating detection of the watermark for the target picture;
• and
• in accordance with a determination that the sum of products of the pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size is not greater than the predefined threshold value, determining that the target picture does not contain a watermark, and performing a transaction based on the target picture.

A non-transitory computer-readable storage medium for identifying whether a standard picture contains a watermark, the computer-readable storage medium storing instructions, the instructions, when executed by one or more processors, cause the processors to perform:

• obtaining a set of sample standard pictures;
• adjusting sample standard pictures in the set of sample standard pictures to a preset size, the sample pictures in the set of sample standard pictures not containing watermark information;
• calculating an average of pixel attribute values of the sample pictures in the set of sample standard pictures at pixel positions of the preset size;
• normalizing the average of the pixel attribute values at the pixel positions of the preset size;
• obtaining watermark-presence probabilities of the pixel positions of the preset size, wherein the watermark-presence probability of the pixel positions of the preset size is defined as a complementary event probability of a probability expressed by the average of the pixel attribute values at the pixel positions of the preset size;
• obtaining a target picture that is adjusted to the preset size;
• and
• calculating a sum of products of pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size;
• in accordance with a determination that the sum of products of the pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size is greater than a predefined threshold value, determining that the target picture contains a watermark, and providing a predefine output prompt indicating detection of the watermark for the target picture;
• and
• in accordance with a determination that the sum of products of the pixel attribute values of the target picture at the pixel positions of the preset size and the corresponding watermark-presence probabilities at the pixel positions of the preset size is not greater than the predefined threshold value, determining that the target picture does not contain a watermark, and performing a transaction based on the target picture.