Research On Copyright Protection Algorithm For Game Character Concept Design

As copyright disputes in the game market continue,copyright certification has become an urgent problem to be solved.Among them,the phenomenon of plagiarism on game character concept designs is the most common.Common plagiarism types are divided into creative plagiarism and tamper plagiarism.Through the study of the plagiarism of a large number of game character concept designs,it is found that game character concept designs have some relatively unchanged characteristics during the plagiarism process:1.The pose of the character is relatively unchanged;2.The area of the body of the character is relatively unchanged;3.The distribution of character joints is relatively unchanged.The existing image plagiarism detection algorithm cannot be directly applied to the plagiarism detection of game character concept designs,because there are detection results that are inaccurate and cannot be applied to scenes where content is tampered with.In view of the plagiarism of game character concept designs and the shortcomings of existing algorithms,this article proposes a copyright protection scheme applicable to game character concept designs from two aspects of passive and active forensics,mainly including the following three algorithms:(1)Aiming at the creative plagiarism scene of passive forensics,a pose-based multi-feature fusion plagiarism detection algorithm is proposed by taking advantage of the invariance of the character’s posture.In order to improve the accuracy of algorithm detection,the algorithm not only introduces posture features that reflect the uniqueness of game characters as detection features,but also takes into account the limitations of single feature detection,fusing multiple image features to describe game characters,making the detection results more accurate.The algorithm includes five steps:First,extract the shoulder turning point of the character through SUSAN corner detection to correct the rotation of the game character,and use the bottom-up pedestrian detection method to extract the character pose joint points.Secondly,the face compress method is used to calculate the representative points of the face joint points,and form pose features with other joint points.Then,pose features are described by using the method of pose invariance.Then,the color,texture and shape features of the image are extracted by the method of color histogram,gray level co-occurrence matrix and geometric invariant moment.Finally,the average of the precision of a single feature is used to assign multiple feature weights,which are fused into a feature vector.According to the similar distance between the feature vectors,it is determined whether the two game character concept designs are plagiarized.Experiments show that the algorithm performs well on plagiarism attacks such as rotation,scaling,color change,and component replacement of game characters,and the detection rate is high.(2)Aiming at the tampering plagiarism scene of active forensics,using the invariance of the character’s torso area,a watermarking algorithm for game character concept design based on skin and texture detection is proposed.In order to improve the imperceptibility of watermarked images,the algorithm uses an improved human skin detection algorithm to realize the skin detection of game characters,and then locate the non-skin of the original painting and the area with the highest texture complexity as the watermark embedding area.The algorithm consists of four steps:First,locate the upper body torso area of the character through the extracted posture joint points,and select blocks in a loop in the upper body torso area.Secondly,the skin color thresholds of the HSV&YCbCr space of a large number of game character skin images are counted,and the human skin detection algorithm is improved to improve the detection accuracy rate of the game character skin.By calculating the skin area ratio and texture complexity of each selected block separately,the selected block with the smallest skin area and the highest texture complexity is used as the watermark embedding area.Then,multi-level wavelet transform and singular value decomposition are performed on the selected block image,and the watermark is embedded in the intermediate frequency subband.Finally,the copyright authentication is carried out by extracting the watermark of the image to be detected.Experiments show that the algorithm embeds the watermark in the non-skin texture complex area of the game character has good imperceptibility,and can resist many common tampering attacks,such as adding text,replacing character parts,changing clothing colors,cutting legs,etc.(3)Aiming at the tampering plagiarism scene of active forensics,using the relative invariance of pose joint points,a watermarking algorithm for game character concept designs based on pose joint points is proposed.Because the traditional feature points used in game character concept designs have the disadvantages of uneven distribution and instability after being attacked,the uniformly distributed,stable and orderly pose joint points are selected as the feature points,and the circular local features with constant rotation are constructed to embed watermark.The algorithm is divided into four steps:First,a circular local feature area is constructed with the extracted pose joint points as the center.Secondly,the local feature area is normalized and supplemented with "0" as the embedded area.Then,the discrete Fourier transform is applied to the candidate region,and the amplitude coefficient of the mid-band is selected to embed the watermark.Finally,the watermark information is extracted according to the order of pose joint points,and the probability of false alarm is used to decide whether to embed the watermark.Experiments show that,compared with existing watermarking algorithms based on local features,the feature points selected by the watermarking algorithm are more stable,and the watermarks are embedded in each joint point in an orderly manner,which can effectively resist multiple attacks of plagiarism and plagiarism of game character concept designs(such as Adding text,replacing character parts,changing clothing colors,cutting legs,cutting body parts,etc.),and has good robustness.