34 results about "Just noticeable distortion" patented technology

The invention discloses a three-dimensional image fragile watermark method based on joint just noticeable distortion and in particular relates to a three-dimensional image location tampering and restoring fragile watermark algorithm based on JJND (Joint Just Noticeable distortion). Firstly, a three-dimensional image block is divided into a relative sensitive block and a relative insensitive block according to a JJND model and the number of three-dimensional image match blocks, then discrete cosine transform and quantization compression are carried out on the image blocks to generate watermarks, and unsymmetrical watermark embedding of different type blocks of the three-dimensional image is built according to the JJND model and types of the image blocks. Restored watermarks can be used for locating the positions of the tampered portions to further improve transparency of the image. Meanwhile, copy embedding of the restored watermarks in the three-dimensional image can improve the capacity for the watermarks to restore tampered information. Experiments show that the three-dimensional image fragile watermark method based on the joint just noticeable distortion is accurate in location on the tampered positions and has higher restoring capacity on the tampered areas.

The invention discloses a measurement method for a space-time domain self-adaptive just noticeable distortion. The method is characterized by comprising the following steps: step one, integrating pattern masking effect PM and luminance adaptation LA to obtain a space-domain JND (Just Noticeable Distortion) threshold JNDS; step two, integrating four time domain sensing parameters including relativemovement I (vr), background movement U(vg), time domain duration I (Tau) and residual fluctuation intensity U (Delta) to obtain a time-domain JND adjusting weight coefficient z; and step three, performing adjusting by using the time-domain JND adjusting weight coefficient z on the basis of the space-domain JND threshold JNDS, thereby obtaining a space-time domain JND threshold JNDST.

The invention discloses a macro block mode fast selecting method based on just noticeable distortion. A just noticeable distortion image of a time-space domain corresponding to each color image in color television video sequences to be processed is obtained, a just noticeable distortion value of each image block in the just noticeable distortion image of the time-space domain is calculated, and then an optimal macro block encoding mode of each macro block in a B-frame color time-space domain is confirmed according to the just noticeable distortion value of each image block in the just noticeable distortion image of the time-space domain. The macro block mode fast selecting method can effectively save encoding time of color videos on the premise that color video visual perception quality is guaranteed and greatly reduces the encoding complexity level of the color videos, and saved encoding time can reach to 72.7% averagely.

The invention discloses a method for quickly coding multi-view color videos based on binocular just perceptible distortion. The method includes the first step of utilizing parallax error information the left view video and the right view video to determine a binocular just perceptible distortion value of each macro block within a non-boundary area in each frame of right view image in the right view video, and the second step of terminating macro block mode selection in advance according to the binocular just perceptible distortion value. On the basis of not causing rate-distortion performance degradation, the method for quickly coding the multi-view color videos can effectively improve coding efficiency of the multi-view color videos. The saved coding time can reach to 66.48% to 71.90%, and saves the coding time by 68.46% on average.

The invention relates to a fast adaptive loop filter algorithm based on a just noticeable distortion (JND) model, which comprises the steps of establishing a JND model, dividing image frames into a region-of-interest (ROI) and a region-of-non-interest (RONI) by using the JND model, dividing the RONI into a region-of-non-interest smooth region (RONISR) and a region-of-non-interest texture region (RONITR) by using a Canny operator, and dividing the ROI into a region-of-interest smooth region (ROISR) and a region-of-interest texture region (ROITR) by using the Canny operator; and carrying out adaptive filtering. According to the invention, an ALF (adaptive loop filter) method is optimized in allusion to an HEVC (high efficiency video coding) structure by being combined with the pixel-domain JND model and the Canny operator, perceptive redundancy in video is removed, and the coding efficiency is improved; and a region which does not need ALF processing can be found out quickly, and the complexity of the adaptive loop filter algorithm is greatly reduced under the condition of not influencing the quality.

The invention discloses a fragile digital watermarking method for tampering and positioning stereoscopic image pixels. At the digital watermarking embedding end, the masking characteristic of binocular visual perception of human eyes, that is, the distortion that can be detected by both eyes, is used to guide the embedding of digital watermarking, so that the stereoscopic image Transparency and watermark embedding capacity have reached a good balance, and according to the high five-bit image information of the left and right viewpoints and the binocular just distortion model as the input of the MD5 hash function to generate a feature watermark image, and then use an adaptive method to embed the watermark information into In the left and right viewpoints of the stereoscopic image, through the above process, the security of the digital watermarking technology is guaranteed; in the process of tampering and positioning, the high five-bit feature watermark information of the attacked stereoscopic image is extracted, and then the watermark information of the attacked stereoscopic image is extracted , comparing the two types of watermark information to initially determine the tampering location, and then using the parallax information to further enhance the accuracy of the tampering location, which can effectively authenticate the authenticity and integrity of the stereoscopic image content.