An objective assessment method of digital image mosaic artifacts visibility based on visual perception

The difference of illumination among images to be mosaicked causes mosaic artifacts while the digital images are being mosaicked together. In order to objectively evaluate the visibility degree of mosaic artifacts in digital images, an objective assessment method of digital image mosaic artifacts visibility based on human visual perception was proposed. The processes of the method are as follows: 1) the gradient errors image is obtained according to the images to be mosaicked; 2) the just noticeable difference (JND) of the reference image is derived by considering the impacts from not only the human visual frequency sensitivity but also the brightness mask effects and the texture mask effects on visual resolution, then, the mosaic artifacts image which is visually perceptible can be acquired by subtracting the JND threshold values from the wavelet coefficients of gradient errors image; 3) the mosaic artifacts visibility (MAV) of digital image is customized with the aid of the average value as well as the information entropy of the mosaic artifacts image, and finally regarded as an objective index for assessing the image stitching seam visibility. The experiment indicates that the MAV related objective assessment result of digital image mosaic artifacts visibility is basically consistent with the one of the subjective perceptual method.