Dynamic color is an important carrier that takes information in some special occupations.However,up to the present,there are no available and objective tests to evaluate dynamic color processing.To investigate the cha...Dynamic color is an important carrier that takes information in some special occupations.However,up to the present,there are no available and objective tests to evaluate dynamic color processing.To investigate the characteristics of dynamic color processing,we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group).ERPs were recorded by Neuroscan system.The results showed that in the normal group,ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms,a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms.In the abnormal group,ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms.No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P】0.05).ERPs of the two groups in response to the static red,green and blue stimulus were not much different,showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms.Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs,which was called "dynamic red blindness".Furthermore,these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.展开更多
A novel image blind watermarking scheme based on Contourlet transform was proposed to embed color watermark image into color host image, which was different from some existing works using the binary or gray-level imag...A novel image blind watermarking scheme based on Contourlet transform was proposed to embed color watermark image into color host image, which was different from some existing works using the binary or gray-level image as watermark. In the process of embedding watermark, each color component of the color host image was decomposed by Contourlet transform. Then, the low-pass sub-band coeffidents were divided to 4 x 4 non-overlapping blocks, and the eoeffidents in the selected block were quantified for embedding the watermark information. In the process of extraction watermark, the watermark could be extracted from the watermarked image without the help of the original host image or the original watermark image. Experimental results show that the proposed color image scheme has better invisibility and stronger robustness against most attacks such as image compression, filtering, adding noise, cropping, rotation, and scaling.展开更多
Blind deblurring for color images has long been a challenging computer vision task.The intrinsic color structures within image channels have typically been disregarded in many excellent works.We investigate employing ...Blind deblurring for color images has long been a challenging computer vision task.The intrinsic color structures within image channels have typically been disregarded in many excellent works.We investigate employing regularizations in the hue,saturation,and value(HSV)color space via the quaternion framework in order to better retain the internal relationship among the multiple channels and reduce color distortions and color artifacts.We observe that a geometric spatial-feature prior utilized in the intermediate latent image successfully enhances the kernel accuracy for the blind deblurring variational models,preserving the salient edges while decreasing the unfavorable structures.Motivated by this,we develop a saturation-value geometric spatial-feature prior in the HSV color space via the quaternion framework for blind color image deblurring,which facilitates blur kernel estimation.An alternating optimization strategy combined with a primal-dual projected gradient method can effectively solve this novel proposed model.Extensive experimental results show that our model outperforms state-of-the-art methods in blind color image deblurring by a wide margin,demonstrating the effectiveness of the proposed model.展开更多
基金supported by a grant from the National High Technology Research and Development Program of China(863Program)(No.2008AA02Z428)
文摘Dynamic color is an important carrier that takes information in some special occupations.However,up to the present,there are no available and objective tests to evaluate dynamic color processing.To investigate the characteristics of dynamic color processing,we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group).ERPs were recorded by Neuroscan system.The results showed that in the normal group,ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms,a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms.In the abnormal group,ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms.No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P】0.05).ERPs of the two groups in response to the static red,green and blue stimulus were not much different,showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms.Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs,which was called "dynamic red blindness".Furthermore,these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.
基金National Natural Science Foundations of China(Nos.61232016,61202111,11405254)Natural Science Foundation of Shandong Province,China(No.ZR2014FM005)+3 种基金Shandong Province Higher Educational Science and Technology Programs,China(Nos.J12LN05,J14LN20)Doctoral Foundations of Ludong University,China(Nos.LY2012023,LY2014034)Shandong Province Science and Technology Plan Projects,China(Nos.2013GGB01231,2014GGB01944,2015GSF116001)the Project Development Plan of Science and Technology of Yantai City,China(No.2016ZH057)
文摘A novel image blind watermarking scheme based on Contourlet transform was proposed to embed color watermark image into color host image, which was different from some existing works using the binary or gray-level image as watermark. In the process of embedding watermark, each color component of the color host image was decomposed by Contourlet transform. Then, the low-pass sub-band coeffidents were divided to 4 x 4 non-overlapping blocks, and the eoeffidents in the selected block were quantified for embedding the watermark information. In the process of extraction watermark, the watermark could be extracted from the watermarked image without the help of the original host image or the original watermark image. Experimental results show that the proposed color image scheme has better invisibility and stronger robustness against most attacks such as image compression, filtering, adding noise, cropping, rotation, and scaling.
基金the National Key R&D Program of China under Grant 2021YFE0203700Grant NSFC/RGC N CUHK 415/19,Grant ITF MHP/038/20,Grant CRF 8730063Grant RGC 14300219,14302920,14301121,CUHK Direct Grant for Research.
文摘Blind deblurring for color images has long been a challenging computer vision task.The intrinsic color structures within image channels have typically been disregarded in many excellent works.We investigate employing regularizations in the hue,saturation,and value(HSV)color space via the quaternion framework in order to better retain the internal relationship among the multiple channels and reduce color distortions and color artifacts.We observe that a geometric spatial-feature prior utilized in the intermediate latent image successfully enhances the kernel accuracy for the blind deblurring variational models,preserving the salient edges while decreasing the unfavorable structures.Motivated by this,we develop a saturation-value geometric spatial-feature prior in the HSV color space via the quaternion framework for blind color image deblurring,which facilitates blur kernel estimation.An alternating optimization strategy combined with a primal-dual projected gradient method can effectively solve this novel proposed model.Extensive experimental results show that our model outperforms state-of-the-art methods in blind color image deblurring by a wide margin,demonstrating the effectiveness of the proposed model.
