运用小波图像融合技术增强痕迹偏振图像

针对单幅痕迹偏振图像存在的灰度反差微弱、痕迹特征残缺等缺陷,提出运用小波图像融合技术对多幅痕迹偏振图像进行融合处理,以增强痕迹图像视觉效果的策略。结合痕迹物证检验工作的需要,对低频子带图像采取基于区域窗口的梯度平方和较大法,而高频子带图像采取基于区域窗口的系数绝对值极大法,并将此方案应用于衣物上的轮胎痕迹偏振图像的增强处理。实验结果表明,经过融合处理后的轮胎痕迹偏振图像无论在主观视觉效果,还是在客观评价数据上都获得了期望的增强效果,满足痕迹物证司法鉴定的技术要求。

Polarization image enhancement of traces based on wavelet image fusion

To deal with the shortcomings existing in the single polarization image of traces,such as weak gray contrast,incomplete trace feature,etc,multiple polarization images of traces are fused by wavelet image fusion to improve the visual effect of trace image effectively.Referring to the trace evidence examination,the low-frequency fusion coefficients are calculated by the region-based gradient square sum rule,and the high-frequency fusion coefficients are calculated by the region-based coefficient absolute maximum rule.As an example,the designed scheme is applied to enhance the polarization image of vehicle tire trace left on the clothes.Experimental results show that the processed polarization image of vehicle tire trace can achieve the good enhancement of image edges and details,which is evaluated by both subjective judgment and objective criterion,and meet requirements of the judicial identification of trace evidence.