公开(公告)号：US06747697B1

公开(公告)日：2004-06-08

申请号：US09614336

申请日：2000-07-12

申请人： Zhongmin Steve Lin ,  David Nicolay ,  Hung Yuet Wong

发明人： Zhongmin Steve Lin ,  David Nicolay ,  Hung Yuet Wong

IPC分类号： H04N964

CPC分类号： G06T5/20 ,  G06T5/005 ,  G06T2207/10121 ,  G06T2207/20012 ,  G06T2207/20032

摘要： An adaptive median filter (40) provides dynamic detection and correction of digital image defects which are caused by defective or malfunctioning elements of a radiation detector array (20). The adaptive median filter receives (100) lines of pixel values of a digital image that may have defects and a user-defined defect threshold. The lines of pixel values are scanned on a pixel-by-pixel basis using a kernel of n×n pixels, where the kernel contains the candidate pixel being examined (120). Each kernel is numerically reordered (130) and a median value is calculated (140). A defect threshold value is calculated by multiplying the user-defined defect threshold criteria and the candidate pixel value (150). A reference value is calculated by subtracting the candidate pixel value and the median value (160). The reference value is compared to the defect threshold value (170). The candidate pixel value is replaced by the median value (180) if it differs from the median value by more than the predefined defect threshold, e.g., 20%. The adaptive median filter is particularly effective in detecting and correcting double line and double column defects in digital images. In addition, the filter minimizes image blurring and maintains image resolution by filtering only defective pixels.

摘要翻译： 自适应中值滤波器（40）提供由辐射探测器阵列（20）的元件的缺陷或故障引起的数字图像缺陷的动态检测和校正。 自适应中值滤波器接收可能具有缺陷的数字图像的像素值（100）和用户定义的缺陷阈值。 使用nxn像素的内核逐像素地扫描像素值的行，其中内核包含正在检查的候选像素（120）。 每个内核在数值上重新排序（130），并计算一个中值（140）。 通过将用户定义的缺陷阈值标准和候选像素值（150）相乘来计算缺陷阈值。 通过减去候选像素值和中值（160）来计算参考值。 参考值与缺陷阈值（170）进行比较。 如果候选像素值与中值相差超过预定义的缺陷阈值（例如20％），则由中值（180）代替。 自适应中值滤波器在检测和校正数字图像中的双线和双列缺陷方面特别有效。 此外，滤镜可最大限度地减少图像模糊，并仅通过滤除缺陷像素来保持图像分辨率。