宽带图像信号的直线提取

Line Extraction for Broadband Image Signals

该文用 FPGA+DSP实现了宽带图像信号的实时直线提取 ,适用于通常的视频图像信号和线阵 CCD成像的连续图像信号 .实现的直线提取模块已经用于高传输率的快速遥感图像处理系统 .算法将直线提取中的参数计算分解为一个可以累加的过程 ,从而简化了计算 ,同时保证了直线参数的准确性 ,在理论上证明了算法的完备性 .文章的最后给出了实验结果及比较 .

A hardware solution for real-time line extraction from broadband image signals is presented. The realization is based upon FPGA+DSP architecture. The line extraction module can process both the common frame-based video signals and the continuous image signals generalized by a line array CCD. The module has been used in a high-speed remote sensing system. The algorithm of the module is based on the gradient phase of the gray level image. In the former line extraction algorithms, three separated steps are included which are the edge detection, the GP (gradient phrase) grouping, and the line fitting. In the proposed algorithm all the three steps are performed simultaneously during a scan of the image. The basic procedural unit is to scan line by line. The LSE method is used to fit the line parameter; the calculation is transformed into a distinct cumulative procedure, which reduces the calculation without degrading the extracted lines. The pixels are input into the FPGA in the scan order. In each scan line, the connected pixels, which have the same gradient phase, are grouped as 'run code'.The DSP collects the line parameters from the run codes by a cumulative procedure. The final parameters of the line are fitted when the line is no longer expanded. The universality of the algorithm is proved. The total delay of the line extraction is less than 5 line-scan periods, and only a little memory is used to store the information about the current scanning line.