激光煤流量测量中光斑条纹过饱和问题研究

Laser speckle stripes supersaturated problems in coal flow measurement research

为解决煤流量三维扫描过程中亮度过饱和激光条纹中心线提取精度的问题,提出了一种对应的中心线提取算法。根据斜射式激光三角法测量原理,搭建了视觉测量系统平台,获取亮度过饱和的煤堆表面激光条纹数字图像并进行预处理。探究激光光强的分布规律,深度剖析激光光条亮度产生过饱和的原因。在分析传统结构光中心线提取方法不适用于本研究的基础之上,针对部分过饱和提出了基于高斯曲线拟合法的中心点提取算法,而针对全部过饱和则提出了一种基于邻域块思想的中心点提取算法。最后确定以激光条纹截面上过饱和采样点数量作为判别依据的中心线提取策略,得到亚像素级坐标精度的条纹中心线。通过设置与灰度重心法、曲线拟合法的对照模拟试验,发现该算法绝对偏差均值更小,提取精度要优于传统算法。最终在煤堆激光条纹图像上开展了试验验证,表明该算法在实际工作环境下抗噪声干扰性能力更强,减少了亮度过饱和现象给煤堆表面激光条纹中心线提取所带来的影响。

In order to solve the problem of extraction accuracy of brightness supersaturated laser stripe centerline in three-dimensional scanning of coal flow,a centerline extraction algorithm is proposed.According to the principle of oblique laser triangulation measurement,a visual measurement system platform was built to obtain the digital image of laser stripes with oversaturated brightness on the surface of coal piles and preprocess it.The distribution law of laser light intensity is explored,and the reason for the supersaturation of laser stripe brightness is analyzed.It is found that the traditional structured light centerline extraction method is not suitable for this study.Therefore,a center point extraction algorithm based on Gaussian curve fitting method is used for partial supersaturation,and a center point extraction algorithm based on neighborhood block idea is applied for total supersaturation.The centerline extraction strategy based on the number of supersaturated sampling points on the laser stripe cross section is proposed to obtain the fringe centerline with sub-pixel coordinate accur-acy.By setting the contrast simulation experiment with the gray center of gravity method and curve fitting method,it is found that the mean absolute deviation of the proposed algorithm is smaller,and the extraction accuracy is better than the traditional algorithm.Finally,the experimental verification is carried out on the laser stripe image of coal heap,and the experimental results indicate that the proposed al-gorithm has stronger anti-noise interference ability in the actual working environment,which can reduce the influence of brightness super-saturation on the extraction of laser stripe centerline on the surface of coal heap.