光子学报, 2019, 48 (4): 0412001, 网络出版: 2019-04-28
提高复杂燃烧流场羟基示踪测速精度的方法
Method to Improve the Velocimetry Measurement Accuracy of Hydroxyl Tagging Velocimetry in Complex Combustion Flow Field
复杂燃烧场 羟基示踪测速技术 速度测量 背景抑制 差分变换 信噪比 Complex combustion field Hydroxyl tagging velocimetry Velocimetry measurement Background suppression Difference transform Signal to noise ratio
摘要
为了提高流速测量精度, 研究OH荧光图像背景抑制的方法.分析识别复杂燃烧流场中存在的背景干扰, 构建染噪的数值仿真模型; 基于干扰图像和OH标记线信号图像的特性, 采用空间变换思想, 提出了自适应差分法消除发动机燃烧室剧烈反应区域的燃烧OH荧光干扰; 利用空域上信号与背景残余的差别, 采用空间滤波法优化背景抑制结果, 最后对仿真模型和实验图片对比, 验证了该方法的有效性, 处理前后峰值信噪比提高了11.83 dB, 信噪比提高了8.66 dB, 速度计算误差改善到了1.2%.该方法可有效的抑制背景噪声, 提高测速精度, 满足激光诊断系统对测量精度的要求.
Abstract
The method for suppressing OH fluorescence images background must be researched to improve the accuracy of image processing and velocity calculation in the complex combustion Hydroxyl Tagging Velocimetry(HTV) measurement. Firstly, the background interference in the complex combustion is analyzed and identified, and the noised signal simulation model is constructed. Secondly, an adaptive difference method combined with adaptive spatial filtering is proposed for background suppression image preprocessing, based on the characteristic of residual background and OH tagging line signal. Interference in the intensive combustion reaction area is eliminated through the adaptive difference method which is utilized by inducing spatial transformation. The background interference elimination results background is optimized through adaptive spatial filtering difference method by exploiting the spatial distribution difference between the signal and the residual background. Finally, simulation and experiments are carried out to test the effectiveness of this method. Results show that, with this image preprocessing method, the signal to noise ratio is raised by 11.83 dB, the peak signal to noise ratio is elevated by 8.66 dB, while the velocimetry calculation error is improved to 1.2% demonstrating that this method meets the accuracy requirements of HTV measurements and is ready for practical application.
邵珺, 方波浪, 叶景峰, 王晟, 李景银. 提高复杂燃烧流场羟基示踪测速精度的方法[J]. 光子学报, 2019, 48(4): 0412001. SHAO Jun, FANG Bo-lang, YE Jing-feng, WANG Sheng, LI Jing-yin. Method to Improve the Velocimetry Measurement Accuracy of Hydroxyl Tagging Velocimetry in Complex Combustion Flow Field[J]. ACTA PHOTONICA SINICA, 2019, 48(4): 0412001.