低气压下火焰视频图像特征研究

为了进行非密封飞机机舱内视频火灾探测技术的研究,借助中国科学技术大学QR0-12步入式环境低气压试验舱开展低气压下(100kPa,90kPa,70kPa,50kPa和30kPa)火焰视频图像特征研究。在实验舱中用正庚烷作为可燃物进行点火实验,拍摄火焰视频,研究低气压环境下火焰的颜色、空间变化、运动、相对稳定性、边缘粗糙度、相邻帧火焰区域面积变化率、面积重叠率、相关性特征。实验结果表明,火焰的颜色、空间变化特征不会随气压变化而变化;而火焰动态特征等都会因气压的不同而发生变化。因此,火焰的颜色和空间变化特征在低气压环境中仍可用于火焰区域分割和识别,而其他动态特征会随着气压发生变化,不能用常压下的方法来训练分类模型,但仍可以用以区别火焰和静止的疑似区域。

Flame features under low atmospheric pressure based on video image analysis

In order to study the video-based fire detection technology in an unsealed aircraft cabin, experiments of flame combustion were conducted in a QR0-12 low air pressure cabin. The experimental pressure ranges from 30 to 100 kPa. N-heptane is used as the fuel in experiments. The examined features captured by CCD flame image include the flame color, spatial variation, motion, stability, and roughness. The change rate and overlap area and the correlation of the area of adjacent frames are calculated and analyzed. Experimental results show that flame color and spatial variance do not vary with the change of air pressure, and the dynamic flame features vary with the change of air pressure. Therefore, flame color and spatial variance can still be used in a low pressure environment for flame region segmentation and recognition. However, dynamic features vary with the air pressure, so the methods used under normal pressure cannot be used to train a classification model here. They can be used to distinguish flame and static suspected areas.