井喷失控预警的远距离自动调焦控制研究

STUDY ON LONG-DISTANCE AUTOMATIC-FOCUSING CONTROL OF PREWARNING FOR THE UNCONTROLLED BLOWOUT

井喷失控是石油及天然气钻井、完井过程可能出现的灾难性事故，给人类生命财产造成严重伤害，污染环境，破坏地下资源以及在城市火灾、森林火灾、环境变化等监测工作中常需要远距离目标监测，为了获得高清晰的实时图像数据，需要实时自动调焦。通过系统分析远距离相机离焦的原因，建立了一个实时调焦数学模型，并以此为基础研制了一种新的对应距离和温度变化的离焦补偿控制系统。该系统采用微型步进电机实现智能控制，通过监测目标距离确定监测相机的初始焦距，以及环境温度变化的实时反馈实现焦距的实时控制，使相机可以在-40～125℃范围内获得清晰、稳定的远距离图像。该系统适用于井喷失控石油及天然气火灾、城市火灾、森林火灾、环境变化等远距离目标的实时监测。

The uncontrolled blowout is the calamitous accident possibly arisen in petroleum drilling and completion, which would cause serious damage to human lives and properties, contaminate the environment, destroy the subterranean resources, and etc. Long-distance target monitoring is often required to get high-resolution real-time images of well blowouts, urban fires, forest fires, environmental changes, etc. The automatic real-time focusing is thus necessary. A mathematic model for real-time focusing has been established by analyzing the causes of long-distance defocus. On the basis of this model, a new defocus-compensating system has been developed corresponding to distance and temperature changes. Intelligent control can be realized by means of mini step motor, in which initial focus will be determined by monitoring object distance, and real-time focus control can be achieved by real-time feedback of environment temperature changes. All these help the camera get clear and steady long-distance images in the range of -40～125℃. This whole system is suitable for long-distance monitoring of oil and gas fires during blowouts out of control, urban fires, forest fires, environment changes, and so on.