Accurate and reliable smoke detection is important to prevent catastrophic fire incidents. It becomes more challenging when the smoke detection is required for wide closed area such as tunnel and subway where long distance sensing is required. Recent visible laser technology suggests that the far-infrared transmitters and receivers can be used in object detection and Zigbee wireless communication technology can be applied for alarm propagation. In this paper, we propose an algorithm that automatically adjusts the focus through multiple infrared lasers and multiple cadmium sulfide sensors, and a high-precision auto focus matching device is designed to support the function. The value of the proposed method is verified in the laboratory simulation test successfully.

准确可靠的烟雾探测对于防止灾难性火灾非常重要。当需要长距离传感的宽阔封闭区域（例如隧道和地铁）需要烟雾检测时，这将变得更具挑战性。最近的可见激光技术表明，远红外发射器和接收器可用于物体检测，而Zigbee无线通信技术可用于警报传播。本文提出了一种通过多个红外激光和多个硫化镉传感器自动调节焦点的算法，并设计了一种高精度的自动焦点匹配装置来支持该功能。在实验室模拟测试中成功验证了该方法的价值。