应用变焦曲线校正电动变焦镜头的电机原点

摘要

In order to ensure the adjustment range of the optical zoom digital surveillance camera’s zoom and focus stepper motors, a correction method based on zoom tracking curve is designed. First, select a standard curve from the zoom tracking curve manufacturers provided. Second, the real zoom tracking curve with the same distance of the standard curve is collected by the method of automatic focusing. Then, offset of the highest points in two curves is calculated. Finally, with the principle of minimum squared difference, optimal offset value is found in a small area near the offset. This correction method is realized in high-definition digital video camera with 30× lens. Experiments show that this correction method is a good solution for solving the problems of stall phenomenon and out of focusing caused by motor origin error.%为了保证电动变焦数字监控摄像机的变焦步进电机和调焦步进电机的调节范围在厂家设计的可聚焦范围内，设计了一种基于变焦曲线的变焦电机和调焦电机的原点位置校正方法。首先，从镜头厂家提供的镜头变焦曲线中选定一条作为标准曲线。接着，利用自动调焦方法采集标准曲线对应距离下的实际变焦曲线。然后，计算标准变焦曲线的最高点和实际变焦曲线的最高点的偏移量。最后，在该偏移量附近的一个小范围内按照平方差最小的原则求出最佳偏移量即为原点位置的补偿值。在30倍光学变焦数字高清摄像机中实现了该方法，实验结果表明：48台采用本文方法成功校正的镜头在设计调节范围内均没有出现电机堵转和无法聚焦的现象，校正成功率96%，很好地解决了由于原点位置误差造成的问题。