Auto-focus device and method for visible light lens

Abstract

The invention relates to an auto-focus device for a visible light lens. The auto-focus device comprises an FPGA (field programmable gate array) controller, a video input circuit, a power management module, a motor driving circuit and a serial port communication circuit, wherein the FPGA controller drives a focus motor to move to the best focus position through the motor driving circuit. A focus method includes the steps: a) determining the farthest clear position and setting the position of the motor as A; b) determining the nearest clear position and setting the position of the motor as B; c) determining the whole focus course between the two points A and B; d) judging whether trigger signals are generated or not; e) moving to the nearest local end point; f) seeking a primary focus clear point; g) seeking a secondary focus clear point; h) seeking a tertiary focus clear point. According to the auto-focus device and the method, the focus mode of the maximum stroke of a focus motor in the past is avoided, focus speed is high, the focus motor successively approximates the focus position by gradually decreasing the speed and the step length of the focus motor, so that the final focus position is more accurate, and images are clearer.

Description

technical field [0001] The present invention relates to an automatic focusing device and method of a visible light lens, more specifically, to an automatic focusing device and method of a visible light lens with a short focusing stroke and successively approaching clear imaging positions. Background technique [0002] Autofocus (AutoFocus, AF) technology means that the lens automatically adjusts the focus on the object being photographed, so as to obtain the clearest image. like figure 1 As shown, the schematic diagram of the existing autofocus method is given, which has the following units: imaging optical lens, imaging device, autofocus unit, processor, and motor drive unit. In the automatic focus system, it is first necessary to judge whether the system is currently in the correct focus state according to the obtained image information. If the system deviates from the focus state, the system gives a control strategy to drive the motor and drive the lens to move. In the s...

AI Technical Summary

Problems solved by technology

Therefore, even for different machines of the same model, it is still necessary to fine-tune the compensation value before leaving the factory, which will make debugging more cumbersome

Images