用二次触发法改进接触式传感器线阵相机的曝光性能

Abstract

As the frequency changing of external trigger signal from an external trigger Contact Image Sensor(CIS)camera will cause the nonuniform of a scanned image gray value,a new exposure method——two-trigger method was proposed.First,the reason that the frequency changing of external trigger signal affects the image gray value was analyzed.Then,the two-trigger method was introduced.With the method,an external trigger signal was converted to two trigger signals,the first one was used to control the exposure and the second one was used to control the CIS to output data.Finally,it explained that the method can improve the image quality theoretically.A 1.6meter non-distortion long-term array CIS camera was fabricated based on this method.The experimental results show that the fluctuation range of scanned image gray value is reduced by 75%,and the horizontal stripes on the image is eliminated at different trigger frequencies.When it is applied to an intelligent visionstitch digital printing machine,the image of 1mm×1mm hole in the embroidered cloth is clear.It concludes that the proposed method reduces the effect of the frequency changing of external trigger signal on images effectively and improves the image quality successfully.