CAJ | 학술논문

传统的梯度自动调焦算法计算量大，抗噪声能力弱，影响调焦的实时性及调焦曲线的单峰性和灵敏度，因此提出一种梯度阈值自动调焦算法，提高调焦性能，满足光电跟踪系统能实时、准确地进行自动调焦的要求。该算法先以图像的局部方差作为局部阈值区分边缘像素与非边缘像素，再计算整幅图像的一种新的标准差作为全局阈值来削弱噪声和背景的影响，最后对阈值预处理后的图像采用梯度调焦算法计算其调焦值，进行清晰度评价。大量实验结果表明，该算法具有实时性好，单峰性强，灵敏度高的特点和良好的抗噪性能。该算法用于光电跟踪系统的自动调焦中时，依然保持上述良好的性能，明显优于传统梯度自动调焦算法。
전통적제도자동조초산법계산량대，항조성능력약，영향조초적실시성급조초곡선적단봉성화령민도，인차제출일충제도역치자동조초산법，제고조초성능，만족광전근종계통능실시、준학지진행자동조초적요구。해산법선이도상적국부방차작위국부역치구분변연상소여비변연상소，재계산정폭도상적일충신적표준차작위전국역치래삭약조성화배경적영향，최후대역치예처리후적도상채용제도조초산법계산기조초치，진행청석도평개。대량실험결과표명，해산법구유실시성호，단봉성강，령민도고적특점화량호적항조성능。해산법용우광전근종계통적자동조초중시，의연보지상술량호적성능，명현우우전통제도자동조초산법。
Traditional gradient auto-focus algorithms have large amount of calculation which will cause the reduction of real-time performance. These algorithms are also weak in anti-noise capability which will result in the decline of unimodality and sensitivity. So a gradient threshold auto-focus algorithm was proposed to improve the focusing performance to meet the requirements of real time and accuracy in auto-focusing subsystem of photoelectric tracking system. The proposed algorithm took the local variance as a local threshold to distinguish the edge pixels from non-edge pixels. Then it used a kind of new standard deviation of the whole image as a global threshold to weaken the effects of noise and background. At last, it used one of traditional gradient auto-focus algorithms to calculate the focusing value of the pre-processed image for clarity-evaluation. The results of lots of experiments show that the proposed algorithm has good real-time performance, strong unimodality, high sensitivity and powerful anti-noise capability. When the proposed algorithm is used in the auto-focusing subsystem of photoelectric tracking system, all the attractive performances remain, which traditional gradient auto-focus algorithm can′t achieve.