摘要
在机载综合显示系统中,需要将本地生成的参数表盘近景画面与地形图等远景特征画面进行叠加显示。由于近景中图形元素均为反走样图元,图元边界处像素灰度等级较低;而叠加的远景平均灰度远高于近景图元的边界灰度。采用传统的α混合算法,由于混合系数是固定的,当近景的α混合系数偏大时,会在图元边界处形成一条锯齿暗边,产生较大的对比度,使得混合效果变差、反走样效果降低。针对上述问题,改进算法在不同像素点处的混合系数是可变的。算法根据近景像素点的灰度,自适应的调整混合系数,在近景中灰度较低的像素点处,增加远景的混合比重,提高混合画面在此像素点的灰度,降低图元边界处对比度。通过实验结果比对,证明改进算法在做视频叠加时,可有效去除图元边界的锯齿暗边。
In the airborned integrated display system, it＇s necessary for displaying to combine local-generated images with external feature images such as topographic map. Due to the graphic elements in the local-generated images are all anti-aliasing,gray level of pixels in the element＇s edge is low;The average gray level in external images is much higher than the gray level of element＇s edge of local-generated images. Using traditional alpha hybrid algorithm,due to mixing coefficient is fixed,when the alpha mixing coefficient of local-generated images is larger,it will form a sawtooth dark side in the element＇s edge of local-generated images, and will produce bigger contrast. Thus, the mixing effect becomes poor,the anti-aliasing effect reduced. According to the above problems, improved algorithm makes mixed coefficient varied in different pixel point. Based on the gray-level of the pixels of local-generated images, the algorithm adaptively adjusts mixing coefficient：lower the gray level of pixels in the local-generated images is, higher the mixing proportion of external images is, increasing pixel gray level of mixed images, decreasing the contrast of element＇s edge of mixed images. Proved by the experiment result, when doing video overlay,the algorithm can effectively remove sawtooth dark edge of graphic elements.
出处
《电子测量技术》
2013年第12期20-24,共5页
Electronic Measurement Technology
关键词
视频叠加
α混合
自适应算法
变参数
抗锯齿
video overlay
a-mixing
adaptive algorithm
variable parameters
anti-aliasing
作者简介
王栋,1988年出生,工学硕士,主要研究方向为仪器与测试技术、图像生成与加速技术、信号处理技术等.E-mail：changganli@sina.com｜刘文波,1966年出生,工学博士,教授,主要研究方向为信号处理及应用、非线性动力系统分析及工程应用、计算机测试与控制技术.E-mail：wenboliu@nuaa.edu.cn
