液晶与显示, 2014, 29 (5): 793, 网络出版: 2014-08-18
基于FPGA的航拍图像实时增强
Aerial image enhancement processing based on FPGA
图像增强 子层分割 即时操作 组合逻辑 image enhancement segmentation sublayer FPGA FPGA realtime operation combinational logic
摘要
为了更好地增强图像的细节信息、提高图像的对比度,提出了基于子层分割对比度拉伸算法。根据直方图特征将其平均分为4个子层区域,在每个子层中根据其灰度值概率密度之和的大小对灰度区域进行拓展或压缩。为了防止灰度区域被过分压缩或拉伸,引入了约束因子α。以现场可编程门阵列为中央处理器,采用组合逻辑对本文算法进行建模。在得到直方图统计结果的基础上,算法可在一个时钟周期完成,相比于流水线操作时间减少了5×103 ns,可满足50 frame/s的实时图像处理要求。该系统具有集成度高、图像处理速度快和实时性强等特点。
Abstract
In order to enhance the image details and improve image contrast, this paper presents a contrast stretch sublayer segmentation algorithm. First, the histogram is divided into four sublayer equally according to feature of the histogram. In each sublayer, the sublayer are expanded or compressed on the basis of the probability density of gray value. In order to prevent the gray area being overly compressed or stretched, the constraint factor α is introduced. By applying field programmable gate array (FPGA) as the central processor, the algorithm is modeled on combination of logic mode-ling. Based on the histogram statistics results, the algorithm can be completed in a single clock cycle,and the time was reduced by 5×103 ns compared to the pipeline operation.This system can meet the requirements of realtime processing for 50 frames/s image processing and has high integration, and high image processing speed and realtime features.
赵凡, 张葆. 基于FPGA的航拍图像实时增强[J]. 液晶与显示, 2014, 29(5): 793. ZHAO Fan, ZHANG Bao. Aerial image enhancement processing based on FPGA[J]. Chinese Journal of Liquid Crystals and Displays, 2014, 29(5): 793.