在车辆行进过程中进行测距是近年来国内外相关方面的学者们非常感兴趣的研究课题。车辆自动测距系统包括三部分：图像采集及预处理；在含有车辆的复杂背景中确定车辆的位置；对车辆上的图形和文字进行切割、特征提取和识别以实现精确测距。 本文采用数字图像处理的理论与方法，研究分析了数字图像预处理方式、目标图形检测技术和测距模型建立方法，给出了单目摄像机和带有目标检测图形的测距方案。测距方案目的是：通过对单目摄像机捕获的图像进行一系列处理，获得前方目标检测图形与摄像头间的距离。首先，对运动目标图形进行图像处理，结合图像的色彩空间变换进行目标图形定位检测；然后，采用边缘增强与Hough变换对图像中目标图形进行特征提取，根据检测出的目标物体的边界，利用统计像素点计算面积法计算出目标图形的实时面积，依据计算出的目标图形面积的大小变化推导出测距公式，实现距离的测量；最后，利用计算机语言搭建测距实验程序，通过测距实验程序对捕获图像进行处理，获得测距结果，并将其与实际距离进行了比较与分析。 本文以VC++6.0和Matlab为工具，得到了模拟视频监控系统中的运动目标与摄像头间的测距数据。通过对实验数据与图像的研究与分析，该测距方法简洁有效，是一种可行的车辆相向运行时的测距方法。

In recent years, the researchers in information are interested in an subject which is machine eyes instead of man eyes. A whole traffic managerment system is consisted of three parts one is getting image and preprocessing, the other is comfirming position of cars from a complex background, the last is cars’ charactics being collected. On the basis of digital image processing application of the theories and methods, research and analysis of the digital image pre-processing graphics goals Detection and Ranging model approach, based on the construction of a digital image processing operation of the single-head camera at the location opposite the programme. Aimed at adoption of the single-head camera captured images of a series of treatment, access to information from the front aims and the single-head camera. Firstly, the graphics on the moving target image pre-processing, and image of the target color space transform graphical location detection; Secondly, using edge-enhanced image with the Hough transform graphics target feature extraction, in accordance with the objectives of objects detected in the border, pixels calculated using statistical method to calculate the target area of the real-time graphics area, calculated in accordance with the objective of changing the size of graphics area ranging derived formula, the achievement of distance measurement; Finally, the use of computer language structures ranging trial procedures, through the range trial program to capture images for processing, access to location results and the actual distance are compared and analyzed. In this paper, moving target with the range betweet the cemera date in the imitative video monitoring system is developed VC++ 6.0 and Matlab. Through the test data and image analysis, the method of distance measurement is single, effective and aviable run-time of vehicles ranging opposite approach.