中文摘要：

大视场镜头因其可得到较大视场的图像而获得广泛应用，但由于镜头的原因，导致成像的桶形畸变，在直接使用从镜头获取的图像时，会影响对图像的后期处理和分析。针对这种情况，在分析畸变产生原因的基础上，提出一种改进的桶形畸变校正方法。根据畸变与焦距、成像高度之间对应的变化规律提出一种改进的半球形畸变校正模型，并计算近似畸变率，以进行反向映射及双线性插值来得到校正后的图像，设置可调整的参数，给出参数的确定方法和选择范围。最后，利用畸变的对称性降低了校正的计算复杂度和时间。实验结果表明，该算法对广角镜头产生的桶形畸变获得了较好的校正结果，降低了平均畸变率误差。该算法能够准确地校正畸变图像，不需要特定模板和标定参数，计算简单容易实现。

英文摘要：

Large field-of-view lens are widely used because of their wide field-of-view. But the barrel distortion produced by lens when imaging will impact the post-processing and analyses on images while using the images captured directly from lens. In light of such case, we proposed an improved barrel distortion correction method based on analysing the cause of distortion generation. According to the corresponding variation rules between the distortion and the focal length as well as the imaging height, we presented an improved semi-spherical distortion cor/ection model, and calculated the approximated distortion factor in order to conduct reversed mapping and bilinear interpolation to obtain the corrected image. The adjustable parameters were also set, and the determination approach and selection scope of the parameters were given as well. Finally, we also made use of the symmetrical characteristic of distortion to have reduced the computation complexity and time complexity of correction. Experimental results showed that the algorithm had a good correction result on barrel distortion produced by wide- angle lens, and reduced average distortion error factor. The algorithm could correct the distorted image accurately, and was simple in compu- tation and easy to implement without the need of specific model and calibration parameters.