They are widely used for their flexibility and accuracy. proposed distortion correction methods with calibration targets. To date, there has been tremendous progress in mono-focal distortion correction. Most distortion correction methods for current zoom lens cameras are based on a series of mono-focal cameras, and they provide some guidance for distortion correction of zoom lens cameras to some extent. Therefore, building ideal distortion models and conveniently correcting distortion for zoom lens cameras gains more attention. But due to the complex structure of the zoom lens, the distortion conditions of zoom lens cameras are unpredictable, which would severely hurt image registration, reconstruction or measurement. At some changing scenarios with different field of views, such as video monitoring, dynamic measurement and so on, the zoom lens cameras capable of adapting their focal lengths, are chosen for their better performances over fixed focal cameras. An imprecise distortion model would degrade the accuracy of 3D scene reconstruction and remote sensing directly. The precision of photogrammetry and 3D stereovision application is intimately related to the accuracy of the camera calibration, especially related to the camera distortion correction.

Experimental results of different zoom lens cameras validate the feasibility and effectiveness of the proposed method. Using the proposed method, we can rectify all images from the calibrated zoom lens camera. Based on some selected zoom settings, the optimized quadratic functions of distortion parameters are obtained from the global perspective. To gain a rectified image at any zoom settings, a global distortion correction modeling method is developed with bundle adjustment. Then, the appropriate distortion correction model for a zoom lens camera is derived from the comparisons of some existing models and methods. In this paper, a distortion assessment method without coupling effect is depicted by an elaborated chessboard pattern.

Thus, a novel sequential distortion correction method for a zoom lens camera is proposed in this study. However, the challenges of distortion prediction within the whole focal range limit the widespread application of zoom lens cameras greatly. For visual measurement under dynamic scenarios, a zoom lens camera is more flexible than a fixed one.

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