Camera Calibration Method And Applications In Wave Measurement

In the sea,there have abundant resources,such as biology,mineral and water.The ocean has a great influence on the development of the country.Water waves affect the physical,chemical,biological and geological change processes in the ocean.At the same time,the movement of water waves influences the changes of the airflow in the water surface,and thus influences the weather and other changes.Therefore,water wave measurement is more important,it can help us understand the movement rule of sea water.At present,the measuring water wave method have some types,it include the surface wave,the near surface wave,and the under water wave,which can not directly and effectively reflect the water wave information.The stereo photogrammetry method can accurately,image and intuitionistic reflect water wave information.Using the stereo photogrammetry method measurement water wave,it mainly includes some key technologies,such as camera calibration,relative orientation,dense matching.The camera calibration is a critical step in wave measurement,it can be directly influences the follow-up photogrammetric work.At present,the research on camera calibration related algorithms and related models in the field of photogrammetry and computer vision is quite mature.However,due to the causes camera distortion have differ kinds,people can through a lot of camera calibration model experimental research,select the appropriate model.At present,still unable to find the ideal model can be used to all the images.No matter from the accuracy of the camera calibration or the efficiency of the camera calibration,the existing methods of camera calibration can not be taken into account,and there is still residual distortion.In order to meet the requirement of high-precision camera calibration,the traditional method of camera calibration has higher accuracy requirements,high cost,large floor area and high maintenance cost.Therefore,the existing camera inspection and calibration still have residual distortion and the establishment of more complex inspection and calibration field are two key issues in the current camera inspection and calibration study.This paper focuses on these two issues.Aiming at the problems of high cost,large area,difficult maintenance and rather dangerous in the establishment of traditional inspection and calibration field,a simple,convenient and efficient inspection field has been established.In view of the problem of residual distortion in the use of conventional camera calibration method,a new method of camera calibration--The iterative calibration method for camera is proposed.Based on the analysis of the existing camera calibration model,an idea of iterative processing of camera calibration(Camera iterative calibration method)is proposed,which achieves the goal of image distortion correction by using the same calibration model or different model combination for the original image many times.After each iteration,the new distortion coefficient is used to correct the image,and the image obtained after geometric correction is used as the next iteration to decide whether or not.This paper first calibrates the camera,then obtains the stereoscopic image of the water wave by using the calibrated camera,using the optical photogrammetry technology measures the water wave.The camera is calibrated by using the conventional calibration method and the camera iterative calibration method respectively.By using the two methods to calibrate the water wave image data obtained by the camera,the water wave measurement experiment according to the photogrammetry method is carried out.