鱼类行为录像的畸变评估及数据提取研究

Distortion Evaluation and Data Extraction for Behavior Videos of Fishes

选取9个控制点,计算12个畸变评估系数,对拍摄的鱼类行为录像进行了畸变评估;并采用两种方法,即透视原理方法和作者设计的特殊设备提取的方法,提取录像中鱼体准确的空间三维位置坐标。研究结果表明:(1)在其他拍摄条件相同的情况下,拍摄距离越远所产生的横纵畸变量越小,在拍摄距离为5 m的情况下录像所产生的畸变量基本上不影响两种数据信息提取的结果。(2)按透视原理所提取鱼个体位置的空间三维坐标准确度较差,只有当鱼体完全平行于水族箱前缸面时,其结果比较准确,然而该种方法的优点是不会丢失缸体内所有鱼个体的信息。(3)使用专门设备A时,因镜面映照范围小于缸底,而造成贴近缸壁的鱼体的三维数据信息丢失,但此种方法所提取的空间三维坐标相对上一方法在计算上要简单,所需的已知参数少,而且容易得到,所获的空间位置准确。

The image distortion in behavior videos of fishes has been evaluated by means of nine control reference points with 12 distortion evaluation factors;two types of data extracting methods have been developed,one was based on perspective theory and the other one was based on shot with special equipment designed by the authors,the 3-D spatial position of individual fish can be accurately obtained from the video records.The results showed that（1） when the other shooting conditions were the same,the larger the shooting distance between camera and object was,the smaller the image distortion in the photos was;while the shooting distance was 5 m,the image distortion basically not affect extracting results of two kinds of data.（2） The method based on perspective theory could keep all 3-D information without any missing,but was not accurate enough while the fish was not exactly parallel to the front wall of tank.（3） The method by means of a special designed equipment was easier to use and accurate in measurements,but it would lose certain information when the fish was near or close to the wall of tank.