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cross ratio 交比,非調和比,重比。

cross section

Based on projective geometry , the research works about 3d invariance ' s extraction and application have been done in this thesis as following : ( 1 ) the basic theories and concepts in projective geometry are systematically summarized . it includes : the camera models of perspective imaging , projective collineation , cross ratio , a simple compare about invariance ( invariant ) among some geometry transformations , fundamental matrix , epipolar and epipolar line in epipolar geometry , and so on . ( 2 ) the calculation methods for 2d projective transformation are extended from points to multi - element , which includes points , lines , points lines and so on , to get the relationship between two projective planes 基于射影幾何理論,論文圍繞3d不變特征的提取和應用進行了如下的研究工作: ( 1 )系統總結了射影幾何中的若干基礎概念,包括:透視成像的相機模型、射影對應、交比不變量、基于不同幾何變換下的不變量的簡單對比、對極幾何中的基礎矩陣、對極點、對極線等。

In the self - calibration scheme , the thesis emphasizes the accuracy of camera intrinsic and extrinsic parameters . we presents an accurate f method based on corresponding point adjustment . the method adjusts coresponding points according to the fixedness of projective transformed cross ratio , then calculates f matrix accurately through linear and non - linear methods . when computing intrinsic parameter , a matrix , we simplify the step , and stress on the two important parameters of a . the result will be getten through solving kruppa equation based on svd decomposition . in order to compute extrinsic parameters , we use linear method to get initial r and t , then apply non - linear method to accurate them 提出了基于匹配點調整的f求精方法,先根據攝影交比不見性對手工選擇的匹配點進行調整,再用線性、非線性結合的方法求精f矩陣;在計算內部參數a中,進行了一定的簡化,把重心放在a中重要的兩個參數上,用svd分解法計算kruppa方程;在計算外部參數時,首先用線性法求解r 、 t ,然后再用非線性法迭代求精。

A camera calibration method with co - line points is proposed , in which distortion center is located according to cross ratio invariability , and then distortion coefficients are calculated based on a line ' s central projection is a line 摘要提出一種用共線點列標定攝像機鏡頭畸變參數的方法,先根據交叉比不變性確定畸變中心,再利用直線的中心投影仍為直線這一性質確定畸變系數。

Desargues proved that the cross ratio is the same for every section of the projection Desargues證明了投射線的每個截線上的交比都相等。

Desargues proved that the cross ratio is the same for every section of the projection . Desargues證明了投射線的每個截線上的交比都相等。