THE AIM OF THE STUDY: Methods of automatic and semiautomatic picture determination, evaluation of Moiré contourgraph applied to pregnant women
TYPE OF THE STUDY: Development of algorithm, experimental biomechanical study of the dynamics of pregnant women's axial system.
METHOD: Achieving the correct data for 3D picture analysis derived from 2D pictures requires further precision making. In general, it requires algorithmization and elaboration of software plug-in, which make processing of enormous number of picture data significantly faster. The following corrections, adjustments and calculations had to be done to be used for Moiré contourgraph: correction of the radial distortion of the lens--automatically, aligning the histogram--automatically, picture detection of the defined object shape and determining its centre of gravity with sub-pixel precision--automatically, centre of gravity of the picture of the cross-section of pseudo-contour line of the Moiré contourgraph--semi-automatically, correction of radial shifts in 2D-data orthonormalization--semi-automatically, determining the distance of a projected point in 2D from the net as z-coordinate in 3D--semi-automatically, a) points projected in 2D picture on the pseudo-contour line, b) points not projected in 2D picture on the pseudo-contour line.
RESULTS: Algorithmization of each approach leading to semi-automatic and automatic processing of data obtained from Moiré contourgraphs. Main distortions, errors and inaccuracy of picture data are eliminated. The resulting position of the detected point in 3D derived from the 2D picture is determined with sub-pixel precision of primary picture coordinates.
CONCLUSION: Precision given to coordinates of reference points obtained from original picture data allows for eliminating limiting inaccuracy in determining real coordinates of a 3D object from 2D Moiré contourgraph. Coordinates of a virtual model of a real object corresponding to its real values are determined. This makes the base for non-invasive recording and reconstruction of data on the human body's shape including the details in 3D. The presented file of methods will be used to assess dynamics of the women's axial system during their pregnancy and one year after giving birth.