bundle block adjustment with 3d natural cubic splines

bundle block adjustment with 3d natural cubic splines bundle block adjustment with 3d natural cubic splines

13.07.2015 Views

Fourier transform has strength in signal and data compression, filtering and smoothing.However, Fourier transform has little strength in the representation of a curveaccurately. More terms to represent a free-form line exactly increase the time andthe computation complexity.2.3.3 Implicit polynomialsImplicit polynomials obtained by the computation of the least squares problemfor the coefficients of the polynomial have the mathematical form:X(t) = a 0 + a 1 t + a 2 t 2 + · · · + a n t nY (t) = b 0 + b 1 t + b 2 t 2 + · · · + b n t n (2.26)Z(t) = c 0 + c 1 t + c 2 t 2 + · · · + c n t nwhere a 0 , a 1 , · · · a n , b 0 , · · · b n , c 0 , · · · c n ∈ R 3 and the value of n is the degree of thepolynomial R n .The coefficients a 0 , b 0 , c 0 characterize a point in the object spaceR 3 and remaining parameters represent the direction.The number of parametersrequired to represent the n degree polynomial R n is 3(n + 1). Implicit polynomial ina degree of 3 is analogous to a natural cubic spline.A free-form line is formulated in a simple form geometrically independent accordingto a polynomial fit. However, a quality of the results is implemented in case ofhigh degrees. A prediction of the outcome of fitting with implicit polynomials is difficultsince coefficients are not geometrically correlated. The best solution is optimizedby the iterative try and error method. In the worst case, the implementation seemsto never end with a tight threshold. The number of trials to fit successful coefficientsdepends on the restriction of the search space. Implicit polynomials are originatedthrough constraints and various minimization criteria.32

For other polyline expressions, Ayache and Faugeras[4] described a line as theintersection of two planes that one plane is parallel to the X-axis and the other isparallel to the Y-axis with two constraints to extend this concept to general lines.Two constraints reduced line parameters six to four-dimensional vector.Since standard collinearity model can be extended to adopt parametric representationof spline, 3D natural cubic splines are employed for this research.Thecollinearity equations play an important role in photogrammetry since each controlpoint in the object space produces two collinearity equations for every photographin which the point appears. A natural 3D cubic spline allows the utilization of thecollinearity model for expressing orientation parameters and curve parameters.33

For other polyline expressions, Ayache and Faugeras[4] described a line as theintersection of two planes that one plane is parallel to the X-axis and the other isparallel to the Y-axis <strong>with</strong> two constraints to extend this concept to general lines.Two constraints reduced line parameters six to four-dimensional vector.Since standard collinearity model can be extended to adopt parametric representationof spline, 3D <strong>natural</strong> <strong>cubic</strong> <strong>splines</strong> are employed for this research.Thecollinearity equations play an important role in photogrammetry since each controlpoint in the object space produces two collinearity equations for every photographin which the point appears. A <strong>natural</strong> 3D <strong>cubic</strong> spline allows the utilization of thecollinearity model for expressing orientation parameters and curve parameters.33

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