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The Bernstein Basis and Bezier Curves. Dr. Scott Schaefer. Problems with Interpolation. Problems with Interpolation. Bezier Curves. Polynomial curves that seek to approximate rather than to interpolate. Bernstein Polynomials. Degree 1: (1- t ), t Degree 2: (1- t ) 2 , 2(1- t ) t , t 2
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The Bernstein Basis and Bezier Curves Dr. Scott Schaefer
Bezier Curves • Polynomial curves that seek to approximate rather than to interpolate
Bernstein Polynomials • Degree 1: (1-t), t • Degree 2: (1-t)2, 2(1-t)t, t2 • Degree 3: (1-t)3, 3(1-t)2t, 3(1-t)t2, t3
Bernstein Polynomials • Degree 1: (1-t), t • Degree 2: (1-t)2, 2(1-t)t, t2 • Degree 3: (1-t)3, 3(1-t)2t, 3(1-t)t2, t3 • Degree 4: (1-t)4, 4(1-t)3t, 6(1-t)2t2, 4(1-t)t3,t4
Bernstein Polynomials • Degree 1: (1-t), t • Degree 2: (1-t)2, 2(1-t)t, t2 • Degree 3: (1-t)3, 3(1-t)2t, 3(1-t)t2, t3 • Degree 4: (1-t)4, 4(1-t)3t, 6(1-t)2t2, 4(1-t)t3,t4 • Degree 5: (1-t)5, 5(1-t)4t, 10(1-t)3t2, 10(1-t)2t3 ,5(1-t)t4,t5 • … • Degree n: for
Properties of Bernstein Polynomials Binomial Theorem:
Properties of Bernstein Polynomials Binomial Theorem:
Properties of Bernstein Polynomials Binomial Theorem:
Properties of Bernstein Polynomials Binomial Theorem:
Properties of Bernstein Polynomials • Base case:
Properties of Bernstein Polynomials • Base case:
Properties of Bernstein Polynomials • Base case: • Inductive Step: Assume
Properties of Bernstein Polynomials • Base case: • Inductive Step: Assume
Properties of Bernstein Polynomials • Base case: • Inductive Step: Assume
Properties of Bernstein Polynomials • Base case: • Inductive Step: Assume
Bezier Curve Properties • Interpolate end-points
Bezier Curve Properties • Interpolate end-points
Bezier Curve Properties • Interpolate end-points
Bezier Curve Properties • Interpolate end-points
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge Another Bezier curve of vectors!!!
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge • Curve lies within the convex hull of the control points
Bezier Curve Properties • Interpolate end-points • Tangent at end-points in direction of first/last edge • Curve lies within the convex hull of the control points Bezier Lagrange
Matrix Form of Bezier Curves Computation in monomial basis is unstable!!! Most proofs/computations are easier in Bernstein basis!!!