def _plot(data, px, title=''): df2.figure(9003, docla=True, pnum=(2, 4, px)) df2.plot2(data.T[0], data.T[1], '.', title)
def _plotpts(data, px, color=df2.BLUE, label=''): #df2.figure(9003, docla=True, pnum=(1, 1, px)) df2.plot2(data.T[0], data.T[1], '-', '', color=color, label=label) df2.update()
def get_kp_border(rchip, kp): np.set_printoptions(precision=8) df2.reset() df2.figure(9003, docla=True, doclf=True) def _plotpts(data, px, color=df2.BLUE, label=''): #df2.figure(9003, docla=True, pnum=(1, 1, px)) df2.plot2(data.T[0], data.T[1], '-', '', color=color, label=label) df2.update() def _plotarrow(x, y, dx, dy, color=df2.BLUE, label=''): ax = df2.gca() arrowargs = dict(head_width=.5, length_includes_head=True, label='') arrow = df2.FancyArrow(x, y, dx, dy, **arrowargs) arrow.set_edgecolor(color) arrow.set_facecolor(color) ax.add_patch(arrow) df2.update() def _2x2_eig(M2x2): (evals, evecs) = np.linalg.eig(M2x2) l1, l2 = evals v1, v2 = evecs return l1, l2, v1, v2 #----------------------- # INPUT #----------------------- # We are given the keypoint in invA format (x, y, ia11, ia21, ia22), ia12 = kp, 0 # invA2x2 is a transformation from points on a unit circle to the ellipse invA2x2 = np.array([[ia11, ia12], [ia21, ia22]]) #----------------------- # DRAWING #----------------------- # Lets start off by drawing the ellipse that we are goign to work with # Create unit circle sample tau = 2 * np.pi theta_list = np.linspace(0, tau, 1000) cicrle_pts = np.array([(np.cos(t), np.sin(t)) for t in theta_list]) ellipse_pts = invA2x2.dot(cicrle_pts.T).T _plotpts(ellipse_pts, 0, df2.BLACK, label='invA2x2.dot(unit_circle)') l1, l2, v1, v2 = _2x2_eig(invA2x2) dx1, dy1 = (v1 * l1) dx2, dy2 = (v2 * l2) _plotarrow(0, 0, dx1, dy1, color=df2.ORANGE, label='invA2x2 e1') _plotarrow(0, 0, dx2, dy2, color=df2.RED, label='invA2x2 e2') #----------------------- # REPRESENTATION #----------------------- # A2x2 is a transformation from points on the ellipse to a unit circle A2x2 = np.linalg.inv(invA2x2) # Points on a matrix satisfy (x).T.dot(E2x2).dot(x) = 1 E2x2 = A2x2.T.dot(A2x2) #Lets check our assertion: (x).T.dot(E2x2).dot(x) = 1 checks = [pt.T.dot(E2x2).dot(pt) for pt in ellipse_pts] assert all([abs(1 - check) < 1E-11 for check in checks]) #----------------------- # CONIC SECTIONS #----------------------- # All of this was from the Perdoch paper, now lets move into conic sections # We will use the notation from wikipedia # http://en.wikipedia.org/wiki/Conic_section # http://en.wikipedia.org/wiki/Matrix_representation_of_conic_sections # The matrix representation of a conic is: ((A, B, B_, C), (D, E, F)) = (E2x2.flatten(), (0, 0, 1)) assert B == B_, 'matrix should by symmetric' # A_Q is our conic section (aka ellipse matrix) A_Q = np.array(((A, B / 2, D / 2), (B / 2, C, E / 2), (D / 2, E / 2, F))) assert np.linalg.det(A_Q) != 0, 'degenerate conic' # As long as det(A_Q) is not 0 it is not degenerate and we can work with the # minor 2x2 matrix A_33 = np.array(((A, B / 2), (B / 2, C))) # (det == 0)->parabola, (det < 0)->hyperbola, (det > 0)->ellipse assert np.linalg.det(A_33) > 0, 'conic is not an ellipse' # Centers are obtained by solving for where the gradient of the quadratic # becomes 0. Without going through the derivation the calculation is... # These should be 0, 0 if we are at the origin, or our original x, y # coordinate specified by the keypoints. I'm doing the calculation just for # shits and giggles x_center = (B * E - (2 * C * D)) / (4 * A * C - B**2) y_center = (D * B - (2 * A * E)) / (4 * A * C - B**2) #================= # DRAWING #================= # Now we are going to determine the major and minor axis # of this beast. It just the center augmented by the eigenvecs l1, l2, v1, v2 = _2x2_eig(A_33) dx1, dy1 = 0 - (v1 / np.sqrt(l1)) dx2, dy2 = 0 - (v2 / np.sqrt(l2)) _plotarrow(0, 0, dx1, dy1, color=df2.BLUE) _plotarrow(0, 0, dx2, dy2, color=df2.BLUE) # The angle between the major axis and our x axis is: x_axis = np.array([1, 0]) theta = np.arccos(x_axis.dot(evec1)) # The eccentricity is determined by: nu = 1 numer = 2 * np.sqrt((A - C)**2 + B**2) denom = nu * (A + C) + np.sqrt((A - C)**2 + B**2) eccentricity = np.sqrt(numer / denom) from scipy.special import ellipeinc # Algebraic form of connic #assert (a * (x ** 2)) + (b * (x * y)) + (c * (y ** 2)) + (d * x) + (e * y) + (f) == 0 #--------------------- invA = np.array([[a, 0], [c, d]]) Ashape = np.linalg.inv(np.array([[a, 0], [c, d]])) Ashape /= np.sqrt(np.linalg.det(Ashape)) tau = 2 * np.pi nSamples = 100 theta_list = np.linspace(0, tau, nSamples) # Create unit circle sample cicrle_pts = np.array([(np.cos(t), np.sin(t)) for t in theta_list]) circle_hpts = np.hstack([cicrle_pts, np.ones((len(cicrle_pts), 1))]) # Transform as if the unit cirle was the warped patch ashape_pts = Ashape.dot(cicrle_pts.T).T inv = np.linalg.inv svd = np.linalg.svd U, S_, V = svd(Ashape) S = np.diag(S_) pxl_list3 = invA.dot(cicrle_pts[:, 0:2].T).T pxl_list4 = invA.dot(ashape_pts[:, 0:2].T).T pxl_list5 = invA.T.dot(cicrle_pts[:, 0:2].T).T pxl_list6 = invA.T.dot(ashape_pts[:, 0:2].T).T pxl_list7 = inv(V).dot(ashape_pts[:, 0:2].T).T pxl_list8 = inv(U).dot(ashape_pts[:, 0:2].T).T df2.draw() def _plot(data, px, title=''): df2.figure(9003, docla=True, pnum=(2, 4, px)) df2.plot2(data.T[0], data.T[1], '.', title) df2.figure(9003, doclf=True) _plot(cicrle_pts, 1, 'unit circle') _plot(ashape_pts, 2, 'A => circle shape') _plot(pxl_list3, 3) _plot(pxl_list4, 4) _plot(pxl_list5, 5) _plot(pxl_list6, 6) _plot(pxl_list7, 7) _plot(pxl_list8, 8) df2.draw() invA = np.array([[a, 0, x], [c, d, y], [0, 0, 1]]) pxl_list = invA.dot(circle_hpts.T).T[:, 0:2] df2.figure(9002, doclf=True) df2.imshow(rchip) df2.plot2(pxl_list.T[0], pxl_list.T[1], '.') df2.draw() vals = [cv2.getRectSubPix(rchip, (1, 1), tuple(pxl)) for pxl in pxl_list] return vals
def get_kp_border(rchip, kp): np.set_printoptions(precision=8) df2.reset() df2.figure(9003, docla=True, doclf=True) def _plotpts(data, px, color=df2.BLUE, label=''): #df2.figure(9003, docla=True, pnum=(1, 1, px)) df2.plot2(data.T[0], data.T[1], '-', '', color=color, label=label) df2.update() def _plotarrow(x, y, dx, dy, color=df2.BLUE, label=''): ax = df2.gca() arrowargs = dict(head_width=.5, length_includes_head=True, label='') arrow = df2.FancyArrow(x, y, dx, dy, **arrowargs) arrow.set_edgecolor(color) arrow.set_facecolor(color) ax.add_patch(arrow) df2.update() def _2x2_eig(M2x2): (evals, evecs) = np.linalg.eig(M2x2) l1, l2 = evals v1, v2 = evecs return l1, l2, v1, v2 #----------------------- # INPUT #----------------------- # We are given the keypoint in invA format (x, y, ia11, ia21, ia22), ia12 = kp, 0 # invA2x2 is a transformation from points on a unit circle to the ellipse invA2x2 = np.array([[ia11, ia12], [ia21, ia22]]) #----------------------- # DRAWING #----------------------- # Lets start off by drawing the ellipse that we are goign to work with # Create unit circle sample tau = 2 * np.pi theta_list = np.linspace(0, tau, 1000) cicrle_pts = np.array([(np.cos(t), np.sin(t)) for t in theta_list]) ellipse_pts = invA2x2.dot(cicrle_pts.T).T _plotpts(ellipse_pts, 0, df2.BLACK, label='invA2x2.dot(unit_circle)') l1, l2, v1, v2 = _2x2_eig(invA2x2) dx1, dy1 = (v1 * l1) dx2, dy2 = (v2 * l2) _plotarrow(0, 0, dx1, dy1, color=df2.ORANGE, label='invA2x2 e1') _plotarrow(0, 0, dx2, dy2, color=df2.RED, label='invA2x2 e2') #----------------------- # REPRESENTATION #----------------------- # A2x2 is a transformation from points on the ellipse to a unit circle A2x2 = np.linalg.inv(invA2x2) # Points on a matrix satisfy (x).T.dot(E2x2).dot(x) = 1 E2x2 = A2x2.T.dot(A2x2) #Lets check our assertion: (x).T.dot(E2x2).dot(x) = 1 checks = [pt.T.dot(E2x2).dot(pt) for pt in ellipse_pts] assert all([abs(1 - check) < 1E-11 for check in checks]) #----------------------- # CONIC SECTIONS #----------------------- # All of this was from the Perdoch paper, now lets move into conic sections # We will use the notation from wikipedia # http://en.wikipedia.org/wiki/Conic_section # http://en.wikipedia.org/wiki/Matrix_representation_of_conic_sections # The matrix representation of a conic is: ((A, B, B_, C), (D, E, F)) = (E2x2.flatten(), (0, 0, 1)) assert B == B_, 'matrix should by symmetric' # A_Q is our conic section (aka ellipse matrix) A_Q = np.array((( A, B / 2, D / 2), (B / 2, C, E / 2), (D / 2, E / 2, F))) assert np.linalg.det(A_Q) != 0, 'degenerate conic' # As long as det(A_Q) is not 0 it is not degenerate and we can work with the # minor 2x2 matrix A_33 = np.array((( A, B / 2), (B / 2, C))) # (det == 0)->parabola, (det < 0)->hyperbola, (det > 0)->ellipse assert np.linalg.det(A_33) > 0, 'conic is not an ellipse' # Centers are obtained by solving for where the gradient of the quadratic # becomes 0. Without going through the derivation the calculation is... # These should be 0, 0 if we are at the origin, or our original x, y # coordinate specified by the keypoints. I'm doing the calculation just for # shits and giggles x_center = (B * E - (2 * C * D)) / (4 * A * C - B ** 2) y_center = (D * B - (2 * A * E)) / (4 * A * C - B ** 2) #================= # DRAWING #================= # Now we are going to determine the major and minor axis # of this beast. It just the center augmented by the eigenvecs l1, l2, v1, v2 = _2x2_eig(A_33) dx1, dy1 = 0 - (v1 / np.sqrt(l1)) dx2, dy2 = 0 - (v2 / np.sqrt(l2)) _plotarrow(0, 0, dx1, dy1, color=df2.BLUE) _plotarrow(0, 0, dx2, dy2, color=df2.BLUE) # The angle between the major axis and our x axis is: x_axis = np.array([1, 0]) theta = np.arccos(x_axis.dot(evec1)) # The eccentricity is determined by: nu = 1 numer = 2 * np.sqrt((A - C) ** 2 + B ** 2) denom = nu * (A + C) + np.sqrt((A - C) ** 2 + B ** 2) eccentricity = np.sqrt(numer / denom) from scipy.special import ellipeinc # Algebraic form of connic #assert (a * (x ** 2)) + (b * (x * y)) + (c * (y ** 2)) + (d * x) + (e * y) + (f) == 0 #--------------------- invA = np.array([[a, 0], [c, d]]) Ashape = np.linalg.inv(np.array([[a, 0], [c, d]])) Ashape /= np.sqrt(np.linalg.det(Ashape)) tau = 2 * np.pi nSamples = 100 theta_list = np.linspace(0, tau, nSamples) # Create unit circle sample cicrle_pts = np.array([(np.cos(t), np.sin(t)) for t in theta_list]) circle_hpts = np.hstack([cicrle_pts, np.ones((len(cicrle_pts), 1))]) # Transform as if the unit cirle was the warped patch ashape_pts = Ashape.dot(cicrle_pts.T).T inv = np.linalg.inv svd = np.linalg.svd U, S_, V = svd(Ashape) S = np.diag(S_) pxl_list3 = invA.dot(cicrle_pts[:, 0:2].T).T pxl_list4 = invA.dot(ashape_pts[:, 0:2].T).T pxl_list5 = invA.T.dot(cicrle_pts[:, 0:2].T).T pxl_list6 = invA.T.dot(ashape_pts[:, 0:2].T).T pxl_list7 = inv(V).dot(ashape_pts[:, 0:2].T).T pxl_list8 = inv(U).dot(ashape_pts[:, 0:2].T).T df2.draw() def _plot(data, px, title=''): df2.figure(9003, docla=True, pnum=(2, 4, px)) df2.plot2(data.T[0], data.T[1], '.', title) df2.figure(9003, doclf=True) _plot(cicrle_pts, 1, 'unit circle') _plot(ashape_pts, 2, 'A => circle shape') _plot(pxl_list3, 3) _plot(pxl_list4, 4) _plot(pxl_list5, 5) _plot(pxl_list6, 6) _plot(pxl_list7, 7) _plot(pxl_list8, 8) df2.draw() invA = np.array([[a, 0, x], [c, d, y], [0, 0, 1]]) pxl_list = invA.dot(circle_hpts.T).T[:, 0:2] df2.figure(9002, doclf=True) df2.imshow(rchip) df2.plot2(pxl_list.T[0], pxl_list.T[1], '.') df2.draw() vals = [cv2.getRectSubPix(rchip, (1, 1), tuple(pxl)) for pxl in pxl_list] return vals