OpenCV捆绑调整

Question

我正在尝试使用OpenCV Bundle Adjustment: LevMarqSparse::bundleAdjust，不幸的是输出结果似乎完全错误：

Iteration: 0, normError: 4.30244e+46 (3.64614e+44)
decreasing lambda to 0.024556
Iteration: 1, normError: 2.72985e+31 (2.31343e+29)
decreasing lambda to 0.0024556
Iteration: 2, normError: 8.00302e+25 (6.78222e+23)
move failed: lambda = 0.024556, e2 = 2.62043e+40 (2.2207e+38) > 8.00302e+25(6.78222e+23)
move failed: lambda = 0.24556, e2 = 7.31034e+40 (6.1952e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556, e2 = 1.59706e+40 (1.35344e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 24.556, e2 = 1.33882e+40 (1.13459e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 245.56, e2 = 1.31518e+40 (1.11456e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2455.6, e2 = 1.31283e+40 (1.11257e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 24556, e2 = 1.3126e+40 (1.11237e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 245560, e2 = 1.31257e+40 (1.11235e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+06, e2 = 1.31257e+40 (1.11235e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+07, e2 = 1.31257e+40 (1.11235e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+08, e2 = 1.31257e+40 (1.11235e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+09, e2 = 1.31257e+40 (1.11235e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+10, e2 = 1.3125e+40 (1.11229e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+11, e2 = 1.31102e+40 (1.11103e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+12, e2 = 1.3103e+40 (1.11042e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+13, e2 = 1.31471e+40 (1.11416e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+14, e2 = 1.29156e+40 (1.09454e+38) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+15, e2 = 1.15709e+40 (9.80585e+37) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+16, e2 = 3.81423e+39 (3.2324e+37) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+17, e2 = 6.59182e+36 (5.58629e+34) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+18, e2 = 8.07694e+34 (6.84487e+32) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+19, e2 = 7.73149e+52 (6.55211e+50) > 8.00302e+25 (6.78222e+23)
move failed: lambda = 2.4556e+20, e2 = 2.061e+40 (1.74661e+38) > 8.00302e+25 (6.78222e+23)
decreasing lambda to 2.4556e+19

如果我手动重新投影我的关键点的第一个猜测，我得到了每个关键点和其三角化点的重投影之间的像素欧几里德距离（误差）的总和为169.541。 在调用LevMarqSparse::bundleAdjust后进行相同的错误检查，得到的误差为5.50025e+12。

请问有人能指点我正确的方向吗？谢谢。

- Teris

Answer 1

通常情况下，当在捆绑调整中发生类似这样的问题时，至少有以下一种错误非常可能：

1. 2D投影不是3D点的正确投影之一，因此一个3D点被重新投影到错误的2D投影上，从而再投影误差会非常大。也许在2D投影和3D点之间的索引中发生了一些问题。
2. 您使用的相机不与OpenCV所需的坐标系相同。想象一下围绕180度旋转或反向移动，3D点将被投影到某个位置，但肯定不是正确的2D位置。因此，尝试使用逆矩阵。如果P是您的4x4齐次投影矩阵之一，请使用P.inv()而不是P。

获取平均再投影误差将有所帮助。总和并不是非常有意义的，因为我们不知道您的重建中有多少3D点和2D投影。

- who9vy