I'm having trouble getting projectPoints to work. I've calibrated the camera and used solvPNP as in this tutorial:
https://longervision.github.io/2017/03/20/opencv-internal-calibration-circle-grid/
The images obtained from the video I recorded showed that the blob detection worked fine, so this part I'm pretty confident works as intended.
Then I got registered some coordinates from an image to their real world corresponding points. I would expect projectPoints should return the same imagePoints coordinates if I would use projectPoints with some of the reference points as inputs, but instead I'm getting output values that are wildly outside the image coordinates.
I wonder what I'm doing wrong? Any help is greatly appreciated! After this I'm also trying to figure out how to do this in inverse: input imagePoints and get out objectPoints with z=0
My input points for projectPoints are:
inPoints = np.zeros((3, 3))
inPoints[0] = (0 , 137.16 , 0)
inPoints[1] = (0 , 548.64 , 0)
inPoints[2] = (548.64 , 548.64, 0)
Expected Output:
(326, 156)
(398, 154)
(406, 170)
What I'm actually getting:
(19748.51884776, 14658.66747407)
(24693.12654318, 9023.29722927)
(33225.96561506, 3969.11639187)
Inputs:
rvec = [[-0.06161642] [ 0.74999101] [ 0.78220654]]
tvec = [[-914.24171214] [-834.30392656] [1188.29684866]]
cameraMatrix = [[2.25545289e+03 0.00000000e+00 1.27534861e+03]
[0.00000000e+00 2.32542640e+03 7.35878530e+02]
[0.00000000e+00 0.00000000e+00 1.00000000e+00]]
distCoeffs = [[-3.18000851e-02 1.83258452e+00 -4.43437310e-03 5.27295127e-03 -1.12934335e+01]]
Full script (after calibration):
import numpy as np
import cv2
import glob
import sys
import yaml
with open('./calib/calibration.yaml') as f:
loadeddict = yaml.load(f)
camera_matrix = loadeddict.get('camera_matrix')
dist_coeffs = loadeddict.get('dist_coeff')
tnsPoints = np.zeros((19, 3))
tnsPoints[0] = (0 , 0 , 0)
tnsPoints[1] = (0 , 137.16 , 0)
tnsPoints[2] = (0 , 548.64, 0)
tnsPoints[3] = (0 , 960.12, 0)
tnsPoints[4] = (0 , 1097.28 , 0)
tnsPoints[5] = (548.64, 137.16, 0)
tnsPoints[6] = (548.64, 548.64, 0)
tnsPoints[7] = (548.64, 960.12, 0)
tnsPoints[8] = (1188.72 , 0, 0)
tnsPoints[9] = (1188.72 , 137.16, 0)
tnsPoints[10] = (1188.72 , 548.64, 0)
tnsPoints[11] = (1188.72 , 960.12, 0)
tnsPoints[12] = (1188.72 , 1097.28, 0)
tnsPoints[13] = (1828.80 , 137.16, 0)
tnsPoints[14] = (1828.80 , 548.64, 0)
tnsPoints[15] = (1828.80 , 960.12, 0)
tnsPoints[16] = (2377.44 , 0 , 0)
tnsPoints[17] = (2377.44 , 137.16 , 0)
tnsPoints[18] = (2377.44 , 548.64 , 0)
#tnsPoints[19] = (2377.44 , 960.12 , 0)
#tnsPoints[20] = (2377.44 , 1097.28 , 0)
imPoints = np.zeros((19,2))
imPoints[0] = (302,158)
imPoints[1] = (326, 156)
imPoints[2] = (398, 154)
imPoints[3] = (471, 150)
imPoints[4] = (494, 148)
imPoints[5] = (319, 172)
imPoints[6] = (406, 170)
imPoints[7] = (491, 167)
imPoints[8] = (270, 206)
imPoints[9] = (306, 206)
imPoints[10] = (421, 203)
imPoints[11] = (532, 197)
imPoints[12] = (570, 195)
imPoints[13] = (283, 266)
imPoints[14] = (446, 260)
imPoints[15] = (607, 252)
imPoints[16] = (146, 390)
imPoints[17] = (235, 387)
imPoints[18] = (499, 374)
retval, rvec, tvec = cv2.solvePnP(tnsPoints, imPoints, np.asarray(camera_matrix), np.asarray(dist_coeffs))
inPoints = np.zeros((3, 3))
inPoints[0] = (0 , 137.16 , 0)
inPoints[1] = (0 , 548.64 , 0)
inPoints[2] = (548.64 , 548.64, 0)
print(rvec)
print(tvec)
print(np.asarray(camera_matrix))
print(np.asarray(dist_coeffs))
outPoints, jacobian = cv2.projectPoints(inPoints, rvec, tvec, np.asarray(camera_matrix), np.asarray(dist_coeffs))
print(outPoints)
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