Closed JeyP4 closed 4 years ago
Hi @JeyP4 you can find many good information searching for "Pin hole camera model".
Hi @JeyP4 you can find many good information searching for "Pin hole camera model".
- (cx, cy) is a principal point that is usually at the image center
- fx, fy are the focal lengths expressed in pixel units.
Thanks I am sorry, I was not clear enough in my question.
My question is in the config file I see these values. Which are required to perform undistort. After undistort, distortion coefficients will vanish. But rectified image will have its new fx, fy, cx , cy. May this wrappper publish somewhere new values?
Each image topic has its own camera parameter associated.
e.g.
/zed2/zed_node/rgb/camera_info
and /zed2/zed_node/rgb/image_rect_color
-> undistorted, but with fx, fy, cx, cy that you can find in the K
parameter in the camera_info
topic:
e.g. K: [531.2548217773438, 0.0, 666.2540283203125, 0.0, 531.2548217773438, 349.59100341796875, 0.0, 0.0, 1.0]
fx = 531.2548217773438
fy = 531.2548217773438
cx = 666.2540283203125
cy = 349.59100341796875
one example of complete camera_info
topic:
---
header:
seq: 1
stamp:
secs: 1595352953
nsecs: 379747070
frame_id: "zed2_left_camera_optical_frame"
height: 720
width: 1280
distortion_model: "plumb_bob"
D: [0.0, 0.0, 0.0, 0.0, 0.0]
K: [531.2548217773438, 0.0, 666.2540283203125, 0.0, 531.2548217773438, 349.59100341796875, 0.0, 0.0, 1.0]
R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
P: [531.2548217773438, 0.0, 666.2540283203125, 0.0, 0.0, 531.2548217773438, 349.59100341796875, 0.0, 0.0, 0.0, 1.0, 0.0]
binning_x: 0
binning_y: 0
roi:
x_offset: 0
y_offset: 0
height: 0
width: 0
do_rectify: False
---
Thanks
Do you mean after undistort new camera_matrix (k_new)
= old camera_matrix (K)
?
No, I have not said that. Indeed you can compare the camera matrix before and after calibration and you will notice that they are different.
e.g. /zed2/zed_node/rgb_raw/camera_info
(raw image) vs /zed2/zed_node/rgb/camera_info
(undistorted image)
Ok Now it's clear. I will check tomorrow.
Thanks.
I understood that distortion correction is performed.
I am interested in what are the cx, cy, fx, fy after rectification
(/zed/zed_node/rgb/image_rect_color)
? (Let's say for VGA)