OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Wed, 14 Mar 2018 06:01:51 -0500Generate intrinsic matrix from exif valueshttp://answers.opencv.org/question/186692/generate-intrinsic-matrix-from-exif-values/Hi all!
I'm trying to find the Essential Matrix in order to find the movement of one camera according to another.
I calculate F using SIFT matches, then findFundamentalMat with ransac to remove outliers then findFundamentalMat with LMEDS. The results seems good (the equation xEx' = 0 is nearly verified for each pairs (x,x').
Now, I would like to calculate E, using the formula E = K'(t)FK.
Since I don't know which camera was used to generate photos, I would like to create K from scratch, but without any way to calibrate it, so I would like to use Exif values to create it.
Actually i'm doing so :
K =
Fx 0 Cx
0 Fy Cy
0 0 1
with (Cx, Cy) = (image.width/2, image.height/2) (I have to assume that the principale point is the middle of the image).
But for (Fx, Fy) actually i'm really not sure of what I'm doing...
Fx = focal_length(mm) * X_res(DPI) / 25.4 (because 1inch = 25.4mm)
and
Fy = focal_length(mm) * Y_res(DPI) / 25.4
1st, i'm not sure if the formula is good and 2nd, I saw that openCV want pixel instead of mm for matrix but I don't understand...
Can someone help me?
Thanks!KirbXWed, 14 Mar 2018 06:01:51 -0500http://answers.opencv.org/question/186692/