# Forum

### Author Topic: use the radial and tangential distortion coefficients  (Read 12719 times)

#### mirco

• Newbie
• Posts: 2
##### use the radial and tangential distortion coefficients
« on: April 24, 2012, 08:43:50 PM »
hi,

i am a student working on a photogrammetry project for my thesis. i work
with a mobile-phone-camera with f4.3 .

for tests i wanted to use the results of your calibration program. i saw in
forum the link http://www.agisoft.ru/forum/index.php?topic=132.msg594#msg594,
how to use the coefficients K1,K2 and K3

so, you wrote:
K1, K2, K3 are used in units of focal length and to convert them into mm or
pixels their values need to be divided by fx(in mm or pix)^2 for K1, fx^4
for K2 and fx^6 for K3.

my focal length (x) for example is 3116 (pix) and my radial coefficients
are k1: 0,14... k2: -0,60...   k3:0,72

is it right for k1: (0,14 / 3116)^2 or (0,14 / 3116^2) for example.

i am not really sure how to use the coefficients to get the right radial distortion.

thanks

mirco