ARToolKit | Mailing List Archive |

[ARFORUM] Need help on camera parameter

From: | Junaidi <junaidia@y ........> | Received: | Sep 24, 2001 |

To | arforum@t ......... | ||

Subject: | [ARFORUM] Need help on camera parameter | ||

Hi, Can anybody explain what does the camera parameter shows to us. I know 283.5 287.5 16.9 1.006383 is for image center point, dist factor and size adjust. But what about the other 3 columns below it. Thank you in advance. Junaidi. *** Camera Parameter *** ------------------------- SIZE = 640, 480 Distotion factor = 283.5 287.5 16.9 1.006383 1064.44696 0.0 312.0 0.0 0.0 1090.06425 290.0 0.0 0.0 0.0 1.0 0.0 ------------------------- __________________________________________________ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger. http://im.yahoo.com ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |

From: | Mark Lennerton <mjlenne1@n ...........> | Received: | Sep 24, 2001 |

To | arforum@t ......... | ||

Subject: | RE: [ARFORUM] Need help on camera parameter | ||

Junaidi, It appears you are working with ARToolKit. This link may help: http://www.hitl.washington.edu/research/shared_space/download/. You may find documentation for the version you are using. ARToolKit2.11 PC Documentation Only [MS Word 1.2 mb] may be most useful to you. Good luck, Mark -----Original Message----- From: Junaidi [mailto:junaidia@y ........] Sent: Monday, September 24, 2001 11:04 AM To: arforum@t ......... Subject: [ARFORUM] Need help on camera parameter Hi, Can anybody explain what does the camera parameter shows to us. I know 283.5 287.5 16.9 1.006383 is for image center point, dist factor and size adjust. But what about the other 3 columns below it. Thank you in advance. Junaidi. *** Camera Parameter *** ------------------------- SIZE = 640, 480 Distotion factor = 283.5 287.5 16.9 1.006383 1064.44696 0.0 312.0 0.0 0.0 1090.06425 290.0 0.0 0.0 0.0 1.0 0.0 ------------------------- __________________________________________________ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger. http://im.yahoo.com ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |

From: | Junaidi <junaidia@y ........> | Received: | Sep 25, 2001 |

To | arforum@t ......... | ||

Subject: | Re: [ARFORUM] Need help on camera parameter | ||

Hello, Thank you very much. Junaidi. --- Miguel Ribo <ribo@e ................> wrote: > Junaidi wrote: > > > > Hi, > Hello, > > > > > But > > what about the other 3 columns below it. Thank you > in > > advance. > > > > *** Camera Parameter *** > > ------------------------- > > SIZE = 640, 480 > > Distotion factor = 283.5 287.5 16.9 1.006383 > > 1064.44696 0.0 312.0 0.0 > > 0.0 1090.06425 290.0 0.0 > > 0.0 0.0 1.0 0.0 > > ------------------------- > The matrix above is the so-called intrisic matrix > (i.e., internal > canera geometriy and optical characteristics). It > give you the > transformation between a point in the camera > coordinate > system and a pixel in the image coordinate system. > In this case the pricinpal point (optical axis > intersects the image > plane) [u0, v0] is [312.0, 290.0]. If you multiply > '1064.44696' > by the pixel size of your camera, you will "find" > the focal length > of your camera. > > Hope this helps, > Miguel > -- > vr|vis center for virtual reality and visualisation > Schie_stattgasse 14b, 8010 Graz, Austria > <ribo@e ................> (http://www.vrvis.at) > Tel: +43 316 873 7766 | Fax: +43 316 873 4279 > > > __________________________________________________ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger. http://im.yahoo.com ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |

From: | Miguel Ribo <ribo@e ................> | Received: | Sep 25, 2001 |

To | arforum@t ......... | ||

Subject: | Re: [ARFORUM] Need help on camera parameter | ||

Junaidi wrote: > > Hi, Hello, > > But > what about the other 3 columns below it. Thank you in > advance. > > *** Camera Parameter *** > ------------------------- > SIZE = 640, 480 > Distotion factor = 283.5 287.5 16.9 1.006383 > 1064.44696 0.0 312.0 0.0 > 0.0 1090.06425 290.0 0.0 > 0.0 0.0 1.0 0.0 > ------------------------- The matrix above is the so-called intrisic matrix (i.e., internal canera geometriy and optical characteristics). It give you the transformation between a point in the camera coordinate system and a pixel in the image coordinate system. In this case the pricinpal point (optical axis intersects the image plane) [u0, v0] is [312.0, 290.0]. If you multiply '1064.44696' by the pixel size of your camera, you will "find" the focal length of your camera. Hope this helps, Miguel -- vr|vis center for virtual reality and visualisation Schießstattgasse 14b, 8010 Graz, Austria <ribo@e ................> (http://www.vrvis.at) Tel: +43 316 873 7766 | Fax: +43 316 873 4279 ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |

From: | wayne@c .............. | Received: | Sep 25, 2001 |

To | arforum@t ......... | ||

Subject: | RE: [ARFORUM] Need help on camera parameter | ||

Hi, I read your email and I am working on a problem which is similar. I know that most of the values in the matrix are generated as values to compensate for the camera being rotated slightly or not centred. What would the matrix look like if the camera res was 640x480 with centre point (320, 240) and Dist F=16.9 and Size adjust=1.006383, with a perfectly smooth and aligned camera lens in a theoretical perfect world? I've been trying to work out what the values mean so I can play with them, but no luck :) I have posted another message to the mailing list along with this one which covers the problem I am working on. It seems like the compensation is performed twice, inside the toolkit when it is detecting the targets and producing their matrices, and then later on when the final image is drawn to the screen. Since I use my own code and interface to arGetTransMat(), I don't get to use the second calibration matrix for GL_PROJECTION and so I get bad alignment. If I use a camera file which is distortion free or which has been hacked to bring the centre point closer to the middle of the image, I get better results. So I was thinking of cheating around the calibration if I can't find the real solution I need to my other email, and I found your post interesting in trying to do that. I hope what I just said makes sense :) Please see my other email posting ... thanks, Wayne ---------------------------------------------------------------------- Wayne Piekarski - PhD Student / Lecturer Phone: +61-8-8302-3669 Advanced Computing Research Centre Fax: +61-8-8302-3381 University of South Australia Mobile: 0407-395-889 Internet: wayne@c .............. Research & Development Manager wayne@s ........... SE Network Access Pty Ltd http://www.cs.unisa.edu.au/~ciswp Miguel Ribo wrote: > Junaidi wrote: > > > > Hi, > Hello, > > > > > But > > what about the other 3 columns below it. Thank you in > > advance. > > > > *** Camera Parameter *** > > ------------------------- > > SIZE = 640, 480 > > Distotion factor = 283.5 287.5 16.9 1.006383 > > 1064.44696 0.0 312.0 0.0 > > 0.0 1090.06425 290.0 0.0 > > 0.0 0.0 1.0 0.0 > > ------------------------- > The matrix above is the so-called intrisic matrix (i.e., internal > canera geometriy and optical characteristics). It give you the > transformation between a point in the camera coordinate > system and a pixel in the image coordinate system. > In this case the pricinpal point (optical axis intersects the image > plane) [u0, v0] is [312.0, 290.0]. If you multiply '1064.44696' > by the pixel size of your camera, you will "find" the focal length > of your camera. > > Hope this helps, > Miguel > -- > vr|vis center for virtual reality and visualisation > Schießstattgasse 14b, 8010 Graz, Austria > <ribo@e ................> (http://www.vrvis.at) > Tel: +43 316 873 7766 | Fax: +43 316 873 4279 > > > ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |

From: | Junaidi <junaidia@y ........> | Received: | Oct 3, 2001 |

To | arforum@t ......... | ||

Subject: | Re: [ARFORUM] Need help on camera parameter | ||

Hello, Thanks for your help. This question might sound silly but do you know how to accurately get the pixel size of a camera in order to calculate the focal length. I'm using a camera that comes with the SGI computer. Thanx. Junaidi --- Miguel Ribo <ribo@e ................> wrote: > Junaidi wrote: > > > > Hi, > Hello, > > > > > But > > what about the other 3 columns below it. Thank you > in > > advance. > > > > *** Camera Parameter *** > > ------------------------- > > SIZE = 640, 480 > > Distotion factor = 283.5 287.5 16.9 1.006383 > > 1064.44696 0.0 312.0 0.0 > > 0.0 1090.06425 290.0 0.0 > > 0.0 0.0 1.0 0.0 > > ------------------------- > The matrix above is the so-called intrisic matrix > (i.e., internal > canera geometriy and optical characteristics). It > give you the > transformation between a point in the camera > coordinate > system and a pixel in the image coordinate system. > In this case the pricinpal point (optical axis > intersects the image > plane) [u0, v0] is [312.0, 290.0]. If you multiply > '1064.44696' > by the pixel size of your camera, you will "find" > the focal length > of your camera. > > Hope this helps, > Miguel > -- > vr|vis center for virtual reality and visualisation > Schie_stattgasse 14b, 8010 Graz, Austria > <ribo@e ................> (http://www.vrvis.at) > Tel: +43 316 873 7766 | Fax: +43 316 873 4279 > > > __________________________________________________ Do You Yahoo!? Listen to your Yahoo! Mail messages from any phone. http://phone.yahoo.com ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?a84Ao5.a9zIQj Or send an email To: arforum-unsubscribe@t ......... This email was sent to: webmaster@e ............ T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ |