Quantcast

Convert image to world coordinates

classic Classic list List threaded Threaded
3 messages Options
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Convert image to world coordinates

opencv-users mailing list
Hello,


I am currently solving a problem of scene calibration but I am a bit
puzzled with the problem constrains.
Given a road surveillance video I need to estimate the vehicles speed. Here
are the conditions:
- I have the image/world coordinates correspondence for 8 points in the
scene for calibration purpose
- Don't have the camera intrinsics
- The frame rate is constant and known
- Will track the wheels position (the part touching the ground) to compute
the speed


My main problem here is: how can I compute the pixel/world conversion
matrix without having the camera intrinsics? Is there any OpenCV functions
available to solve this problem?


Thanks
G.
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

RE: Convert image to world coordinates

opencv-users mailing list
First for non-linear calibration camera you can learn from the  book:


Learning OpenCV: Computer Vision with the OpenCV Library
by Gary Bradski and Adrian Kaehler
Published by O'Reilly Media, October 3, 2008

The intrinsic and extrinsic parameters you can achieve with a little program available on this book and works well.

Second For linear calibration you can use cvFindHomography. The book is full of examples or Bradski site.

For convert   pixel world  to real world you need an object that knows the dimensions and then  with distortions corrected  you can use a rule of three to convert.

Everything is well explained by the book.


Marcus RenĂª Giannetti
http://lattes.cnpq.br/0431160327535046
Contato (31)9 8827-4864 (Whatsapp - oi)
               (31) 98819-3620 (Whatsapp)

CallSend SMSCall from mobileAdd to SkypeYou'll need Skype CreditFree via SkypeCallSend SMSCall from mobileAdd to SkypeYou'll need Skype CreditFree via SkypeCallSend SMSCall from mobileAdd to SkypeYou'll need Skype CreditFree via Skype

From: [hidden email]
To: [hidden email]
Date: Thu, 12 Nov 2015 12:23:26 +0000
Subject: [OpenCV] Convert image to world coordinates














































      Hello,


I am currently solving a problem of scene calibration but I am a bit puzzled with the problem constrains.
Given a road surveillance video I need to estimate the vehicles speed. Here are the conditions:
- I have the image/world coordinates correspondence for 8 points in the scene for calibration purpose
- Don't have the camera intrinsics
- The frame rate is constant and known
- Will track the wheels position (the part touching the ground) to compute the speed


My main problem here is: how can I compute the pixel/world conversion matrix without having the camera intrinsics? Is there any OpenCV functions available to solve this problem?


Thanks
G.


























     
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: Convert image to world coordinates

keghn
In reply to this post by opencv-users mailing list
 Use GPS and then triangulate  to you region of interest? Walk over to your ROI and take another GPS reading?
Loading...