Jump to content
  • 1
erminio

Placing models with CameraMatch in distorted photos

Question

Posted (edited)

Hi all,

I'm using CM occasionally since Vectorworks 2010 for architecture purpose

Now I'm asked to place large models in big areas far from me

So customers usually take pictures made by smartphones  with bad quality and big distortion

These areas  have no certain references and I've often to create panoramas merging pictures, adding even more distortion

Sometimes I also have to use Street Views snapshots

Is it possible to correct these kind of distortion?

Fortunately a big precision is not requested

Having a reasonable margin, I've tried the following trick but unsuccessfully 

First I place the Ref Point, then the vert. lines and after the left and right lines, as better as possible

Try to see if the calculated horizontal line matches the picture one

I trace a new reference line where I think the horizontal line has to be and put the two vanishing points on it, moving green and red lines

Then I slide the vanishing points right and left  on the HL to match the perspective

The problem is that at a certain point green and red lines  misalign with the correspondent ref point. axes and the preview box goes out of perspective, getting me crazy 

This has nothing to do with the picture distortion

What's wrong about that?

Does the error refers to blu vertical lines alignment?

PS: the picture is just an example of street view photo

 

Prove Camera Match 2.vwx

Schermata 2019-03-27 alle 23.53.10.png

Edited by erminio
Updated example

Share this post


Link to post

3 answers to this question

Recommended Posts

  • 0

Hi @erminio,

 

Lens barrel distortion can be corrected in image editors. There's an inexpensive application called PTLens designed just for this and has a huge database of camera and lenses with correction information. If you open an image taken by a camera and lens from its database, it will auto-correct it for you. I haven't used it in a few years, but it worked wonderfully when I did. It was well worth the price for me (I think it was 25 USD).

 

As for matching images that have been stitched together:  All bets are off.  The problem with this is that each image has its own set of vanishing points. Maybe you can get something close enough through trial and error, but I make no promises.

 

The preview object's perspective strays from the control lines when the vanishing points are positioned in an impossible (unrealistic) configuration. The pure math behind it all cannot calculate the view because the object could never be viewed with the three vanishing points in those locations. Usually it's the most parallel pair of control lines causing this problem. In your case, this would be the blue (vertical) control lines. Moving the top end of them slightly to the left or right might help correct the issue. Keep in mind: The closer to parallel a pair of control lines are, the bigger the change when changing the angle of them.

  • Like 1

Share this post


Link to post
  • 0
On 3/29/2019 at 8:26 PM, Matt Panzer said:

Hi @erminio,

 

Lens barrel distortion can be corrected in image editors. There's an inexpensive application called PTLens designed just for this and has a huge database of camera and lenses with correction information. If you open an image taken by a camera and lens from its database, it will auto-correct it for you. I haven't used it in a few years, but it worked wonderfully when I did. It was well worth the price for me (I think it was 25 USD).

 

As for matching images that have been stitched together:  All bets are off.  The problem with this is that each image has its own set of vanishing points. Maybe you can get something close enough through trial and error, but I make no promises.

 

The preview object's perspective strays from the control lines when the vanishing points are positioned in an impossible (unrealistic) configuration. The pure math behind it all cannot calculate the view because the object could never be viewed with the three vanishing points in those locations. Usually it's the most parallel pair of control lines causing this problem. In your case, this would be the blue (vertical) control lines. Moving the top end of them slightly to the left or right might help correct the issue. Keep in mind: The closer to parallel a pair of control lines are, the bigger the change when changing the angle of them.

Thank you Matt for your kind answer

As you say, I've seen CM cannot do magics on irrealistic images, so I gave it up

What I've done, to solve that, is placing a flat transparent image in Vectorworks, orienting the model as better as possible on that, then adjust in Photoshop

Not so easy and fast as CM, but works

Share this post


Link to post
  • 0

You're welcome!

 

17 hours ago, erminio said:

What I've done, to solve that, is placing a flat transparent image in Vectorworks, orienting the model as better as possible on that, then adjust in Photoshop

 Not so easy and fast as CM, but works

 

Yes. Not fun. That sounds like what I used to do before developing Camera Match. 😉

Good to hear you were able to get something you can use.

  • Like 2

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

 

7150 Riverwood Drive, Columbia, Maryland 21046, USA   |   Contact Us:   410-290-5114

 

© 2018 Vectorworks, Inc. All Rights Reserved. Vectorworks, Inc. is part of the Nemetschek Group.

×