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Excel Tool for scale measurements from photos
Killy
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Posted: Sunday, March 16, 2008 - 07:56 AM UTC
I too would appreciate a copy of this tool, sounds very useful. If you would like I could also upload it to my website so people could just download it from there rather than you having to email it to so many people.

Cheers

Killy
Whiskey6
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Posted: Tuesday, March 18, 2008 - 06:41 AM UTC

Quoted Text

I too would appreciate a copy of this tool, sounds very useful. If you would like I could also upload it to my website so people could just download it from there rather than you having to email it to so many people.



Killy -

That is a great offer. Where should I send the file?

Semper Fi,
Dave
Killy
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Posted: Wednesday, March 19, 2008 - 05:45 AM UTC
Sorry about not leaving a email address just send it to: [email protected]

Cheers

Killy
jackpogorsky
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Posted: Wednesday, March 19, 2008 - 08:37 AM UTC
Could I trouble you for a copy? Thanks

[email protected]
rwaldram
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Posted: Thursday, March 20, 2008 - 11:15 PM UTC
I'd love to try this out too, can you please send me a copy to [email protected] If it's ok, i have a few friends that do a lot of scratchbuilding too would you mind if i forwarded it to them?
Whiskey6
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Posted: Friday, March 21, 2008 - 12:40 AM UTC
All -

Work has been substantially crazy this week...even the voices in my head got tired......and I am going to be out of town this weekend. I will try to e-mail the file to the most recent requests before I go, but it may be Sunday evening before I can get that done.

Sorry for the delays.

Semper Fi,
Dave
Whiskey6
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Posted: Friday, March 21, 2008 - 01:29 AM UTC

Quoted Text

Work has been substantially crazy this week...even the voices in my head got tired......and I am going to be out of town this weekend. I will try to e-mail the file to the most recent requests before I go, but it may be Sunday evening before I can get that done.



All -

I had a few minutes this morning and finally got the most recent batch of files sent. One of the files went to Killy who has generously offered to post it on his web site.

I am working on an enhanced version of the model, but would like to have your feedback before I go too far with it. My current thought is to add lines for each part of the model. I don;t know much about CAD programs, but my thinking is that the new model measurements (output from these calculations could be entered (or even uploaded) into a CAD program and used to generate the plans.

In response to an earlier question....it is fine with me if you share this worksheet. I only request that you pass it along for free.

Your thoughts????

Semper Fi,
Dave
rwaldram
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Posted: Friday, March 21, 2008 - 05:22 PM UTC
Got the email this morning, gave it a try on a few known dimensions and it came up with the correct dimension/scale.

Thanks, it will hopefuly make life a bit easier in future.
NICK-NAUPLIO
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Posted: Saturday, March 22, 2008 - 02:40 AM UTC
Hi Dave
If it would be easy could you send it to me please2 when ever possible at
[email protected] , thanks mate.
tambo
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Posted: Saturday, March 22, 2008 - 05:35 PM UTC
Dave,

Could you send me a copy to [email protected]

thank you
Holdfast
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IPMS-UK KITMAKER BRANCH
#056
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Posted: Saturday, March 22, 2008 - 09:06 PM UTC
Great stuff David, I would really appreciate a copy, PM sent.

Mal
perlossing
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Posted: Sunday, March 23, 2008 - 02:13 AM UTC
David,

Could you send me a copy to [email protected]
Thanks,
per
Killy
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Posted: Sunday, March 23, 2008 - 05:36 AM UTC
Well I checked my email and got the tool, and it seems to work perfectly! Good job creating it.

Here is the link to it on my website:
http://www.killy.it/files/ModelScalefromPhotos.zip

Cheers

Killy
Whiskey6
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Posted: Wednesday, March 26, 2008 - 12:56 PM UTC
All -

I just finished sending out the most recent batch of files this evening. If you don;t receive a copy, please let me know.

Also, Killy has been kind enough to post a copy on his web site. A copy of the link is in his most recent post. Thanks, Killy.

I'm still working on the next version of the model, but work is nuts, so this may take a while. Early reports are that the current version works well.

Semper Fi,
Dave
amerikaner
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Posted: Wednesday, March 26, 2008 - 01:29 PM UTC
I wouldn't mind a look at this, thanks! [email protected]
okdoky
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Posted: Wednesday, March 26, 2008 - 02:52 PM UTC
Got the excel doc through Ryan (thanks mate) and I gotta say that this wee computer tool worked a treat once I figured out where to add the info and read off the required scale equivelant! Am using it to on photos I have of German Luftwaffe VW crew cab pick up convert the 1/24 Revell VW Bus UN to the pick up.



Is a pity there is not an easy one that works out measurements from angled pictures (I know Architects use them for buildings and structures) as the number of occasions that would come in handy for are vast.

Thanks David for passing it out.
sgtreef
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Posted: Wednesday, March 26, 2008 - 10:29 PM UTC
Got mine also Thanks David.
Whiskey6
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Posted: Thursday, March 27, 2008 - 01:29 AM UTC

Quoted Text

Is a pity there is not an easy one that works out measurements from angled pictures (I know Architects use them for buildings and structures) as the number of occasions that would come in handy for are vast.



I can probably add that feature to the Excel model. Can you explain a bit more what you would like for it to do? What would the inputs be? ...the outputs? Are you talking about calculating angles on the subject of the photo (for example the angle between two plates of armor)? Or are you talking about accounting for the angle of the camera if it is not exactly 90 degrees from the subject of the photo. (I am guessing that it is the latter.)

I has been a long time since I had any trigonometry, but I think i can figure out either one of those problems. What I don't know for the latter is how we would determine or estimate the angle of the camera...but there has to be a way. (The burning rubber smell you are experiencing is my old brain cells working on this problem.)

Semper Fi,
Dave
okdoky
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Posted: Thursday, March 27, 2008 - 09:05 AM UTC
For example a tall or wide building where perspective begins to shorten the image and you need calculation to restore the correct dimensions and then give you a scale equivelant.

Or looking down a street where the perspective gives the shortening of dimensions.

Same effect if you only have a single or series of three-quarter views of a vehicle rather than flat elevation or plan views at 90 degrees to the subject.



Can you cope with problems like this pic where either the vehicle or buildings are at an angle or were on a slope?

For a simple building photo where you don't have the luxury of owning a laser measuring device but you can get a square on image!
From memory one would need to have an idea of the height of the camera from the ground (say eye level of person taking pic).

Assuming a level site, then the distance to a point horizontally on the building (may require to pace or measure this when taking your pictures).

Then using trigonometry to calculate the height or widths of items but allowing for a degree of distortion. I know that you can take a simple angle finder with a simple spirit level like the type used for woodworking, and place it on the same tripod used to take pictures from. Some spirit levels now have a cheap lazer added to them which you can see at great distances (helped by cheap binos).

With an angle (lining along he straight edge at a roof ridge or chimney, and a measured distance from the building you can work out fairly accurate dimensions using SOH, CAH, TOA rules

Computer programmes can factor in for changes of angle and perspective that would be very hard to compute manually.

Would be great to have a simple programme that would work with some cheap tooling.

Any thoughts guys?

Nige

.



The trig on paper I could do,,,,,,,,,,,,,,,,, making it into a computer programme??? That is a techy kind of thing!!!!!!!!!!
Whiskey6
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Posted: Thursday, March 27, 2008 - 10:14 AM UTC

Quoted Text

The trig on paper I could do,,,,,,,,,,,,,,,,, making it into a computer programme??? That is a techy kind of thing!!!!!!!!!!



Nige -

At the risk of overstating my limits, I think if you can do a sample calculation on paper, I can get it into the Excel template.

Absent other information about the photo, I think we can assume a standard height of the camera to be approximately 6 feet (or 2 meters). That will likely be a bit high, but probably within tolerances.

As for the angle of the camera vs. the subject, I think we would likely require at least two key known measurements.....for example the width of the tractor in the picture and the length of either the entire rig or at least the trailer. This would be different than the initial approach that would require only a single known measurement.

My brain hurts!!! I think I need to think on this one a while. Anyone else have this problem solved????

Semper Fi,
Dave
Whiskey6
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Posted: Thursday, March 27, 2008 - 10:23 AM UTC
Nige -

I think I see it now. The length of the image of the tractor in the photo represents the hypotenuse from the right front to the left rear of the tractor. With the actual measurements of length and width of the tractor, we can calulate the actual hypotenuse....which then becomes the "known" input for the scaling calculation. We then input the length of the image (right front to left rear) in the photo inito the existing template......bingo we have our scale conversion.

I think I can pull it off, although it likely won't be until this weekend. Here in the U.S. we are in the middle of "March Madness", the college basketball tournament. My favorite team (UNC) is currently doing well. I'm not likely to be worth too much until they either win it all or get eliminated.....but I'll try.

Semper Fi,
Dave
Whiskey6
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Posted: Friday, March 28, 2008 - 02:12 AM UTC

Quoted Text

I think I see it now. The length of the image of the tractor in the photo represents the hypotenuse from the right front to the left rear of the tractor. With the actual measurements of length and width of the tractor, we can calulate the actual hypotenuse....which then becomes the "known" input for the scaling calculation. We then input the length of the image (right front to left rear) in the photo inito the existing template......bingo we have our scale conversion.



Nige -

I rethought this solution last night and it is flawed. While a simple solution to the issue of linear scaling if the camera is at a 45 degreee angle, it breaks down as the angle moves away form 45 degrees. Additionally, it does nothing for the problems caused by "perspective." Back to the drawing board...literally. I need to do some research on the whole business of drawing 3D perspectives.

Are any of you engineers, architects or artists out there able to help out with the calculations/algorithms? We need algorithms that will allow us to dynamically calculate the size of distant objects in the pictures based upon the paralax(correct term?) introduced by the camera angle, when the camera angle and distance from the subject are not known.

Semper Fi,
Dave
djms_rr
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Posted: Thursday, April 24, 2008 - 06:34 AM UTC
Hi Dave

Could you send a copy to [email protected]
Would like to give it a try with respect to scratchbuilding diesel loco.

MK
Plasticat
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Posted: Thursday, April 24, 2008 - 09:01 AM UTC
Can you send a copy to me at
[email protected] ?

Thanks
Whiskey6
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Posted: Thursday, April 24, 2008 - 02:16 PM UTC
Copies are on the way...let me know if you have any problems with the template or if you have any ideas for enhancing it.

Semper Fi,
Dave