Photogrammetry data

The subject of how to tell who owns a photo in a copyright dispute came up in Foresnics class the other night. We learned about metadata that's
behind the photograph. It's known as EXIF (EXchangeable Image Format). The example showed to us in class had the date, time, type of camera, f-stop, focal length, exposure time, flash (or not), among other data.
If your graphics program doesn't dig this stuff up you could probably find a program to dig it out of the photo if it's there (it isn't always; depend on the camera). From there it's simple trig to figure out dimensions.
I didn't about this. Maybe you guys did.
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behind the photograph. It's known as EXIF (EXchangeable Image Format).< Film or digital? I would guess digital however most pictures in the RR field that might spark controversy are probably film.
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Yep, JPG does have a freedataspace available for those that want to use it. the space is at the beginning of the file. Other imaging transport systems may or may not have such a space available. Converting a JPG to a BMP file will erase any of that info, for example.
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On Thu, 10 Aug 2006 04:53:40 GMT, Jay Cunnington

I once testified as an expert witness in a court case, where I used photogrammetry to determine the location of a marker (railroad tie, oddly enough) in a property line dispute. Knowing the field of view is helpful, but establishing the location of the camera, and the actual size of one object in the image is much more important. In the case of the photos I analysed, a 55 gal burn barrel that was in all the images established the relationships. Using the known diameter, and the focal length of the polaroid camera used to take the photos, I was able to verify camera positions.
A tip when photographing something you know you'll have to analyse later: keep a soccer ball in your car. When it comes time to take a photo, drop the soccer ball on the ground and step 10 paces back, or place the ball at a location near the object to be photographed and include it in a number of shots. A ball is a fixed diameter, no matter what angle you shoot it from, and no lawyer in his right mind will suggest that you had an odd-sized soccer ball. A dowel or stake that you have marked off foot marks, stuck vertically in the ground, is also helpful, but unless you keep it, the dimensions on it can be argued.
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snipped-for-privacy@electricrailroad.com wrote:

Except there ARE different size soccer balls... young kids use a ball that is significantly smaller that older kids, who use one smaller than "regulation" older kids/adults. So no, a soccer ball isn't that reliable a reference.
I have a yardstick I've used a marker on, to make a alternating black and "white" (natural wood) pattern. I put self-adhesive magnetic strip on the back so it will stick to steel. There's enough of the advertising left showing that it can be identified, if necessary, and if you can make out the smaller 1/2" divisions at the end of the stick, then you can read the large print of the advertising.
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snipped-for-privacy@electricrailroad.com wrote:

With chemical film, the simple way is to print the copies you are giving to the world slightly smaller than the original that you are keep the world from seeing. 1/4 inch around the outside of a pix with 'border stuff' won't have much effect on the picture as a whole, but what a difference in court when you bring in your original and show the judge exactly how the photo the other guy claims ownership fits in your original. Pretty much means that the other guy had to be at the same location at the same time taking a pix of the same thing at the same view angle with the same focal point and focal distance as you were. You were by yourself now wern't ya? Take this with a grain of salt as I expect that if you took a pix with a blue sky border your mileage may vary.
Flame on -> as I know that ya'll will have fun with that one!
todh
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I wasn't going at this for a "who owns it?" exercise so much as having the focal length, f-stop, distance to target, etc. for calculating unknown dimensions on something from trigonometry vs. size of the picture.
The other stuff is interesting, yes, but not what I intended in posting this.
ctclibby wrote:

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