Measure Anything with a Camera and Software 208
Kevin C. Tofel writes "Using a simple concept, iPhotoMEASURE software can measure any objects you can take a picture of. Include a printout of a 7.5- or 15-inch square in the photo and the software can measure any distance or object in the pic to within 99.5% accuracy. Although geared towards contractors, there's any number of consumer usage scenarios as well. Enough to justify a $99 price tag? Jury's still out on that."
Unfortunately... (Score:5, Insightful)
There are already a number of laser rangefinders with compasses built-in that can do the same thing using simple trig.
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It might have to do something trickier. If you look at their example:
http://jkontherun.blogs.com/.shared/image.html?/ photos/uncategorized/iphotomeasure.jpg
They measure objects that are two distances from the camera. (The garage, and the windows on the house which are a few feet forward). Since they are closer, they would appear to the camera as slightly larger, making the software inaccurate. So, either the software doesn't work, or it does do some trickery.
I think that's the marketing dept. (Score:5, Insightful)
http://jkontherun.blogs.com/jkontherun/2007/02/ho
Looking at that photo, I'm not buying that it can measure all those distances from a single photo. I think there is some advertising hyperbole going on here. I get that you could measure all those distances and dimensions, using multiple photos -- one each of every flat surface, moving the target each time so it's the same distance from the camera as the surface being measured -- but I don't think it would work from a single photo.
The only way you could measure everything from a single photo like that, would be if the camera was stereoscopic, or had some other form of depth perception. Otherwise, as you noticed, there's no way for it to know that the window that's closer to the camera is not really bigger than the garage door that's further away.
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So the "hard" part in this software remains to automatically (hopefully it is automatic) find the DigiTarget and calculate a "more or less aff
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Yes - it must take foreshortening into account. Briefly what it does is calibrate the camera's parameters (field-of-view for one) from the reference DigiTarget image which has known dimensions, and generates a perspective transformation from that. This should be a simple exercise in computer vision. Notice how it only measures horizontal and vertical lengths. This is because these have particularly special invariance properties under a perspective transfor
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If you have a flat wall with that target on it you can correct for perspective on the bottom and top of that wall, but you can't figure out the dimensions of another wall that's closer or farther from the camera.
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For evaluating "Escort service" photos in preparation for that big night on the town, of course. *tee hee*
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You put the square on your street, then you take a picture when your ex is violating their restraining order.
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Married moms tell their husband to do the feat.
I can't believe I replied to this, or that this was moderated up. These marketing lists of people that might find a product useful are rarely surveyed, quantified, or measured, but rather just a product of a brainstorming session.
I guess this software won't make a great gift because the marketing people didn't tell me it would?!?!
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There is something known as 'depth from defocus [rma.ac.be]'. If you know the focal distance and depth of field, you can detect range by how out of focus things become. It sounds inaccurate, but some people report 1/200 [cmu.edu] accuracy. However, I gather
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I thought $99 was a little steep to start with, but after seeing your post and reading the website and determining you're right, you have to run up to the object, stick the label on, then run back to where you were to snap the picture. That makes the software darn near worthless, for $99 they could probably make an entire camera with built-in rangefinder to figure out distance fr
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For my PhD about 15 years ago (that long?!) I had a custom-built system to measure distances and dimensions (even speeds from one frame to the next) that employed the perspective differences between two cameras a set distance apart. Back in those days I had to develop each print separat
Good news (Score:3, Funny)
... for all of us guys. The subject of how to measure with a with a tape measure has long been a controversial one, and thus the size debate has been marred by a lack of common consensus. This gadget will settle things once and for all!
How to measure that square? (Score:2)
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Presumably you're a geek, and the summary indicates you can also use a 15" square.
CDs are known to be 5.25", so 3 of them span 15 3/4". Find your own clever approximation for 3/4" (probably just smaller than a quarter). I bet with 10 minutes, some string, and a pencil most people around here could give you a good approximation of a 15" square from that.
From there, some nice simple bisection of two angles to get you a 7.5"
OSS equivalent? (Score:2)
A more effective solution (Score:3, Insightful)
Just a thought.
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thats very cool, and I have just the image to try (Score:2, Funny)
Cost prohibitive?!? (Score:5, Insightful)
Honestly, I could see almost every contractor getting into this...
I think people need to realize that this will be it's major market as surveying costs run in the $20~30/hour range for a single trained surveyor... this is skilled work. If companies can instead send out untrained (or barely trained) individuals at $10-$15/hr with much less time spent in calculation and only a $100 sunk cost into the software there is no reason they wouldn't choose this method. Very good news for contractors, bad for surveyors.
The price is almost low enough for consumers with a need to calculate distances relatively regularly to purchase this software.
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I doubt it (Score:4, Insightful)
You'd have to stick known distance marks on everything in your picture.
Impossible (Score:2, Insightful)
This means two things, either you provide the software with more information or you need a calibration target for e
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However, nothing on the website indicates how many pictures you need to take for their software to work. I suspect it is not just as simple as taking one picture and being done with it. Digital photogrammetry generally takes a fair amount of post-processing.
tax on people who can't do math (Score:4, Informative)
But what really gets me is the claim in the advert, claims that hyperbolic if not outright lies. I can easily construct a photo in which a house appears to be the same dimensions of the squares. One more effective way to do what the software is proposing is to know the dimensions of a feature that is part of the object you wish to measure, and use similarity to approximate the dimensions of the smaller or larger object.
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What I was thinking of was the Physmo [sourceforge.net] project on sourceforge. It has some nice features, but the last version I used had more stability issues than tracker.
Both are in java.
I think many are missing the point (Score:2, Funny)
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Now, calculating how stretched the elastic is holding everything back is going to be much more difficult.
Can't work as advertised (Score:2)
By putting the reference printout in the image you can determine the distance and orientation of the reference, but how does that tell you about the distance to other points in the image?
It can only work for points in the same plane as the reference printout, such as the features on a flat wall.
It cannot tell you anything about the dimensions of a complex object like a car.
There are systems I've seen that can do similar jobs using video or multiple images to triangu
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http://www.visionbib.com/bibliography/motion-i789
$99 seems too cheap (Score:2)
It's not going to be useful to someone who needs precise measurements, like a contractor. Those people will use a measuring tape, which is more than 99.5% accurate when used properly.
But for estimators and appraisers this sounds like a killer app. Usually one would charge a lot more than $99 for such a niche application. Because of its niche status, there will not be as much competition f
Waste of money! (Score:5, Informative)
Re:Not nearly that simple. (Score:2)
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I would have to consider at least some parts of this story to be apocryphal -- there's a lot more factors involved in making a good knock-off of a musical instrument than building at an exactly 1:1 scale.
And honestly, if th
I did something similar once... (Score:3, Interesting)
I was taking a mechanical design class, and I wanted to know the coordinates of a bunch of screwholes in a mounting plate. I looked at it for a second, grinned, and darted to the nearest computer with a scanner -- as my teammates shook their heads (and micrometers) at me, saying "damnit, you're being impractical; it'll never work." (They thought I was too interested in theory and not enough in turning the cranks on lathes and mills; though we generally got along, we did have -- philosophical differences.) Scanning took a few seconds, after which I took a minute to note the pixel coordinates of the hole centers in a spreadsheet. Then I measured one edge of the part with the micrometer to get a pixel-to-inch scale, popped that number into the spreadsheet, and out came the x,y coordinates of all the holes in the part. When we CNCed the new plate with those hole locations, they all lined up with the part-to-be-mounted perfectly -- at which point they were pretty much forced to admit that maybe the kid knew what the hell he was doing!
I've thought since then that some software designed for the task (with edge-recognition algorithms, measurement features, etc) could turn consumer-grade scanners into decent reverse-engineering tools (for planar parts).
Some optics nitpicking. (Score:3, Insightful)
ARToolkit (Score:2, Interesting)
ARToolkit's been used by the University of South Australia to create ARQuake [unisa.edu.au] which is a lot of fun to use with the actual wearable computer
I'm not sure if they used ARToolkit or something more in-house to make Tinmith [tinmith.net],
Matrox Imaging has been doing this for years... (Score:2)
Matrox Imaging has been offering a software product known as the Matrox Imaging Library (MIL) [matrox.com] for years which provides standard measurement functions and now even a metrology module that measures arcs, tolerances and more.
Best of all, it supports Windows AND Linux!
Similar software for decoration purposes (Score:2, Interesting)
good idea, but no patent (Score:2)
Needs stereo (Score:3, Informative)
99.5% is also no good unless you don't really want to measure things accurately.
The example shown in the link shows a garage that is farther from you than the windows, and the windows are not directly in line of sight but actually off to the side a little.
I think it would really only be useful if you have a very high resolution digital camera and stand quite far from the building. But for closeup work you might as well have a ruler.
It would be useful for things you can't reach though, if you can get directly in line with it.
Needs stereo (Score:2)
99.5% is also no good unless you don't really want to measure things accurately.
The example shown in the link shows a garage that is farther from you than the windows, and the windows are not directly in line of sight but actually off to the side a little.
I think it would r
Re:Expensive (Score:4, Insightful)
No so expensive if you think about it in this way.
Re:Expensive (Score:5, Insightful)
Never under-price. (Score:5, Interesting)
It's definitely possible to under-price your product if you're not careful. Actually, having a $1299 version might even help drive sales of the $99 version, because people would perceive the $99 version as a sort of 'deal,' as in "hey, for $99 I'm getting 60% of the features of the $1300 version! That's great! I'll take three."
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Damn cheap in my book. (Score:5, Insightful)
$99 is nothing. If it can save material purchased for a big job it will most likely pay for itself instantly, not counting all the time saved photographing and measuring that is now with manual processing afterward.
Hourly contractors hate to save time! (Score:2)
If you bill by the hour, then this software will actually cause you to make a lot less money, because it saves you time, so you can't bill for as many hours!
-Don
Guess there's a lot of "trash." (Score:5, Insightful)
You do know that's impossible, right? I could use a laser interferometer, and determine the distance between two objects down to a fraction of a nanometer, and it would still not be "100% accurate."
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This could make something like this a thing of the past. If w
Re:Guess there's a lot of "trash." (Score:4, Insightful)
Really. So you understand the difference between an estimate and the craftsman doing the actual work then, right? The estimator's job is to be close enough that they come out just about right. Overages, OR underages, are bad. Yet, it's an _estimate_. This is a tool to get reasonable accuracy (so it's claimed) for doing estimates. No finish carpenter worth employing would use these measurements as a cutlist, that's not what it's for. This is so they can say "OK, homeowner, that's 527 square feet of siding, 240 feet of soffit and facia, 220 feet of gutter, and 12 square of shingles, so your cost estimate for materials is blah". Obviously nobody is going to go and cut the siding to 17' 4-11/16" based on something like this.
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My favourite quote from engineering school: "Measure with a micrometer, mark with chalk, cut with an axe"
And if you designed it (measured and calculated!) right from the start, it'll survive the tolerances inherent to both mass production and real-world usage. I love that saying, because I get so tired of dealing with people who come up with designs which are beautiful but impossible to actually build.
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Overages, OR underages, are bad. Yet, it's an _estimate_. This is a tool to get reasonable accuracy (so it's claimed) for doing estimates.
Heh... I'm sure the parent's estimates are acCtually about as good as his accuracy.
You just replied to a guy who probably thinks that screwing a new case fan into the existing holes constitutes building something. Or that assembling Ikea furniture makes him handy. To dismiss such a product, he's clearly never actually built anything, whether it be a renovated bathroo
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You just replied to a guy who probably thinks that screwing a new case fan into the existing holes constitutes building something. Or that assembling Ikea furniture makes him handy. To dismiss such a product, he's clearly never actually built anything, whether it be a renovated bathroom, a waterblock for a CPU cooler, or a stretched frame for his Jeep Cherokee Limousine.
Yup, I know folks like that. I work in IT, but, I built my house. Every board, every nail, foundation, footings, plumbing, electrical, the whole deal. Hired out the well, septic, excavation (didn't have a backhoe at the time), and concrete flatwork. Everything else, I've done, kitchen cabinets I made from lumber I milled from cherry trees I cut down. Took a long time. BUT, it has given me an immense respect for tradespeople and the sheer amount of effort involved in doing it, and then the huge incre
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Well, I suppose you could measure the house to 100% accuracy... but then you'd have the problem that it would be moving at a totally unknown speed in a totally unknown direction, and you'd never find it again.
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In the building of new homes, perhaps everything is standardized these days. In the existing stock of homes, no frickin' way. I can say that as the proud owner of a few custom-sized doors and storm doors, which unfortunately do not come cheap. One was about half an inch off a stock size, but of course that's not close enough.
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Anyone fool enough to shell out that much for this deserves everything they get.
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Perhaps those who would buy it aren't blessed with your amazing talents. You know -- the ability to write a program such as this in under four hours? That's what a low end contractor gets -- ~25 hr.
Academia's lack of real world experience shows again.
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I would be highly suspicious of code written to completion in four hours. Code must be planned, written, thoroughly tested, then released. Anyone who claims to be able to do that in four hours is lying.
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That would make you highly suspicious of Open Source... In Open Source, it's 'release early, release often', because the testing is done by your enthousiast users and yourself in parallel, and your users may actually turn out to be codevelopers to boot...
If you would have released it, then maybe somebody else would have maybe taken it and integrated it into the gimp or
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Four hours is not enough time to write anything of significance, and code *must* be tested, or the other people who take it to use have to do your testing and fixing for you before improving it and adding their own stuff.
Not all bugs can be found, but if you haven't even tested for basic errors then your code is awful, and unlikely to get used.
Releasing after a few days perhaps, or a w
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Four hours is not enough time to write anything of significance, and code *must* be tested, or the other people who take it to use have to do your testing and fixing for you before improving it and adding their own stuff."
That's just bullshit. In many cases it takes MUCH less than four hours to make good code that is ready for release to the 'Open Source community'. If you think you sho
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Perhaps you should go back to sleep.
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also of more general interest on how the price of items can be set is The Undercover Economist [tinyurl.com] (indirect link to Amazon), where he touches on the dotcom boom and microsoft's monopoly.
Re:Not practical. (Score:5, Informative)
No matter how many times you go out to a job site to measure and verify things, something always comes up that requires you to go back. For this reason, we take a lot of pictures in hopes that the camera will catch something we might not be looking for at the time.
I can't begin to count how many times I've counted bricks in those pictures to estimate distances. If I had software that could look at the image and provide measurements with 99.5% accuracy, that would be extremely useful. At $99 it would probably pay for itself after three or four uses just on time saved going back out to the site.
=Smidge=
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Autocad. and other CAD programs can. you open the photo as a background or item and then measure one known item. write down the numbers from that . now measure all that you are after (ASSUMING you have good lenses and are not using a fisheye or wide andlge lens that will screw it up.)
and a simple calculator can do the rest for you.
I can give you all the dimensions in the photo within 5 minutes doing that. accuracy at the edges drops fast because most contractors have crappy p
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=Smidge=
photogrammetry (Score:2, Informative)
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The problem there (Score:2)
So the way I see it, if you remembered to do that, then you pretty much remembered to measure it in the first place. If you didn't, well, you're going to go back anyway.
And if it shows up at the right angle in the picture of something else you did measure, then it doesn't do anything you couldn't h
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One use, tops (Score:2)
I got a Stanley FatMax laser distance meter last year - $99 shipped. I got it for an 8000SF church admin building I had to map. A helper and I did the whole thing - two levels and about 40-50 rooms total, including a labyrinthine lower level, in about 6.5 hours. I'd say it would have been a 2 day job with a tape measure. The best part is that once we got back, the building closed within an 1". Freaking amazing - I'd say we would have be
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From an industrial process plant designer's perspective, this technology ca
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It would also allow engineers to get rough measures of distances and allow inspectors
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Doesn't sound like it's too complicated. (Score:3, Interesting)
The hardest part is just picking out the target from the photo. In most interior scenes, the target they're using would probably work pretty well (it's a white square with heavy black edges) although it seems like there are some backgrounds where locating it might be a problem. But there are, if I'm not mistaken, some OSS efforts to do things like automatic facial recognition, and that's a much more complex pr
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To get distances away from the camera you need depth information. This requires either multiple pictures at different focal lengths from one spot, or else multiple pictures from separate spots.
If all you have to work with is a single standard image then it is possible to construct two entities with completely different dimensions that will look the same from the vantage point of the camera. (Look up "force
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