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Google Releases Key Part of Street View Pipeline

Soulskill posted about 2 years ago | from the now-you-can-map-your-pillow-fort dept.

Google 44

New submitter drom writes "Google released a key part of their Street View pipeline as open source on Tuesday: Ceres Solver. It's a large-scale nonlinear least squares minimizer. What does that mean? It's a way to fit a model (like expected position of a car) to data (like GPS positions or accelerometers). The library is completely general and works for many problems. It offers state of the art performance for bundle adjustment problems typical in 3D reconstruction, among others."

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44 comments

Problem is (-1, Offtopic)

brazils (2630323) | about 2 years ago | (#39866099)

Problem is that it's not that good technology from Google. Sure, it works for larger cities and streets, but they might be checked manually anyway. However, my city has tons of alleys, sideways and small roads. They aren't even straight streets, most curve and go pretty much randomly. Not that it's bad, it makes for a nice and warm feeling city (not so planned and modernized), but after Google street view cars visited here you can see the sheer amount of problems in their technology. For example, most of the street lines seem to go into walls and buildings instead of staying in the roads. The positions are tricky. If you want to click to side street, you will usually be clicking towards a buildings wall, which looks just stupid. Good effort I guess, but there is much better technology out there.

Mind telling us what are the "Better Technology" ? (5, Insightful)

Taco Cowboy (5327) | about 2 years ago | (#39866145)

Good effort I guess, but there is much better technology out there.

Mind telling us what are the "Better Technology" ?

Thank you !

Re:Mind telling us what are the "Better Technology (2)

S3D (745318) | about 2 years ago | (#39869087)

Well, I did some 3d reconstruction so I can answer that. The deficiency (not so important for most potential users) is that methods mostly 10-20 years old, no latest methods present. In robust estimators sections ("robust cost function) only "soft" L1 estimator present, no nonsmooth L1 estimators with solvers based on thresholds like Split Bregman and others. No constrained minimizers (solvers) which use Interior Point, Augmented Lagrangian etc. No dense and patch based reconstruction methods support. No global minimization methods(divide and conquer, convexification) I can continue here, but that's not a point. The point is that this package probably for industry users, not for researchers or people who want absolute cutting edge to squeeze maximum out of hardware or have difficult input images. That could be considered to be intentional, because more methods mean more choices, more approaches to test, more parameters to tune.

Re:Problem is (0)

Anonymous Coward | about 2 years ago | (#39866149)

Does this edge-case spotting count for a spotter's fee?

Poor effort, there's much better trolls out there (5, Interesting)

Anonymous Coward | about 2 years ago | (#39866151)

Your comment suggests you don't know what at minimizer is, and I think you just wanted to say "Google is bad" to the first story related to Google.

Which is a pity, but smarter trolls than you will have a go at them later.

If this is a constrained minimizer then Libre Office and Open Office will suddenly get a major improvement in their solver functionality for example, because at the heart of a solver is a decent non linear minimizer.

----
Fox News loves Bin Laden, hates President Obama for killing him.

Re:Poor effort, there's much better trolls out the (1)

Garble Snarky (715674) | about 2 years ago | (#39869961)

Where is there a solver in open office?

Re:Poor effort, there's much better trolls out the (0)

Anonymous Coward | about 2 years ago | (#39870927)

I also wanna know (can't check now), but there's probably some regression routines in spreadsheet thingie.

Extra features (4, Funny)

Canazza (1428553) | about 2 years ago | (#39866105)

Does it come with built-in Wi-Fi snooping?

Re:Extra features (-1, Offtopic)

Canazza (1428553) | about 2 years ago | (#39866759)

Flamebait? come on, that was a joke.

Re:Extra features (1, Troll)

mcgrew (92797) | about 2 years ago | (#39869163)

Fanboys get mod points sometimes. As do employees. Hell, I've been modded down for mentioning Sony's evils in a story about Sony.

Re:Extra features (0)

Anonymous Coward | about 2 years ago | (#39871395)

Nope. Just use Kismet. It's what they did.

Evil! (-1)

Anonymous Coward | about 2 years ago | (#39866115)

More unadulterated EVIL from Google! How dare they!

Google+ account? (-1, Troll)

mikhela (2630371) | about 2 years ago | (#39866189)

Why does it ask me to create Google+ account with my real name?

Re:Google+ account? (1)

Anonymous Coward | about 2 years ago | (#39866269)

I'd imagine it's probably because you're a troll.

Nonlinear least squares for dummies? (2)

bjourne (1034822) | about 2 years ago | (#39866271)

Can any math pro explain what practical uses solving nonlinear least squares equations have? The Wikipedia page is to high-brow for me. :)

Re:Nonlinear least squares for dummies? (-1, Troll)

dvh.tosomja (1235032) | about 2 years ago | (#39866313)

> Can any math pro explain what practical uses solving nonlinear least squares equations have?

For illiterates like you, there is video in the first link mentioned in the summary

Re:Nonlinear least squares for dummies? (1)

justdiver (2478536) | about 2 years ago | (#39866373)

How does failure to watch a video make someone illiterate? There's not even text in the video.

Re:Nonlinear least squares for dummies? (-1)

Anonymous Coward | about 2 years ago | (#39866381)

I'd explain it to you, but my only means of communication with you is the written word, and quite clearly you are illiterate.

Ignore dvh (5, Informative)

Anonymous Coward | about 2 years ago | (#39866409)

The video shows you how they use it, not what it is. Parent is just trolling.

Take a curve, represented by some function with parameters.
Take a set of data points.
Fit the curve to the data points by changing the parameters.
Minimizing the error distances between data points and curve so you get a best fit.

It's easy enough for lines and polynomials, but for more general functions it becomes a real pain. The maths is straightforward, but the implementation can make a huge difference. Google's library looks like a well implemented minimizer and it's been road tested too.

This is good.

Re:Ignore dvh (2, Interesting)

Anonymous Coward | about 2 years ago | (#39866535)

To be fair, he did ask for *practical uses*, not what it is mathematically. Practical uses include the examples given in the article. Another example from computer vision would be to find world positions of 2D image features based on a set of pictures from different positions.

Re:Ignore dvh (1)

Frans Faase (648933) | about 2 years ago | (#39866865)

Aside from the fact that it is a linear problem to solve (simple polynomial if you add lens correction), you also need a good feature extractor to create a 3D model from a set of 2D pictures. There are some excellent packages for doing 3D reconstruction, but they also come with a high price tag. There are some free implementations as well, but they are not very good.

Is seems to be an interesting solver, but you have to add a lot more for building an application for 3D reconstruction. I wonder if Google is going to release the software behind PhotoTour as well. And preferable for Windows.

Re:Ignore dvh (2)

qubezz (520511) | about 2 years ago | (#39870281)

To be fair, he did ask for practical uses...

Your "another example" is the example from the article...

I also have some authority in practical uses of technology (such as HTML 2.0-level markup), so I'll pipe up. For munitions guidance, this could be used to refine the inertial navigation position model for intercontinental delivery of ordinance by missile, maybe? When they outlaw nuclear missiles, only outla^h^h^h^h^h they will have nuclear missiles.

Re:Ignore dvh (-1)

Anonymous Coward | about 2 years ago | (#39868307)

"road tested." Your a bad person.

Re:Nonlinear least squares for dummies? (1)

mcgrew (92797) | about 2 years ago | (#39868863)

For illiterates like you

Don't you mean "innumerates?"

Re:Nonlinear least squares for dummies? (0)

gnapster (1401889) | about 2 years ago | (#39869661)

No, GP meant "illiterate", because GGP was unable to read and understand the Wikipedia page.

Re:Nonlinear least squares for dummies? (3, Funny)

Anonymous Coward | about 2 years ago | (#39866387)

Least squares is an optimization goal which minimizes a particular metric for a global deviation between an ideal and an achievable solution, that metric being the sum of the squares of individual deviations. A non-linear optimizer performs the optimization for a problem which is formulated in nonlinear equations (i.e. which is not described by a matrix).

Re:Nonlinear least squares for dummies? (1)

Hatta (162192) | about 2 years ago | (#39867009)

Can any math pro explain what practical uses solving nonlinear least squares equations have?

Mapping the expected position of a car to GPS data, for example.

Re:Nonlinear least squares for dummies? (0)

Anonymous Coward | about 2 years ago | (#39867903)

How does this relate to the Kalman filter, which is used for similar purposes?

Re:Nonlinear least squares for dummies? (2)

LeDopore (898286) | about 2 years ago | (#39871417)

Kalman filters assume a linear relationship between predictor and response, while nonlinear least squares allow there to be a parametric known nonlinear relationship.

Re:Nonlinear least squares for dummies? (3, Informative)

Ouilsen (1459391) | about 2 years ago | (#39867349)

Least squares is also often used in parameter fitting. Suppose you have a simulation with an somehow unknown parameter p. First you use a first guess as a value of p. That you run your simulation and get observed values y_obs.

Now you compare the computed values y_obs with the measured values y_mes using squares: cost = (y_obs - y_mes)^2.

By computing d p / d cost you may adapt p and redo the above steps till the squares are minimized... thus a least squares problem.

Re:Nonlinear least squares for dummies? (2)

BlackPignouf (1017012) | about 2 years ago | (#39867377)

Let's say you have a very weird car with 4 engines, 12 wheels turning in different directions, 8 steering wheels, 5 gearboxes and 20 buttons.
You have no idea what each control does : some appear not to have any influence, some need to be used together, some have delayed influence, some cancel each other...
You can probably forget to get a perfect understanding of the car, and will never find the perfect driving strategy.

You just need a driver assistance system that will minimise the time needed as well as the number of dents and bumps for a given travel.

Yeah... (5, Funny)

IamTheRealMike (537420) | about 2 years ago | (#39866531)

From the source code:

// The reason why the Triggs approximation becomes so poor is
// because the curvature correction that it applies to the gauss
// newton hessian goes from being a full rank correction to a rank
// deficient correction making the inversion of the Hessian fraught
// with all sorts of misery and suffering.

Yeah, that's pretty much how maths makes me feel as well ...

Re:Yeah... (0)

Anonymous Coward | about 2 years ago | (#39867081)

Now you know how mathematicians feel when computer scientists open their mouths full of acronyms ...

Re:Yeah... (0)

Anonymous Coward | about 2 years ago | (#39867099)

It's only scary if you don't know what those words mean. Don't be scared of maths! Hit Google and enjoy killing a few hours in a productive way! :)

Re:Yeah... (1)

rdnetto (955205) | about 2 years ago | (#39900397)

Wow, I actually understood some of that. And they said I'd never have a use for anything we learnt in linear algebra...

Usefulness of least squares (4, Insightful)

Anonymous Coward | about 2 years ago | (#39866679)

When you have several measured points, and you want to fit a function to them, least squares is how you measure how closely your function fits. This is useful anytime you want to infer a trend into the future (extrapolation) or infer what values come between the measured values (interpolation).

If you can speed up least-squares calculation, you can test your theories faster and possibly using less hardware - making that kind of statistical analysis more accessible.

In Google's case, they are using it to adjust their raw GPS data so that they can get a more accurate idea of where they are.

Slashdot (0)

Anonymous Coward | about 2 years ago | (#39868599)

Slashdot isn't stagnant because of the shit quality of the site and the Video section and new BIsexual section. It's because a story like this, is the root of what slashdot was. And it has 30 comments.

That's why this site has gone to shit.

Released: (2 minutes ago) (0)

Anonymous Coward | about 2 years ago | (#39869253)

Woa, very timely slashdot!

from file download:
Released: (2 minutes ago)
Uploaded: Today (2 minutes ago)

3D Reconstruction (2)

wasteoid (1897370) | about 2 years ago | (#39869263)

With this code, one could develop an application that can automatically render a 3D model from a series of images or a video. In other words, you could use a camera to "paint" a nearly photorealistic 3D model - no hours/days/weeks of Blender/CAD work to create a model, just scan with cheap camera. They state, "We have a working Android port but it's not ready yet." Envision an Android app that does this - scan your friends or nearby person into a 3D model - get complete geometry (height, calculated weight, other dimensions).
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