9,970 reputation
22149
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location Munich, Germany
age 36
visits member for 2 years, 6 months
seen 1 hour ago

I work at a small mechanical engineering company, where I develop software and image processing algorithms for camera-based inspection machines.


Mar
28
answered Importation multiple dcm images
Mar
18
awarded  Notable Question
Mar
12
awarded  Good Question
Mar
7
awarded  Guru
Feb
26
comment Correctly set up FindMinimum
I can't try without a sample image, so this is just a guess: Did you try restricting the scfac parameter to ?NumericQ (see here: mathematica.stackexchange.com/questions/18393/…). Also, you should probably Round the size parameter to ImageResize
Feb
20
comment detecting the radius of an incomplete circle
@John: I think AreaRadiusCoverage (for each connected component) takes a disc centered at the centroid, with the same area as the component, and measures the overlap between that disc and the component. For a ring, where all pixels are far from the centroid, this should always be small. Other suitable measurements might be the ConvexCoverage, or maybe something like (MaxCentroidDistance-MinCentroidDistance)/MeanCentroidDistance
Feb
20
revised detecting the radius of an incomplete circle
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Feb
20
comment detecting the radius of an incomplete circle
@Murta: It's not a duplicate (I think): The answers in that question all use the center of mass of the marked pixels (the centroid). When the circle isn't closed or the "thickness" varies, the center of mass is not the center of the best-fit circle.
Feb
20
answered detecting the radius of an incomplete circle
Feb
4
comment Differentiating a Dot Product
You can even write D[xVec.pVec, {pVec}] to get the gradient wrt pVec, or D[xVec.pVec, {pVec, 2}] to get the Hessian. It took me a long time to figure that out...
Jan
26
awarded  Yearling
Jan
25
comment Labelling objects in a picture with numbers
@andy: I'm sorry, but no, I won't give you my email address. I'm not a private tutor. And if I were, I would tell you the same thing: get a good book, read the documentation. It'll be quicker, more fun and you'll learn more that way than by having someone doing your homework.
Jan
24
answered Labelling objects in a picture with numbers
Jan
7
comment Mathematica quine
I'm pretty sure #0 is cheating. It's like fopen("program.c", "r") in C.
Jan
2
comment Specific Mathematica algorithms, for example LU Decomposition
IIRC, on a x86 CPU, floating point numbers on the FPU stack are stored and processed in 80 bit long double format, even when the variable data type is 64 bit double. This can lead to the confusing effect that changing compiler options or reordering (independent) operations can change calculation results, depending on whether a value is moved to a 64-bit memory location or can stay in the stack for the whole calculation. On modern SSE-enabled CPUs, you also have separate commands that work on 64/32bit FP numbers directly. That might explain differences in the last few bits.
Dec
31
comment Why can Format be used on the left side?
I had trouble grasping "definitions" like these, too. Until I stopped thinking about them as "definitions" and started to see them as "replacement rules", i.e. telling the interpreter "if you see something that matches the pattern on the left, replace it with that stuff on the right side of the :=". Then it started making sense.
Dec
16
comment Find the best parallel lines to a given data set
@RahulNarain: Depends on the number of data points. If you have 10^6 or 10^7 points, really simple things might take some time ;-)
Dec
16
revised Find the best parallel lines to a given data set
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Dec
16
comment Find the best parallel lines to a given data set
That happens a lot. Just look up convex hull algorithms and implement one in the language of your choice. Don't try to hand in somebody else's implementation for your own. They'll know. Good luck in college!
Dec
16
comment Find the best parallel lines to a given data set
Do you realize that you posted your question on a Q&A site for the Mathematica programming environment?