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location Munich, Germany
age 36
visits member for 2 years, 11 months
seen 32 mins ago

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


Dec
14
comment ReplaceImageValue and ReplacePixelValue extremely slow
If you just want to highlight pixels, you can use: HighlightImage[image, bin], which is very fast. In general, working with coordinates/indices seems to be much slower than using converting images to arrays with ImageData and using simple arithmetic.
Dec
8
awarded  Good Question
Dec
4
comment Mask outliers in an image
You wrote "I can do the outliner detection" but you didn't give any details: What's the result of your outlier detection? A list of coordinates? A binary image (or 2d array)? Component data from ComponentMeasurements? Also: working with lists of indices is often much slower than working with a 2d array containing 0's and 1's (because of vectorization).
Dec
2
awarded  Good Answer
Nov
18
comment What does it mean: “Assuming a matrix | Use a list of lists instead”?
In Mathematica, a matrix is just a list of lists, so don't worry. This just means that the suggestions bar offers suggestions for matrices. If you clicked on "list of lists", you'd see different suggestions.
Nov
13
comment More on performance of Sum[]
I would guess that the resolution of AbsoluteTiming is system dependent. For example, on my Win 7 PC, I never get a value between 0 and 0.0005, so that's probably the resolution of some clock that AbsoluteTiming uses. If you compare only timings large compared to the clock resolution (e.g. t > 0.01), the graphs do look very similar.
Nov
13
comment Finding a specific number of eigenvalues in Mathematica
If m is a square matrix, then Eigenvalues[m,n] gives the first n eigenvalues.
Nov
13
comment FindPeaks does not smooth noise on peak?
MaxDetect[data, 0.01] where 0.01 is a "noise threshold" is also worth a try - the resulting vector is 1 for (possibly extended) maxima, and 0 elsewhere.
Nov
6
comment Best fit equation from a scanned image
Related: mathematica.stackexchange.com/questions/3831/…
Nov
4
awarded  Good Question
Oct
29
comment Usage of @ symbol in Mathematica
Have you seen this? mathematica.stackexchange.com/questions/18393/…
Oct
25
comment how to speedup subpixel registration
The simplest way is to replace (# + {x, y}) & with TranslationTransform[{x, y}] - that makes it about 10x faster on my PC (I'm guessing ImageTransformation is optimized for TransformationFunctions). Replacing NMinimize with FindMinimum makes it 10x faster, again. You can probably make it faster if you carefully think about how ImageTransformation interpolates between pixels (there might even be a closed form solution?), but that's a lot more work for 0.2 seconds.
Oct
24
awarded  Enlightened
Oct
23
awarded  Nice Answer
Oct
23
answered Intersecting parabolas in an image
Oct
20
answered Nothing happens when I click the mouse clicked on my graphics
Oct
16
asked How does MapThread work with Associations
Oct
16
awarded  Good Question
Oct
11
answered Counting the number of instances where items at the same position in two matrices are equal?
Sep
29
comment Curve fit based on minimal data
According to the wikipedia link, the polar form is just $r=b+a\cos\theta$ - so maybe you could convert your points to polar coordinates and use Fit?