I'm trying to make a discrete graph with time intervals. I need to do something like this or this
Does anyone know how to do this on chartjs?
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In chartjs (v3) I'm programmatically zooming and panning by setting the min and max values for a series.
This works great, except if the series has a logarithmic scale ... this method doesn't seem to work, and has some strange results.
Any ideas on how I can achieve programmatic panning and zoom with logarithmic scales? Simply adding/subtracting the min/max values doesn't work correctly
EDIT: I see that the zoom plugin API has a zoomScale() function, but setting the min and max has the same effect... should min and max be calculated differently for logarithmic scales?
EDIT2: I'm trying to call the pan() function, which accepts Scale[] as a parameter ... I'm strugging to work out how to pass one of my scales, any ideas?
For zooming and panning, I'm using Zoom plugin: https://github.com/chartjs/chartjs-plugin-zoom
You can also find a specific sample on log axis: https://www.chartjs.org/chartjs-plugin-zoom/latest/samples/wheel/log.html
For anyone with a similar problem, I've got it working ...
I simply need to call the pan function like this:
mychart.pan(10, [mychart.scales['yMyScale']], 'none');
The task is to extract stable background out of the video, the idea is to choose n random frames from the video and take median for each pixel. I was doing this task in python using numpy
medianFrame = np.median(frames, axis=0).astype(dtype=np.uint8)
But now i need to perform the same task in C++. I have tried the naive way of splitting channels and going through rows*cols number of pixels for n frames to calculate the median frame but its not efficient at all and takes way more time than what np.median was taking. I also try to use xtensor for performing the task but wasn`t able to worlk with it. Any suggestions or direction about how to approach this task would greatly help me, Thanks!
I have been working to find temporal displacement between audio signals using a spectrogram. I have a short array containing data of a sound wave (pulses at specific frequencies). Now I want to plot spectrogram from that array. I have followed this steps (Spectrogram C++ library):
It would be fairly easy to put together your own spectrogram. The steps are:
window function (fairly trivial, e.g. Hanning)
FFT (FFTW would be a good choice but if licensing is an issue then go for Kiss FFT or
similar)
calculate log magnitude of frequency domain components(trivial: log(sqrt(re * re + im * im))
Now after performing these 3 steps, I am stuck at how to plot the spectrogram from this available data? Being naive in this field, I need some clear steps ahead to plot the spectrogram.
I know that a simple spectrogram has Frequency at Y-Axis, time at X-axis and magnitude as the color intensity.
But how do I get these three things to plot the spectrogram? (I want to observe and analyze data behind spectral peaks(what's the value on Y-axis and X-axis), the main purpose of plotting spectrogram).
Regards,
Khubaib
I'm applying 3D graph cuts based on Yuri Boykov's implementation in C++, itk and boost for min cut/max flow. First I provide some foreground and background seeds. Then I create the graph and assign the weight to the edges using 3D neighborhood (boundary term):
weight=vcl_exp(-vcl_pow(pixelDifference,2)/(2.0*sigma*sigma)),
being sigma a noise function.
Then I assign the source/sink edges depending on the intensity probability histogram (regional term):
this->Graph->add_tweights(nodeIterator.Get(),
-this->Lambda*log(sinkHistogramValue),
-this->Lambda*log(sourceHistogramValue));
So the energy function is E= regional term+boundary term. Then, the cut is compute with Boycov's implementation, but I don't understand exactly how. Anyway, now I want to add a shape prior to the cut, but I have no clue on how to do it.
Do I have to change the weight of the edges?
Do I have to create another energy function? And if so, how?
How could I provide both functions to the mincut/max flow algorithm?
Hope my questions are easily understandable.
Thank you very much,
Karen
I'm trying to graph some data with RRDtool and I have problems with defining the exact graph command.
The kind of graph I want is something like this:
http://oss.oetiker.ch/rrdtool/gallery/gate.spamd.week.600.png - the blue graph.
I can not "cook up" the definition for creating a graph like the one which is light blue and is on the background. It's a something between a line and an area :) . Any ideas what can I try?
Thank you in advance!
I guess it is an area stacked on a transparent area or on a line ... in that way you can create a 'floating' area.