Bug in AutoThresholder / Minimum algorithm?

Hi, I was looking into the AutoThresholder.Minimum method code, and I’ve noticed something that does not make sense, starting at the line 635:

double [] tHisto = iHisto;
while (!bimodalTest(iHisto) ) {
    //smooth with a 3 point running mean filter
    for (int i=1; i<255; i++)
        tHisto[i]= (iHisto[i-1] + iHisto[i] +iHisto[i+1])/3;
    tHisto[0] = (iHisto[0]+iHisto[1])/3; //0 outside
    tHisto[255] = (iHisto[254]+iHisto[255])/3; //0 outside
    iHisto = tHisto;

• First the line double [] tHisto = iHisto; is just a pointer affectation, not a copy. And then in the loop, we have the opposite iHisto = tHisto;. This pointer affectation followed by the opposite affectation does not have any sense.
• Second, a smoothing is performed into the while loop. But the result in put into tHisto (for example tHisto[i]= (iHisto[i-1] + iHisto[i] +iHisto[i+1])/3;), but we’ve seen before that double [] tHisto = iHisto;. So the result is in fact put directly into the original array. When doing a smoothing, the result has to be stored into a separated array.

I think that a bug and it comes from a misunderstanding of the MatLab code. I guess that MatLab duplicates the code when doing an affectation like in the first line.

Am I wrong?

[landinig]

@FiReTiTi I remember it now, @imagejan mentioned it recently: Open a pull request. https://help.github.com/articles/creating-a-pull-request/ Go to the Pull request tab and create a new one.

[imagejan]

All three code location have been fixed: ImageJ1: https://github.com/imagej/imagej1/commit/031cbd239c89d5acb9038db86f3d1953a9604048 Fiji: https://github.com/fiji/Auto_Threshold/pull/6 ImageJ-Ops: https://github.com/imagej/imagej-ops/pull/423

Closing this now.