Testing for Unimodal (Unimodality) or Bimodal (Bimodality) Distribution in MATLAB

Is there a way in MATLAB to check whether the histogram distribution is unimodal or bimodal?

EDIT

Do you think Hartigan's Dip Statistic would work? I tried passing an image to it, and get the value 0. What does that mean?

And, when passing an image, does it test the distribution of the histogram of the image on the gray levels?

Thanks.