On Jun 6, 7:49 am, azrael <[EMAIL PROTECTED]> wrote: > the otsu filter is a filter that takes a image and from its histogram > calculates the values at which the image should be thresholded to > acomplish an optimal seperation of a foregtround and background > object.
So I learned from the PDF I linked you to. Take a good look at it. The equation is fairly simple to begin with, and the paper shows how to simplify the calculation quite a bit. Also, the Wikipedia article at http://en.wikipedia.org/wiki/Otsu's_method even gives a simple pseudo-code implementation. I've tried it myself in Python, and it seems give good results. > I didn't hear about, but I used it through the ImageJ tool. It gave me > optimal results. I'm working on a project for my clases, and the last > thing I need to accomplish my goal is this filter. Is there anyone who > implemented it. > > Thanks Hyuga > > On Jun 5, 6:02 pm, Hyuga <[EMAIL PROTECTED]> wrote: > > > On Jun 5, 10:19 am, azrael <[EMAIL PROTECTED]> wrote: > > > > Hy guys. > > > I'd like to ask you for a favour. > > > I tried several times to implement the otsu threshold filter in > > > python. but I failed every time. I found the soucre code i n Java from > > > the ImageJ project but I never worked in Java and there have been used > > > some built in Java functions which I don't know how they behave. I > > > also found the otsu threshold in the ia636 python module and would > > > like only this filter and don't want to import this library. > > > Is there anyone who wold like to help me. I need a function that takes > > > a list of 256 elements as an argument and returns the threshold values > > > for the threshold according to Otsu. > > > > In addvance, I don't expect someone to do my homework. I really tried > > > it, I have been googling and didn't find a standalone function. I > > > wasn't able write a standalone function because I don't understand the > > > Otsu method. I just know that it works well and that I need it. > > > > If there is no one that wants to help me with this problem, can > > > someone at least explain me in a detailed way how to implement it. > > > > Thanks > > > What is the whole assignment meant to accomplish? Is the assignment > > to implement the Otsu method? If so, you shouldn't be trying to find > > library functions. Or is it just something you need for some larger > > task? > > > I would ask exactly what problems you're running into, but: > > > > it, I have been googling and didn't find a standalone function. I > > > wasn't able write a standalone function because I don't understand the > > > Otsu method. I just know that it works well and that I need it. > > > How do you know you need it? Did you learn about this in class? And > > if so, are you expected to understand it? > > I've never even heard of it, but I googled it, and found the fourth > > hit pretty > > good:http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/MORSE/thresho... > > This gives a reasonable explanation. I couldn't tell you *exactly* > > why it works, but it's understandable enough from that that I can see > > that it should work, and to see how to implement it. > > > Not to mention that the above PDF basically *gives* you the > > implementation for free (just make sure not to miss the recurrence > > relations at the end of the section on the Otsu method, or else you'll > > be screwing yourself). > > > So give that a look and see if it helps. > > > Hyuga -- http://mail.python.org/mailman/listinfo/python-list
