MATLAB code to python conversion

I have this piece of MATLAB code that I wanted to convert to Python. I used this online tool called OMPC to convert 90% of the code. There's this one block of code which I couldn't convert. Code:

function [fd, labels] = imFeretDiameter(img, varargin)
theta = 180;
if ~isempty(varargin)
    var1 = varargin{1};
    if isscalar(var1)
        theta = var1;
        varargin(1) = [];
    elseif ndims(var1) == 2 && sum(size(var1) ~= [1 2]) ~= 0
        theta = var1;
        varargin(1) = [];
    end
end
spacing = [1 1];
origin  = [1 1];
calib   = false;
if ~isempty(varargin) && sum(size(varargin{1}) == [1 2]) == 2
    spacing = varargin{1};
    varargin(1) = [];
    calib = true;
    origin = [0 0];
end
if ~isempty(varargin) && sum(size(varargin{1}) == [1 2]) == 2
    origin = varargin{1};
end
nTheta = length(theta);
labels = [];
if ~isempty(varargin) && size(varargin{1}, 2) == 1
    labels = varargin{1};
end
if isempty(labels)
    labels = imFindLabels(img);
end
nLabels = length(labels);
fd = zeros(nLabels, nTheta);

for i = 1:nLabels
    [y, x] = find(img==labels(i));
    if isempty(x)
        continue;
    end
    if calib
        x = (x-1) * spacing(1) + origin(1);
        y = (y-1) * spacing(2) + origin(2);
    end
    try 
        inds = convhull(x, y);
        x = x(inds);
        y = y(inds);
    catch ME
    end
    x = x - mean(x);
    y = y - mean(y);
    for t = 1:nTheta
        theta2 = -theta(t) * pi / 180;
        x2  = x * cos(theta2) - y * sin(theta2);
        xmin    = min(x2);
        xmax    = max(x2);
        dl = spacing(1) * abs(cos(theta2)) + spacing(2) * abs(sin(theta2));
        fd(i, t) = xmax - xmin + dl;
    end
end

The code is a function that I'm using. 'img' is a black and white image and varargin is an array

[0 90 180]

The part of code which I couldn't convert:

try 
        inds = convhull(x, y);
        x = x(inds);
        y = y(inds);
catch ME

Any help in converting this piece of code is appreciated. Thank you!

[Pratik Somaiya]

Since your Catch Me-end block contains nothing, you can use try & except for python conversion, scipy has convhull function you can give it a try!

Cheers!!

[Prb]

hI what was the equivalent function for zeros in python

Shifts = zeros(length(Filters)-1,1,'int16');

Answer 1

[Bo Li]

You may consider calling the MATLAB function directly from Python instead of converting it:

http://www.mathworks.com/help/matlab/matlab-engine-for-python.html

[Nikhil Hegde]

I'll be using the python code later on RPi. I'm new to RPi and Python so I'm not really sure if I can call matlab from RPi

Answer 2

[Luis]

You may also take a look to this more recent development: https://pypi.python.org/pypi/smop/0.26.2

Answer 3

[Walter Roberson]

http://scipy.github.io/devdocs/generated/scipy.spatial.ConvexHull.html

[Nikhil Hegde]

Thanks for replying. Like I said before I used this online tool called OMPC to convert my matlab code to python. I've no idea about python and I would be absolutely grateful if you could give me the python subsitute for that piece of code.

[Walter Roberson]

scipy is Python code.