Matlab - GUI fijar directorio entrada y de salida

a=uigetdir;

cd(a);

function varargout = Abrir_imagen_guardar_cvs(varargin)

gui_Singleton = 1;

gui_State = struct('gui_Name',       mfilename, ...

                   'gui_Singleton',  gui_Singleton, ...

                   'gui_OpeningFcn', @Abrir_imagen_guardar_cvs_OpeningFcn, ...

                   'gui_OutputFcn',  @Abrir_imagen_guardar_cvs_OutputFcn, ...

                   'gui_LayoutFcn',  [] , ...

                   'gui_Callback',   []);

if nargin && ischar(varargin{1})

    gui_State.gui_Callback = str2func(varargin{1});

end

if nargout

    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});

else

    gui_mainfcn(gui_State, varargin{:});

end

function Abrir_imagen_guardar_cvs_OpeningFcn(hObject, eventdata, handles, varargin)

handles.output = hObject;

guidata(hObject, handles);

function varargout = Abrir_imagen_guardar_cvs_OutputFcn(hObject, eventdata, handles)

varargout{1} = handles.output;

function pushbutton1_Callback(hObject, eventdata, handles)

[filename, pathname] =  uigetfile({'*.jpg';'*.bmp';},' Elegir Imagen');

 if isequal(filename,0)

   return;

else

    b=imread(fullfile(pathname, filename));

    axes(handles.axes1)

    imshow(b);

    h=mean(b);

    handles.h=h;

    guidata(hObject, handles);

 end

function pushbutton2_Callback(hObject, eventdata, handles)

h=handles.h;

[filename, pathname] =  uiputfile({'*.csv'},' Guardar data');

 if isequal(filename,0)

   return;

 else

    nombre=fullfile(pathname, filename);

    xlswrite(nombre,h);

 end