function r=pv(image,x,y,method)
[widht height]=size(image);
if 1>x|| x>width || 1>y || y>height
    if strcmp(method, 'nearest')%si if=0 =>faux
    %nearest
        r=image(round(x),round(y));
        mode='nearest'
    else
    %linear    
        xmin=fix(x);xmax=xmin+1;xecart=x-xmin;
        ymin=fix(y);ymax=ymin+1;yecart=y-ymin;
        mode='bilinear'
        %pour x=x'  y=y
        Y0val=image(ymin, xmin)+xecart*(image(ymin ,xmax)-image(ymin, xmin));
        Y1val=image(ymax, xmin)+xecart*(image(ymax ,xmax)-image(ymax, xmin));
        r=YOval+yecart*(Y1val-Y0val);
    end
else
    r=255;

end
r
end