Hi,
I want to make u clear what my problem is.Actually i was given
some matlab code.By using that matlab code i have to write a c
program which is similar to matlab code and scales an image and save
the image into another file..
Here i am giving the matlab code.If possible go through the code and
try to give me what went wrong in my code.i dont know any thing
about matlab that's why the problem arises i think can u solve me
the problem..
function [imout, phasex, phasey]=scaler(im, OutHeight, OutWidth)
%
% im : Input image
% OutHeight : Output image height
% OutWidth : Output image width
%
% Mohammad Usman.
% March 21, 2007.
%
f = [0.25 0.5 0.25];
ntapsx = length(f);
ntapsy = length(f);
InHeight = size(im, 1);
InWidth = size(im, 2);
kx = InWidth / OutWidth;
ky = InHeight / OutHeight;
% Resize the input image for edge pixels.
im = [zeros(InHeight, fix(ntapsx/2+0.5), 3) ...
im zeros(InHeight, fix(ntapsx/2+0.5), 3)];
% Horizontal filtering.
fprintf(1, 'Performing horizontal filtering ... \n');
for k = 1:3
for i = 1: InHeight
step = kx;
for j = 1: OutWidth
Ptr_in = j*kx;
% Interger and fractional part.
ptr = fix(Ptr_in);
ph = Ptr_in-ptr;
% Load the data.
if (ptr > 3) & (ptr < (InWidth-3))
x = double(im(i,ptr-1:ptr+2, k));
% Get the output sample.
imout(i, j, k) = (x(1)*(1-ph) + x(2)*ph)*f(1) ...
+ (x(2)*(1-ph) + x(3)*ph)*f(2) ...
+ (x(3)*(1-ph) + x(4)*ph)*f(3);
else
imout(i,j,k) = 0;
end
end
end
end
% Output image of this stage is input to the next one.
im = imout;
% Resize the output image size.
im = [zeros(fix(ntapsy/2+0.5), OutWidth, 3);
im;
zeros(fix(ntapsy/2+0.5), OutWidth, 3)];
% Vertical filtering.
fprintf(1, 'Performing vertical filtering ... \n');
for k = 1:3
% Go over the columns
for j = 1: OutWidth
step = ky;
for i = 1: OutHeight
Ptr_in = i*ky;
% Find interger and fractional part.
ptr = fix(Ptr_in);
ph = Ptr_in-ptr;
% Get the output sample.
if (ptr > 3) & (ptr < (InWidth-3))
% Load the data.
x = double(im(ptr-1:ptr+2, j, k));
imout(i, j, k) = (x(1)*(1-ph) + x(2)*ph)*f(1) ...
+ (x(2)*(1-ph) + x(3)*ph)*f(2) ...
+ (x(3)*(1-ph) + x(4)*ph)*f(3);
else
imout(i,j,k) = 0;
end
end
end
end
imout = imout(1:OutHeight, 1:OutWidth, :);
--- In [email protected], Thomas Hruska <[EMAIL PROTECTED]> wrote:
>
> rafiuddin syed wrote:
> > Hi,
> > Sorry to trouble you
> >
> > what does this mean..
> > 1. rolling your own library (instead of using a
> > third-party library)
> > 2.nearest neighbor scaling
>
> 1) "Rolling your own library" means you opted to write your own
code
> instead of using something someone else (or, in the case of
ImageMagick,
> many "someones") has written and debugged and generally worked out
most
> issues (e.g. performance). Most libraries also have built-in
scaling
> algorithms (that are also debugged). There are merits to rolling
your
> own library but you should have a good reason to do so before
doing such
> things. The BMP file format is a lot more complex than your code
> currently handles.
>
> 2) There are different scaling algorithms. Start Photoshop and
scale
> an image using "Nearest Neighbor". That's roughly the output
you'll get
> from your code and it looks ugly when scaling smaller and usually
pretty
> ugly when scaling larger on non-25% increments. It is easy to do
> nearest neighbor. For more complex algorithms, you should rely on
a
> third-party library.
>
> --
> Thomas Hruska
> CubicleSoft President
> Ph: 517-803-4197
>
> *NEW* VerifyMyPC 2.5
> Change tracking and management tool.
> Reduce tech. support times from 2 hours to 5 minutes.
>
> http://www.CubicleSoft.com/VerifyMyPC/
>
