how can i make a change in my image ?

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hamed
hamed on 1 Sep 2014
Commented: Image Analyst on 3 Sep 2014
hi guys . i have an image (257*161) .
im = f(x,y)
how can i change my image equation to im = f(x/8 , y/12 )
could you please help me ?
thanks
  3 Comments
Stephen23
Stephen23 on 1 Sep 2014
Edited: Stephen23 on 1 Sep 2014
I downloaded your file matlab.mat , and using the MATLAB function image it created a lovely figure showing some torso cross-section, like from a CT scan.
What is the problem with the image? What exactly do you mean by "image equation"? What is the function f ? What are the variables x and y ? How should the image be different?
Do you wish to scale, resize or skew the image?
hamed
hamed on 1 Sep 2014
Edited: hamed on 1 Sep 2014
Hi i want to do scale and translation normalization
i read in a site :
p(x/a+x1,y/a+x2) to p(x,y),where p(x,y) is original image, x1 and x2 are the centroid of p(x,y),x1=m10/m00,x2=m01/m00,a=sqrt(β/m00),β is a predetermined value. In fact, this is doing scale and translation normalization
i computed m= a+x1 and n=a+x2 . now how can i compute P(x/m , y/n)??

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Answers (1)

Image Analyst
Image Analyst on 1 Sep 2014
Do you possibly mean imresize()?
[rows, columns, numberOfColorChannels] = size(im);
% Get new x-width and y-height using formulas x/8 , y/12
% Remember, arrays are (rows, columns) = (y, x) NOT (x,y)!!!!!!!!!!
newRows = round(rows/12); % New y height
newColumns = round(columns / 8); % New x width
% Resize image
resizedImage = imresize(im, [newRows, newColumns]);
  5 Comments
hamed
hamed on 3 Sep 2014
Edited: hamed on 3 Sep 2014
thanks a lot for you answer and attention
i read some paper about Zernike moment and scale invariant problem. some of them solve it with this method :
image MUST first be normalized w.r.t. scale and translation
i.e. centroid of image is at image center, and image
has geometrical moment m00 = fixed number/scale
M00: sum of grey level (for greytone images)
or in another text i read
Moments η i j where i + j ≥ 2 can be constructed to be invariant to both translation and changes in scale by dividing the corresponding central moment by the properly scaled (00)th moment, using the following formula.
i want to write these equation in matlab and change my image scale with this equations but i don't know could you please help me ??
Image Analyst
Image Analyst on 3 Sep 2014
hamed, see my attached demo where I compute the first 4 image moments, mean, standard deviation, skewness, and kurtosis.

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