Hints for Problem #3 - MRI of healthy human man

[MATLAB logo] Exploiting MATLAB's Data Structures

The function whos only directly displays the sizes of variables that are 2- or 3-D. To determine the size of a 4-D or larger array, use must use size.
A sequence of images in the Image Processing toolbox are stored in 4-D arrays where the first two dimensions are the number of pixels along the rows and columns, the 3rd dimension is the number of color components (1 for gray scale, 3 for RGB, etc), and the 4th dimension is the number of images. Hence a sequence of 27 gray scale images are stored in a m-by-n-by-1-by-27 array.
To display a gray scale image X use the commands image(X)
colormap(gray)
The image in mri.mat is stored as a uint8 array. This saves space in both the MAT-file and in the workspace since the image contains less than 256 gray levels. To do any computation on the image, it must be converted to double precision first, via the function double, since arithmetic operations are not available for uint8 arrays in MATLAB.
The function slice(X,col_slices,row_slices,z_slices)requires 3-D double precision input. Use reshape and double to convert the 4-D uint8 array into an equivalent 3-D double precision array.
The function Y = reshape(X,newsize) changes the size of the array without affecting its contents. prod(newsize) must be the same as prod(size(X)).