MATLAB: How do you convert a 4D logical matrix to a 3D uint8 matrix

4d logicalimage

Hi, so I have a 4D logical matrix in form of x,y,3,8 representing an image, where the 3rd dimension is each layer and the 4 dimension is the 8 bits representing the colour channel value. I need to convert this into a 3D unit8 matrix, similar to what is produced when an image is imported.

Best Answer

With a Matlab version >= R2016b:

x = 100;
y = 200;
Img4D = (randi([0,1], x,y,3,8) == 1);
Img3D = uint8(sum(Img4D .* reshape(2.^(0:7), 1, 1, 1, 8), 4));

Multiplying the logical values with the powers of 2 and summing it up converts the bits to an uint8 value. Example:

sum([1, 0, 1, 0, 1, 1, 1, 0] .* [1, 2, 4, 8, 16, 32, 64, 128])
>> 117

Related Solutions

MATLAB: I need to plot 8 bit long 256 data in two dimension axis

y = mod(YourData, 16);
x = fix(YourData ./ 16);
scatter(x, y)

Notice I only did a 2D plot. You have not indicated what your Z value should be.

You have also not indicated what you want to have happen when multiple values map to the same (X,Y) coordinates, as must happen when you have more than 256 entries in your matrix.

MATLAB: I cant display the image

RGB images use 3 channels. You image has 8 channels. Therefor you have to consider how to reduce the channel size.

img = randi([0, intmax('uint16')], 832, 2016, 8, 'uint16');  % Test data
rgb = im2double(img(:, :, 1:3));  % For example
imshow(rgb)

Or perhaps:

img = double(img);
rgb = cat(3, sum(img(:, :, [1,2,3]), 3), ...
             sum(img(:, :, [4,5,6]), 3), ...
             sum(img(:, :, [7, 8]),  3));
rgb = rgb / max(rgb(:));

Best Answer

Related Solutions

MATLAB: I need to plot 8 bit long 256 data in two dimension axis

MATLAB: I cant display the image

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