Not getting a full image from raw data

I am trying to make an Xray image using x, y, and z coordinates of raw data. Here is what I have:

data = readmatrix('Chest_XRay_Raw_Data.txt');
% Extract x, y, z coordinates and grayscale values
x = data(:,1);
y = data(:,2);
z = data(:,3); % If needed, otherwise ignore
grayscale = data(:,4);
%Find bounds
x_range = min(x):max(x);
y_range = min(y):max(y);
% Initialize the image matrix
image = zeros(length(y_range), length(x_range));
% Populate the image matrix with grayscale values
for i = 1:length(x)
    x_idx = find(x_range == x(i));
    y_idx = find(y_range == y(i));
    image(y_idx, x_idx) = grayscale(i);
end
%normalize image
image = mat2gray(image);
% Display the image
imshow(image);
title('Reconstructed Image from Raw Data');

Raw data example:

+4.23789300E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23619400E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23449400E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23279500E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23109600E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.22939700E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.22769700E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.22599800E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.22429900E+002, +0.00000000E+000, +0.00000000E+000, +420

An image window pops up with only one solid line with a little blank space in the middle. Any suggestions to fix this?

[Voss]

Please upload the .txt file using the paperclip button.

[Voss]

How about if you compress it to a zip archive, or copy and paste the first ten thousand or so lines of text into a new text file and upload that?

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[Walter Roberson]

x_range = min(x):max(x);
y_range = min(y):max(y);

That code assumes that most of the x and y are integers (or at least integers plus a constant offset).

+4.23789300E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23619400E+002, +0.00000000E+000, +0.00000000E+000, +420

+4.23789300E+002 is not an integer. +4.23619400E+002 is not an integer either -- and it is not the same constant offset relative to the other non-integer.

[Walter Roberson]

is there a command o fix this?

Not without a lot of assumptions.

You would need to find the common divisor between the differences in values, and scale everything by that common divisor.

format long g
A = [+4.23789300E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.23619400E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.23449400E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.23279500E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.23109600E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.22939700E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.22769700E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.22599800E+002, +0.00000000E+000, +0.00000000E+000,    +420
+4.22429900E+002, +0.00000000E+000, +0.00000000E+000,    +420];
udA = unique(diff(sort(A(:,1))))

udA = 4x1

0.169899999999984 0.169900000000041 0.169999999999959 0.170000000000016

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you would have to scale by something that divides each of those.

Unless you are willing to round to the nearest 0.17...

RA = round(A(:,1)/0.17)

RA = 9x1

2493 2492 2491 2490 2489 2488 2487 2486 2485

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take the max() and min() of urA as the range of values,

[minRA, maxRA] = bounds(RA);
sRA = RA - minRA + 1

sRA = 9x1

9 8 7 6 5 4 3 2 1

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