Convert Grayscale image to XYZ file..

How i can convert a GrayScale image to XYZ file ?

Answer 1

[Image Analyst]

You have row, columns, and at every (row, column) (= (y, x)) location you have a gray level. What are you referring to as "Z"? What does your Z represent? Gray level? If so, then the image array is already what you want. Or were you looking to display the image with surf()?

[George]

thanks for your interest Image Analyst!! i have a grayscale image and i want to export a txt file with XYZ coordinates.. (X,Y)= pixels coordinates and Z= Gray level

[Sukuchha]

by any chance, do you have access to ArcGIs. If yes, then have a look at http://shreshai.blogspot.ch/2011/01/converting-raster-dataset-to-xyz-in.html

If not, you can still do it in MALTAB. Some f the function that will help is meshgrid, transpose. Try yourself first.

[George]

[height, width] = size(image);
[X, Y] = meshgrid(1:width, 1:height);
points = [X(:) Y(:) image(:)]
*i write this but i have a problem with photos larger than 255*255 pixels
because the values X,Y stop to 255*

[Image Analyst]

They should not. See my demo code below. I'd have to see it to believe it.

grayImage = imread('moon.tif');
[height, width] = size(grayImage)
[X, Y] = meshgrid(1:width, 1:height);
numberOfPixels = length(X(:))
points = [X(:) Y(:) grayImage(:)];
whos X  Y  points

height =
   537
width =
   358
numberOfPixels =
      192246
  Name             Size               Bytes  Class     Attributes

X              537x358            1537968  double              
Y              537x358            1537968  double              
points      192246x3               576738  uint8

By the way, don't use image as the name of a variable since it's already the name of a built-in function.

[George]

Look at variable editor-points 'X' it stop to 255 not at 358 and 'Y' it stop to 255 not at 537. That's my problem. Thanks

[HOSUNG LEE]

how can I get the Z coordinate form this code?

Answer 2

[Image Analyst]

See my attached code. It produces a CSV text file with x,y,gray level.