How can I convert a XYZ format to an image format
显示 更早的评论
I have a text file with 3 columns; #ith pixel #jth pixel #Height of the (ith,jth) pixel in microns
(its basically a data for plotting the surface height from a camera)
How can I convert this to a gray scale image format so that I could use the Image Processing Toolbox?
Thanks, Shayan
采纳的回答
Walter Roberson
2011-7-11
If the spacing of the data is not completely regular, you could use griddata() or possibly interp2() to create a regular mesh grid.
If the spacing of the data is regular, then you can probably read the text file, extract the third column, and reshape() it (with possibly a transposition or two thrown in.)
[Edit: Moving part of answer from a comment to the answer - AU]
In the special case where your I and J are positive integers, you can use the following to build the matrix and fill any unused locations with the given FillValue:
FillValue = nan;
DataMatrix = accumarray(YourData(:,1:2),YourData(:,3),[],[],FillValue);
This will, though, construct the matrix indexed at 1 to max(I) and 1 to max(J); if your I and J span a subrange of that then it is more efficient to offset them when building the matrix. If your I or J can be non-positive then to use accumarray() you would have to offset them; e.g.,
Ioffset = min(YourData(:,1)) - 1;
Joffset = min(YourData(:,2)) - 1;
accumarray([YourData(:,1)-Ioffset, YourData(:,2)-Joffset], ...)
4 个评论
Shayan
2011-7-11
Walter Roberson
2011-7-12
In the special case where your I and J are positive integers, you can use the following to build the matrix and fill any unused locations with the given FillValue:
FillValue = nan;
DataMatrix = accumarray(YourData(:,1:2),YourData(:,3),[],[],FillValue);
This will, though, construct the matrix indexed at 1 to max(I) and 1 to max(J); if your I and J span a subrange of that then it is more efficient to offset them when building the matrix. If your I or J can be non-positive then to use accumarray() you would have to offset them; e.g.,
Ioffset = min(YourData(:,1)) - 1;
Joffset = min(YourData(:,2)) - 1;
accumarray([YourData(:,1)-Ioffset, YourData(:,2)-Joffset], ...)
Shayan
2011-7-13
Chad Greene
2016-4-26
更多回答（2 个）
Ashish Uthama
2011-7-12
0 个投票
What is the range and resolution of i's and j's? Can you scale these coordinates into integer values?
If you could scale them into a 1 to N and 1 to M range, you could create a matrix of NaN's/zeros/base height with size [N M] and then index into it with the i's and j's to populate the height values.
Pixel locations with no entry in your data file will remain at the initial value.
Shayan
2011-7-12
0 个投票
1 个评论
Ashish Uthama
2011-7-12
If you have all your pixels in the vector form, as Walter suggested, using reshape might do the trick.
Please consider accepting Walter's answer if it works for you and staring another question for the cross correlation question.
类别
在 帮助中心 和 File Exchange 中查找有关 Language Support 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
