Basic Q- How can I stitch together multiple images and how do I append a variable to a string?

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Fri, 07/12/2013 - 02:12 pm

I am working with a 100 row X 100 column image that I would like to split into several smaller 10X10 segments. I've attached the code I have so far:

Function CreateSections()
    variable i=0
    variable j=10
    do
        duplicate/o/r=((j-10),j)(0,10) fly section_i
        newimage section_i
        AutoPositionWindow/E $WinName(0,1)
        j=j+10
        i=i+1
    while(i<=10)
End    


Ideally, completion of this program will yield 11 images named section_0, section_1, section_2, ..., and section_10. Instead, only one image called section_i is created. What is the appropriate syntax for appending a variable to a string? Also, what function could I use to stitch these images back together after the program runs to completion?

Thanks in advance,

-jry
First, your stitching question: I don't consider this to be real stitching because you have clear boundaries which makes this an easy case where you can use ImageTransform with the keyword insertImage. To do that you would first create a wave to accommodate the full final image and then loop over the images inserting them into the appropriate locations using the /INSX and /INSY flags. For example, if your full image wave is fullImageWave and you want to insert into it an image from imageWave starting from pixel (x1,y1) you would execute:
ImageTransform /INSI=imageWave/INSX=(x1)/INSY=(y1) InsertImage fullImageWave


Your code segment for creating the sub-images should be changed. If I understand correctly that you want 10x10 images out of 100x100 image you would want to use for row rr and column cc:
// generate distinct wave name:
String imageName="wave_"+num2str(rr)+"_"+num2str(cc)
Variable rs=rr*10
Variable cs=cc*10
// copy the data into a new wave:
Duplicate/O/R=[rs,rs+9][cc,cc+9] fullImageWave,$imageName


I hope this helps,

A.G.
WaveMetrics, Inc.

July 12, 2013 at 05:08 pm - Permalink

Quote:
What is the appropriate syntax for appending a variable to a string?


Use + to append strings. Use num2istr or num2str to convert a number to a string. You could also use sprintf.

Here is a solution for your task. I separated the step of creating the sub-images from the step of creating the plots. This splits the function into two clear parts which makes each of them easier to code, read and use.

Function/S GetSubImageName(baseName, startRow, startColumn)
    String baseName
    Variable startRow, startColumn
   
    String name = "SubImage_" + num2istr(startRow) + "_" + num2istr(startColumn)
    return name
End

Function CreateSubImages(wIn, baseName, startColumn, endColumn)
    Wave wIn                // Assumed to be a 100x100 matrix
    String baseName     // Base name for output waves - e.g., "SubImage"
    Variable startColumn, endColumn         // e.g., 0, 9 for the first 10 columns
   
    Variable startRow=0, endRow
    for(startRow=0; startRow<100; startRow+=10)
        endRow = startRow + 9
        String name = GetSubImageName(baseName, startRow, endRow)
        Duplicate /O /R=[startRow,endRow][startColumn,endColumn] wIn, $name
        Wave subImageWave = $name       // You would use this if you wanted to do something with the wave just created by Duplicate
    endfor 
End    

Function DisplaySubImages(baseName, startColumn, endColumn)
    String baseName
    Variable startColumn, endColumn             // e.g., 0, 9 for the first 10 columns
   
    Variable startRow=0, endRow
    for(startRow=0; startRow<100; startRow+=10)
        endRow = startRow + 9
        String name = GetSubImageName(baseName, startRow, endRow)
        Wave subImageWave = $name
        NewImage /K=1 subImageWave          // /K=1 means "kill with no dialog" if user closes graph window
        String graphName = WinName(0,1)
        AutoPositionWindow/E $graphName
    endfor 
End

Function Demo()
    Make/O/N=(100,100) mainImage = p + 10*q
    String baseName = "SubImage"
    Variable startColumn=0, endColumn=9         // First 10 columns - 0 through 9
    CreateSubImages(mainImage, baseName, startColumn, endColumn)
    DisplaySubImages(baseName, startColumn, endColumn)
End

July 12, 2013 at 05:24 pm - Permalink