# Append 2 volumes change in resolution?
**URL:** https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036
**Category:** Uncategorized
**Created:** [July 11, 2019, 5:59pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036 "2019-07-11T17:59:39Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@srbn.ghosh89](https://discourse.itk.org/u/srbn.ghosh89)
#### Post date: [July 11, 2019, 5:59pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036/1 "2019-07-11T17:59:39Z")
I am trying to Append 2 volumes. But thereafter I can see that the resolution has changed a lot. Why did this happen? These pictures are before and after.
 
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [July 11, 2019, 6:55pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036/2 "2019-07-11T18:55:40Z")
What code are you using to append them? It is hard to judge from screenshots what changed regarding resolution. The change in pixel intensities is obvious - is that what you are asking?
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### Author:  [@srbn.ghosh89](https://discourse.itk.org/u/srbn.ghosh89)
#### Post date: [July 11, 2019, 7:07pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036/3 "2019-07-11T19:07:13Z")
I need the pixel intensity same. I don’t want change in intensities. Is that any other way to do that?
#include “itkImageFileReader.h”
#include “itkImageFileWriter.h”
#include “itkTileImageFilter.h”
int main( int argc, char\* argv[] )
{
const char \* inputFileName1 = “input2.nii”;
const char \* inputFileName2 = “input1.nii”;
const char \* outputFileName = “output.nii”;
const unsigned int Dimension = 3;
typedef unsigned char PixelType;
typedef itk::Image\< PixelType, Dimension \>ImageType;
typedef itk::ImageFileReader\< ImageType \>ReaderType;
ReaderType::Pointer reader1 = ReaderType::New();
reader1-\>SetFileName( inputFileName1 );
typedef itk::ImageFileReader\< ImageType \>ReaderType;
ReaderType::Pointer reader2 = ReaderType::New();
reader2-\>SetFileName( inputFileName2 );
typedef itk::TileImageFilter\< ImageType, ImageType \>TileFilterType;
TileFilterType::Pointer tileFilter = TileFilterType::New();
tileFilter-\>SetInput( 0, reader1-\>GetOutput() );
tileFilter-\>SetInput( 1, reader2-\>GetOutput() );
TileFilterType::LayoutArrayType layout;
layout[0] = 1;
layout[1] = 1;
layout[2] = 2;
tileFilter-\>SetLayout( layout );
typedef itk::ImageFileWriter\< ImageType \>WriterType;
WriterType::Pointer writer = WriterType::New();
writer-\>SetFileName( outputFileName );
writer-\>SetInput( tileFilter-\>GetOutput() );
try
{
writer-\>Update();
}
catch( itk::ExceptionObject & error )
{
std::cerr \<\< "Error: " \<\< error \<\< std::endl;
return EXIT\_FAILURE;
}
return EXIT\_SUCCESS;
}
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [July 11, 2019, 7:12pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036/4 "2019-07-11T19:12:02Z")
> [@srbn.ghosh89](#):
>
> typedef unsigned char PixelType;
I think this is your problem. You must use the pixel type which is big enough for pixel intensities of both images. Try `short` or `unsigned short`.
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### Author:  [@srbn.ghosh89](https://discourse.itk.org/u/srbn.ghosh89)
#### Post date: [July 15, 2019, 8:02pm UTC](https://discourse.itk.org/t/append-2-volumes-change-in-resolution/2036/5 "2019-07-15T20:02:59Z")
Thank you.