# I can‘t open a bmp image using vtkbmpreader
**URL:** https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025
**Category:** Support
**Created:** [July 27, 2022, 3:57am UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025 "2022-07-27T03:57:37Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@BOB0Young](https://discourse.vtk.org/u/BOB0Young)
#### Post date: [July 27, 2022, 3:57am UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/1 "2022-07-27T03:57:37Z")
vtkSmartPointerReader = vtkSmartPointer::New();
//Reader-\>SetAllow8BitBMP(16);
Reader-\>SetDataScalarTypeToUnsignedChar();
Reader-\>SetFileDimensionality(3);
Reader-\>SetFilePrefix(“/home/yanghantao/Documents/ruxian/”);
//Reader-\>SetFileNameSliceSpacing(1);
Reader-\>SetFilePattern(“%s%03d\_R.bmp”);
Reader-\>SetDataExtent(0, 2047, 0, 2047, 1, 30);
Reader-\>SetDataSpacing(1, 1, 10);
Reader-\>Update();
ERROR: In /home/yanghantao/Documents/VTK-8.2.0/IO/Image/vtkImageReader2.cxx, line 595
vtkBMPReader (0xe0f1b0): Initialize: Could not open file /home/yanghantao/Documents/ruxian/000\_R.bmp
---
### Author:  [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [July 27, 2022, 3:16pm UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/2 "2022-07-27T15:16:56Z")
Hello,
An inaccessible file may be caused by a multitude of factors.
The usual checklist applies (assuming you are on some Unix-like system):
- Do an `ls /home/yanghantao/Documents/ruxian/000_R.bmp` to test whether it exists or is accessible if any of those directories was mounted from some network share.
- Do a `cat /home/yanghantao/Documents/ruxian/000_R.bmp` to test whether you have at least read access to it.
- Do an `ls` on each directory all the way down to the file to test whether you have the execution flag set properly on each of them.
- Open `/home/yanghantao/Documents/ruxian/000_R.bmp` in another program to rule out file corruption.
TIP: place your code between two ``` so it doesn’t get parsed by the markup parser.
regards,
Paulo
---
### Author:  [@BOB0Young](https://discourse.vtk.org/u/BOB0Young)
#### Post date: [July 28, 2022, 6:57am UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/3 "2022-07-28T06:57:37Z")
Thank you, I have solved my problem.
---
### Author:  [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [July 28, 2022, 1:04pm UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/4 "2022-07-28T13:04:09Z")
How did you solve it? Others may run into the same problem in the future.
---
### Author:  [@BOB0Young](https://discourse.vtk.org/u/BOB0Young)
#### Post date: [July 29, 2022, 3:04am UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/5 "2022-07-29T03:04:23Z")
> [@BOB0Young](#):
>
> Reader-\>SetAllow8BitBMP(16);
Actually，I don’t really know why. I use another way to reader my series of image. But it seems that `reader->SetAllow8BitBMP(16)` is necessarly.
```auto
vtkSmartPointer fileArray =
vtkSmartPointer< vtkStringArray >::New();
char fileName[128];
for(int i = 1; i < 31; i++)
{
sprintf(fileName,"/home/yanghantao/Documents/ruxian/%03d_R.bmp", i);
std::string fileStr(fileName);
fileArray->InsertNextValue(fileStr);
}
//read BMP
vtkSmartPointer reader = vtkSmartPointer::New();
reader->SetFileNames(fileArray);
reader->SetAllow8BitBMP(16);
```
Another quetion about the code `Reader->SetDataExtent(0, 2047, 0, 2047, 1, 30);` I have already I set the fifth and sixth parameters to be 1 and 30 respectively. Why my console show me ` Could not open file /home/yanghantao/Documents/ruxian/000_R.bmp`. Actually I didn’t let him to read the 000\_R.bmp
---
### Author:  [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)
#### Post date: [August 2, 2022, 1:42pm UTC](https://discourse.vtk.org/t/i-can-t-open-a-bmp-image-using-vtkbmpreader/9025/6 "2022-08-02T13:42:03Z")
Hello,
I suggest you to use a debugger to track down the source of that incorrect string. Your loop starts with 1. So why you’re getting an all-zero path you have to probe your code carefully. I’d certainly avoid those dreaded `char *`-based C functions like `printf` and the sort. They are common sources of hard-to-find bugs. Try using modern C++ replacements like:
```cpp
#include
#include
(...)
std::string filename;
(...)
std::stringstream ss;
ss << "/home/yanghantao/Documents/ruxian/" << std::setw(3) << std::setfill('0') << i << "_R.bmp";
filename = ss.str();
(...)
```
take care,
Paulo