QFileDialog and OpenCV's imread()-Problem

[Pablo J. Rogina]

@Denni-0 said in QFileDialog and OpenCV's imread()-Problem:

I do not have a problem with the forward slashes in a Windows environment

From this Python examples page for cv2.imread(), it seems to be the case since the examples looks like Windows paths (D: drive) with forward slashes

img = cv2.imread('D:/image-1.png')

[SGaist]

I remember reading that recent versions of Windows (well the command line / power shell / maybe another one) improved the support for that. But the OP didn't say which one he is running.

[JonB]

@SGaist
Once the OP just puts in print(name) we won't have to guess any more....

[elias_hh]

@JonB If i do print(name) then i get the following path like: C:/Users/Image_name . I think the problem is "/". Windows or OpenCV cant handle path with "/". If i use the same code with my macbook, it works fine.

[JonB]

@elias_hh
If that's so, it looks like exactly what @SGaist suggested. If you are saying when you use a literal "C:\\Users\\Image_name" (i.e. value C:\Users\Image_name) it works but when you pass the result from QFileDialog.getOpenFileNames() which is C:/Users/Image_name it does not, then you have your difference/answer. cv2.imread(), does not appear to like forward slashes under Windows (forward slashes would be correctly native under Mac/Linux), though that seems to go against the example quoted by @Pablo-J-Rogina ....

In any case, try what @SGaist suggested:

nativeName = QDir.toNativeSeparators(name)
pic = cv2.imread(nativeName, cv2.IMREAD_ANYDEPTH)

Does that indeed now work?

In any case, I would always use https://doc.qt.io/qt-5/qdir.html#toNativeSeparators when passing any Qt-generated path to anything non-Qt, unless the external documentation states it expects paths to be in forward-slash format.

Under Windows each program can deal with paths with / vs \ differently. For example, the following two OS commands differ:

dir \w
dir /w

The first lists a file named w in the root directory on the current drive (i.e. \w). The second lists files in the current directory, using the /w listing option.

[elias_hh]

Hi, guys,

i apologize for the unnecessary confusion. the problem all along was not the back slash or the fordwar slash, but something completely different. I already mentioned that i get C:/Users/Image_name by using print(name). But apparently it has nothing to do with it. The bottom line is that the problem is the following:

(Pre-information: my code is in the folder "GUI" and in "GUI" is also the folder with the images named "pics")

when i select an image from this path C:/Users/Myname/Desktop/GUI/pics --> it doesn work, i become for pic = cv2.imread(name, cv2.IMREAD_ANYDEPTH) a print(pic) = none

And here comes the weird part:

when i select the same image from another path like: C:/Users/Myname/pics --> it works ! But i have realy no idea why.

[SGaist]

Any chances that your Windows is not in English ?

[elias_hh]

@SGaist i dont thing so

[JonB]

@elias_hh
Show the actual paths printed out via the print(name), copied & pasted to here not typed in, of what does work and what does not.

[elias_hh]

@JonB Ok. I show you the print(name). This is the path, which doesnt work:

C:/Users/hrezaie/Desktop/Hamid Rezaie/GUI/pics/mocim_FPLERW_3_3CM_10mm_MPW_6.0_für_Ex_Versuch1.bmp

So, and if i choose the same image but from another path, it works. see here:

C:/Users/hrezaie/Desktop/Hamid Rezaie/pics/mocim_FPLERW_3_3CM_10mm_MPW_6.0_für_Ex_Versuch1.bmp

Again, to repeat. My Python code is in "GUI".

[JonB]

@elias_hh
Then show me from a Command Prompt :

dir "C:\Users\hrezaie\Desktop\Hamid Rezaie\GUI\pics\mocim_FPLERW_3_3CM_10mm_MPW_6.0_für_Ex_Versuch1.bmp"

Please use copy & paste from what I have written. (In Command Prompt, right click should insert what you have copied to the clipboard, or click its menu in top-left-hand corner and Edit > Paste.)