How to install openCv in Qt

Trav · wrote on 15 May 2016, 04:47

Hello,

I am looking for context in regards to getting openCv essentially in my application to work. I have managed to do what I would like to accomplish but am taking a learning curve and diving into Qt for lots of obvious reasons and at this point I just am learning and navigating so far what I have found though is to put (see below) into the .pro file but nothing is happening or suggesting when [example ] #include<opencv>

LIBS += -L/usr/local/lib
-lopencv_core /
-lopencv_imgproc /
-lopencv_features2d/
-lopencv_highgui

SGaist · wrote on 15 May 2016, 21:16

Hi,

You must use backslashes when doing multiline assignments like this one.

Trav · wrote on 15 May 2016, 22:14

Im using he backslashes just essentially replaced what I had above ****** LIBS += -L\usr\local\lib
-lopencv_core
-lopencv_imgproc
-lopencv_features2d
-lopencv_highgui

But still am having difficulties is there something I'm missing here? I am using Mac OSX... and have accomplished this is Xcode but just doesn't seem to be working is there anything else to configure etc?

SGaist · wrote on 16 May 2016, 20:23

I meant: use backslashes when marking a new line. For the paths themselves use forward slashes.

What error are you getting ?

Trav · wrote on 17 May 2016, 04:15

@Trav said:

LIBS += -L/usr/local/lib
-lopencv_core /
-lopencv_imgproc /
-lopencv_features2d/
-lopencv_highgui

2 days ago

sorry for the wait... all I'm getting is opencv.cpp not found... is there solid documentation somewhere on this subject? thank you

SGaist · wrote on 17 May 2016, 06:50

opencv.cpp not found ? Where's that file coming from ?

Not knowing what your current error relates to I can't give you any recommendation.

Trav · wrote on 17 May 2016, 23:09

The actual file itself 'openCV ' is located on my desktop... I made a file 'build' inside the folder and then 'lib' where all the files are located ; highgui etc. Is there a crucial step I missed here ? I mean I downloaded openCV installed Cmake by following a tutorial and installed this perfectly fine in Xcode.. But since moving to Qt I have not been able to get the same results.

Trav · wrote on 18 May 2016, 00:23

Could you please tell me in your case how would you do this if you were using Mac assuming we have Qt installed and openCV...

SGaist · wrote on 18 May 2016, 06:30

There are several possibilities.

You can use pkg-config or do it like you do currently and provide the INCLUDEPATH and LIBS with the adequate data.

Can you share your complete .pro file ? From the bits you've given, one time you have used the wrong line ending char and the other you are complete missing it.

Example:

LIBS += \
    -L/usr/local/lib \
    -lopencv_core \
    -lopencv_highgui

INCLUDEPATH += \
    /usr/local/include

You should also post the exact error you are having.

Trav · wrote on 19 May 2016, 04:47

Yes please see bottom for code. If it at all has changed I have been modifying it and tuning it according to different tutorials to see if it'll work etc. But essentially the end result is the same ERROR: opencv.h not found' when using ' #include <opencv.h> or something similar; highgui, core ...

#-------------------------------------------------

Project created by QtCreator 2016-05-15T23:16:25

#-------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = cam
TEMPLATE = app

// new
QT += core
QT -= gui

TARGET = RP_openCV_01
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp
mainwindow.cpp

LIBS += -L/opt/local/lib
-lopencv_highgui.3.1.0
-lopencv_core.3.1.0

INCLUDEPATH += /opt/local/include

HEADERS += mainwindow.h

FORMS += mainwindow.ui

Trav · wrote on 19 May 2016, 04:54

Only error is the error that is indicating the header files are not found " OPENCV.H not found!'

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = cam
TEMPLATE = app

// new
QT += core
QT -= gui

TARGET = RP_openCV_01
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp
mainwindow.cpp

LIBS += -L/opt/local/lib
-lopencv_highgui.3.1.0
-lopencv_core.3.1.0

INCLUDEPATH += /opt/local/include

HEADERS += mainwindow.h

FORMS += mainwindow.ui

SGaist · wrote on 19 May 2016, 21:26

Shouldn't it be #include <opencv2/opencv.hpp> ?

Trav · wrote on 20 May 2016, 02:17

Sorry, yes; I have used the #include <opencv2/opencv.hpp> and the error I stated above is still valid

SGaist · wrote on 20 May 2016, 06:55

Do you mean the opencv.h not found error ?

Trav · wrote on 21 May 2016, 21:57

Hey, thanks for your help I actually got it and have reproduced the desired outcome... essentially what happened because I am new to Qt & OpenCV etc. It seems I have placed the code before Sources' in the project.pro file which produced the errors... I did this before as well I don't quite understand why it decides to work now but did not before? but essentially I'm good :) thanks for support

SGaist · wrote on 21 May 2016, 22:20

Good !

In that case, please mark the thread as solved using the "Topic Tool" button so that other forum users may know a solution has been found :)