IplImage <--> Mat conversion

[Mauro Nonnis]

I'm facing issues while converting IplImages to Mat. When I run the simple code below I get a fatal error runtime on the third instruction:

IplImage origImg = cvLoadImage(workingDir+filename, CV_LOAD_IMAGE_COLOR);

Mat imgMat = new Mat(origImg);
IplImage origImg2 = new IplImage(imgMat);

This is what I founded in console:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x000000011a2ad060, pid=2703, tid=4867
#
# JRE version: Java(TM) SE Runtime Environment (7.0_60-b19) (build 1.7.0_60-b19)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (24.60-b09 mixed mode bsd-amd64 compressed oops)
# Problematic frame:
# C  [libopencv_core.3.0.dylib+0x16e060]  _IplImage::_IplImage(cv::Mat const&)+0x80
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again


I'm pretty sure that origiImg is properly initialized (I used it for other stuff), and the result no change with other Mat initialization, like this:

CvMat cvMatImg = origiImg.asCvMat(); 
Mat imgMat = new Mat(cvMatImg);
IplImage origImg2 = new IplImage(imgMat);

In this case the error is the following:

OpenCV Error: Assertion failed (m.dims <= 2) in _IplImage, file .../javacpp-presets-master/opencv/cppbuild/macosx-x86_64/opencv-3.0.0/modules/core/src/matrix.cpp, line 5411
Exception in thread "main" java.lang.RuntimeException: .../javacpp-presets-master/opencv/cppbuild/macosx-x86_64/opencv-3.0.0/modules/core/src/matrix.cpp:5411: error: (-215) m.dims <= 2 in function _IplImage

	at org.bytedeco.javacpp.opencv_core$IplImage.allocate(Native Method)
	at org.bytedeco.javacpp.opencv_core$IplImage.<init>(opencv_core.java:3229)
	at org.bytedeco.javacv.OpenCVFaceRecognizer.detectFace(OpenCVFaceRecognizer.java:142)
	at org.bytedeco.javacv.OpenCVFaceRecognizer.main(OpenCVFaceRecognizer.java:171)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)

Thanks in advance for your help.

[Amrita]

Hi Mauro,

I tried recreating the error you got, but the code worked fine for me. Maybe someone else will pitch in later, but for now perhaps you can try this:

String filePath = workingDir.concat(filename);

System.out.println(filePath) ;//just to check

CvMat image = cvLoadImageM(filePath,CV_LOAD_IMAGE_COLOR);

Mat imgMat = new Mat(image);

IplImage origImg = imgMat.asIplImage();

Also, this is probably not the problem but have you checked that the path to your image file is correct using a print statement? For example, are you sure it includes a separator before filename? And does filename end with the proper extension?

[Samuel Audet]

On 08/06/2015 11:19 PM, Mauro Nonnis wrote:
> I'm facing issues while converting IplImages to Mat. When I run the simple
> code below I get a fatal error runtime on the third instruction:
>
> IplImage origImg = cvLoadImage(workingDir+filename, CV_LOAD_IMAGE_COLOR);
>
> Mat imgMat = new Mat(origImg);
> IplImage origImg2 = new IplImage(imgMat);

They changed the API for that starting with OpenCV 3.0. Try this:
Mat imgMat = cvarrToMat(origImg);

IplImage origImg2 = new IplImage(imgMat);

Samuel

[Mauro Nonnis]

Thanks, now seems to work.

I noticed that many API changes came up with OpenCV 3.0. Can you suggest me the best approach to find the new APIs when oldest are no more available?

Thanks.

[Samuel Audet]

On 08/11/2015 11:13 PM, Mauro Nonnis wrote:
> Thanks, now seems to work.
> I noticed that many API changes came up with OpenCV 3.0. Can you suggest
> me the best approach to find the new APIs when oldest are no more available?

There appears to be a transition guide here:
http://docs.opencv.org/master/db/dfa/tutorial_transition_guide.html
But it's not very extensive, so when it doubt ask questions I guess :)

Samuel