Object reference not set to an instance of an object. using Emgu CV

Question

Please guys help me for resolving the issue in the following statement:

MCvAvgComp[][] Detector = IMAGEgray.DetectHaarCascade(face, 2.1, 10, 
 Emgu.CV.CvEnum.HAAR_DETECTION_TYPE.DO_CANNY_PRUNING, new Size(20, 20));"

After debugging the solution The compiler show me the following Error:

Object reference not set to an instance of an object.

Answer 1

Because you're dealing with Haar Cascade logic, IMAGEGray looks to be the gray scale image of type

Image<Gray, byte> IMAGEGray;

Ensure that it is correctly initialized OR converted rightly from a frame. Basically check that it is not null.

and in this line:

IMAGEgray.DetectHaarCascade(face, 2.1, 10, Emgu.CV.CvEnum.HAAR_DETECTION_TYPE.DO_CANNY_PRUNING, new Size(20, 20));

face is a variable initialized something like:

var face = new HaarCascade("haarcascade_some_tree.xml");

Ensure that face is not null.

If both the variables are not null, then the DetectHaarCascade method probably expects some fields in the face object to be non-null and it is finding null.

Ensure if the face object fields are non-null. (some key ones once the variable is initialized)

Answer 2

Is IMAGEgray a static class? If it isn't then it's probably a null field and the source of your issue.

Otherwise, it sounds like a bug in the method you're calling.

Answer 3

you need to add .xml file in your .../bin/Debug. Then type in your ProcesFrame Method: //haar is HaarCascade haar = new HaarCascade("haarcascade_frontalface_default.xml");