'**SUMMARY**
Create a new, empty OpenCV bitmap with the specified number of channels (default 3).
This method basically creates an empty copy of the image. This is handy for
interfacing with OpenCV functions directly.
**PARAMETERS**
* *channels* - The number of channels in the returned OpenCV image.
**RETURNS**
Returns an black OpenCV IplImage that matches the width, height, and color
depth of the source image.
**EXAMPLE**
>>> img = Image("lenna")
>>> rawImg  = img.getEmpty()
>>> cv.SomeOpenCVFunc(img.getBitmap(),rawImg)
**SEE ALSO**
:py:meth:`getBitmap`
:py:meth:`getFPMatrix`
:py:meth:`getPIL`
:py:meth:`getNumpy`
:py:meth:`getGrayNumpy`
:py:meth:`getGrayscaleMatrix`'

def getEmpty(self, channels=3):

    bitmap = cv.CreateImage(self.size(), cv.IPL_DEPTH_8U, channels)
    cv.SetZero(bitmap)
    return bitmap
