ImageJ API scripting in Jython - how to convert to and from ImgPlus and ImagePlus. http://javadoc.scijava.org

convert_ImagePlus_to_ImgPlus.py

"""Converting from ImagePlus to ImgPlus.
When an ImagePlus is made available by ImageJ 1.x, 
you can pass it to ImgLib2 as an Img via ImageJFunctions.wrap(imp)
http://javadoc.scijava.org/ImgLib2/net/imglib2/img/display/imagej/ImageJFunctions.html
"""
from ij import IJ
from net.imglib2.img import ImagePlusAdapter

image = IJ.openImage() # opens a file picker, or you can add the filename string as an argument.
output = ImagePlusAdapter.wrapImgPlus(image) #
output.show()

convert_Img_to_ImgPlus.py

"""Wrap any Img as an ImgPlus."""
from net.imagej import ImgPlus

imgplus = ImgPlus(img)

convert_ImgPlus_to_ImagePlus.py

# @Dataset img
"""Converting from ImagePlus to ImgPlus.
When an ImgLib2 RandomAccessibleInterval needs to be passed to ImageJ 1.x, it can be wrapped into an ImagePlus via ImageJFunctions.wrap(img, title).
"""
from net.imglib2.img.display.imagej import ImageJFunctions

output = ImageJFunctions.wrap(img, "title") # wraps the ImgPlus as an ImagePlus
output.show()