def extend_image(image):
IJ.run(image, "Select All", "")
IJ.run(image, "Copy", "")
width = image.getWidth()
height = int(image.getHeight() + extend)
image_new = IJ.createImage(imp.getTitle(), "32-bit black", width, height, 1)
image_new.setRoi(0, 0, image.getWidth(), image.getHeight())
IJ.run(image_new, "Paste", "")
IJ.run(image_new, "Enhance Contrast", "saturated=0.35")
IJ.run(image_new, "Select None", "")
cal = Calibration(image)
cal.pixelWidth = dispersion
cal.xOrigin = offset
image_new.setCalibration(cal)
return image_new
