compare_images#

compare_images(im1, im2, threshold=1, use_vtk=True)[source]#

Compare two different images of the same size.

Parameters

im1filename, numpy.ndarray, vtkRenderWindow, or vtkImageData: Render window, numpy array representing the output of a render window, or vtkImageData.
im2filename, numpy.ndarray, vtkRenderWindow, or vtkImageData: Render window, numpy array representing the output of a render window, or vtkImageData.
thresholdint, optional: Threshold tolerance for pixel differences. This should be greater than 0, otherwise it will always return an error, even on identical images.
use_vtkbool, optional: When disabled, computes the mean pixel error over the entire image using numpy. The difference between pixel is calculated for each RGB channel, summed, and then divided by the number of pixels. This is faster than using vtk.vtkImageDifference but potentially less accurate.

Returns

float: Total error between the images if using use_vtk=True, and the mean pixel error when use_vtk=False.

Examples

Compare two active plotters.

>>> import pyvista
>>> pl1 = pyvista.Plotter()
>>> _ = pl1.add_mesh(pyvista.Sphere(), smooth_shading=True)
>>> pl2 = pyvista.Plotter()
>>> _ = pl2.add_mesh(pyvista.Sphere(), smooth_shading=False)
>>> error = pyvista.compare_images(pl1, pl2)

Compare images from file.

>>> import pyvista
>>> img1 = pyvista.read('img1.png')  
>>> img2 = pyvista.read('img2.png')  
>>> pyvista.compare_images(img1, img2)  