Not able to recognize some images.

[Aozhi]

I have print some music scores using MuseScore. However, when I tested these images using moonlight, I got this kind of error message:

/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/numpy/core/fromnumeric.py:3373: RuntimeWarning: Mean of empty slice.
out=out, **kwargs)
/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/numpy/core/_methods.py:170: RuntimeWarning: invalid value encountered in double_scalars
ret = ret.dtype.type(ret / rcount)
Traceback (most recent call last):
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/omr.py", line 105, in
tf.app.run()
File "/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/tensorflow_core/python/platform/app.py", line 40, in run
_run(main=main, argv=argv, flags_parser=_parse_flags_tolerate_undef)
File "/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/absl/app.py", line 303, in run
_run_main(main, args)
File "/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/absl/app.py", line 251, in _run_main
sys.exit(main(argv))
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/omr.py", line 90, in main
output_notesequence=FLAGS.output_type == 'NoteSequence')
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/omr.py", line 67, in run
input_pngs, output_notesequence=output_notesequence)
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/engine.py", line 116, in run
self._get_page(feed_dict={self.png_path: png}) for png in input_pngs)
File "/home/benny/.cache/bazel/_bazel_benny/be8eb7a47da6580e14f40472dc81c452/execroot/main/bazel-out/k8-fastbuild/bin/moonlight/omr.runfiles/com_google_protobuf/python/google/protobuf/internal/containers.py", line 386, in extend
for message in elem_seq:
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/engine.py", line 116, in
self._get_page(feed_dict={self.png_path: png}) for png in input_pngs)
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/engine.py", line 177, in _get_page
self.glyph_classifier.staffline_extractor)
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/page_processors.py", line 64, in process
for processor in create_processors(structure, staffline_extractor):
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/page_processors.py", line 58, in create_processors
yield barlines.Barlines(structure)
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/structure/barlines.py", line 37, in init
staff_detector=structure.staff_detector))
File "/home/benny/Applications/moonlight/bazel-bin/moonlight/omr.runfiles/main/moonlight/structure/barlines.py", line 175, in assign_barlines_to_staves
barline_staff_start = np.argmin(barline_staff_start_distance, axis=0)
File "<array_function internals>", line 6, in argmin
File "/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/numpy/core/fromnumeric.py", line 1269, in argmin
return _wrapfunc(a, 'argmin', axis=axis, out=out)
File "/home/benny/anaconda2/envs/tf15/lib/python3.6/site-packages/numpy/core/fromnumeric.py", line 58, in _wrapfunc
return bound(*args, **kwds)
ValueError: attempt to get argmin of an empty sequence

The test images are shown below: