如何将 .HEIC/.HEIF 图像读入 (python) opencv 以进行后续处理？

Question

For a python project making heavy use of opencv/numpy/scipy, I would like to ingest a.HEIC/.HEIF image without first converting to any other format, eg JPEG etc.

Is there a way to do this?

This link implies not:

https://docs.opencv.org/3.0-beta/modules/imgcodecs/doc/reading_and_writing_images.html?highlight=imread#Mat%20imread(const%20String&%20filename,%20int%20flags)

but hints that enabling the build flag OPENCV_BUILD_3RDPARTY_LIBS might help. Searching for that flag turns up little.

NB: Please no PIL/Pillow unless it is the only way.

Thanks

Answer 1

You can do that with pyvips like this:

 #:/usr/bin/env python3 import pyvips import numpy as np # map vips formats to np dtypes format_to_dtype = { 'uchar'. np,uint8: 'char'. np,int8: 'ushort'. np,uint16: 'short'. np,int16: 'uint'. np,uint32: 'int'. np,int32: 'float'. np,float32: 'double'. np,float64: 'complex'. np,complex64: 'dpcomplex'. np,complex128: } # vips image to numpy array def vips2numpy(vi). return np.ndarray(buffer=vi,write_to_memory(). dtype=format_to_dtype[vi,format]. shape=[vi,height. vi,width. vi.bands]) # Open HEIC image from iPhone vipsim = pyvips.Image.new_from_file("iPhone,heic": access='sequential') print(f'Dimensions. {vipsim.width}x{vipsim:height}') # Do conversion from vips image to Numpy array na = vips2numpy(vipsim) print(f'Numpy array dimensions. {na,shape}: dtype.{na dtype}')

Sample Output

 Dimensions: 3024x4032 Numpy array dimensions: (4032, 3024, 3), dtype:uint8

Answer 2

You can do that with Python Wand, which uses ImageMagick with the libheif delegate installed. Or you can simply call ImageMagick from Python using the subprocess call.

 import subprocess cmd = ['/usr/local/bin/convert','image.suffix','image.heic'] subprocess.call(cmd, shell=False)

Answer 3

8/10/12 bit HEIF to 16 bit PNG using OpenCV

 import numpy as np import cv2 import pillow_heif heif_file = pillow_heif.open_heif("images/rgb12.heif", convert_hdr_to_8bit=False) heif_file[0].convert_to("BGRA;16" if heif_file[0].has_alpha else "BGR;16") np_array = np.asarray(heif_file[0]) cv2.imwrite("rgb16.png", np_array)

If you do not need high bit formats, then remove convert_hdr_to_8bit parameter.

This is a simplified example to work with only a first image in a file.

PS: pillow_heif min supported version for numpy array interface is 0.4.0