OpenCV - 读取 Python 中的 16 位 TIFF 图像（sentinel-1 数据）

Question

I'm trying to read a 16 bit TIFF image (26446 x 16688) in Python. Using OpenCV only reads a black image (all the intensities reads 0) by:

 self.img = cv2.imread(self.filename, cv2.IMREAD_UNCHANGED)

Can openCV handle 16 bit or large images (~840mb)? Any workaround?

EDIT: Also cv2.imshow("output", self.img[0:600]) displays a black image.

Answer 1

Use image libraries specific to raster data (in your case, sentinel-1). For example you can use rasterio for reading and displaying satellite images.

Example:

 import rasterio from rasterio.plot import show img = rasterio.open("image.tif") show(img)

Answer 2

As suggested by Andrew Paxson a different library can be used. There is a library dedicated exclusively for playing with tiff images.

Use the following code for the same. Make sure you have tif installed in your system.

 import tifffile as tiff import matplotlib.pyplot as plt filename = 'Image.tif' img = tiff.imread(filename) plt.imshow(img)

Answer 3

Yes, OpenCV can read uint16 perfectly fine:

 img_np = cv2.imread(path, cv2.IMREAD_ANYDEPTH | cv2.IMREAD_UNCHANGED)

Speaking of file size limitation, depends on number of pixels:

By default number of pixels must be less than 2^30. Limit can be set using system variable OPENCV_IO_MAX_IMAGE_PIXELS

https://docs.opencv.org/3.4/d4/da8/group__imgcodecs.html#ga288b8b3da0892bd651fce07b3bbd3a56