Hello, I would say there are two differences between 'Saving the data' and 'Displaying the data'. An image is discretized to `uint8` or `uint16` prior to being saved as standard formates (`.png` or `.jpg`). You could do something like ``` import numpy as np from skimage import io, util A = np.random.rand(100,100) io.imsave('tmp.png', A) B = util.img_as_float(io.imread('tmp.png') assert np.allclose(A, B) # ERROR ``` But you will find some discretization errors, which makes `B != A`. Having said that, if you want to preserve the data in `B`, I think the best option is to export the data using another format, e.g. numpy arrays: ``` import numpy as np A = np.random.rand(100,100) np.save('tmp.npy', A) B = np.load('tmp.npy') assert np.allclose(A, B) # True ``` Or alternatively, if you really want to save the data in a visualizable format, exporting the image as `.tif` format, which preserves data information, should also work: ``` A = np.random.rand(100,100) io.imsave('tmp.tif', A) B = io.imread('tmp.tif') assert np.allclose(A, B) # True ``` However, I would personally store my data in non-visualizable formats such as `.npy, .h5` (the later if you work with tons of data) as they usually offer another advantages (e.g. Datasets in HDF5). Hope it helps, Imanol On 07/12/16 04:41, wine lover wrote:
Dear All,
In a program, I generate an numpy array, with shape (128,128), which is supposed to represent an image.
For instance, I havean array |temp_mask|, which is of type|float32 and shape (128,128)|, the maximum value is|1.0|and the minimum value is|0.0. |I saved it using|io.imsave(‘mask_image’,temp_mask)|However, after I re-opened this image using|img_mask = io.imread(‘mask_image’)|. The read image turns out to have type|unit16|, the max value becomes|6553|5 and the min value is|0| . It seems to me that io.imsave automatically transform the float32 array into an unit16 array.
Is it possible to save the image while keeping the original type? If not, what’s the correct way to save an image represented as an array, with type|float32|and the range of value |[0.0,1.0]|?
Thank you very much!
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