DNG原始图片导入为16位深，但意外的plt.show（）结果 [英] DNG raw pictures imported as 16 bit deep but unexpected plt.show() result

问题描述

尝试使用 rawpy 在Python中处理原始DNG图片，结果很奇怪。

  import rawpy 
从matplotlib import pyplot导入imageio 
为plt 
 
 path ='/ home / stefan / aiJ / RAW.DNG'
 with rawpy.imread（path）as raw：
 rgb = raw.postprocess（）
 plt.imshow（rgb）
 plt.show（）
  

结果是一个带有8位值的rgb图像数组，而我的相机会产生14位原始图像。

可视化 rgb 数组得出预期结果：

从某些googleing中我了解到可以导入相同的文件，但输出为16位。

我在后处理函数中使用了以下参数：

  rgb = raw.postproc ess（output_bps = 16，demosaic_algorithm = None，output_color = rawpy.ColorSpace.Adobe）
  

现在 rgb 数组包含16位值，但可视化结果如下：

有人能告诉我如何获得类似于第一个结果但处理16位值的可视化？

最初我认为这与我的相机产生14位图像而不是16位的事实有关，但是将参数 output_bps 更改为14会导致更糟糕的可视化结果。

提前致谢！

根据要求，我会在这里添加PENTAX K的原始图片-5但它是18MB大，论坛有2MB的限制（可能是另一种传递文件的方式？）。

解决方因此，如果您有兴趣直观地检查16位图像中的读取结果，我建议您单独检查波段，

  plt.imshow（rgb [：，：0]）
  

等等带;或者将rgb转换为8位并显示，用

  rgb8 =（rgb / 256）.astype（'uint8' ）
 plt.imshow（rgb8）
  

Trying to process raw DNG pictures in Python with rawpy ends with strange results.

import rawpy
import imageio
from matplotlib import pyplot as plt

path = '/home/stefan/AIJ/RAW.DNG'
with rawpy.imread(path) as raw:
    rgb = raw.postprocess()
plt.imshow(rgb)
plt.show()

The result is an rgb picture array with 8-bit values while my camera generates 14 bit raw pictures.

Visualizing the rgb array gives an expected result:

From some googleing I understood that it is possible to import the same file but with an output in 16-bit.

I used the following parameters in the postprocess function:

rgb = raw.postprocess(output_bps=16,demosaic_algorithm=None,output_color = rawpy.ColorSpace.Adobe)

Now the rgb array contains 16 bit values but visualizing results in the following:

Could someone tell me how I could obtain a visualization similar to the first result but handling 16-bit values?

Initially I thought it was related to the fact that my camera is producing 14 bit images rather than 16 bit, but changing the parameter output_bps into 14 gives even worse visualization results.

Thanks in advance!

On request, I would add here the raw picture from a PENTAX K-5 but it is 18MB big and the forum has a limit of 2MB (may be another way to pass you the file?).

解决方案

I don't think the issue has to do with how you are reading the image, as imshow does not display 16-bit RGB images. So, if you are interested in visually checking the results of reading in the 16-bit image, I would suggest either inspecting bands individually, with

plt.imshow(rgb[:, :, 0])

and so on for each band; or converting the rgb to 8-bit and displaying that, with

rgb8 = (rgb / 256).astype('uint8')
plt.imshow(rgb8)

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