问题
I am trying to use a dicom image and manipulate it using OpenCV in a Python environment. So far I have used the pydicom library to read the dicom(.dcm) image data and using the pixel array attribute to display the picture using OpenCV imshow method. But the output is just a blank window. Here is the snippet of code I am using at this moment.
import numpy as np
import cv2
import pydicom as dicom
ds=dicom.dcmread('sample.dcm')
cv2.imshow('sample image dicom',ds.pixel_array)
cv2.waitkey()
If i print out the array which is used here, the output is different from what i would get with a normal numpy array. I have tried using matplotlib imshow method as well and it was able to display the image with some colour distortions. Is there a way to convert the array into a legible format for OpenCV?
回答1:
I don't think that is a correct answer. It works for that particular image because most of your pixel values are in the lower range. Check this OpenCV: How to visualize a depth image. It is for c++ but easily adapted to Python.
回答2:
Faced a similar issue. Used exposure.equalize_adapthist() (source). The resulting image isn't a hundred percent to that you would see using a DICOM Viewer but it's the best I was able to get.
import numpy as np
import cv2
import pydicom as dicom
from skimage import exposure
ds=dicom.dcmread('sample.dcm')
dcm_sample=ds.pixel_array
dcm_sample=exposure.equalize_adapthist(dcm_sample)
cv2.imshow('sample image dicom',dcm_sample)
cv2.waitkey()
回答3:
I have figured out a way to get the image to show. As Dan mentioned in the comments, the value of the matrix was scaled down and due to the imshow function, the output was too dark for the human eye to differentiate. So, in the end the only thing i needed to do was multiply the entire mat data with 128. The image is showing perfectly now. multiplying the matrix by 255 over exposes the picture and causes certain features to blow. Here is the revised code.
import numpy as np
import cv2
import pydicom as dicom
ds=dicom.dcmread('sample.dcm')
dcm_sample=ds.pixel_array*128
cv2.imshow('sample image dicom',dcm_sample)
cv2.waitkey()
来源：https://stackoverflow.com/questions/53707851/using-dicom-images-with-opencv-in-python