在 Python 中使用 opencv 进行灰度缩放后颜色显示异常

Question

I am trying to use Opencv in python to process digital pathology images. I convert the csv image into array and I want to convert the image to gray scale, here is my code:

start = time.time()
slide = openslide.open_slide("/Users/mihaoyang/Desktop/Pathology_Images/348980_case2_CD4.svs")
level_count = slide.level_count
print('level_count = ', level_count)
[column, row] = slide.dimensions
print('dimensions = ', column, row)
[column0, row0] = slide.level_dimensions[0]
[column1, row1] = slide.level_dimensions[1]
[column2, row2] = slide.level_dimensions[2]
print('dimensions[0] = ', [column0, row0])
print('dimensions[1] = ', [column1, row1])
print('dimensions[2] = ', [column2, row2])

slide_level_downsamples = slide.level_downsamples[2]
print(slide_level_downsamples)


slide_downsamples = slide.get_best_level_for_downsample(20.0)
print(slide_downsamples)

slide_normal = numpy.array(slide.read_region((12000, 15500), 0, (500, 500)))
slide_gray = numpy.array(slide.read_region((12000, 15500), 0, (500, 500)).convert('L'))

After I run the code, the following image was obtained

Answer 1

Assuming you are using MatPlotLib to plot the image it looks like it is viridis colormap check them out here . If you want to change the colormap to gray scale pass gray into plt.imshow() .

ie

plt.figure()
plt.imshow(slide_gray, 'gray')
plt.show()

If you're not using matplotlib then that will still be your problem so check out the image plotting library documentation for changing colormaps.