Python convert .dcm to .png, images are too bright

Question

I have to convert some files which come by default as .dcm to .png, I've found some code samples to achieve that around here but the end results are too bright. Could anybody have a look at this, please?

 def convert_to_png(file):
    ds = pydicom.dcmread(file)

    shape = ds.pixel_array.shape

    # Convert to float to avoid overflow or underflow losses.
    image_2d = ds.pixel_array.astype(float)

    # Rescaling grey scale between 0-255
    image_2d_scaled = (np.maximum(image_2d,0) / image_2d.max()) * 255.0

    # Convert to uint
    image_2d_scaled = np.uint8(image_2d_scaled)

    # Write the PNG file
    with open(f'{file.strip(".dcm")}.png', 'wb') as png_file:
        w = png.Writer(shape[1], shape[0], greyscale=True)
        w.write(png_file, image_2d_scaled)

I've tweaked around the code but nothing seems to work.

This is how the actual thing looks like as dicom and on the right side is the result of running this code

Answer 1

一些 DICOM 数据集需要原始像素强度的窗口中心/宽度重新缩放（通过VOI LUT 模块中的 (0028,1050)窗口中心和 (0028,1051)窗口宽度元素），以重现它们被“查看”的方式.

pydicom有一个函数apply_voi_lut()来应用这个窗口：

from pydicom import dcmread
from pydicom.pixel_data_handlers.util import apply_voi_lut

ds = dcmread(file)
if 'WindowWidth' in ds:
    print('Dataset has windowing')

windowed = apply_voi_lut(ds.pixel_array, ds)

# Add code for rescaling to 8-bit...

根据数据集类型，您可能需要事先使用apply_modality_lut()。