[Python][CV2]cv2.imwrite写jpg图像会引入噪声

cv2.imwrite写jpg图像会引入噪声，而写png图像就不会，差点被坑。猜测可能因为jpg是压缩格式？

P_mask_id_uint8 = 255 * np.uint8(P_mask[patch_id])
# plt.imshow(P_mask_id_uint8)
# plt.show()
# '_mask.jpg'  '_mask.png'
cv2.imwrite(path_mask + p_name + '_' + str(patch_id) + '_mask.png', P_mask_id_uint8)