odir_image_crop.py

# Copyright 2019-2020 Jordi Corbilla. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
import cv2
import numpy as np
import logging
import os


class ImageCrop:
    def __init__(self, source_folder, destination_folder, file_name):
        self.logger = logging.getLogger('odir')
        self.source_folder = source_folder
        self.destination_folder = destination_folder
        self.file_name = file_name

    def remove_black_pixels(self):
        file = os.path.join(self.source_folder, self.file_name)
        image = cv2.imread(file)

        # Mask of coloured pixels.
        mask = image > 0

        # Coordinates of coloured pixels.
        coordinates = np.argwhere(mask)

        # Binding box of non-black pixels.
        x0, y0, s0 = coordinates.min(axis=0)
        x1, y1, s1 = coordinates.max(axis=0) + 1  # slices are exclusive at the top

        # Get the contents of the bounding box.
        cropped = image[x0:x1, y0:y1]
        # overwrite the same file
        file_cropped = os.path.join(self.destination_folder, self.file_name)
        cv2.imwrite(file_cropped, cropped)