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- # Copyright 2021 Huawei Technologies Co., Ltd
- #
- # 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 numpy as np
-
- def convert_rgb_to_y(img):
- if isinstance(img, np.ndarray):
- return 16. + (64.738 * img[:, :, 0] + 129.057 * img[:, :, 1] + 25.064 * img[:, :, 2]) / 256.
- raise Exception('Unknown Type', type(img))
-
- def convert_rgb_to_ycbcr(img):
- if isinstance(img, np.ndarray):
- y = 16. + (64.738 * img[:, :, 0] + 129.057 * img[:, :, 1] + 25.064 * img[:, :, 2]) / 256.
- cb = 128. + (-37.945 * img[:, :, 0] - 74.494 * img[:, :, 1] + 112.439 * img[:, :, 2]) / 256.
- cr = 128. + (112.439 * img[:, :, 0] - 94.154 * img[:, :, 1] - 18.285 * img[:, :, 2]) / 256.
- return np.array([y, cb, cr]).transpose([1, 2, 0])
- raise Exception('Unknown Type', type(img))
-
- def convert_ycbcr_to_rgb(img):
- if isinstance(img, np.ndarray):
- r = 298.082 * img[:, :, 0] / 256. + 408.583 * img[:, :, 2] / 256. - 222.921
- g = 298.082 * img[:, :, 0] / 256. - 100.291 * img[:, :, 1] / 256. - 208.120 * img[:, :, 2] / 256. + 135.576
- b = 298.082 * img[:, :, 0] / 256. + 516.412 * img[:, :, 1] / 256. - 276.836
- return np.array([r, g, b]).transpose([1, 2, 0])
- raise Exception('Unknown Type', type(img))
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