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""" |
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Functions for transforming and preprocessing images for training |
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""" |
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import numpy as np |
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import pandas as pd |
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import cv2 |
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from scipy.ndimage.interpolation import map_coordinates |
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def coordinates_remap(image, factor_alpha, factor_sigma): |
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"""Transforming image using remaping coordinates.""" |
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alpha = image.shape[1] * factor_alpha |
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sigma = image.shape[1] * factor_sigma |
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shape = image.shape |
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blur_size = int(4*sigma) | 1 |
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dx = alpha * cv2.GaussianBlur((np.random.rand(*shape) * 2 - 1), |
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ksize=(blur_size, blur_size), |
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sigmaX=sigma) |
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dy = alpha * cv2.GaussianBlur((np.random.rand(*shape) * 2 - 1), |
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ksize=(blur_size, blur_size), |
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sigmaX=sigma) |
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x, y = np.meshgrid(np.arange(shape[1]), np.arange(shape[0])) |
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indices = np.reshape(y+dy, (-1, 1)), np.reshape(x+dx, (-1, 1)) |
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return np.array(map_coordinates(image, indices, order=1, mode='constant').reshape(shape)) |
