在python中使用openCV和PIL通过填充、保存高度和宽度的分辨率以及固定分辨率来调整图像大小

2023-03-26 21:47| 来源: 网络整理| 查看: 265

今天我不得不写一个包含这些需求的模块。我想这将是很好的分享给其他正在研究类似问题的人，也作为将来自己的文档。

下面是一个process_image.py文件，代码如下：

import cv2 from PIL import Image import math # Set input image filename input_image = 'input_image.jpg' # Function to: Resize the input image to a square by padding the smaller dimension with a white background. def reformat_image_to_square_by_padding(image): """ Resize the input image to a square by padding the smaller dimension with a white background. :param image: str, path to the input image :return: Image, resized and padded image """ image = Image.open(image, 'r') width, height = image.size if width != height: bigside = max(width, height) background = Image.new('RGBA', (bigside, bigside), (255, 255, 255, 255)) offset = (int(round(((bigside - width) / 2), 0)), int(round(((bigside - height) / 2), 0))) background.paste(image, offset) new_image = background.convert('RGB') return new_image, width, height, new_image.size else: new_image = image.convert('RGB') return new_image, width, height, new_image.size # Function to: Resize the input image while preserving its aspect ratio. def reformat_image_preserve_aspect_ratio(image, width=None, height=None, inter=cv2.INTER_AREA): """ Resize the input image while preserving its aspect ratio. :param image: str, path to the input image :param width: int, desired width of the resized image (default: None) :param height: int, desired height of the resized image (default: None) :param inter: interpolation method used for resizing (default: cv2.INTER_AREA) :return: tuple, resized image and its dimensions """ # Read the image image = cv2.imread(image) # Get the original image dimensions (h, w) = image.shape[:2] if width is None and height is None: return image if width is None: r = height / float(h) dim = (int(math.ceil(w * r)), height) else: r = width / float(w) dim = (width, int(math.ceil(h * r))) # Resize the image new_image = cv2.resize(image, dim, interpolation=inter) # return new_image, w, h, r, dim return new_image, image, w, h, r, dim # Function to: Resize the input image to the desired dimensions without preserving its aspect ratio. def reformat_image_resolution(image, width=None, height=None): """ Resize the input image to the desired dimensions without preserving its aspect ratio. :param image: str, path to the input image :param width: int, desired width of the resized image :param height: int, desired height of the resized image :return: tuple, resized image and its dimensions """ image = cv2.imread(image) original_image = image.copy() original_height, original_width = image.shape[:2] # find the ratio of original:requested resolution # ACRONYM: ratio_width_O2R -> ratio of width Original to Requested requested_W, requested_H = width, height ratio_width_O2R = original_width / float(requested_W) ratio_height_O2R = original_height / float(requested_H) newW, newH = width, height rW = original_width / float(newW) rH = original_height / float(newH) new_image = cv2.resize(image, (requested_W, requested_H)) new_height, new_width = new_image.shape[:2] return new_image, original_image, original_width, original_height, ratio_width_O2R, ratio_height_O2R, new_width, new_height # Method 1: Resize to square by padding output_image, width, height, new_width_height = reformat_image_to_square_by_padding(input_image) output_image.save("output_image_padded_and_squared.jpg") # NOTE: saving method for this output image is different because it is PIL object. print("Resize to square by padding") print("original width, original height, new_width_height") print(width, height, new_width_height) print() # Method 2: Resize at desired resolution output_image, original_image, *dimensions = reformat_image_resolution(input_image, width=320, height=320) # print("original_height, original_width, rW, rH, new_height2, new_width2 \n", *dimensions) print("Resize at desired resolution") print("original_width, original_height, ratio_width_O2R, ratio_height_O2R, new_width, new_height \n", *dimensions) cv2.imwrite("output_image_resized_wxh_at_desired_resolution.jpg", output_image) print() # Method 3: Resize while preserving aspect ratio output_image, original_image, w, h, r, dim = reformat_image_preserve_aspect_ratio(input_image, height=500) print("Resize while preserving aspect ratio") print("original_width, original_height, ratio, (new_width, new_height) \n", w, h, r, dim) cv2.imwrite("output_image_resized_height_with_preserved_aspect_ratio.jpg", output_image) print()

输出：

$ python preprocess_image.py Resize to square by padding original width, original height, new_width_height 1280 720 (1280, 1280) Resize at desired resolution original_width, original_height, ratio_width_O2R, ratio_height_O2R, new_width, new_height 1280 720 4.0 2.25 320 320 Resize while preserving aspect ratio original_width, original_height, ratio, (new_width, new_height) 1280 720 0.6944444444444444 (889, 500)

输入图片：

输出镜像：

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