读取一个MSCOCO格式的json文件，统计数据集中的boundingbox尺寸分布，把height、width信息保存到两个list中去，然后绘制统计图，可视化尺寸分布。

        还可以自己加一些别的功能

import json
import matplotlib.pyplot as plt


def bbox_distribution(json_file, small_h, small_w):
    with open(json_file, 'r') as f:
        data = json.load(f)

    bbox_widths = []
    bbox_heights = []

    for annotation in data['annotations']:
        bbox = annotation['bbox']
        bbox_widths.append(bbox[2])
        bbox_heights.append(bbox[3])
        # 如果height或者width小于阈值，把annotation信息保存到一个txt文件
        if bbox[2] < small_w or bbox[3] < small_h:
            with open('small.txt', 'a') as f:
                f.write(str(annotation) + '\n')

    return bbox_widths, bbox_heights


def plot_distribution(widths, heights):
    plt.figure(figsize=(12, 6))

    plt.subplot(1, 2, 1)
    plt.hist(widths, bins=40, color='blue', edgecolor='black')
    plt.title('Distribution of BBox Widths')
    plt.xlabel('Width')
    plt.ylabel('Count')

    plt.subplot(1, 2, 2)
    plt.hist(heights, bins=40, color='blue', edgecolor='black')
    plt.title('Distribution of BBox Heights')
    plt.xlabel('Height')
    plt.ylabel('Count')

    plt.tight_layout()
    plt.show()


# 绘制长在0-100之间的bbox的分布
def plot_distribution_small(widths, heights):
    plt.figure(figsize=(12, 6))

    plt.subplot(1, 2, 1)
    plt.hist(widths, bins=20, color='blue', edgecolor='black', range=(0, 100))
    plt.title('Distribution of BBox Widths')
    plt.xlabel('Width')
    # x轴的刻度
    plt.xticks(range(0, 100, 5))
    plt.ylabel('Count')

    plt.subplot(1, 2, 2)
    plt.hist(heights, bins=20, color='blue', edgecolor='black', range=(0, 100))
    plt.title('Distribution of BBox Heights')
    plt.xlabel('Height')
    plt.xticks(range(0, 100, 5))
    plt.ylabel('Count')

    plt.tight_layout()
    plt.show()


def main():
    json_file = 'RSOD/train.json'
    small_h = 5
    small_w = 5
    bbox_widths, bbox_heights = bbox_distribution(json_file, small_h, small_w)
    plot_distribution(bbox_widths, bbox_heights)
    plot_distribution_small(bbox_widths, bbox_heights)


if __name__ == "__main__":
    main()