問題描述
我正在開發一個對象檢測模型來使用 YOLO 檢測船舶.我想使用 COCO 數據集.有沒有辦法只下載帶有注釋的圖像?
I am developing an object detection model to detect ships using YOLO. I want to use the COCO dataset. Is there a way to download only the images that have ships with the annotations?
推薦答案
要下載特定類別的圖片，可以使用 COCO API.這是一個 demo 筆記本，通過這個和其他用法.整體流程如下:
To download images from a specific category, you can use the COCO API. Here's a demo notebook going through this and other usages. The overall process is as follows:
- 安裝pycocotools
- 從 COCO 數據集 下載其中一個注釋 json
- Install pycocotools
- Download one of the annotations jsons from the COCO dataset
下面是一個示例，說明我們如何下載包含 person 的圖像子集并將其保存在本地文件中:
Now here's an example on how we could download a subset of the images containing a person and saving it in a local file:
from pycocotools.coco import COCO
import requests
# instantiate COCO specifying the annotations json path
coco = COCO('...path_to_annotations/instances_train2014.json')
# Specify a list of category names of interest
catIds = coco.getCatIds(catNms=['person'])
# Get the corresponding image ids and images using loadImgs
imgIds = coco.getImgIds(catIds=catIds)
images = coco.loadImgs(imgIds)
它返回一個字典列表，其中包含有關圖像及其 url 的基本信息.我們現在可以使用 requests 來 GET 圖像并將它們寫入本地文件夾:
Which returns a list of dictionaries with basic information on the images and its url. We can now use requests to GET the images and write them into a local folder:
# Save the images into a local folder
for im in images:
img_data = requests.get(im['coco_url']).content
with open('...path_saved_ims/coco_person/' + im['file_name'], 'wb') as handler:
handler.write(img_data)
請注意，這將保存指定類別中的所有張圖片.因此，您可能希望將 images 列表切片為第一個 n.
Note that this will save all images from the specified category. So you might want to slice the images list to the first n.
這篇關于如何下載 Coco Dataset 的特定部分?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！