The COCO dataset: All you need to know

Intorduction

Ilyes Rezgui
4 min readFeb 18, 2024

The computer vision research community relies on standardized datasets to assess the efficacy of novel models and enhancements to existing ones. These datasets function as universally applicable benchmarks, facilitating comparisons across different models. This methodology enables the evaluation of the relative effectiveness of various models, shedding light on their comparative performance.

In this article, we explore the Common Objects in Context (COCO) dataset, a prominent illustration of a benchmarking dataset widely employed in the computer vision research community.

Source : COCO

Released by Microsoft in 2015, the MS COCO dataset is a comprehensive collection crafted for tasks such as object detection, image segmentation, and captioning. Esteemed across the fields of machine learning and computer vision, this dataset finds widespread adoption among experts undertaking diverse computer vision projects. In the realm of computer vision, a foundational goal is to comprehend visual scenes, encompassing activities such as identifying present objects, precisely locating them in 2D and 3D space, ascertaining object attributes, and elucidating relationships between objects. As a result, the MS COCO dataset stands as a valuable asset for training algorithms focused on object detection and classification.

Source: Paper

Use-case:

The COCO dataset stands out as a versatile resource catering to a range of computer vision tasks. Its frequent utilization extends to applications such as object detection, semantic segmentation, and keypoint detection. In the following section, we will delve into each of these problem types to foster a comprehensive understanding.

  • Object detection with COCO: Every object contained in the dataset comes with annotations comprising a bounding box and an associated class label.
  • Keypoint detection with COCO: In keypoint detection, human subjects undergo annotation with key points of significance, encompassing joints such as the elbow and knee. These key points play a crucial role in tracking specific movements, enabling tasks like distinguishing whether a person is standing or sitting down. The COCO dataset encompasses annotations for over 250,000 individuals, each annotated with their respective keypoints.
Source : COCO 2020 Keypoint Detection Task
  • Semantic Segmentation with COCO:Semantic segmentation entails the process of labeling object boundaries with masks and assigning class labels to objects. This methodology facilitates the accurate identification of the locations of various objects within a photo or video, providing a finer level of detail in the analysis of visual content.
Source : Semantics segmentation

Classes :

The COCO dataset encompasses a diverse set of 80 class labels, including:

‘person’, ‘bicycle’, ‘car’, ‘motorcycle’, ‘airplane’, ‘bus’, ‘train’, ‘truck’, ‘boat’, ‘traffic light’, ‘fire hydrant’, ‘stop sign’, ‘parking meter’, ‘bench’, ‘bird’, ‘cat’, ‘dog’, ‘horse’, ‘sheep’, ‘cow’, ‘elephant’, ‘bear’, ‘zebra’, ‘giraffe’, ‘backpack’, ‘umbrella’, ‘handbag’, ‘tie’, ‘suitcase’, ‘frisbee’, ‘skis’,’snowboard’, ‘sports ball’, ‘kite’, ‘baseball bat’, ‘baseball glove’, ‘skateboard’, ‘surfboard’, ‘tennis racket’, ‘bottle’, ‘wine glass’, ‘cup’, ‘fork’, ‘knife’, ‘spoon’, ‘bowl’, ‘banana’, ‘apple’, ‘sandwich’, ‘orange’, ‘broccoli’, ‘carrot’, ‘hot dog’, ‘pizza’, ‘donut’, ‘cake’, ‘chair’, ‘couch’, ‘potted plant’, ‘bed’, ‘dining table’, ‘toilet’, ‘tv’, ‘laptop’, ‘mouse’, ‘remote’, ‘keyboard’, ‘cell phone’, ‘microwave’, ‘oven’, ‘toaster’, ‘sink’, ‘refrigerator’, ‘book’, ‘clock’, ‘vase’, ‘scissors’, ‘teddy bear’, ‘hair dryer’, ‘toothbrush’.

Dataset Format:

A COCO dataset comprises five key sections, each providing essential information for the dataset:

Info: Offers general information about the dataset.

"info": {
"year": int,
"version": str,
"description": str,
"contributor": str,
"url": str,
"date_created": datetime
}

Licenses: Provides details about the licenses governing the images in the dataset.

"licenses": [
{
"id": int,
"name": str,
"url": str
}
]

Images: Contains a comprehensive list of all the images in the dataset.

"images": [
{
"id": int,
"width": int,
"height": int,
"file_name": str,
"license": int,
"flickr_url": str,
"coco_url": str,
"date_captured": datetime
}
]

Annotations: Encompasses a detailed list of annotations, including bounding boxes, for all images in the dataset.

"annotations": [
{
"id": int,
"image_id": int,
"category_id": int,
"segmentation": RLE or [polygon],
"area": float,
"bbox": [x, y, width, height],
"iscrowd": 0 or 1
}
]

Categories: Provides a comprehensive list of label categories used within the dataset.

"categories": [
{
"id": int,
"name": str,
"supercategory": str,
"isthing": int,
"color": list
}
]

Conclusion:

In summary, the COCO dataset is a prominent and extensively utilized benchmark within the field of computer vision. This dataset offers a diverse collection of images, meticulously annotated to support various tasks, including object detection, segmentation, and image captioning. Its comprehensive nature and wide adoption make it a valuable resource for advancing research and development in computer vision applications

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Ilyes Rezgui

I write about life and technologies || CS Research masters student || Ai research