FAQ

Computer vision

Eight computer vision benchmarks and what each is actually for

COCO, ImageNet, Open Images, Pascal VOC, CelebA, LFW, ScanNet and NYU Depth V2 — the ones your tooling already assumes.

These eight are less a shortlist than the furniture of computer vision. Most tooling assumes at least one of them, and two of the formats have outlived the datasets that introduced them.

COCO JSON and VOC XML are now interchange formats in their own right. You will read and write them long after you stop training on the datasets.

The licensing is stricter than people assume: ImageNet is non-commercial research, CelebA and Pascal VOC are academic, and ScanNet's data needs a signed terms-of-use agreement (only its code is MIT). Even COCO is CC BY 4.0 for the annotations only; the images remain under their Flickr owners' terms.

The same object in three conventions. A corner/centre mix-up shifts a box by half its size, so a wrong conversion looks fine on small objects and is badly wrong on large ones.
DatasetModalitySizeLicenceBest for
COCOImage~330,000 imagesMixed — see belowDetection + segmentation
ImageNetImage1.28M imagesResearch onlyBackbone pre-training
Open ImagesImage9M+ imagesCC BY 4.0Scale detection
Pascal VOCImage20,000 imagesResearch onlyLegacy baseline
CelebAImage200,000+ face imagesResearch onlyFacial attributes
Labeled Faces in the WildImage13,000+ imagesNot statedVerification
ScanNet3D1,513 RGB-D scansGated accessIndoor 3D
NYU Depth V2Image1,449 imagesNot statedDepth estimation
Licences in this shortlist — computed from the 8 datasets below. Red marks licences that are unclear or restricted; amber marks non-commercial, share-alike or mixed terms.
A student bedroom photograph with coloured bounding boxes: one around the whole frame labelled Building, and others around a wall shelf, a television, two tables, two blue chairs, a bed and a bedside object, with a desk and chair also enclosed by a broader box labelled Furniture.
Open Images boxes on a CC BY 2.0 Flickr photograph. The labels come from a hierarchy, so a desk and its chair can sit inside a broader Furniture box and the whole frame is boxed as Building — a convention to resolve before mixing these annotations with COCO's flat class list. Image (cropped): openimages/dataset · CC BY 2.0 (image) and CC BY 4.0 (annotations) · from “The Open Images Dataset V4”, arXiv:1811.00982 · Photo: “STANZA STUDENTI.S.S. ANNUNZIATA” by ersupalermo, Flickr, CC BY 2.0, cropped
№ 01

COCO

ImageDetectionSegmentation
Size
~330,000 images
Licence
Annotations CC BY 4.0; images remain their Flickr owners' copyright under the Flickr Terms of Use

Around 330,000 images with JSON annotations covering detection, segmentation, keypoints and captions. The default benchmark for object detection, and the format most tooling expects — COCO JSON has become a lingua franca well beyond the dataset itself.

What to train on it

Object detection, instance segmentation and keypoints. If you report mAP, this is the dataset behind it.

Source: innovatiana.com/datasets

№ 02

ImageNet

ImageClassification
Size
1.28M train images · 1,000 classes
Licence
Non-commercial research

1,281,167 training images across 1,000 classes, with 50,000 validation and 100,000 test. Almost every vision backbone you will use was pre-trained here, which is why its class biases quietly propagate into models that never touch it directly.

What to train on it

Classification benchmarking and backbone pre-training. Non-commercial research use only.

Source: innovatiana.com/datasets

№ 03

Open Images

ImageDetection
Size
9M+ images
Licence
Annotations CC BY 4.0; images listed as CC BY 2.0 (Google does not verify each image)

Over nine million images with detailed CSV annotations spanning detection, segmentation and relationships. Larger and more permissively licensed than ImageNet, and the relationship annotations support tasks the others cannot.

What to train on it

Large-scale detection, and visual relationship prediction between objects.

Source: innovatiana.com/datasets

№ 04

Pascal VOC

ImageDetection
Size
~20,000 images · 20 classes
Licence
Academic research

Around 20,000 images with XML annotations across 20 object categories. Superseded by COCO in scale, but VOC XML remains a format you will meet constantly, and the smaller size makes it a fast iteration loop.

What to train on it

Quick detection experiments, and anything that has to read or write VOC XML.

Source: innovatiana.com/datasets

№ 05

CelebA

ImageAttributesFaces
Size
200,000+ face images
Licence
Academic · conditions apply

Over 200,000 celebrity face images with attribute annotations in TXT. Widely used for attribute prediction and as a generative benchmark — and widely criticised for demographic skew, which is worth measuring before you build on it.

What to train on it

Facial attribute prediction and face generation. Academic use under specific conditions.

Source: innovatiana.com/datasets

№ 06

Labeled Faces in the Wild

ImageVerificationFaces
Size
13,000+ images
Licence
No licence stated by UMass; this Kaggle copy is labelled LGPL-3.0

Over 13,000 JPEGs at 250×250, commonly resized to 62×47. The original face verification benchmark: given two photographs, same person or not. Small and long since saturated, but still the quickest sanity check for a verification pipeline.

What to train on it

Face verification baselines and pipeline smoke tests.

Source: innovatiana.com/datasets

№ 07

ScanNet

3DSegmentation3D
Size
1,513 RGB-D scans
Licence
ScanNet Terms of Use for the data (signed agreement, access on request); code under MIT

1,513 annotated RGB-D scans of indoor scenes, with 2D and 3D representations including voxels, meshes and depth maps. The multiple representations let you compare approaches on identical scenes. Note the licence split: the code is MIT, but the data is released under the ScanNet Terms of Use, which you must sign before downloading.

What to train on it

3D semantic segmentation, scene reconstruction and indoor robotics.

Source: innovatiana.com/datasets

№ 08

NYU Depth V2

ImageDepth3D
Size
1,449 annotated images · 407,024 raw frames
Licence
Not stated (citation requested)

1,449 densely annotated RGB-D images plus 407,024 raw frames. NYU states no licence and asks only for a citation; the Apache 2.0 tag comes from a Hugging Face Parquet copy that holds a FastDepth-preprocessed subset, not the full release. The reference dataset for monocular depth estimation: train on the raw frames, evaluate on the annotated subset.

What to train on it

Monocular depth estimation and indoor scene understanding.

Source: innovatiana.com/datasets

A heat map over image pixel positions, about 320 by 240, coloured from blue (near 0 mm) to yellow (2 mm or more): mostly blue and green in the centre with yellow speckles and patches increasing towards the edges and corners.
Per-pixel depth noise of a first-generation Kinect, the kind of sensor NYU Depth V2 was recorded with, capped at 2 mm for display (blue near 0 mm, yellow 2 mm or more). Noise is patchy across the frame, with a high-noise stripe down the middle and more noise towards the edges, and the same study measures it at several distances. The depth 'ground truth' a benchmark supplies carries that sensor's error. Image: Figure 5 of the article · CC BY 4.0 · from Tölgyessy et al. 2021, Sensors, “Evaluation of the Azure Kinect and Its Comparison to Kinect V1 and Kinect V2”, doi:10.3390/s21020413

How this list was put together

All eight are listed in Innovatiana's open-dataset catalogue; each entry links to the page carrying the full licence text and size string.

Image counts are quoted as published. Where train, validation and test splits are given separately, the table shows the training figure.

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