CloudSEN12-high / README.md
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Improving Dataset Handling for Sentinel-1 and Sentinel-2 Images (#1)
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CloudSEN12 HIGH-QUALITY

A Benchmark Dataset for Cloud Semantic Understanding

CloudSEN12 Images

CloudSEN12 is a LARGE dataset (~1 TB) for cloud semantic understanding that consists of 49,400 image patches (IP) that are evenly spread throughout all continents except Antarctica. Each IP covers 5090 x 5090 meters and contains data from Sentinel-2 levels 1C and 2A, hand-crafted annotations of thick and thin clouds and cloud shadows, Sentinel-1 Synthetic Aperture Radar (SAR), digital elevation model, surface water occurrence, land cover classes, and cloud mask results from six cutting-edge cloud detection algorithms.

CloudSEN12 is designed to support both weakly and self-/semi-supervised learning strategies by including three distinct forms of hand-crafted labeling data: high-quality, scribble and no-annotation. For more details on how we created the dataset see our paper.

Ready to start using CloudSEN12?

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Paper - Scientific Data

Inference on a new S2 image

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CloudSEN12 in Google Earth Engine


General Description


File Name Scale Wavelength Description Datatype
L1C_ & L2A_ B1 0.0001 443.9nm (S2A) / 442.3nm (S2B) Aerosols. np.int16
B2 0.0001 496.6nm (S2A) / 492.1nm (S2B) Blue. np.int16
B3 0.0001 560nm (S2A) / 559nm (S2B) Green. np.int16
B4 0.0001 664.5nm (S2A) / 665nm (S2B) Red. np.int16
B5 0.0001 703.9nm (S2A) / 703.8nm (S2B) Red Edge 1. np.int16
B6 0.0001 740.2nm (S2A) / 739.1nm (S2B) Red Edge 2. np.int16
B7 0.0001 782.5nm (S2A) / 779.7nm (S2B) Red Edge 3. np.int16
B8 0.0001 835.1nm (S2A) / 833nm (S2B) NIR. np.int16
B8A 0.0001 864.8nm (S2A) / 864nm (S2B) Red Edge 4. np.int16
B9 0.0001 945nm (S2A) / 943.2nm (S2B) Water vapor. np.int16
B11 0.0001 1613.7nm (S2A) / 1610.4nm (S2B) SWIR 1. np.int16
B12 0.0001 2202.4nm (S2A) / 2185.7nm (S2B) SWIR 2. np.int16
L1C_ B10 0.0001 1373.5nm (S2A) / 1376.9nm (S2B) Cirrus. np.int16
L2A_ AOT 0.001 - Aerosol Optical Thickness. np.int16
WVP 0.001 - Water Vapor Pressure. np.int16
TCI_R 1 - True Color Image, Red. np.int16
TCI_G 1 - True Color Image, Green. np.int16
TCI_B 1 - True Color Image, Blue. np.int16
S1_ VV 1 5.405GHz Dual-band cross-polarization, vertical transmit/horizontal receive. np.float32
VH 1 5.405GHz Single co-polarization, vertical transmit/vertical receive. np.float32
angle 1 - Incidence angle generated by interpolating the ‘incidenceAngle’ property. np.float32
EXTRA_ CDI 0.0001 - Cloud Displacement Index. np.int16
Shwdirection 0.01 - Azimuth. Values range from 0°- 360°. np.int16
elevation 1 - Elevation in meters. Obtained from MERIT Hydro datasets. np.int16
ocurrence 1 - JRC Global Surface Water. The frequency with which water was present. np.int16
LC100 1 - Copernicus land cover product. CGLS-LC100 Collection 3. np.int16
LC10 1 - ESA WorldCover 10m v100 product. np.int16
LABEL_ fmask 1 - Fmask4.0 cloud masking. np.int16
QA60 1 - SEN2 Level-1C cloud mask. np.int8
s2cloudless 1 - sen2cloudless results. np.int8
sen2cor 1 - Scene Classification band. Obtained from SEN2 level 2A. np.int8
cd_fcnn_rgbi 1 - López-Puigdollers et al. results based on RGBI bands. np.int8
cd_fcnn_rgbi_swir 1 - López-Puigdollers et al. results based on RGBISWIR bands. np.int8
kappamask_L1C 1 - KappaMask results using SEN2 level L1C as input. np.int8
kappamask_L2A 1 - KappaMask results using SEN2 level L2A as input. np.int8
manual_hq 1 High-quality pixel-wise manual annotation. np.int8
manual_sc 1 Scribble manual annotation. np.int8

Label Description

CloudSEN12 KappaMask Sen2Cor Fmask s2cloudless CD-FCNN QA60
0 Clear 1 Clear 4 Vegetation 0 Clear land 0 Clear 0 Clear 0 Clear
2 Dark area pixels 1 Clear water
5 Bare Soils 3 Snow
6 Water
11 Snow
1 Thick cloud 4 Cloud 8 Cloud medium probability 4 Cloud 1 Cloud 1 Cloud 1024 Opaque cloud
9 Cloud high probability
2 Thin cloud 3 Semi-transparent cloud 10 Thin cirrus 2048 Cirrus cloud
3 Cloud shadow 2 Cloud shadow 3 Cloud shadows 2 Cloud shadow

Dataset information, working with np.memmap:

Sentinel-1 and Sentinel-2 collect images that span an area of 5090 x 5090 meters at 10 meters per pixel. This results in 509 x 509 pixel images, presenting a challenge.

Given each layer is a two-dimensional matrix, true image data is held from pixel (1,1) to (509,509)

The subsequent images have been padded with three pixels around the image to make the images 512 x 512, a size that most models accept.

To give a visual representation of where the padding has been added: x marks blank pixels stored as black (255)

xxxxxxxxxxxxxx
x			xx
x           xx
x           xx
x           xx
x           xx
xxxxxxxxxxxxxx
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The effects of the padding can be mitigated by adding a random crop within (1,1) to (509, 509) or completing a center crop to the desired size for network architecture.

The current split of image data is into three categories:

  • Training: 84.90 % of total
  • Validation: 5.35 % of total
  • Testing: 9.75 % of total

For the recomposition of the data to take random samples of all 10,000 available images, we can combine the np.memmap objects and take random selections at the beginning of each trial, selecting random samples of the 10,000 images based on the desired percentage of the total data available.

This approach ensures the mitigation of training bias based on the original selection of images for each category.


Example

train shape: (8490, 512, 512)
val shape: (535, 512, 512)
test shape: (975, 512, 512)

import numpy as np

# Read high-quality train
train_shape = (8490, 512, 512)
B4X = np.memmap('train/L1C_B04.dat', dtype='int16', mode='r', shape=train_shape)
y = np.memmap('train/manual_hq.dat', dtype='int8', mode='r', shape=train_shape)

# Read high-quality val
val_shape = (535, 512, 512)
B4X = np.memmap('val/L1C_B04.dat', dtype='int16', mode='r', shape=val_shape)
y = np.memmap('val/manual_hq.dat', dtype='int8', mode='r', shape=val_shape)


# Read high-quality test
test_shape = (975, 512, 512)
B4X = np.memmap('test/L1C_B04.dat', dtype='int16', mode='r', shape=test_shape)
y = np.memmap('test/manual_hq.dat', dtype='int8', mode='r', shape=test_shape)

This work has been partially supported by the Spanish Ministry of Science and Innovation project PID2019-109026RB-I00 (MINECO-ERDF) and the Austrian Space Applications Programme within the SemantiX project.