Improving Dataset Handling for Sentinel-1 and Sentinel-2 Images
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by
rwilliams
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README.md
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@@ -97,22 +97,53 @@ Ready to start using **[CloudSEN12](https://cloudsen12.github.io/)**?
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<br>
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**train shape: (8490, 512, 512)**
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**val shape: (535, 512, 512)**
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**test shape: (975, 512, 512)**
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### **Example**
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```py
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import numpy as np
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@@ -135,7 +166,6 @@ y = np.memmap('test/manual_hq.dat', dtype='int8', mode='r', shape=test_shape)
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This work has been partially supported by the Spanish Ministry of Science and Innovation project
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PID2019-109026RB-I00 (MINECO-ERDF) and the Austrian Space Applications Programme within the
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**[SemantiX project](https://austria-in-space.at/en/projects/2019/semantix.php)**.
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# **Dataset information, working with np.memmap:**
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Sentinel-1 and Sentinel-2 collect images that span an area of 5090 x 5090 meters at 10 meters per pixel.
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This results in 509 x 509 pixel images, presenting a challenge.
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**Given each layer is a two-dimensional matrix, true image data is held from pixel (1,1) to (509,509)**
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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.
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To give a visual representation of where the padding has been added:
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x marks blank pixels stored as black (255)
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The effects of the padding can be mitigated by adding a random crop within (1,1) to (509, 509)
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or completing a center crop to the desired size for network architecture.
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### The current split of image data is into three categories:
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- Training: 84.90 % of total
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- Validation: 5.35 % of total
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- Testing: 9.75 % of total
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For the recomposition of the data to take random samples of all 10,000 available images,
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we can combine the np.memmap objects and take random selections at the beginning of each trial,
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selecting random samples of the 10,000 images based on the desired percentage of the total data available.
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This approach ensures the mitigation of training bias based on the original selection of images for each category.
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<br>
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### **Example**
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**train shape: (8490, 512, 512)**
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<br>
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**val shape: (535, 512, 512)**
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<br>
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**test shape: (975, 512, 512)**
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<br>
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```py
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import numpy as np
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<br>
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This work has been partially supported by the Spanish Ministry of Science and Innovation project
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PID2019-109026RB-I00 (MINECO-ERDF) and the Austrian Space Applications Programme within the
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**[SemantiX project](https://austria-in-space.at/en/projects/2019/semantix.php)**.
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