Automatically Detecting Cloud Edges

Manually we can just measure the pixel height of using a program like Gimp or Inkscape, this isn't feasible to do for all 15000 images though! cloudtop_pixel_heights.py uses OpenCV to automatically find the cloud top edge.

Process

Read in image

Grey scale it

Grey Scale with openCV

Apply Mask using whiteness threshold, and apply Guassian blur

• Mask out the bottom 360 pixels as in every photo has the horizon above 360 pixel.
• Mask out pixels below a whiteness threshold of 115
• Blur out noise with Guassian blur

Use open CV edge detection

• Use openCV Canny edge detection.

Box cloud

• Use OpenCV bounding box to box round the contours

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Examples