mirror of
https://github.com/SatDump/SatDump
synced 2026-08-13 17:47:30 -04:00
57 lines
1.8 KiB
Lua
57 lines
1.8 KiB
Lua
-- NDVI
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function init()
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--create an empty image for the LUT
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img_lut = image_t.new()
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--load the LUT
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image_load_png(img_lut, get_resource_path("lut/NDVI.png"))
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--return 3 channels, RGB
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return 3
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end
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function process()
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for x = 0, rgb_output:width() - 1, 1 do
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for y = 0, rgb_output:height() - 1, 1 do
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--get channels from satdump.json
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local cch1 = get_calibrated_value(0, x, y, true)
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local cch2 = get_calibrated_value(1, x, y, true)
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--perform NDVI
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local ndvi = (cch2-cch1)/(cch2+cch1)
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--range convert from -1 -> 1 to 0 -> 256
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local ndvi_lutval = (((ndvi-(-1))*256) / (1-(-1)))
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--sanity checks (noise)
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if ndvi_lutval < 0 then
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ndvi_lutval = 0
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end
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if ndvi_lutval > 255 then
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ndvi_lutval = 255
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end
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--don't forget to create a table!
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local lut_result = {}
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--send the ndvi_lutval to the LUT, retrieve it back in the table as 3 R,G,B channels
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lut_result[0] = img_lut:get(0 * img_lut:height() * img_lut:width() + ndvi_lutval * img_lut:width() + ndvi_lutval) / 255.0
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lut_result[1] = img_lut:get(1 * img_lut:height() * img_lut:width() + ndvi_lutval * img_lut:width() + ndvi_lutval) / 255.0
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lut_result[2] = img_lut:get(2 * img_lut:height() * img_lut:width() + ndvi_lutval * img_lut:width() + ndvi_lutval) / 255.0
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--return RGB 0=R 1=G 2=B
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set_img_out(0, x, y, lut_result[0])
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set_img_out(1, x, y, lut_result[1])
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set_img_out(2, x, y, lut_result[2])
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end
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--set the progress bar accordingly
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set_progress(x, rgb_output:width())
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end
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end
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