73 lines
2.2 KiB
Python
Executable File
73 lines
2.2 KiB
Python
Executable File
#!/usr/bin/python
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import sys
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import logging
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#logging.basicConfig(level = logging.DEBUG)
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import gi
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gi.require_version('Vips', '8.0')
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from gi.repository import Vips
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#Vips.cache_set_trace(True)
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# Run a function expecting a complex image on a two-band image
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def run_cmplx(fn, image):
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if image.format == Vips.BandFormat.FLOAT:
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new_format = Vips.BandFormat.COMPLEX
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elif image.format == Vips.BandFormat.DOUBLE:
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new_format = Vips.BandFormat.DPCOMPLEX
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else:
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raise "run_cmplx: not float or double"
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# tag as complex, run, revert tagging
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cmplx = image.copy(bands = 1, format = new_format)
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cmplx_result = fn(cmplx)
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return cmplx_result.copy(bands = 2, format = image.format)
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def to_polar(image):
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"""Transform image coordinates to polar.
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The image is transformed so that it is wrapped around a point in the
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centre. Vertical straight lines become circles or segments of circles,
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horizontal straight lines become radial spokes.
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"""
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# xy image, origin in the centre, scaled to fit image to a circle
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xy = Vips.Image.xyz(image.width, image.height)
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xy -= [image.width / 2.0, image.height / 2.0]
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scale = min(image.width, image.height) / float(image.width)
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xy *= 2.0 / scale
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# to polar, scale vertical axis to 360 degrees
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index = run_cmplx(lambda x: x.polar(), xy)
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index *= [1, image.height / 360.0]
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return image.mapim(index)
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def to_rectangular(image):
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"""Transform image coordinates to rectangular.
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The image is transformed so that it is unwrapped from a point in the
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centre. Circles or segments of circles become vertical straight lines,
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radial lines become horizontal lines.
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"""
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# xy image, vertical scaled to 360 degrees
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xy = Vips.Image.xyz(image.width, image.height)
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xy *= [1, 360.0 / image.height]
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# to rect, scale to image rect
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index = run_cmplx(lambda x: x.rect(), xy)
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scale = min(image.width, image.height) / float(image.width)
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index *= scale / 2.0
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index += [image.width / 2.0, image.height / 2.0]
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return image.mapim(index)
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a = Vips.Image.new_from_file(sys.argv[1])
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a = to_polar(a)
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a = to_rectangular(a)
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a.write_to_file(sys.argv[2])
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