Remove NTSC color space.

Reason: it was not clear exactly what this was and what it was for. The color
space used for NTSC video is YIQ, not RGB NTSC.

scikits/image/color/colorconv.py

@@ -26,7 +26,6 @@ Supported color spaces
         Derived from the RGB CIE color space. Chosen such that
         ``x == y == z == 1/3`` at the whitepoint, and all color matching
         functions are greater than zero everywhere.
-* NTSC
 
 :author: Nicolas Pinto (rgb2hsv)
 :author: Ralf Gommers (hsv2rgb)
@@ -44,8 +43,9 @@ References
 
 from __future__ import division
 
-__all__ = ['rgb2hsv', 'hsv2rgb', 'rgb2xyz', 'xyz2rgb', 'rgb2rgbcie', 'rgbcie2rgb',
-           'rgb2ntsc', 'ntsc2rgb']
+__all__ = ['rgb2hsv', 'hsv2rgb', 'rgb2xyz', 'xyz2rgb', 'rgb2rgbcie',
+           'rgbcie2rgb']
+
 __docformat__ = "restructuredtext en"
 
 import numpy as np
@@ -224,17 +224,6 @@ rgbcie_from_xyz = linalg.inv(xyz_from_rgbcie)
 rgbcie_from_rgb = np.dot(rgbcie_from_xyz, xyz_from_rgb)
 rgb_from_rgbcie = np.dot(rgb_from_xyz, xyz_from_rgbcie)
 
-# from Travis' code. "Matrices from Jain". TODO: find reference.
-ntsc_from_xyz = np.array([[1.910, -0.533, -0.288],
-                          [-0.985, 2.000, -0.028],
-                          [0.058, -0.118, 0.896]])
-
-xyz_from_ntsc = linalg.inv(ntsc_from_xyz)
-
-# construct matrices to and from rgb:
-ntsc_from_rgb = np.dot(ntsc_from_xyz, xyz_from_rgb)
-rgb_from_ntsc = np.dot(rgb_from_xyz, xyz_from_ntsc)
-
 
 #-------------------------------------------------------------
 # The conversion functions that make use of the matrices above
@@ -409,71 +398,3 @@ def rgbcie2rgb(rgbcie):
     >>> lena_rgb = rgbcie2rgb(lena_hsv)
     """
     return _convert(rgb_from_rgbcie, rgbcie)
-
-def rgb2ntsc(rgb):
-    """RGB to NTSC color space conversion.
-
-    Parameters
-    ----------
-    rgb : ndarray
-        The image in RGB format, in a 3-D array of shape (.., .., 3).
-
-    Returns
-    -------
-    out : ndarray
-        The image in NTSC format, in a 3-D array of shape (.., .., 3).
-
-    Raises
-    ------
-    ValueError
-        If `rgb` is not a 3-D array of shape (.., .., 3).
-
-    References
-    ----------
-    .. [1] http://en.wikipedia.org/wiki/NTSC
-
-    Examples
-    --------
-    >>> import os
-    >>> from scikits.image import data_dir
-    >>> from scikits.image.io import imread
-
-    >>> lena = imread(os.path.join(data_dir, 'lena.png'))
-    >>> lena_ntsc = rgb2ntsc(lena)
-    """
-    return _convert(ntsc_from_rgb, rgb)
-
-def ntsc2rgb(ntsc):
-    """NTSC to RGB color space conversion.
-
-    Parameters
-    ----------
-    ntsc : ndarray
-        The image in NTSC format, in a 3-D array of shape (.., .., 3).
-
-    Returns
-    -------
-    out : ndarray
-        The image in RGB format, in a 3-D array of shape (.., .., 3).
-
-    Raises
-    ------
-    ValueError
-        If `ntsc` is not a 3-D array of shape (.., .., 3).
-
-    References
-    ----------
-    .. [1] http://en.wikipedia.org/wiki/NTSC
-
-    Examples
-    --------
-    >>> import os
-    >>> from scikits.image import data_dir
-    >>> from scikits.image.io import imread
-
-    >>> lena = imread(os.path.join(data_dir, 'lena.png'))
-    >>> lena_ntsc = rgb2ntsc(lena)
-    >>> lena_rgb = ntsc2rgb(lena_hsv)
-    """
-    return _convert(rgb_from_ntsc, ntsc)
-

scikits/image/color/tests/test_colorconv.py

@@ -20,8 +20,7 @@ from scikits.image.io import imread
 from scikits.image.color import (
     rgb2hsv, hsv2rgb,
     rgb2xyz, xyz2rgb,
-    rgb2rgbcie, rgbcie2rgb,
-    rgb2ntsc, ntsc2rgb
+    rgb2rgbcie, rgbcie2rgb
     )
 
 from scikits.image import data_dir
@@ -132,28 +131,6 @@ class TestColorconv(TestCase):
                             self.colbars_array)
 
 
-    # RGB to NTSC
-    def test_rgb2ntsc_conversion(self):
-        gt = np.array([[[ 0.96880981,  1.03331573,  0.91265003],
-                        [ 0.29994641,  1.01478128,  0.89649967],
-                        [ 0.70133987, -0.04145057,  0.86950234],
-                        [ 0.03247648, -0.05998501,  0.85335198]],
-                       [[ 0.93633333,  1.09330074,  0.05929805],
-                        [ 0.26746994,  1.0747663 ,  0.04314769],
-                        [ 0.66886339,  0.01853444,  0.01615036],
-                        [ 0.        ,  0.        ,  0.        ]]])
-        assert_almost_equal(rgb2ntsc(self.colbars_array), gt)
-
-
-    # NTSC to RGB
-    def test_ntsc2rgb_conversion(self):
-        # only roundtrip test, we checked rgb2ntsc above already
-        assert_almost_equal(ntsc2rgb(rgb2ntsc(self.colbars_array)),
-                            self.colbars_array)
-
-
-
-
 if __name__ == "__main__":
     run_module_suite()