skimage.color.convert_colorspace (arr, …) | Convert an image array to a new color space. |
skimage.color.guess_spatial_dimensions (image) | Make an educated guess about whether an image has a channels dimension. |
skimage.color.rgb2hsv (rgb) | RGB to HSV color space conversion. |
skimage.color.hsv2rgb (hsv) | HSV to RGB color space conversion. |
skimage.color.rgb2xyz (rgb) | RGB to XYZ color space conversion. |
skimage.color.xyz2rgb (xyz) | XYZ to RGB color space conversion. |
skimage.color.rgb2rgbcie (rgb) | RGB to RGB CIE color space conversion. |
skimage.color.rgbcie2rgb (rgbcie) | RGB CIE to RGB color space conversion. |
skimage.color.rgb2grey (rgb) | Compute luminance of an RGB image. |
skimage.color.rgb2gray (rgb) | Compute luminance of an RGB image. |
skimage.color.gray2rgb (image[, alpha]) | Create an RGB representation of a gray-level image. |
skimage.color.grey2rgb (image[, alpha]) | Create an RGB representation of a gray-level image. |
skimage.color.xyz2lab (xyz[, illuminant, …]) | XYZ to CIE-LAB color space conversion. |
skimage.color.lab2xyz (lab[, illuminant, …]) | CIE-LAB to XYZcolor space conversion. |
skimage.color.lab2rgb (lab[, illuminant, …]) | Lab to RGB color space conversion. |
skimage.color.rgb2lab (rgb[, illuminant, …]) | RGB to lab color space conversion. |
skimage.color.rgb2hed (rgb) | RGB to Haematoxylin-Eosin-DAB (HED) color space conversion. |
skimage.color.hed2rgb (hed) | Haematoxylin-Eosin-DAB (HED) to RGB color space conversion. |
skimage.color.lab2lch (lab) | CIE-LAB to CIE-LCH color space conversion. |
skimage.color.lch2lab (lch) | CIE-LCH to CIE-LAB color space conversion. |
skimage.color.rgb2yuv (rgb) | RGB to YUV color space conversion. |
skimage.color.yuv2rgb (yuv) | YUV to RGB color space conversion. |
skimage.color.rgb2yiq (rgb) | RGB to YIQ color space conversion. |
skimage.color.yiq2rgb (yiq) | YIQ to RGB color space conversion. |
skimage.color.rgb2ypbpr (rgb) | RGB to YPbPr color space conversion. |
skimage.color.ypbpr2rgb (ypbpr) | YPbPr to RGB color space conversion. |
skimage.color.rgb2ycbcr (rgb) | RGB to YCbCr color space conversion. |
skimage.color.ycbcr2rgb (ycbcr) | YCbCr to RGB color space conversion. |
skimage.color.rgb2ydbdr (rgb) | RGB to YDbDr color space conversion. |
skimage.color.ydbdr2rgb (ydbdr) | YDbDr to RGB color space conversion. |
skimage.color.separate_stains (rgb, conv_matrix) | RGB to stain color space conversion. |
skimage.color.combine_stains (stains, conv_matrix) | Stain to RGB color space conversion. |
skimage.color.label2rgb (label[, image, …]) | Return an RGB image where color-coded labels are painted over the image. |
skimage.color.deltaE_cie76 (lab1, lab2) | Euclidean distance between two points in Lab color space |
skimage.color.deltaE_ciede94 (lab1, lab2[, …]) | Color difference according to CIEDE 94 standard |
skimage.color.deltaE_ciede2000 (lab1, lab2[, …]) | Color difference as given by the CIEDE 2000 standard. |
skimage.color.deltaE_cmc (lab1, lab2[, kL, kC]) | Color difference from the CMC l:c standard. |
skimage.color.convert_colorspace(arr, fromspace, tospace)
[source]
Convert an image array to a new color space.
Parameters: |
|
---|---|
Returns: |
|
Conversion is performed through the “central” RGB color space, i.e. conversion from XYZ to HSV is implemented as XYZ -> RGB -> HSV
instead of directly.
>>> from skimage import data >>> img = data.astronaut() >>> img_hsv = convert_colorspace(img, 'RGB', 'HSV')
skimage.color.guess_spatial_dimensions(image)
[source]
Make an educated guess about whether an image has a channels dimension.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
skimage.color.rgb2hsv(rgb)
[source]
RGB to HSV color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Conversion between RGB and HSV color spaces results in some loss of precision, due to integer arithmetic and rounding [1].
[1] | (1, 2) http://en.wikipedia.org/wiki/HSL_and_HSV |
>>> from skimage import color >>> from skimage import data >>> img = data.astronaut() >>> img_hsv = color.rgb2hsv(img)
skimage.color.hsv2rgb(hsv)
[source]
HSV to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Conversion between RGB and HSV color spaces results in some loss of precision, due to integer arithmetic and rounding [1].
[1] | (1, 2) http://en.wikipedia.org/wiki/HSL_and_HSV |
>>> from skimage import data >>> img = data.astronaut() >>> img_hsv = rgb2hsv(img) >>> img_rgb = hsv2rgb(img_hsv)
skimage.color.rgb2xyz(rgb)
[source]
RGB to XYZ color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
The CIE XYZ color space is derived from the CIE RGB color space. Note however that this function converts from sRGB.
[1] | http://en.wikipedia.org/wiki/CIE_1931_color_space |
>>> from skimage import data >>> img = data.astronaut() >>> img_xyz = rgb2xyz(img)
skimage.color.xyz2rgb(xyz)
[source]
XYZ to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
The CIE XYZ color space is derived from the CIE RGB color space. Note however that this function converts to sRGB.
[1] | http://en.wikipedia.org/wiki/CIE_1931_color_space |
>>> from skimage import data >>> from skimage.color import rgb2xyz, xyz2rgb >>> img = data.astronaut() >>> img_xyz = rgb2xyz(img) >>> img_rgb = xyz2rgb(img_xyz)
skimage.color.rgb2rgbcie(rgb)
[source]
RGB to RGB CIE color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | http://en.wikipedia.org/wiki/CIE_1931_color_space |
>>> from skimage import data >>> from skimage.color import rgb2rgbcie >>> img = data.astronaut() >>> img_rgbcie = rgb2rgbcie(img)
skimage.color.rgbcie2rgb(rgbcie)
[source]
RGB CIE to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | http://en.wikipedia.org/wiki/CIE_1931_color_space |
>>> from skimage import data >>> from skimage.color import rgb2rgbcie, rgbcie2rgb >>> img = data.astronaut() >>> img_rgbcie = rgb2rgbcie(img) >>> img_rgb = rgbcie2rgb(img_rgbcie)
skimage.color.rgb2grey(rgb)
[source]
Compute luminance of an RGB image.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
The weights used in this conversion are calibrated for contemporary CRT phosphors:
Y = 0.2125 R + 0.7154 G + 0.0721 B
If there is an alpha channel present, it is ignored.
[1] | http://www.poynton.com/PDFs/ColorFAQ.pdf |
>>> from skimage.color import rgb2gray >>> from skimage import data >>> img = data.astronaut() >>> img_gray = rgb2gray(img)
skimage.color.rgb2gray(rgb)
[source]
Compute luminance of an RGB image.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
The weights used in this conversion are calibrated for contemporary CRT phosphors:
Y = 0.2125 R + 0.7154 G + 0.0721 B
If there is an alpha channel present, it is ignored.
[1] | http://www.poynton.com/PDFs/ColorFAQ.pdf |
>>> from skimage.color import rgb2gray >>> from skimage import data >>> img = data.astronaut() >>> img_gray = rgb2gray(img)
skimage.color.gray2rgb(image, alpha=None)
[source]
Create an RGB representation of a gray-level image.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
If the input is a 1-dimensional image of shape (M, )
, the output will be shape (M, 3)
.
skimage.color.grey2rgb(image, alpha=None)
[source]
Create an RGB representation of a gray-level image.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
If the input is a 1-dimensional image of shape (M, )
, the output will be shape (M, 3)
.
skimage.color.xyz2lab(xyz, illuminant='D65', observer='2')
[source]
XYZ to CIE-LAB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
By default Observer= 2A, Illuminant= D65. CIE XYZ tristimulus values x_ref=95.047, y_ref=100., z_ref=108.883. See function get_xyz_coords
for a list of supported illuminants.
[1] | http://www.easyrgb.com/index.php?X=MATH&H=07#text7 |
[2] | http://en.wikipedia.org/wiki/Lab_color_space |
>>> from skimage import data >>> from skimage.color import rgb2xyz, xyz2lab >>> img = data.astronaut() >>> img_xyz = rgb2xyz(img) >>> img_lab = xyz2lab(img_xyz)
skimage.color.lab2xyz(lab, illuminant='D65', observer='2')
[source]
CIE-LAB to XYZcolor space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
By default Observer= 2A, Illuminant= D65. CIE XYZ tristimulus values x_ref = 95.047, y_ref = 100., z_ref = 108.883. See function ‘get_xyz_coords’ for a list of supported illuminants.
[1] | http://www.easyrgb.com/index.php?X=MATH&H=07#text7 |
[2] | http://en.wikipedia.org/wiki/Lab_color_space |
skimage.color.lab2rgb(lab, illuminant='D65', observer='2')
[source]
Lab to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
This function uses lab2xyz and xyz2rgb. By default Observer= 2A, Illuminant= D65. CIE XYZ tristimulus values x_ref=95.047, y_ref=100., z_ref=108.883. See function get_xyz_coords
for a list of supported illuminants.
[1] | https://en.wikipedia.org/wiki/Standard_illuminant |
skimage.color.rgb2lab(rgb, illuminant='D65', observer='2')
[source]
RGB to lab color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
This function uses rgb2xyz and xyz2lab. By default Observer= 2A, Illuminant= D65. CIE XYZ tristimulus values x_ref=95.047, y_ref=100., z_ref=108.883. See function get_xyz_coords
for a list of supported illuminants.
[1] | https://en.wikipedia.org/wiki/Standard_illuminant |
skimage.color.rgb2hed(rgb)
[source]
RGB to Haematoxylin-Eosin-DAB (HED) color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | A. C. Ruifrok and D. A. Johnston, “Quantification of histochemical staining by color deconvolution.,” Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology, vol. 23, no. 4, pp. 291-9, Aug. 2001. |
>>> from skimage import data >>> from skimage.color import rgb2hed >>> ihc = data.immunohistochemistry() >>> ihc_hed = rgb2hed(ihc)
skimage.color.hed2rgb(hed)
[source]
Haematoxylin-Eosin-DAB (HED) to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | A. C. Ruifrok and D. A. Johnston, “Quantification of histochemical staining by color deconvolution.,” Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology, vol. 23, no. 4, pp. 291-9, Aug. 2001. |
>>> from skimage import data >>> from skimage.color import rgb2hed, hed2rgb >>> ihc = data.immunohistochemistry() >>> ihc_hed = rgb2hed(ihc) >>> ihc_rgb = hed2rgb(ihc_hed)
skimage.color.lab2lch(lab)
[source]
CIE-LAB to CIE-LCH color space conversion.
LCH is the cylindrical representation of the LAB (Cartesian) colorspace
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
The Hue is expressed as an angle between (0, 2*pi)
>>> from skimage import data >>> from skimage.color import rgb2lab, lab2lch >>> img = data.astronaut() >>> img_lab = rgb2lab(img) >>> img_lch = lab2lch(img_lab)
skimage.color.lch2lab(lch)
[source]
CIE-LCH to CIE-LAB color space conversion.
LCH is the cylindrical representation of the LAB (Cartesian) colorspace
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
>>> from skimage import data >>> from skimage.color import rgb2lab, lch2lab >>> img = data.astronaut() >>> img_lab = rgb2lab(img) >>> img_lch = lab2lch(img_lab) >>> img_lab2 = lch2lab(img_lch)
skimage.color.rgb2yuv(rgb)
[source]
RGB to YUV color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Y is between 0 and 1. Use YCbCr instead of YUV for the color space which is commonly used by video codecs (where Y ranges from 16 to 235)
[1] | https://en.wikipedia.org/wiki/YUV |
skimage.color.yuv2rgb(yuv)
[source]
YUV to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | https://en.wikipedia.org/wiki/YUV |
skimage.color.rgb2yiq(rgb)
[source]
RGB to YIQ color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
skimage.color.yiq2rgb(yiq)
[source]
YIQ to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
skimage.color.rgb2ypbpr(rgb)
[source]
RGB to YPbPr color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | https://en.wikipedia.org/wiki/YPbPr |
skimage.color.ypbpr2rgb(ypbpr)
[source]
YPbPr to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
[1] | https://en.wikipedia.org/wiki/YPbPr |
skimage.color.rgb2ycbcr(rgb)
[source]
RGB to YCbCr color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Y is between 16 and 235. This is the color space which is commonly used by video codecs, it is sometimes incorrectly called “YUV”
[1] | https://en.wikipedia.org/wiki/YCbCr |
skimage.color.ycbcr2rgb(ycbcr)
[source]
YCbCr to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Y is between 16 and 235. This is the color space which is commonly used by video codecs, it is sometimes incorrectly called “YUV”
[1] | https://en.wikipedia.org/wiki/YCbCr |
skimage.color.rgb2ydbdr(rgb)
[source]
RGB to YDbDr color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
This is the color space which is commonly used by video codecs, it is also the reversible color transform in JPEG2000.
[1] | https://en.wikipedia.org/wiki/YDbDr |
skimage.color.ydbdr2rgb(ydbdr)
[source]
YDbDr to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
This is the color space which is commonly used by video codecs, it is also the reversible color transform in JPEG2000.
[1] | https://en.wikipedia.org/wiki/YDbDr |
skimage.color.separate_stains(rgb, conv_matrix)
[source]
RGB to stain color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Stain separation matrices available in the color
module and their respective colorspace:
hed_from_rgb
: Hematoxylin + Eosin + DABhdx_from_rgb
: Hematoxylin + DABfgx_from_rgb
: Feulgen + Light Greenbex_from_rgb
: Giemsa stain : Methyl Blue + Eosinrbd_from_rgb
: FastRed + FastBlue + DABgdx_from_rgb
: Methyl Green + DABhax_from_rgb
: Hematoxylin + AECbro_from_rgb
: Blue matrix Anilline Blue + Red matrix Azocarmine + Orange matrix Orange-Gbpx_from_rgb
: Methyl Blue + Ponceau Fuchsinahx_from_rgb
: Alcian Blue + Hematoxylinhpx_from_rgb
: Hematoxylin + PAS[1] | (1, 2) http://www.dentistry.bham.ac.uk/landinig/software/cdeconv/cdeconv.html |
>>> from skimage import data >>> from skimage.color import separate_stains, hdx_from_rgb >>> ihc = data.immunohistochemistry() >>> ihc_hdx = separate_stains(ihc, hdx_from_rgb)
skimage.color.combine_stains(stains, conv_matrix)
[source]
Stain to RGB color space conversion.
Parameters: |
|
---|---|
Returns: |
|
Raises: |
|
Stain combination matrices available in the color
module and their respective colorspace:
rgb_from_hed
: Hematoxylin + Eosin + DABrgb_from_hdx
: Hematoxylin + DABrgb_from_fgx
: Feulgen + Light Greenrgb_from_bex
: Giemsa stain : Methyl Blue + Eosinrgb_from_rbd
: FastRed + FastBlue + DABrgb_from_gdx
: Methyl Green + DABrgb_from_hax
: Hematoxylin + AECrgb_from_bro
: Blue matrix Anilline Blue + Red matrix Azocarmine + Orange matrix Orange-Grgb_from_bpx
: Methyl Blue + Ponceau Fuchsinrgb_from_ahx
: Alcian Blue + Hematoxylinrgb_from_hpx
: Hematoxylin + PAS[1] | (1, 2) http://www.dentistry.bham.ac.uk/landinig/software/cdeconv/cdeconv.html |
>>> from skimage import data >>> from skimage.color import (separate_stains, combine_stains, ... hdx_from_rgb, rgb_from_hdx) >>> ihc = data.immunohistochemistry() >>> ihc_hdx = separate_stains(ihc, hdx_from_rgb) >>> ihc_rgb = combine_stains(ihc_hdx, rgb_from_hdx)
skimage.color.label2rgb(label, image=None, colors=None, alpha=0.3, bg_label=-1, bg_color=(0, 0, 0), image_alpha=1, kind='overlay')
[source]
Return an RGB image where color-coded labels are painted over the image.
Parameters: |
|
---|---|
Returns: |
|
skimage.color.deltaE_cie76(lab1, lab2)
[source]
Euclidean distance between two points in Lab color space
Parameters: |
|
---|---|
Returns: |
|
[1] | http://en.wikipedia.org/wiki/Color_difference |
[2] | A. R. Robertson, “The CIE 1976 color-difference formulae,” Color Res. Appl. 2, 7-11 (1977). |
skimage.color.deltaE_ciede94(lab1, lab2, kH=1, kC=1, kL=1, k1=0.045, k2=0.015)
[source]
Color difference according to CIEDE 94 standard
Accommodates perceptual non-uniformities through the use of application specific scale factors (kH
, kC
, kL
, k1
, and k2
).
Parameters: |
|
---|---|
Returns: |
|
deltaE_ciede94 is not symmetric with respect to lab1 and lab2. CIEDE94 defines the scales for the lightness, hue, and chroma in terms of the first color. Consequently, the first color should be regarded as the “reference” color.
kL
, k1
, k2
depend on the application and default to the values suggested for graphic arts
Parameter | Graphic Arts | Textiles |
---|---|---|
kL | 1.000 | 2.000 |
k1 | 0.045 | 0.048 |
k2 | 0.015 | 0.014 |
[1] | http://en.wikipedia.org/wiki/Color_difference |
[2] | http://www.brucelindbloom.com/index.html?Eqn_DeltaE_CIE94.html |
skimage.color.deltaE_ciede2000(lab1, lab2, kL=1, kC=1, kH=1)
[source]
Color difference as given by the CIEDE 2000 standard.
CIEDE 2000 is a major revision of CIDE94. The perceptual calibration is largely based on experience with automotive paint on smooth surfaces.
Parameters: |
|
---|---|
Returns: |
|
CIEDE 2000 assumes parametric weighting factors for the lightness, chroma, and hue (kL
, kC
, kH
respectively). These default to 1.
[1] | http://en.wikipedia.org/wiki/Color_difference |
[2] | http://www.ece.rochester.edu/~gsharma/ciede2000/ciede2000noteCRNA.pdf (doi:10.1364/AO.33.008069) |
[3] | M. Melgosa, J. Quesada, and E. Hita, “Uniformity of some recent color metrics tested with an accurate color-difference tolerance dataset,” Appl. Opt. 33, 8069-8077 (1994). |
skimage.color.deltaE_cmc(lab1, lab2, kL=1, kC=1)
[source]
Color difference from the CMC l:c standard.
This color difference was developed by the Colour Measurement Committee (CMC) of the Society of Dyers and Colourists (United Kingdom). It is intended for use in the textile industry.
The scale factors kL
, kC
set the weight given to differences in lightness and chroma relative to differences in hue. The usual values are kL=2
, kC=1
for “acceptability” and kL=1
, kC=1
for “imperceptibility”. Colors with dE > 1
are “different” for the given scale factors.
Parameters: |
|
---|---|
Returns: |
|
deltaE_cmc the defines the scales for the lightness, hue, and chroma in terms of the first color. Consequently deltaE_cmc(lab1, lab2) != deltaE_cmc(lab2, lab1)
[1] | http://en.wikipedia.org/wiki/Color_difference |
[2] | http://www.brucelindbloom.com/index.html?Eqn_DeltaE_CIE94.html |
[3] | F. J. J. Clarke, R. McDonald, and B. Rigg, “Modification to the JPC79 colour-difference formula,” J. Soc. Dyers Colour. 100, 128-132 (1984). |
© 2011 the scikit-image team
Licensed under the BSD 3-clause License.
http://scikit-image.org/docs/0.14.x/api/skimage.color.html