colour_hdri Package¶
Sub-Packages¶
Module Contents¶
Colour - HDRI¶
HDRI - Radiance image processing algorithms for Python.
Subpackages¶
- calibration: Camera calibration computations.
- examples: Examples for the sub-packages.
- generation: HDRI / radiance image generation.
- models: Colour models conversion.
- plotting: Diagrams, figures, etc…
- process: Image conversion helpers.
- recovery: Clipped highlights recovery.
- resources: Resources sub-modules.
- sampling: Image sampling routines.
- tonemapping: Tonemapping operators.
- utilities: Various utilities and data structures.
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colour_hdri.
linear_conversion
(a, old_range, new_range)[source]¶ Performs a simple linear conversion of given array between the old and new ranges.
Parameters: - a (array_like) – Array to perform the linear conversion onto.
- old_range (array_like) – Old range.
- new_range (array_like) – New range.
Returns: Return type: ndarray
Examples
>>> a = np.linspace(0, 1, 10) >>> linear_conversion(a, np.array([0, 1]), np.array([1, 10])) array([ 1., 2., 3., 4., 5., 6., 7., 8., 9., 10.])
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colour_hdri.
vivification
()[source]¶ Implements supports for vivification of the underlying dict like data-structure, magical!
Returns: Return type: defaultdict Examples
>>> vivified = vivification() >>> vivified['my']['attribute'] = 1 >>> vivified['my'] # doctest: +ELLIPSIS defaultdict(<function vivification at 0x...>, {u'attribute': 1}) >>> vivified['my']['attribute'] 1
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colour_hdri.
vivified_to_dict
(vivified)[source]¶ Converts given vivified data-structure to dictionary.
Parameters: vivified (defaultdict) – Vivified data-structure. Returns: Return type: dict Examples
>>> vivified = vivification() >>> vivified['my']['attribute'] = 1 >>> vivified_to_dict(vivified) {u'my': {u'attribute': 1}}
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colour_hdri.
path_exists
(path)[source]¶ Returns if given path exists.
Parameters: path (unicode) – Path to check the existence. Returns: Return type: bool Examples
>>> path_exists(__file__) True >>> path_exists('') False
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colour_hdri.
filter_files
(directory, extensions)[source]¶ Filters given directory for files matching given extensions.
Parameters: Returns: Filtered files.
Return type:
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colour_hdri.
parse_exif_data
(data)[source]¶ Parses given exif data output from exiftool.
Parameters: data (unicode) – Exif data. Returns: Parsed exif data. Return type: list
Returns given image exif image tags.
Parameters: image (unicode) – Image file. Returns: Exif tags. Return type: defaultdict
Copies given source image file exif tag to given image target.
Parameters: - source (unicode) – Source image file.
- target (unicode) – Target image file.
Returns: Definition success.
Return type:
Updates given images siblings images pairs exif tags.
Parameters: images (list) – Image files to update. Returns: Definition success. Return type: bool
Deletes all given image exif tags.
Parameters: image (unicode) – Image file. Returns: Definition success. Return type: bool
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colour_hdri.
read_exif_tag
(image, tag)[source]¶ Returns given image exif tag value.
Parameters: - image (unicode) – Image file.
- tag (unicode) – Tag.
Returns: Tag value.
Return type: unicode
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colour_hdri.
write_exif_tag
(image, tag, value)[source]¶ Sets given image exif tag value.
Parameters: - image (unicode) – Image file.
- tag (unicode) – Tag.
- value (unicode) – Value.
Returns: Definition success.
Return type:
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colour_hdri.
exposure_value
(f_number, exposure_time, iso)[source]¶ Computes the exposure value from given image FNumber, Exposure Time and ISO values.
Parameters: - f_number (array_like) – Image FNumber.
- exposure_time (array_like) – Image Exposure Time.
- iso (array_like) – Image ISO.
Returns: Image exposure value.
Return type: ndarray
Examples
>>> exposure_value(8, 1, 100) 6.0
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colour_hdri.
adjust_exposure
(a, EV)[source]¶ Adjusts given array exposure using given \(EV\) exposure value.
Parameters: - a (array_like) – Array to adjust the exposure.
- EV (numeric) – Exposure adjustment value.
Returns: Exposure adjusted array.
Return type: ndarray
Examples
>>> adjust_exposure(np.array([0.25, 0.5, 0.75, 1]), 1) array([ 0.5, 1. , 1.5, 2. ])
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colour_hdri.
average_luminance
(f_number, exposure_time, iso, k=12.5)[source]¶ Computes the average luminance from given image FNumber, Exposure Time and ISO values.
Parameters: - f_number (array_like) – Image FNumber.
- exposure_time (array_like) – Image Exposure Time.
- iso (array_like) – Image ISO.
- k (numeric, optional) – Reflected light calibration constant \(K\).
Returns: Image average luminance.
Return type: ndarray
References
[1] Wikipedia. (n.d.). EV as a measure of luminance and illuminance. Retrieved November 14, 2015, from https://en.wikipedia.org/wiki/Exposure_value#EV_as_a_measure_of_luminance_and_illuminance Examples
>>> average_luminance(8, 1, 100) 0.125
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class
colour_hdri.
Metadata
[source]¶ Bases:
colour_hdri.utilities.image.Metadata
Defines the base object for storing exif metadata relevant to HDRI / radiance image generation.
Parameters: - f_number (array_like) – Image FNumber.
- exposure_time (array_like) – Image Exposure Time.
- iso (array_like) – Image ISO.
- black_level (array_like) – Image Black Level.
- white_level (array_like) – Image White Level.
- white_balance_multipliers (array_like) – Image white balance multipliers, usually the As Shot Neutral matrix.
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class
colour_hdri.
Image
(path=None, data=None, metadata=None)[source]¶ Bases:
object
Defines the base object for storing an image along its path, pixel data and metadata needed for HDRI / radiance images generation.
Parameters: - path (unicode, optional) – Image path.
- data (array_like, optional) – Image pixel data array.
- metadata (Metadata, optional) – Image exif metadata.
-
path
¶
-
data
¶
-
metadata
¶
-
data
Property for self._data private attribute.
Returns: self._data. Return type: unicode
-
metadata
Property for self._metadata private attribute.
Returns: self._metadata. Return type: unicode
-
path
Property for self._path private attribute.
Returns: self._path. Return type: unicode
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read_data
()[source] Reads image pixel data at
Image.path
attribute.Returns: Image pixel data. Return type: ndarray
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read_metadata
()[source] Reads image relevant exif metadata at
Image.path
attribute.Returns: Image relevant exif metadata. Return type: Metadata
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class
colour_hdri.
ImageStack
[source]¶ Bases:
collections.abc.MutableSequence
Defines a convenient stack storing a sequence of images for HDRI / radiance images generation.
-
ImageStack
()¶
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static
from_files
(image_files)[source] Returns a
ImageStack
instance with given image files.Parameters: image_files (array_like) – Image files. Returns: Return type: ImageStack
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colour_hdri.
samples_Grossberg2003
(image_stack, samples=1000, n=256)[source]¶ Returns the samples for given image stack intensity histograms using Grossberg (2003) method.
Parameters: Returns: Intensity histograms samples.
Return type: ndarray
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colour_hdri.
light_probe_sampling_variance_minimization
(light_probe, lights_count=16, luminance_factors=array([0.2126, 0.7152, 0.0722]))[source]¶ Sample given light probe to find lights using Viriyothai (2009) variance minimization light probe sampling algorithm.
Parameters: - light_probe (array_like) – Array to sample for lights.
- lights_count (int) – Amount of lights to generate.
- luminance_factors (array_like) – Weighting factors for Luminance conversion.
Returns: list of
Light_Specification
lights.Return type:
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colour_hdri.
normal_distribution_function
(a, mu=0.5, sigma=0.15)[source]¶ Returns given array weighted by a normal distribution function.
Parameters: - a (array_like) – Array to apply the weighting function onto.
- mu (numeric, optional) – Mean or expectation.
- sigma (numeric, optional) – Standard deviation.
Returns: Weighted array.
Return type: ndarray
Examples
>>> normal_distribution_function(np.linspace(0, 1, 10)) array([ 0.00386592, 0.03470859, 0.18002174, 0.53940751, 0.93371212, 0.93371212, 0.53940751, 0.18002174, 0.03470859, 0.00386592])
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colour_hdri.
hat_function
(a)[source]¶ Returns given array weighted by a hat function.
Parameters: a (array_like) – Array to apply the weighting function onto. Returns: Weighted array. Return type: ndarray Examples
>>> hat_function(np.linspace(0, 1, 10)) array([ 0. , 0.95099207, 0.99913557, 0.99999812, 1. , 1. , 0.99999812, 0.99913557, 0.95099207, 0. ])
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colour_hdri.
weighting_function_Debevec1997
(a, domain_l=0.01, domain_h=0.99)[source]¶ Returns given array weighted by Debevec (1997) function.
Parameters: - a (array_like) – Array to apply the weighting function onto.
- domain_l (numeric, optional) – Domain lowest possible value, values less than
domain_l
will be set to zero. - domain_h (numeric, optional) – Domain highest possible value, values greater than
domain_h
will be set to zero.
Returns: Weighted array.
Return type: ndarray
References
[1] Debevec, P., & Malik, J. (1997). Recovering High Dynamic Range Radiance Maps from Photographs, (August), 1–10. doi:10.1145/258734.258884 Examples
>>> weighting_function_Debevec1997(np.linspace(0, 1, 10)) array([ 0. , 0.23273657, 0.48849105, 0.74424552, 1. , 1. , 0.74424552, 0.48849105, 0.23273657, 0. ])
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colour_hdri.
image_stack_to_radiance_image
(image_stack, weighting_function=<function weighting_function_Debevec1997>, weighting_average=False, camera_response_functions=None)[source]¶ Generates a HDRI / radiance image from given image stack.
Parameters: - image_stack (ImageStack) – Stack of single channel or multi-channel floating point images. The
stack is assumed to be representing linear values except if
camera_response_functions
argument is provided. - weighting_function (callable, optional) – Weighting function \(w\).
- weighting_average (bool, optional) – Enables weighting function \(w\) computation on channels average instead of on a per channel basis.
- camera_response_functions (array_like, optional) – Camera response functions \(g(z)\) of the imaging system / camera if the stack is representing non linear values.
Returns: Radiance image.
Return type: ndarray
- image_stack (ImageStack) – Stack of single channel or multi-channel floating point images. The
stack is assumed to be representing linear values except if
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colour_hdri.
g_solve
(Z, B, l=30, w=<function weighting_function_Debevec1997>, n=256)[source]¶ Given a set of pixel values observed for several pixels in several images with different exposure times, this function returns the imaging system’s response function \(g\) as well as the log film irradiance values \(lE\) for the observed pixels.
Parameters: - Z (array_like) – Set of pixel values observed for several pixels in several images.
- B (array_like) – Log \(\Delta t\), or log shutter speed for images.
- l (numeric, optional) – \(\lambda\) smoothing term.
- w (callable, optional) – Weighting function \(w\).
- n (int, optional) – \(n\) constant.
Returns: Camera response functions \(g(z)\) and log film irradiance values \(lE\).
Return type:
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colour_hdri.
camera_response_functions_Debevec1997
(image_stack, s=<function samples_Grossberg2003>, samples=1000, l=30, w=<function weighting_function_Debevec1997>, n=256, normalise=True)[source]¶ Returns the camera response functions for given image stack using Debevec (1997) method.
Image channels are sampled with \(s\) sampling function and the output samples are passed to
g_solve()
.Parameters: - image_stack (ImageStack) – Stack of single channel or multi-channel floating point images.
- s (callable, optional) – Sampling function \(s\).
- samples (int, optional) – Samples count per images.
- l (numeric, optional) – \(\lambda\) smoothing term.
- w (callable, optional) – Weighting function \(w\).
- n (int, optional) – \(n\) constant.
- normalise (bool, optional) – Enables the camera response functions normalisation. Uncertain camera response functions values resulting from \(w\) function are set to zero.
Returns: Camera response functions \(g(z)\).
Return type: ndarray
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colour_hdri.
camera_space_to_RGB
(RGB, XYZ_to_camera_matrix, RGB_to_XYZ_matrix)[source]¶ Converts given RGB array from camera space to given RGB colourspace.
Parameters: - RGB (array_like) – Camera space RGB colourspace array.
- XYZ_to_camera_matrix (array_like) – Matrix converting from CIE XYZ tristimulus values to camera space.
- RGB_to_XYZ_matrix (array_like) – Matrix converting from RGB colourspace to CIE XYZ tristimulus values.
Returns: RGB colourspace array.
Return type: ndarray
Examples
>>> RGB = np.array([0.80660, 0.81638, 0.65885]) >>> XYZ_to_camera_matrix = np.array([ ... [0.47160000, 0.06030000, -0.08300000], ... [-0.77980000, 1.54740000, 0.24800000], ... [-0.14960000, 0.19370000, 0.66510000]]) >>> RGB_to_XYZ_matrix = np.array([ ... [0.41238656, 0.35759149, 0.18045049], ... [0.21263682, 0.71518298, 0.07218020], ... [0.01933062, 0.11919716, 0.95037259]]) >>> camera_space_to_RGB( ... RGB, ... XYZ_to_camera_matrix, ... RGB_to_XYZ_matrix) # doctest: +ELLIPSIS array([ 0.7564180..., 0.8683192..., 0.6044589...])
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colour_hdri.
camera_space_to_sRGB
(RGB, XYZ_to_camera_matrix)[source]¶ Converts given RGB array from camera space to sRGB colourspace.
Parameters: - RGB (array_like) – Camera space RGB colourspace array.
- XYZ_to_camera_matrix (array_like) – Matrix converting from CIE XYZ tristimulus values to camera space.
Returns: sRGB colourspace array.
Return type: ndarray
Examples
>>> RGB = np.array([0.80660, 0.81638, 0.65885]) >>> XYZ_to_camera_matrix = np.array([ ... [0.47160000, 0.06030000, -0.08300000], ... [-0.77980000, 1.54740000, 0.24800000], ... [-0.14960000, 0.19370000, 0.66510000]]) >>> camera_space_to_sRGB(RGB, XYZ_to_camera_matrix) # doctest: +ELLIPSIS array([ 0.7564350..., 0.8683155..., 0.6044706...])
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colour_hdri.
convert_raw_files_to_dng_files
(raw_files, output_directory)[source]¶ Converts given raw files to dng files using given output directory.
Parameters: - raw_files (array_like) – Raw files to convert to dng files.
- output_directory (unicode) – Output directory.
Returns: dng files.
Return type:
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colour_hdri.
convert_dng_files_to_intermediate_files
(dng_files, output_directory, demosaicing=False)[source]¶ Converts given dng files to intermediate tiff files using given output directory.
Parameters: Returns: Intermediate tiff files.
Return type:
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colour_hdri.
highlights_recovery_blend
(RGB, multipliers, threshold=0.99)[source]¶ Performs highlights recovery using Coffin (1997) method from dcraw.
Parameters: - RGB (array_like) – RGB colourspace array.
- multipliers (array_like) – Normalised camera white level or white balance multipliers.
- threshold (numeric, optional) – Threshold for the highlights selection.
Returns: Highlights recovered RGB colourspace array.
Return type: ndarray
References
[1] Coffin, D. (2015). dcraw. Retrieved from https://www.cybercom.net/~dcoffin/dcraw/
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colour_hdri.
tonemapping_operator_simple
(RGB)[source]¶ Performs given RGB array tonemapping using the simple method: \(\cfrac{RGB}{RGB + 1}\).
Parameters: RGB (array_like) – RGB array to perform tonemapping onto. Returns: Tonemapped RGB array. Return type: ndarray References
[1] Wikipedia. (n.d.). Tonemapping - Purpose and methods. Retrieved March 15, 2015, from http://en.wikipedia.org/wiki/Tone_mapping#Purpose_and_methods Examples
>>> tonemapping_operator_simple(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.3245382..., 0.2601156..., 0.1911532...], [ 0.5830618..., 0.3567839..., 0.2808993...]], <BLANKLINE> [[ 0.8150290..., 0.6831692..., 0.5733340...], [ 0.8683127..., 0.7746486..., 0.6893211...]]])
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colour_hdri.
tonemapping_operator_normalisation
(RGB, colourspace=None)[source]¶ Performs given RGB array tonemapping using the normalisation method.
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
References
[2] (1, 2, 3, 4) Banterle, F., Artusi, A., Debattista, K., & Chalmers, A. (2011). 3.2.1 Simple Mapping Methods. In Advanced High Dynamic Range Imaging (pp. 38–41). A K Peters/CRC Press. ISBN:978-1568817194 Examples
>>> tonemapping_operator_normalisation(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.1194997..., 0.0874388..., 0.0587783...], [ 0.3478122..., 0.1379590..., 0.0971544...]], <BLANKLINE> [[ 1.0959009..., 0.5362936..., 0.3342115...], [ 1.6399638..., 0.8549608..., 0.5518382...]]])
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colour_hdri.
tonemapping_operator_gamma
(RGB, gamma=1, EV=0)[source]¶ Performs given RGB array tonemapping using the gamma and exposure correction method [2].
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- gamma (numeric, optional) – \(\gamma\) correction value.
- EV (numeric, optional) – Exposure adjustment value.
Returns: Tonemapped RGB array.
Return type: ndarray
Examples
>>> tonemapping_operator_gamma(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]]), ... 1.0, -3.0) # doctest: +ELLIPSIS array([[[ 0.0600585..., 0.0439453..., 0.0295410...], [ 0.1748046..., 0.0693359..., 0.0488282...]], <BLANKLINE> [[ 0.5507817..., 0.2695323..., 0.1679692...], [ 0.8242187..., 0.4296892..., 0.2773447...]]])
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colour_hdri.
tonemapping_operator_logarithmic
(RGB, q=1, k=1, colourspace=None)[source]¶ Performs given RGB array tonemapping using the logarithmic method [2].
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- q (numeric, optional) – \(q\).
- k (numeric, optional) – \(k\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
Examples
>>> tonemapping_operator_logarithmic(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]]), ... 1.0, 25) # doctest: +ELLIPSIS array([[[ 0.0884587..., 0.0647259..., 0.0435102...], [ 0.2278222..., 0.0903652..., 0.0636376...]], <BLANKLINE> [[ 0.4717487..., 0.2308565..., 0.1438669...], [ 0.5727396..., 0.2985858..., 0.1927235...]]])
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colour_hdri.
tonemapping_operator_exponential
(RGB, q=1, k=1, colourspace=None)[source]¶ Performs given RGB array tonemapping using the exponential method [2].
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- q (numeric, optional) – \(q\).
- k (numeric, optional) – \(k\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
Examples
>>> tonemapping_operator_exponential(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]]), ... 1.0, 25) # doctest: +ELLIPSIS array([[[ 0.0148082..., 0.0108353..., 0.0072837...], [ 0.0428669..., 0.0170031..., 0.0119740...]], <BLANKLINE> [[ 0.1312736..., 0.0642404..., 0.0400338...], [ 0.1921684..., 0.1001830..., 0.0646635...]]])
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colour_hdri.
tonemapping_operator_logarithmic_mapping
(RGB, p=1, q=1, colourspace=None)[source]¶ Performs given RGB array tonemapping using the logarithmic mapping method.
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- p (numeric, optional) – \(p\).
- q (numeric, optional) – \(q\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
References
[3] Schlick, C. (1994). Quantization Techniques for Visualization of High Dynamic Range Pictures. Proceedings of the Fifth Eurographics Workshop on Rendering, (Section 5), 7–18. Examples
>>> tonemapping_operator_logarithmic_mapping(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.2532899..., 0.1853341..., 0.1245857...], [ 0.6523387..., 0.2587489..., 0.1822179...]], <BLANKLINE> [[ 1.3507897..., 0.6610269..., 0.4119437...], [ 1.6399638..., 0.8549608..., 0.5518382...]]])
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colour_hdri.
tonemapping_operator_exponentiation_mapping
(RGB, p=1, q=1, colourspace=None)[source]¶ Performs given RGB array tonemapping using the exponentiation mapping method [3].
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- p (numeric, optional) – \(p\).
- q (numeric, optional) – \(q\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
Examples
>>> tonemapping_operator_exponentiation_mapping(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.1194997..., 0.0874388..., 0.0587783...], [ 0.3478122..., 0.1379590..., 0.0971544...]], <BLANKLINE> [[ 1.0959009..., 0.5362936..., 0.3342115...], [ 1.6399638..., 0.8549608..., 0.5518382...]]])
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colour_hdri.
tonemapping_operator_Schlick1994
(RGB, p=1, colourspace=None)[source]¶ Performs given RGB array tonemapping using Schlick (1994) method [2]_[3]_.
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- p (numeric, optional) – \(p\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
Examples
>>> tonemapping_operator_Schlick1994(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.1194997..., 0.0874388..., 0.0587783...], [ 0.3478122..., 0.1379590..., 0.0971544...]], <BLANKLINE> [[ 1.0959009..., 0.5362936..., 0.3342115...], [ 1.6399638..., 0.8549608..., 0.5518382...]]])
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colour_hdri.
tonemapping_operator_Tumblin1999
(RGB, L_da=20, C_max=100, L_max=100, colourspace=None)[source]¶ Performs given RGB array tonemapping using Tumblin (1999) method [2].
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- L_da (numeric, optional) – \(L_{da}\) display adaptation luminance, a mid-range display value.
- C_max (numeric, optional) – \(C_{max}\) maximum contrast available from the display.
- L_max (numeric, optional) – \(L_{max}\) maximum display luminance.
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
References
[4] Tumblin, J., Hodgins, J. K., & Guenter, B. K. (1999). Two methods for display of high contrast images. ACM Transactions on Graphics. doi:10.1145/300776.300783 Examples
>>> tonemapping_operator_Tumblin1999(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.0400492..., 0.0293043..., 0.0196990...], [ 0.1019768..., 0.0404489..., 0.0284852...]], <BLANKLINE> [[ 0.2490212..., 0.1218618..., 0.0759427...], [ 0.3408366..., 0.1776880..., 0.1146895...]]])
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colour_hdri.
tonemapping_operator_Reinhard2004
(RGB, f=0, m=0.3, a=0, c=0, colourspace=None)[source]¶ Performs given RGB array tonemapping using Reinhard (2004) method.
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- f (numeric, optional) – \(f\).
- m (numeric, optional) – \(m\).
- a (numeric, optional) – \(a\).
- c (numeric, optional) – \(c\).
- colourspace (colour.RGB_Colourspace, optional) – RGB colourspace used for internal Luminance computation.
Returns: Tonemapped RGB array.
Return type: ndarray
References
[5] Reinhard, E., & Devlin, K. (2005). Dynamic range reduction inspired by photoreceptor physiology. IEEE Transactions on Visualization and Computer Graphics, 11(1), 13–24. doi:10.1109/TVCG.2005.9 Examples
>>> tonemapping_operator_Reinhard2004(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]]), ... -10) # doctest: +ELLIPSIS array([[[ 0.0216792..., 0.0159556..., 0.0107821...], [ 0.0605894..., 0.0249445..., 0.0176972...]], <BLANKLINE> [[ 0.1688972..., 0.0904532..., 0.0583584...], [ 0.2331935..., 0.1368456..., 0.0928316...]]])
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colour_hdri.
tonemapping_operator_filmic
(RGB, shoulder_strength=0.22, linear_strength=0.3, linear_angle=0.1, toe_strength=0.2, toe_numerator=0.01, toe_denominator=0.3, exposure_bias=2, linear_whitepoint=11.2)[source]¶ Performs given RGB array tonemapping using Reinhard (2004) method.
Parameters: - RGB (array_like) – RGB array to perform tonemapping onto.
- shoulder_strength (numeric, optional) – Shoulder strength.
- linear_strength (numeric, optional) – Linear strength.
- linear_angle (numeric, optional) – Linear angle.
- toe_strength (numeric, optional) – Toe strength.
- toe_numerator (numeric, optional) – Toe numerator.
- toe_denominator (numeric, optional) – Toe denominator.
- exposure_bias (numeric, optional) – Exposure bias.
- linear_whitepoint (numeric, optional) – Linear whitepoint.
Returns: Tonemapped RGB array.
Return type: ndarray
References
[6] Habble, J. (2010). Filmic Tonemapping Operators. Retrieved March 15, 2015, from http://filmicgames.com/archives/75 [7] Habble, J. (2010). Uncharted 2: HDR Lighting. Retrieved March 15, 2015, from http://www.slideshare.net/ozlael/hable-john-uncharted2-hdr-lighting Examples
>>> tonemapping_operator_filmic(np.array( ... [[[0.48046875, 0.35156256, 0.23632812], ... [1.39843753, 0.55468757, 0.39062594]], ... [[4.40625388, 2.15625895, 1.34375372], ... [6.59375023, 3.43751395, 2.21875829]]])) # doctest: +ELLIPSIS array([[[ 0.4507954..., 0.3619673..., 0.2617269...], [ 0.7567191..., 0.4933310..., 0.3911730...]], <BLANKLINE> [[ 0.9725554..., 0.8557374..., 0.7465713...], [ 1.0158782..., 0.9382937..., 0.8615161...]]])