RetinaFastToneMapping

Objective-C

@interface RetinaFastToneMapping : Algorithm

Swift

class RetinaFastToneMapping : Algorithm

a wrapper class which allows the tone mapping algorithm of Meylan&al(2007) to be used with OpenCV.

This algorithm is already implemented in thre Retina class (retina::applyFastToneMapping) but used it does not require all the retina model to be allocated. This allows a light memory use for low memory devices (smartphones, etc. As a summary, these are the model properties:

  • 2 stages of local luminance adaptation with a different local neighborhood for each.
  • first stage models the retina photorecetors local luminance adaptation
  • second stage models th ganglion cells local information adaptation
  • compared to the initial publication, this class uses spatio-temporal low pass filters instead of spatial only filters. this can help noise robustness and temporal stability for video sequence use cases.

for more information, read to the following papers : Meylan L., Alleysson D., and Susstrunk S., A Model of Retinal Local Adaptation for the Tone Mapping of Color Filter Array Images, Journal of Optical Society of America, A, Vol. 24, N 9, September, 1st, 2007, pp. 2807-2816Benoit A., Caplier A., Durette B., Herault, J., “USING HUMAN VISUAL SYSTEM MODELING FOR BIO-INSPIRED LOW LEVEL IMAGE PROCESSING”, Elsevier, Computer Vision and Image Understanding 114 (2010), pp. 758-773, DOI: http://dx.doi.org/10.1016/j.cviu.2010.01.011 regarding spatio-temporal filter and the bigger retina model : Vision: Images, Signals and Neural Networks: Models of Neural Processing in Visual Perception (Progress in Neural Processing),By: Jeanny Herault, ISBN: 9814273686. WAPI (Tower ID): 113266891.

Member of Bioinspired

Methods

  • Declaration

    Objective-C

    + (RetinaFastToneMapping*)create:(Size2i*)inputSize NS_SWIFT_NAME(create(inputSize:));

    Swift

    class func create(inputSize: Size2i) -> RetinaFastToneMapping

  • applies a luminance correction (initially High Dynamic Range (HDR) tone mapping)

     using only the 2 local adaptation stages of the retina parvocellular channel : photoreceptors
 level and ganlion cells level. Spatio temporal filtering is applied but limited to temporal
 smoothing and eventually high frequencies attenuation. This is a lighter method than the one
 available using the regular retina::run method. It is then faster but it does not include
 complete temporal filtering nor retina spectral whitening. Then, it can have a more limited
 effect on images with a very high dynamic range. This is an adptation of the original still
 image HDR tone mapping algorithm of David Alleyson, Sabine Susstruck and Laurence Meylan's
 work, please cite: -> Meylan L., Alleysson D., and Susstrunk S., A Model of Retinal Local
 Adaptation for the Tone Mapping of Color Filter Array Images, Journal of Optical Society of
 America, A, Vol. 24, N 9, September, 1st, 2007, pp. 2807-2816

    Declaration

    Objective-C

    - (void)applyFastToneMapping:(nonnull Mat *)inputImage
       outputToneMappedImage:(nonnull Mat *)outputToneMappedImage;

    Swift

    func applyFastToneMapping(inputImage: Mat, outputToneMappedImage: Mat)

    Parameters

    inputImage

    the input image to process RGB or gray levels
    outputToneMappedImage

    the output tone mapped image

  • updates tone mapping behaviors by adjusing the local luminance computation area

    Declaration

    Objective-C

    - (void)setup:(float)photoreceptorsNeighborhoodRadius
    ganglioncellsNeighborhoodRadius:(float)ganglioncellsNeighborhoodRadius
            meanLuminanceModulatorK:(float)meanLuminanceModulatorK;

    Swift

    func setup(photoreceptorsNeighborhoodRadius: Float, ganglioncellsNeighborhoodRadius: Float, meanLuminanceModulatorK: Float)

    Parameters

    photoreceptorsNeighborhoodRadius

    the first stage local adaptation area
    ganglioncellsNeighborhoodRadius

    the second stage local adaptation area
    meanLuminanceModulatorK

    the factor applied to modulate the meanLuminance information (default is 1, see reference paper)

  • updates tone mapping behaviors by adjusing the local luminance computation area

    Declaration

    Objective-C

    - (void)setup:(float)photoreceptorsNeighborhoodRadius
    ganglioncellsNeighborhoodRadius:(float)ganglioncellsNeighborhoodRadius;

    Swift

    func setup(photoreceptorsNeighborhoodRadius: Float, ganglioncellsNeighborhoodRadius: Float)

    Parameters

    photoreceptorsNeighborhoodRadius

    the first stage local adaptation area
    ganglioncellsNeighborhoodRadius

    the second stage local adaptation area (default is 1, see reference paper)

  • updates tone mapping behaviors by adjusing the local luminance computation area

    Declaration

    Objective-C

    - (void)setup:(float)photoreceptorsNeighborhoodRadius;

    Swift

    func setup(photoreceptorsNeighborhoodRadius: Float)

    Parameters

    photoreceptorsNeighborhoodRadius

    the first stage local adaptation area (default is 1, see reference paper)

  • updates tone mapping behaviors by adjusing the local luminance computation area

     (default is 1, see reference paper)

    Declaration

    Objective-C

    - (void)setup;

    Swift

    func setup()