howe

howe#

howe stimulus example

You can find an interactive version of this example here

stimupy.stimuli.whites.howe(visual_size=None, ppd=None, shape=None, frequency=None, n_bars=None, bar_width=None, period='ignore', intensity_bars=(0.0, 1.0), intensity_target=0.5, target_indices_top=None, target_indices_bottom=None, target_center_offset=0, target_height=None, intensity_stripes=(0.0, 1.0), round_phase_width=True)#

Howe variation of White’s stimulus

Parameters:

  • visual_size (Sequence[Number, Number], Number, or None (default)) – visual size [height, width] of image, in degrees

  • ppd (Sequence[Number, Number], Number, or None (default)) – pixels per degree [vertical, horizontal]

  • shape (Sequence[Number, Number], Number, or None (default)) – shape [height, width] of image, in pixels

  • frequency (Number, or None (default)) – spatial frequency of grating, in cycles per degree visual angle

  • n_bars (int, or None (default)) – number of bars in the grating

  • bar_width (Number, or None (default)) – width of a single bar, in degrees visual angle

  • period ("even", "odd", "either" or "ignore" (default)) – ensure whether the grating has “even” number of phases, “odd” number of phases, either or whether not to round the number of phases (“ignore”)

  • intensity_bars ((float, float)) – intensity values of bars

  • intensity_target (float) – intensity value of target

  • target_indices_top (int or tuple of ints) – bar indices where top target(s) will be placed. As many targets as ints.

  • target_indices_bottom (int or tuple of ints) – bar indices where bottom target(s) will be placed. As many targets as ints.

  • target_center_offset (float) – offset from target centers to image center in degree visual angle.

  • target_height (float, or Sequence[float, ...]) – height of targets in degrees visual angle

  • intensity_stripes ((float, float)) – intensity values of horizontal stripes

  • round_phase_width (Bool) – if True (default), round phase width of grating

Returns:

dict with the stimulus (key: “img”), mask with integer index for each target (key: “mask”), and additional keys containing stimulus parameters

Return type:

dict[str, Any]

References

Blakeslee, B., Pasieka, W., & McCourt, M. E. (2005).

Oriented multiscale spatial filtering and contrast normalization: a parsimonious model of brightness induction in a continuum of stimuli including White, Howe and simultaneous brightness contrast. Vision Research, 45, 607-615.

Howe, P. D. L. (2001).

A comment on the Anderson (1997), the Todorovic (1997), and the Ross and Pessoa (2000) explanations of White’s effect. Perception, 30, 1023-1026

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