VisionScienceList: Motion vs. Static Conspicuity Measures & Minimization

From: Frank J. Iannarilli (franki@aerodyne.com)
Date: Tue Mar 27 2001 - 12:05:06 PST

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    Hi,

    We (colleagues/myself) are attempting to computationally optimize
    (minimize) the "pre-attentive" conspicuity of an opaque pattern (blob of
    pixels):
      1. as (occlusionally) inserted statically against a natural outdoor
    background;
      2. and also when moving across scene (within a glimpse period).

    We wish to ask here for opinions on the proper/useful conspicuity measures.

    We employ static conspicuity measures which turn out to be quite
    efficacious: blob-to-local-background mismatch in mean, variance, and
    2-order texture, for each of three color channels. The texture mismatch
    measure is based on a gaussian markov random field (GMRF) parameterization
    of local background texture (essentially 2-point correlation over various
    lags).

    Since we are optimizing, such measures need only be relative, and
    monotonically related to conspicuity (i.e., we don't need absolute d'
    measures). The scaling (weighting) factors applied to each metric above
    are varied empirically to each optimization case (given background).

    Our present measure for motion detectibility is:
       a. apply a bandpass temporal filter on the motion sequence of images (of
    moving blob against fixed background)
       b. take absolute value of signed resultant, and pool spatially.
    We attempt to minimize this "motion energy". The sequence is typically
    several frames spanning a glimpse period of about 100msec. The temporal
    impulse response filter is from [Watson & Ahumada (1985)] attempting to
    mimick flicker response.

    Questions:

    1. How sensible is our motion detectibility measure? Any better
    suggestions?

    2. Is there a "rule of thumb" magnitude relationship between motion and
    static measures of conspicuity? IOW, what is the ratio of absolute motion
    to absolute static conspicuities?

    3. Is it sensible (as typically assumed) that motion cues ensue only from
    luminance representations, and not chromatic?

    Regards,

    Frank J. Iannarilli, franki@aerodyne.com
    Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821 USA
    www.aerodyne.com/cosr.html

    Frank J. Iannarilli, franki@aerodyne.com
    Aerodyne Research, Inc., 45 Manning Rd., Billerica, MA 01821 USA
    www.aerodyne.com/cosr.html



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