Two eyes' views together contain more spatial or geometric information than what can be represent faithfully from one vantage point. Just as it is impossible to paint an "authentic" picture on canvas, it is impossible for the visual system to make a "faithful visual" picture. We conducted several psychophysical experiments using stereoscopic displays. Experimental results on judging direction showed that the visual system solves the problem of fitting the two eyes' views, in their entirety, into a single cyclopean view by "displacing" and "compressing", perceptually, a portion of the visual field. The experimental results on judging shape showed that the visual system has a "correcting" mechanism to adjust for the consequences of the directional displacement and compression. We hypothesize that the operation of this "correcting" mechanism is triggered by the pictoral cue of occlusion and that this mechanism is responsible for the Kanizsa and Poggendorff illusions when three-dimensional stimuli are drawn a sheet of paper.
A new pattern comparison method called LDM (log-derivative- matching) based on the calculus of object reflectance is proposed. We introduce a log-derivative operator for the local operator, and correlation for global integration. We show two facts about LDM: (1) Under a few assumptions on illumination change, our log-derivative operator minimizes the influence of illuminaton. (2) The LDM method can be used for pattern comparison. Experimental results and also a mathematical analysis show that the proposed method permits pattern matching even under strong shadow.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.