Experiment II: Control vs. Illusion Results.

<p>Accuracy (in terms of % correct) for the control versus ML images. Values shown are the average of 10 runs. Error bars indicate standard error of the mean.</p

HMAX Model architecture.

<p>Information flows unidirectionally through the hierarchical layers. Input to the system is a 256×256 greyscale image and the output is a classification of the image as LONG or SHORT. The input image is first transformed onto multiple scales via the Image Layer. The following four layers alternate in their functionality, dedicated to template matching (S layers) or feature pooling (C layers). The final SVM layer performs binary classification.</p

Experiment III: Illusion Strength Affected by Angle.

<p>Results here are plotted as psychometric curves with values on the left representing the SHORT condition, and values on the right representing the LONG condition. The control condition with all angles collapsed shows no bias. For illusory lines with 40 degree fins we see a PSE of approximately 12 pixels. Illusory lines with 20 degree fins show a larger PSE, congruent with human data. Illusory lines with 60 degree fins no longer demonstrate an illusory effect, indicated by intersection of the curve through 50% when the line length difference is zero.</p

Experiment I: Control Results.

<p>Accuracy for the control condition versus the network size of S2 units. Values shown are the average of 10 runs. Error bars show standard error of the mean.</p

Images presented to the model, categorised as LONG (top row) or SHORT (bottom row).

<p><i>Column 1</i>: Cross Fin (XF) images are used for training in all experiments. <i>Column 2</i>: Control (LR) images are used to test accuracy levels for a standard stimulus. <i>Column 3</i>: Illusion (ML) images are used to test performance levels for images that induce human perceptual error.</p

The ML illusion in various forms.

<p>A: The classical four-wing form illustrates the perceptual effect of the top line appearing shorter than the bottom line, even though the lines are of equal length. B: Terminating circles still induce a perceptual effect of line length misjudgement. C: The effect persists even when shafts are removed from the original figure.</p

An image of the Müller-Lyer Illusion high and low pass filtered.

<p>A: the original image B: The image high pass filtered at 5 cycles per image. C: The image low pass filtered at 5 cycles per image.</p