Figure 2. Reconstruction of natural scenes from the responses of
a population of neurons. (a), Receptive fields of 177 cells used
in the reconstruction. Each receptive field was fitted with a
two-dimensional Gaussian function. Each ellipse represents the contour at
one standard deviation from the center of the Gaussian fit. Note that the
actual receptive fields (including surround) are considerably larger than
these ellipses. Red: On center. Blue: Off center.
An area of 32 by 32 pixels (0.2 degrees/pixel) where movie signals were
reconstructed is outlined in white. The grid inside the white square
delineates the pixels. (b), Comparison between the actual and the
reconstructed images in an area of 6.4 degrees by 6.4 degrees
(white square in (a)). Each panel shows four consecutive frames
(interframe interval: 31.1 msec) of the actual (upper) and the
reconstructed (lower) movies. Top panel: scenes in the woods,
with two trunks of trees as the most prominent objects. Middle
panel: scenes in the woods, with smaller tree branches. Bottom
panel: a face at slightly different displacements on the screen.
(c), Quantitative comparison between the reconstructed and the actual movie
signals. Top: histogram of temporal correlation coefficients
between the actual and the reconstructed signals (both as functions of time)
at each pixel. The histogram was generated from 1024 (32x32)
pixels in the white square. Bottom: histogram of spatial
correlation coefficients between the actual and the reconstructed signals
(both as functions of spatial position) at each frame. The histogram was
generated from 4096 frames (512 frames/movie, 8 movies).
Last modified by GBS on August 20, 1999