Disclosed are method and apparatus for obtaining relatively high dynamic
range images using a relatively low dynamic range image sensor without
significant loss of resolution. The image sensor has an array of
light-sensing elements with different sensitivity levels in accordance
with a predetermined spatially varying sensitivity pattern for the array
of light-sensing elements. An image of a scene is captured with the image
sensor and stored as brightness values at respective pixel positions in a
linear or two-dimensional uniform grid. The brightness values of the
captured image at the pixel positions are then used to estimate the
brightness values at off-grid positions of a uniform off-grid array
located at respective interstices of the pixel position grid. The
estimated off-grid brightness values are either used directly as the
pixel brightness values of a relatively high dynamic output image or
interpolated to derive resampled on-grid brightness values at the pixel
positions of the pixel position grid to provide a relatively high dynamic
range output image. Alternatively, the brightness values of the captured
image are interpolated by an on-grid interpolation filter to derive pixel
brightness values of a relatively high dynamic range output image, each
pixel brightness value of the output image being derived from a
corresponding plurality of the captured image brightness values. In each
instance, either the captured image brightness values or the pixel
brightness values of the output image may be compensated for
non-linearities of the radiometric response function of the light-sensing
elements of the image sensor.