A digital imaging system includes an image sensor, a frame buffer and a
tone correction circuit. The tone correction circuit computes tone
corrected pixel data using one or more tone correction curves. In
operation, tone corrected pixel data for a first pixel is computed by
generating a pixel mask for an m.times.n neighborhood of pixels
surrounding the first pixel, applying a blending mask of weight factors
to the pixel mask and computing a selector value based on the pixel mask
and weight factors associated with the blending mask. The selector value
is used to derive a first tone correction curve for use to compute the
tone corrected pixel data for the first pixel. The first tone correction
curve can be selected from the multiple tone correction curves based on
the selector value or it can be derived by blending multiple tone
correction curves based on the selector value.