1. Imaging apparatus, comprising: a first non-linear mapping circuit, which is configured to receive a stream of input pixel values and to implement a first non-linear mapping function to map the input pixel values to a mapped stream of mapped pixel values, wherein the input pixel values have an input blur caused by a point spread function (PSF) of a set of objective optics, wherein the input pixel values include a first subset of low-amplitude pixel values having a first range of amplitude values, and wherein the first non-linear mapping function maps the first subset of low-amplitude pixel values to a first corresponding subset of mapped pixel values having a first mapped range of amplitude values that is greater than the first range of amplitude values, such that the first non-linear mapping function causes the first subset of low-amplitude pixel values to be spread out over a larger range of mapped pixel values; and a linear convolution filter, which is configured to filter the mapped stream of mapped pixel values to generate a filtered stream of filtered pixel values, wherein the linear convolution filter comprises a deconvolution filter, which has a filter kernel determined according to the PSF, and which is configured to filter the mapped pixel values to cause the filtered pixel values to have less blur than the input pixel values.