  High Dynamic Range (HDR) imaging is gaining increased attention due to its
realistic content, for not only regular displays but also smartphones. Before
sufficient HDR content is distributed, HDR visualization still relies mostly on
converting Standard Dynamic Range (SDR) content. SDR images are often
quantized, or bit depth reduced, before SDR-to-HDR conversion, e.g. for video
transmission. Quantization can easily lead to banding artefacts. In some
computing and/or memory I/O limited environment, the traditional solution using
spatial neighborhood information is not feasible. Our method includes noise
generation (offline) and noise injection (online), and operates on pixels of
the quantized image. We vary the magnitude and structure of the noise pattern
adaptively based on the luma of the quantized pixel and the slope of the
inverse-tone mapping function. Subjective user evaluations confirm the superior
performance of our technique.
