Ultra HDR (High Definition Range) is an image format that utilizes improved implementation of existing HDR technology to enhance the visual perception of photos on HDR displays via a luminance modulation technique called gain mapping which reallocates pixel intensity on a per-pixel basis based on its spatial factors. This format was engineered by Google in 2023 and first deployed on the Android 14 operating system. [1].
| Developer(s) | |
|---|---|
| Initial release | 2023 |
| Website | Android Developers |
Comparisons
editUltra HDR format is an enhancement of conventional HDR, where gain mapping technology allows further pushing the boundaries of existing HDR. However, not all displays can render the full capabilities of HDR and Ultra HDR formats. To overcome this issue, a tone mapping technique is used to adjust the brightness and contrast to match the quality of capable displays. HDR has the capability of recording a much wider color gamut in comparison to a traditional 24-bit RGB (SDR). Ultra HDR takes a step further, improving the visualization of the image. Moreover, it has a wider range of tones and subtle gradients, reaching the limits of the Rec.2020 color space, and providing a much wider spectrum than HDR10’s DCI-P3.[2] [3] .
Color Volume
editThe distinctions in between SDR, HDR and Ultra HDR can be can be evaluated using the equation, where Color Volume is used as a metric for the range and richness of colours that each format can show. [4]
Where:
- L(R,G,B) represents luminance function across the RBG colours.
- C(R,G,B) represents coverage function, which captures a color gamut boundaries and bit depth.
- dR represents differential of Red variable R, change in the red channel's intensity
- dG represents differential of Green variable G, change in the green channel's intensity
- dB represents differential of Blue variable B, change in the blue channel's intensity
SDR
editRepresentative values are as follows:
Color VolumeSDR ≈ 1.67 billion
Referring to the calculation of Color Volume, we obtain an approximate value of 1.67 billion across the color space, representing 1.67 billion possible colors variations on RBG Model.
HDR
editRepresentative values are as follows:
Color VolumeSDR ≈ 1 trillion billion
Referring to the calculation of Color Volume, we obtain an approximate value of 1 trillion over the color space, representing 1 trillion possible color variations.
Ultra HDR
editRepresentative values are as follows:
- Luminance: 4000-1000 nits.
- Chromaticity: ≥1 billion colors (DCI-P3 color gamut).
Color VolumeSDR (taking 4000 nits as luminance) ≈ 4.28 trillion billion
Referring to the calculation of Color Volume, we obtain an approximate value of 4.28 trillion over the color space, representing 4.28 trillion possible color variations.
Comparison Summary
editVUltra HDR > VHDR > VSDR
Based on the previously expressed formula, the mathematical comparison can be seen in terms of Color volume capabilities.
See also
editReferences
edit- ^ "HDR photo editing with machine learning". Google Research. Google.
- ^ Reinhard, Erik (2010). High Dynamic Range Imaging. p. 91. ISBN 9780123749147.
- ^ "HDR Color Space Conversion: DCI-P3 vs. Rec. 2020". Ittiam. Ittiam Systems. Retrieved 2024-11-07.
- ^ Kunkel, T (2016). High Dynamic Range Video From Acquisition to Display and Applications. ISBN 978-0-08-100412-8.
- ^ "SDR/HDR standard/high dynamic range". ViCueSoft.
- ^ "HLG HDR". VMI.TV.