High dynamic range

About: High dynamic range is a research topic. Over the lifetime, 4280 publications have been published within this topic receiving 76293 citations. The topic is also known as: HDR.

High quality HDR video compression using HEVC main 10 profile

Abstract: This paper describes high-quality compression of high dynamic range (HDR) video using existing tools such as the HEVC Main 10 profile, the SMPTE ST 2084 (PQ) transfer function, and the BT.2020 non-constant luminance Y'CbCr color representation. First, we present novel mathematical bounds that reduce complexity of luminance-preserving subsampling (luma adjustment). A nested look-up table allows for further speedup. Second, an adaptive QP scheme is presented that obtains a better bit allocation balance between dark and bright areas of the picture. Third, a method to control the bit allocation balance between chroma and luma by adjusting the chroma QP offset is presented. The result is a considerable increase in perceptual quality compared to the anchors used in the 2015 MPEG High Dynamic Range/Wide Color Gamut Call for Evidence. All techniques are encoder-side-only, making them compatible with a regular decoder capable of supporting HEVC Main10/PQ/BT.2020, which is already available in some TV sets on the market.

Scene-adaptive high dynamic range display for low latency augmented reality

Abstract: For generalized augmented reality to be feasible, the augmenting elements must be visible in varied environments and under rapidly changing, high dynamic range lighting, from bright sunlight to deep shadows. We present a high dynamic range, optical see-through, augmented reality display that dynamically adjusts the brightness of the virtual imagery to match the current brightness of the real scene. Critical components include the spatial brightness sensor array and the positional brightness image intensity matcher. The color, scene-adaptive HDR display system is based on a high-rate (15 kHz) DMD projector using a high-speed RGB LED illuminator, each color with independent 16 bit intensity control for each binary DMD frame. The critical input to the intensity matching algorithm is the output of an array of high sensitivity light sensors. This paper discusses the implementation of the system and reports performance via still and video demonstrations under a variety of lighting conditions.

Amorphous silicon phototransistor as nonlinear optical device for high dynamic range imagers

Abstract: An amorphous silicon bulk barrier phototransistor is studied as a basic element for the pixel of high dynamic photosensor arrays. The device is an n-i-/spl delta/p-i-n structure whose optical gain shows a nonlinear dependence on the illumination intensity. For each applied bias voltage, a quasi-hyperbolic decrease of the optical gain as a function of the incident power is found. This behavior can be explained taking into account both the material characteristics (defect distribution, dopant concentration), and the structure properties. Our measurements lead to a minimum detectable signal of about 0.7 nW/cm/sup 2/ independently on the applied voltage, making the device suitable for low illumination conditions. On the other hand, by increasing the input power up to 35 mW/cm/sup 2/, we did not find saturation of output photocurrent leading to a dynamic range of at least of 120 dB. This value can be further increased by using as basic cell of the pixel the phototransistor and a resistor connected between the voltage supply and the collector electrode.

Systems and methods for backward compatible high dynamic range/wide color gamut video coding and rendering

Abstract: A method to encode high dynamic range and wide color gamut video content with a backward compatible base layer. The base layer may be an HDTV or UHDTV program with Rec.709 colorimetry coded with AVC/H.264 or HEVC/H.265. The coding method provides information for properly rendering the content on displays with a wide range of color and brightness capabilities.

Robust Watermarking Framework for High Dynamic Range Images Against Tone-Mapping Attacks

Abstract: As digital cameras become more and more popular recently, it is very easy for us to take many digital photos. Unfortunately, they are rarely true measurements of relative radiance in the scene due to the limited dynamic range in the image acquisition devices. High dynamic range (HDR) images emphasis in image processing fields because they can accommodate a greater dynamic range of luminance between the brightest and darkest parts of an image. Dynamic range is the ratio between the brightest and darkest luminance values of a scene. In general, human eyes can handle a very large dynamic range of approximately 100000:1 in a single view. However, a standard photo taken with a standard camera with film or an electronic imaging array always has a limited dynamic range [1]. A standard image, called a LDR image, cannot reproduce the luminance ratio observed in the real world. A scene containing very bright highlights and deep shadows always loses some detail if the exposure time is not suitably determined. Over the past decade, many researchers have developed HDR imaging techniques (Debevec & Malik, 1997)(Reinhard et al, 2005) (Reinhard et al, 2007). Debevec and Malik proposed a method to recover the single high dynamic range radiance map from multiple images with different exposure times (Debevec & Malik, 1997), this method has been implemented in many HDR software.