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.

Two approaches to derive LED driving signals for high‐dynamic‐range LCD backlights

Abstract: — The LED-array backlight technique dramatically enhances the dynamic range of an LCD and hence extends its ability to present images with high reality. This is achieved by modulating LEDs individually, thus providing an area-adaptive backlight for the display. The spatial overlap of light from the LED (crosstalk) occurs due to the diffusion screen placed between the backlight and LCD layer. However, the crosstalk is not only a blessing for supplying high brightness but is also a curse for causing potential artifacts, making the derivation of an LED driving signal a challenging task. This paper formulates the problem into two mathematical models: an iterative de-convolution approach and a linear optimization approach. Algorithms for solving these two models are provided. The first approach provides instantaneous and satisfactory results except for high-intensity highlights in the image. The linear optimization method conquers this drawback, but requires much more computation, possibly requiring preprocessing of the target, and also introduces undesired artifacts. These two approaches are extensively evaluated by building an image database composed of 161 high-dynamic-range images.

High-dynamic-range ultra wide band transceiver

Abstract: An UWB Transceiver for Multi-Band OFDM communication including an antenna switch ( 342 ), a receive front end and down-converter ( 303 ), an up-converter and power amplifier ( 305 ), and a frequency synthesizer ( 211 ). The transceiver achieves high dynamic range by employing a synthesizer ( 211 ) with very low spurious components and a receive front end with an efficient receive RF filtering embodiment. The synthesizer ( 211 ) may rapidly switch frequencies in a manner that minimizes spurious components outside the band group used for communication. The receiver ( 200 ) also achieves high selectivity and sensitivity by dividing the receive signal path into even and odd band groups.

Neural Auto-Exposure for High-Dynamic Range Object Detection

Abstract: Real-world scenes have a dynamic range of up to 280 dB that todays imaging sensors cannot directly capture. Existing live vision pipelines tackle this fundamental challenge by relying on high dynamic range (HDR) sensors that try to recover HDR images from multiple captures with different exposures. While HDR sensors substantially increase the dynamic range, they are not without disadvantages, including severe artifacts for dynamic scenes, reduced fill-factor, lower resolution, and high sensor cost. At the same time, traditional auto-exposure methods for low-dynamic range sensors have advanced as proprietary methods relying on image statistics separated from downstream vision algorithms. In this work, we revisit auto-exposure control as an alternative to HDR sensors. We propose a neural net-work for exposure selection that is trained jointly, end-to-end with an object detector and an image signal processing (ISP) pipeline. To this end, we use an HDR dataset for automotive object detection and an HDR training procedure. We validate that the proposed neural auto-exposure control, which is tailored to object detection, outperforms conventional auto-exposure methods by more than 6 points in mean average precision (mAP).

High Dynamic Range image & video compression a review

Abstract: High Dynamic Range (HDR) imaging technologies can provide high levels of immersion through a dynamic range that meets and even exceeds the instantaneous range of the Human Visual System (HVS). This increase in the level of immersion comes at the cost of significantly higher bit-rate requirements compared to those associated with conventional imaging technologies. As a result, efficient HDR-relevant coding solutions have to be developed. In this paper, we present a review of existing HDR image and video coding methods, thus establishing the current state of the art. We additionally present some of our own recent results in this area.

Inter-layer prediction for backwards compatible high dynamic range video coding with SVC

Abstract: We present a backwards compatible high dynamic range video coding framework based on H.264/AVC. It allows to extract a standard low dynamic range (LDR) as well as high dynamic range (HDR) video from one compressed bit stream. A joint global and local inter-layer prediction method is proposed to reduce the redundancy between the LDR and HDR layers. It is based on a common color space which can represent HDR video data perceptually lossless. We show how the inter-layer prediction parameters can be estimated in a rate-distortion optimized way and efficiently encoded to reduce side information. Our evaluations demonstrate that the proposed framework performs best, compared to the state-of-the-art for arbitrary tone-mapping operators. W.r.t. simulcast it allows for up to 50% bit rate saving.