Tone mapping

About: Tone mapping is a research topic. Over the lifetime, 1713 publications have been published within this topic receiving 48490 citations.

High Dynamic Range Visual Quality of Experience Measurement: Challenges and Perspectives

Abstract: Traditional capture and display devices can only support a limited dynamic range (contrast) and color gamut given the hardware limitations. As a result, the real physical luminance present in a natural scene cannot be captured by these. However, with the recent advancements in the related software and hardware technologies, it is now possible to capture or reproduce higher contrast and luminance ranges. Such scene-referred visual signals are known as high dynamic range (HDR) signals. They are visually more appealing because they can represent the dynamic range of the visual stimuli present in the real world more accurately. Not surprisingly, the emergence of HDR is seen as an important step towards improving the visual quality of experience (QoE) of the end users. However, HDR comes with its own set of challenges including capture, storage, processing, display, and so on. This chapter focuses on some of those issues from a QoE viewpoint.

A 1.3 megapixel FPGA-based smart camera for high dynamic range real time video

Abstract: A camera is able to capture only a part of a high dynamic range scene information. The same scene can be fully perceived by the human visual system. This is true especially for real scenes where the difference in light intensity between the dark areas and bright areas is high. The imaging technique which can overcome this problem is called HDR (High Dynamic Range). It produces images from a set of multiple LDR images (Low Dynamic Range), captured with different exposure times. This technique appears as one of the most appropriate and a cheap solution to enhance the dynamic range of captured environments. We developed an FPGA-based smart camera that produces a HDR live video colour stream from three successive acquisitions. Our hardware platform is build around a standard LDR CMOS sensor and a Virtex 6 FPGA board. The hardware architecture embeds a multiple exposure control, a memory management unit, the HDR creating, and the tone mapping. Our video camera enables a real-time video at 60 frames per second for a full sensor resolution of 1, 280 × 1, 024 pixels.

Compressing high dynamic range images

Abstract: A method of compressing a high dynamic range original image to provide compressed image data for use with (i) a high dynamic range decoder for viewing the high dynamic range image and (ii) a reduced bit depth decoder for viewing an image of lower dynamic range which has been derived from the high dynamic range original image. The difference between the image of the high dynamic range original image and the lower dynamic range is measured and that difference information is compressed. Compressed image data is produced comprising the compressed image of the lower dynamic range and the compressed image data.

Objective quality assessment of tone-mapped videos

Abstract: With the fast advances in video acquisition, computational imaging, and display technologies, there has been a growing interest in high dynamic range (HDR) videos. Tone mapping operators (TMOs) that convert HDR content to low dynamic range (LDR) ones provide a practically useful solution for the visualization of HDR videos on standard LDR displays, where the user experience highly depends on the performance of the TMOs being used. Without an appropriate perceptual quality measure, different TMOs cannot be compared. Subjective experiments may be a reliable solution, but is time consuming, expensive, and difficult to be embedded into optimization processes. Here we make one of the first attempts to develop an objective quality assessment model for tone-mapped videos that incorporates structural fidelity, statistical naturalness and memory effect. Validation using subject-rated tone-mapped videos show that the proposed method is well-correlated with subjective scores.