Tone mapping

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

Adaptive Dynamic Range Reduction for SAR Images

Abstract: The visualization of SAR images involves the mapping of high dynamic range amplitude values to gray levels for lower dynamic range display devices. This dynamic range reduction process determines the visibility of details in the displayed result. It is therefore an important part of SAR visualization systems. The problem of dynamic range reduction for SAR images is related to the tone mapping problem for optical images. Tone mapping is used to prepare high dynamic range optical images for display on lower dynamic range display devices. In this paper, we present new dynamic range reduction methods for SAR images. The methods are based tone mapping techniques. They are adaptive, improve the visibility of local details, and are suitable for use in interactive visualization systems.

Multi-exposure image fusion method

Abstract: The invention provides a multi-exposure image fusion method. The multi-exposure image fusion method comprises the following steps: inputting an original image; performing feature analysis on the original image; obtaining an exposure type of the original image; adjusting the exposure value of a camera simulation curve function according to the exposure type of the original image; generating k exposure images with different exposure degrees, respectively calculating a brightness mean value weight, a saturation weight and a contrast weight of each exposure image; calculating to obtain a fusion weight of each exposure image according to the brightness mean value weight, saturation weight and contrast weight of each exposure image; weighing and fusing k exposure images with different exposure degrees according to the fusion weight of each exposure image. The fusion image is obtained. Tone mapping is carried out on the fusion image to obtain the target image. The problem that a traditional multi-exposure image fusion method enables the target image to be overall ashed and low in contrast is solved. The local contrast of the target image is improved, the color of the target image is enhanced, and the target image presents more details.

Color correction for high dynamic range images using a chromatic adaptation method

Abstract: In the image capturing process using a camera, poor illumination has an influence on the image quality, especially in regards to the contrast and details in the dark regions. Generally, high dynamic range (HDR) imaging techniques are used to match the quality between the real scene and the displayed image. However, in images using the multi-exposure technique or regular photography, the images are limited by the veiling glare, which is scene-, exposure-, lens-, aperture-, and camera-dependent. This study mainly addressed images using the multi-exposure technique and developed a color correction scheme that uses a chromatic adaptation method. In the tone mapping using a Gaussian pyramid, the adaptation level is obtained based on a linear Gaussian filter. The resulting image is then processed through the developed tone-mapping function. This allows the chromatic adaptation method to address the mismatches between the real world and the displayed image. The experiment results show that the proposed method yields a better color correction performance compared to conventional methods.

Optimizing the high dynamic range imaging pipeline

Abstract: High dynamic range (HDR) imaging is a rapidly growing field in computer graphics and image processing. It allows capture, storage, processing, and display of photographic information within a scene-referred framework. The HDR imaging pipeline consists of the major steps an HDR image is expected to go through from capture to display. It involves various techniques to create HDR images, pixel encodings and file formats for storage, tone mapping for display on conventional display devices and direct display on HDR capable screens. Each of these stages have important open problems, which need to be addressed for a smoother transition to an HDR imaging pipeline. We addressed some of these important problems such as noise reduction in HDR imagery, preservation of color appearance, validation of tone mapping operators, and image display on HDR monitors. The aim of this thesis is thus, to present our findings and describe the research we have conducted within the framework of optimizing the HDR imaging pipeline.