Tone mapping

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

Methods and Apparatus for Tone Mapping High Dynamic Range Images

Abstract: Methods, apparatus, and computer-readable storage media for tone mapping High Dynamic Range (HDR) images An input HDR image is separated into luminance and color Luminance is processed to obtain a base layer and a detail layer The base layer is compressed according to a non-linear remapping function to reduce the dynamic range, and the detail layer is adjusted The layers are combined to generate output luminance, and the output luminance and color are combined to generate an output image A base layer compression technique may be used that analyzes the details and compresses the base layer accordingly to provide space at the top of the intensity scale where the details are displayed to thus generate output images that are visually better than images generated using conventional techniques User interface elements may be provided via which a user may control one or more parameters of the tone mapping method

Modeling Radiometric Uncertainty for Vision with Tone-Mapped Color Images.

Abstract: To produce images that are suitable for display, tone-mapping is widely used in digital cameras to map linear color measurements into narrow gamuts with limited dynamic range. This introduces non-linear distortion that must be undone, through a radiometric calibration process, before computer vision systems can analyze such photographs radiometrically. This paper considers the inherent uncertainty of undoing the effects of tone-mapping. We observe that this uncertainty varies substantially across color space, making some pixels more reliable than others. We introduce a model for this uncertainty and a method for fitting it to a given camera or imaging pipeline. Once fit, the model provides for each pixel in a tone-mapped digital photograph a probability distribution over linear scene colors that could have induced it. We demonstrate how these distributions can be useful for visual inference by incorporating them into estimation algorithms for a representative set of vision tasks.

Vehicle camera image quality improvement in poor visibility conditions by contrast amplification

Abstract: A vision system for a vehicle includes an imaging sensor disposed at the vehicle and having an exterior field of view, and an image processor. The imaging sensor captures image data and the image processor is operable to process successive frames of captured image data. Responsive to a determination of a low visibility driving condition, the image processor increases the contrast of the captured images to enhance discrimination of objects in the field of view of the imaging sensor. The image processor may execute a first brightness transfer function on frames of captured image data to enhance the contrast of captured image data, and may execute a second brightness transfer function over successive frames of earlier captured image data and may execute a tone mapping of the earlier captured image data and the currently captured image data to generate a contrast enhanced output image.

Robust Match Fusion Using Optimization

Abstract: In this paper, we present a novel patch-based match and fusion algorithm by taking account of moving scene in a multiple exposure image sequence using optimization. A uniform iterative approach is developed to match and find the corresponding patches in different exposure images, which are then fused in each iteration. Our approach does not need to align the input multiple exposure images before the fusion process. Considering that the pixel values are affected by various exposure time, we design a new patch-based energy function that will be optimized to improve the matching accuracy. An efficient patch-based exposure fusion approach using the random walker algorithm is developed to preserve the moving objects from the input multiple exposure images. To the best of our knowledge, our algorithm is the first patch-based exposure fusion work to preserve the moving objects of dynamic scenes that does not need the registration process of different exposure images. Experimental results of moving scenes demonstrate that our algorithm achieves visually pleasing fusion results without ghosting artifacts, while the results produced by the state-of-the-art exposure fusion and tone mapping algorithms exhibit different levels of ghosting artifacts.

Generation of Tone Mapping Function for Dynamic Pixel and Backlight Control

Abstract: Systems, methods, and devices are provided for generating a tone mapping function used in adjusting the power consumed by a backlight of an electronic display. One such method includes sampling an image frame in framebuffer space and generating a tone mapping function in linear space. The tone mapping function may have at least two portions: a nondistorting portion that does not to distort pixels to which it applies when an intensity of a backlight of the electronic display is modified and a distorting portion that does distort pixels to which it applies when the intensity of the backlight is modified. Thereafter, the intensity of the backlight may be modified based at least in part on the nondistorting portion of the tone mapping function, the tone mapping function converted to framebuffer space, and the tone mapping function applied to the image frame or a subsequent image frame.