Tone mapping

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

Image data processing for multi-exposure wide dynamic range image data

Abstract: Disclosed examples include integrated circuits, merge circuits and methods of processing multiple-exposure image data, in which a single pre-processing circuit is used for pre-processing first input exposure data associated with a first exposure of the image, and then for pre-processing second input exposure data associated with a second exposure of the image, and the first and second pre-processed exposure data are merged to generate merged image data for tone mapping and other post-processing. An example merge circuit includes a configurable gain circuit to apply a gain to the first and/or second exposure data, as well as a configurable weighting circuit with a weight calculation circuit and a motion adaptive filter circuit to compute a first and second weight values for merging the pre-processed first and second exposure data.

A 148dB focal-plane tone-mapping QCIF imager

Abstract: This paper presents a QCIF HDR imager where visual information is simultaneously captured and adaptively compressed by an in-pixel tone-mapping scheme [1]. The tone mapping curve (TMC) is calculated from the histogram of an auxiliary previous image, which serves as a probability indicator of the distribution of illuminations within the current frame. The chip maps 148dB scenes onto 7-bit/pixel coding, containing illuminations from 2.2mlux (SNR10) to 55.33klux -with extreme values captured at 8s and 2.34µs, respectively. Pixels use an Nwell-Psubstrate photodiode and autozeroing for establishing the reset voltage. Measured sensitivity is 5.79 V over lux·s. Dark current effects in the final image are attenuated by an automatic programming of the DAC levels. The chip has been fabricated in the 0.35µm OPTO technology from AMS.

Image processing for wide dynamic range (wdr) sensor data

Abstract: A signal processing chain implements wide dynamic range (WDR) multi-frame processing including receiving raw image signals from a WDR sensor including a plurality of frames including a first frame including first exposure time pixel data and a second frame including second exposure time pixel data. Statistics for camera control are generated including first statistics for the first pixel data and second statistics for the second pixel data. The first and second pixel data are merged using WDR merge algorithm in a WDR merge block which utilizes the first and second statistics to generate a raw higher bit width single frame image. The single frame image is post-processed in post-processing block using at least a defect pixel correction algorithm, and at least a portion of tone mapping is performed on the single frame image after the post-processing to provide an output toned mapped image.

µ-Law Based HDR Coding and Its Error Analysis

Abstract: In this paper, we propose a coding algorithm for High Dynamic Range Images (HDRI). Our encoder applies a tone mapping model based on scaled µ-Law encoding, followed by a conventional Low Dynamic Range Image (LDRI) encoder. The tone mapping model is designed to minimize the difference between the tone-mapped HDRI and its LDR version. By virtue of the nature of the µ-Law model, not only the quality of the HDRI but also the one of the LDRI is improved, compared with a state of the art in conventional HDRI coding methods. Furthermore the error limit caused by our encoding is theoretically analyzed.