Access to eBooks is limited to institutions that have purchased or currently subscribe to the SPIE eBooks program. eBooks are not available via an individual subscription. SPIE books (print and digital) may be purchased individually on SPIE.Org.

Contact your librarian to recommend SPIE eBooks for your organization.
Chapter 6:
Automatic High Dynamic Range Control
Abstract
In most linear response sensors, there are mechanisms for selecting the correct exposure and correct gain to provide the best exposure and noise tradeoff. These regulators act on exposure and gain settings to target a certain average image brightness for a complete image or for a region of an image (or a weighted average of several regions, sometimes called tiles). If the image is too dark, exposure time or gain can be increased. If the image is too bright, exposure time or gain can be decreased. The decision to work on gain or exposure depends on the situation and on the sensor. High gains should be avoided because of the resulting noise amplification and reduction of precision in exposure time settings due to enlarged steps. Exposure time variation is preferable when possible, i.e., until exposure reaches a maximum value, defined by the type of scene and frame rate requirements. Still scenes allow for long exposures, while moving objects require short exposures and a higher gain. Compared to photography, exposure time is the shutter time, and gain is the ISO speed.
Online access to SPIE eBooks is limited to subscribing institutions.
CHAPTER 6


SHARE
Back to Top