Pulse or flash lighting may be used, for instance, to provide short-term illumination to a dark scene or to change the quality of an existing light, such as an ambient light, and is widely used in many field, including, for instance, in photography, stage lighting, art illumination, medical illumination, etc. Traditionally, electronic flashes provide light with a satisfactory high intensity and short flash duration. Unfortunately, an illumination target under this type of high-intensity lighting is frequently viewed or imaged as unnatural. Although the flash light provides sufficient illumination to view or image the target, it may also function as a disturbance to the lighting environment, because of its incompatibility with the existing light.
In addition, suitable illumination for viewing or imaging a target may require lighting which facilitates good characterization of the target being illuminated. Such characterization may be completed by measuring optical interaction between the available light and the target. In many cases, existing light is insufficient in terms of illuminance or an ability to reveal the full characteristics of the illumination target in terms of color quality. As a result, a pulse or flash lighting source may be used, which works together with the existing light to shed suitable light on the target, for the purpose of general illumination and/or appropriate characterization of the target. Recently, flash light-emitting diode (LED) illumination has been used as flash sources in, for instance, camera phones with advantages of low voltage operation, high efficiency and small sizes.