Olympus files a patent for HDR exposure bracketing during live preview
posted Tuesday, August 26, 2014 at 9:30 AM EST
Due to the limited dynamic range of digital imaging sensors, high contrast scenes often require the capture of bracketed exposures and subsequent HDR conversion in order to convey their full tonal range. The capture of bracketed exposures usually takes a couple seconds, depending on how many exposures are taken, and it requires both camera and subject to stay absolutely still during the whole process.
In addition to that, there's no way of previewing the effect of a specific exposure bracketing setting, as the bracketed exposures are usually only combined into an HDR exposure after they were taken. While some cameras sport an integrated HDR mode that does all the work, many advanced and professional photographers prefer to create their HDR images after the shoot on the computer.
A new patent from Olympus, which was recently published by Egami, appears not only to be solving the preview issue, but also to speed up the whole HDR capturing process at the same time. Instead of a steady stream of live-view images at the 'correct' exposure setting, the camera captures over- and underexposed live-view images in rapid succession.
If we understand Egami's description of the patent correctly, not only can an HDR preview be created during live view this way, but the exposure information from the bracketed live view images can also be used to create an HDR image from only a single, 'correct' exposure. This would speed up the HDR capturing process up significantly, as the over- and underexposed images are already being captured before the shutter button is pressed.
The patent description also adresses the issue of the lower resolution of the bracketed live view images as compared to the final full exposure, and mentions that "interpolation processing and synthesizing the image of the appropriate exposure" (machine translation) will be performed. However, considering that modern sensors are already capable of recording 4K video footage at high frame rates, it is entirely possible that future cameras could include such a live HDR mode that would record live view images at full resolution.
For now, we have to take this patent as what it is, a sketch of a possible technology that may or may not be implemented in actual products anytime soon. In any case, it's a very enticing concept that we'd love to see realized in future camera models.