HDR Image Processing from Embedded Cell Phone Camera

Abstract

In photo-realistic image synthesis the incoming light from the environment is particularly important. In this work we focus on capturing the incoming light in the form of the radiance map using a common mobile device. This involves the reconstruction of the spherical panorama sky-dome in high dynamic range (HDR) quality and save it to a usable data format. Our setup requires a common smartphone devices with an additional fish-eye lens attached to the camera. In this paper we discuss the calibration of our setup and the implementation of selected tone mapping operator (TMO) allowing satisfactory display of HDR images on the mobile device screen. Built-in cameras on mobile devices do not generally capture the HDR image. In this work, we describe an algorithm for capturing an HDR image on the Android platform. Using an optimization method we are able to acquire the camera response curve needed in the reconstruction of the HDR image from multiple snapshots. Subsequent HDR panoramas represent radiance sphere-maps of the incoming light from an environment. These radiance sphere-maps are useful in realistic image synthesis to illuminate the objects in the 3D scenes.