Multiple exposure

Abstract: A wide dynamic range CMOS image sensor with a burst readout multiple exposure method is proposed. In this method, maximally four different exposure-time signals are read out in one frame. To achieve the high-speed readout, a compact cyclic analog-to-digital converter (ADC) with noise canceling function is proposed and arrays of the cyclic ADCs are integrated at the column. A prototype wide dynamic range CMOS image sensor has been developed with 0.25-/spl mu/m 1-poly 4-metal CMOS image sensor technology. The dynamic range is expanded maximally by a factor of 1791 compared to the case of single exposure. The dynamic range is measured to be 19.8 bit or 119 dB. The 12-bit ADC integrated at the column of the CMOS image sensor has DNL of +0.2/-0.8 LSB.

Abstract: Most imaging sensors have limited dynamic range and hence are sensitive to only a part of the illumination range present in a natural scene. The dynamic range can be improved by acquiring multiple images of the same scene under different exposure settings and then combining them. In this paper, we describe a camera design for simultaneously acquiring multiple images. The cross-section of the incoming beam from a scene point is partitioned into as many parts as the required number of images. This is done by splitting the aperture into multiple parts and directing the beam exiting from each in a different direction using an assembly of mirrors. A sensor is placed in the path of each beam and exposure of each sensor is controlled either by appropriately setting its exposure parameter, or by splitting the incoming beam unevenly. The resulting multiple exposure images are used to construct a high dynamic range image. We have implemented a video-rate camera based on this design and the results obtained are presented.

Abstract: A panoramic high-dynamic range (HDR) image method and system of combining multiple images having different exposures and at least partial spatial overlap wherein each of the images may have scene motion, camera motion, or both. The major part of the panoramic HDR image method and system is a two-pass optimization-based approach that first defines the position of the objects in a scene and then fills in the dynamic range when possible and consistent. Data costs are created to encourage radiance values that are both consistent with object placement (defined by the first pass) and of a higher signal-to-noise ratio. Seam costs are used to ensure that transitions occur in regions of consistent radiances. The result is a high-quality panoramic HDR image having the full available spatial extent of the scene along with the full available exposure range.