Today, most advanced mobile phone cameras integrate multi-image technologies such as high dynamic range (HDR) imaging. The objective of HDR imaging is to overcome some of the limitations imposed by the sensor physics, which limit the performance of small camera sensors used in mobile phones compared to larger sensors used in digital single-lens reflex (DSLR) cameras. In this context, it becomes more and more important to establish new image quality measurement protocols and test scenes that can differentiate the image quality performance of these devices. In this work, we describe image quality measurements for HDR scenes covering local contrast preservation, texture preservation, color consistency, and noise stability. By monitoring these four attributes in both the bright and dark parts of the image, over different dynamic ranges, we benchmarked four leading smartphone cameras using different technologies and contrasted the results with subjective evaluations.
Differential Binary Pixel Technology is a threshold-based timing, readout and image reconstruction method that utilizes sub-frame partial charge transfer technique in a standard four-transistor (4T) pixel CMOS Image sensor (CIS) to achieve HDR video with Stop Motion. This technology improves low light signal-tonoise ratio (SNR) by up to 21dB. The method is verified in silicon using a TSMC 65nm 1.1μm pixel technology 1 megapixel (MP) test chip array and is compared with a traditional 4× oversampling technique using full charge transfer. The test chip is also compared with the iPhone 6s rear view camera to show superior HDR video capability.