The Fusion of Optics and Digital Image Processing: JOIPO Platform
To create high-performance, ultra-compact, and sophisticated electro-optical imaging systems, we have established our JOIPO platform to design the conventional separate lens optics and electronic image processing subsystems as an integrated system.
JOIPO (Joint Optics/Image Processing Optimization): A new way of thinking
JOIPO is a new platform Ricoh established to design the electro-optical imaging systems used in many image sensors, such as those found in industrial cameras, car-mounted cameras, document scanners, telescopes, and endoscopes. In the past, the lens optics and electronic image processing subsystems were designed separately, but by designing these subsystems simultaneously, we are able to achieve high-performance, ultra-compact, and sophisticated imaging systems.
For hundreds of years, optics designers have sought imaging systems able to obtain high-quality optical images from the lens optics alone, based on the premise that the final image would be viewed by the human eye. Recently, however, it has become possible for optical images formed by lenses to be subsequently sensed by digital sensors such as CMOS sensors or CCD arrays, digitally processed, and viewed as beautiful digital images on a display screen.
With traditional design methods, high-quality lens optics and high-quality digital image processing were designed separately, and then combined to form the imaging system as a whole. In contrast, JOIPO was achieved when we realized that images in the optical sensing stage do not need to be beautiful, because the interim optical image temporarily formed on a digital sensor is only "seen" by a computer and not a person. This realization allowed us to pursue freer and bolder ideas in our designs, making it possible to overcome the limits of imaging systems designed using the traditional approach.
Figure 1: Higher definition realized by fusing optics and digital image processing
Thanks to this fresh perspective, imaging systems built on top of the JOIPO platform bring with them a variety of unprecedented advantages.
With imaging systems designed using JOIPO, we can decrease the number of lenses compared to conventional systems. This is possible because there is no need to absorb distortions, defocusing, or other image defects using costly lens optics alone; images can be recovered by subsequent digital image processing. Fewer lenses also enable the optics to be substantially reduced in size.
Further, by controlling lens distortion and defocusing for subsequent cleanup by digital image processing before output, it becomes possible to add features not available in conventional imaging systems. These features include extending the depth of field while maintaining brightness (Extended Depth-of-Field Camera), precisely measuring the distance to an object (Stereo Camera), and acquiring multispectral images (Multispectral Camera).
Beyond the above, it is now possible to design systems where temperature-related changes in the optics are corrected for by digital image processing in applications where lens thermal characteristics are extremely important. As a result, imaging systems usable over much wider temperature ranges can become a reality.
By actively using the JOIPO platform in this way, we are able to achieve compact and sophisticated imaging systems that would have been unthinkable in the past.