Aimed at standardizing camera modules in mobile devices, Nokia and STMicroelectronics today announced a comprehensive specification, Standard Mobile Imaging Architecture (SMIA), that covers electrical, mechanical and functional interfaces, along with characterization, optical performance and reliability.

With camera phone shipments expected to exceed 200 million units this year, demand for higher image quality and resolution is on the rise. SMIA is an effort to fulfill these new requirements and enable mobile handset vendors to work with multiple suppliers. Further, the target of SMIA is to specify functional and optical behavior of camera modules and therefore enable cost-efficient multiple sourcing of the module at the phone level.

ST and Nokia worked on the spec for more than two years with both companies contributing intellectual property to its development.

The demand for higher image resolution to mega pixel and beyond has prompted the need for increasing bandwidth on the interface, while keeping the pin count low and EMI (electro-magnetic interference) consistent with mobile phone design constraints. In addition, significant cost reductions are made possible by optimizing the architecture of the camera phone as a whole, as opposed to viewing the camera as a peripheral subsystem. SMIA proposes a framework for defining the related metrics including imaging sub-element partitioning to enable independent technology evolution and optimal design development. The optics and sensor will be implemented on the SMIA camera module and imaging processing will be executed based on a partitioned architecture approach, for example, by the mobile phone’s main application processor engine.

The SMIA standard focuses on six areas that cover all key aspects of a camera module such as the electrical interface specifying the physical layer (voltage levels, pin-count, timing), data rate (up to 650Mbits/sec), EMI performance, and output image format; the functional specification specifying frame and field formats, register maps for set-up and control, and three profiles that help video usability with high resolution sensors; the mechanical interface proposes a family of set of modules that provide mechanical outlines specifically designed for volume manufacturing; characterization of optical-performance metrics and sensor noise standards; reliability by environmental-test and drop-test standards.

A software model is also provided in the SMIA specification, including reference device drivers and software architecture.

Nokia and ST hold the patents and other intellectual property utilized in the SMIA specification, however, have opened them up to any third party and will not assert those rights against anyone implementing a fully compliant SMIA module in a no fee or royalty model.

By: DocMemory
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