Module definition aids handset camera integration

Nokia and STMicroelectronics are releasing a comprehensive specification for camera modules, aimed at standardising this increasingly important component in mobile devices.

Nokia and STMicroelectronics are releasing a comprehensive specification for camera modules, aimed at standardising this increasingly important component in mobile devices.

The specification, dubbed Standard Mobile Imaging Architecture, or SMIA, will cover all aspects of the modules, including their electrical, mechanical, and functional interfaces, and also address other key areas such as characterisation, optical performance, and reliability.

The SMIA specification is offered for free to the mobile imaging industry and is available at www.smia-forum.org.

The mobile-phone camera-module industry has developed rapidly in terms of technology, with dramatic increases in image quality and higher resolution.

SMIA is a standardisation effort to fulfil the emerging new requirements and enable mobile handset vendors to work with multiple suppliers.

SMIA's target is to address the task of specifying functional and optical behavior of camera modules and therefore truly enable cost-efficient multiple sourcing of the module at the phone level.

"The camera phone market will increase rapidly with cameras entering into key product segments of mobile devices".

"Nokia recently estimated that the camera phone market would exceed 200 million units this year".

"SMIA's target is to streamline and accelerate the camera module development, ultimately contributing to creation of the state-of art imaging mobile devices, independent of vendors", said Janne Haavisto, Director, Camera Entity, Nokia Technology Platforms.

"ST and Nokia have worked on this specification for more than two years and both companies are contributing significant intellectual property into SMIA", said Marc Vasseur, General Manager of ST's Imaging Division.

"ST has been immensely successful in this market due to best-in-class pixel performance, sensor and module development capabilities, and full ownership of the manufacturing flow".

"Now, the standardisation of interfaces and system partitioning, via SMIA, will enable us to address significantly more opportunities in the mobile phone industry".

The demand for higher image resolution to megapixel and beyond has prompted the need for increasing bandwidth on the interface, while keeping the pin count low and EMI consistent with mobile phone design constraints.

In addition, significant cost reductions are made possible by optimising 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.

SMIA specifies imaging subelement partitioning that will enable independent technology evolution and optimal design development.

Based on a partitioned architecture approach, the optics and sensor will be implemented on the SMIA camera module and imaging processing will be executed, for example, by the mobile phone's main application processor engine.

SMIA has six chapters that cover all key aspects of a camera module.

The electrical interface specifies the physical layer (voltage levels, pin-count, timing), datarate (up to 650Mbit/s), EMI performance, and output image format.

The functional specification specifies frame and field formats, register maps for setup and control and has three profiles that helps easy 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.

The characterisation chapter provides for optical-performance metrics and sensor noise standards.

The reliability chapter includes environmental-test and drop-test standards Finally, a software model is also provided in the SMIA specification, including reference device drivers and software architecture.

Although Nokia and ST hold key patents and other intellectual property in the SMIA specification, both companies have decided to open these up to any third party and will not assert those rights against anyone implementing a fully compliant SMIA module.

No fee, nor royalty, will be levied.

A simple licence form can be found on www.smia-forum.org.

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