Ambarella A5 SoC developed for hybrid cameras

The A5 platform enables key hybrid camera functions such as 10 mega-pixel (MP) still images, full high-definition (HD) recording, and simultaneous dual-resolution recording for fast internet sharing.

The A5 family consists of three products: the A530, A550 and A570.

Each is available with a full reference design.

The A530 integrated circuit can capture 10 MP still pictures while generating and compressing HD video in both 720p60 and 1080p30 formats.

The A550 in addition supports the standard HD broadcast format 1080i60.

The A570 captures as many as 5.3 MP at 60 frames per second.

This allows full HD video recording while concurrently storing 5.3 MP still images (16:9 aspect ratio) without interrupting the video recording.

The A5 family includes many advanced features of contemporary cameras - such as face detection - to help auto focus and local exposure contrast.

A key feature is the dual recording capability: both HD and mobile video are recorded at the same time.

The A550 and A570 support sensors with a high-speed serial interface.

The A570 captures data as fast as 320 MP per second - this is in excess of 60 frames per second at 5.3 MP.

As is common in digital still cameras (DSC) and in most HD camcorders, a single colour filter array sensor (Bayer) generates red, green and blue primaries (RGB).

The A570 converts data from Bayer pattern to RGB (de-mosaicing) with a virtually artefact-free and full-resolution video signal.

This is more accurate in terms of clean edges, no Bayer artifacts, and so on than the simple binning (combination of adjacent pixels) commonly used in many cameras.

It also yields a higher resolution output than the extrapolative techniques used with three sensors (3 CCD).

Imaging sensors generate a substantial amount of noise in low light, making it necessary to filter this noise to produce high-quality images.

For still cameras, the A5 family implements advanced algorithms to enable clean, high-quality pictures at 3200 ISO.

In video the challenge is to reduce the noise without causing a loss of resolution or a loss of detail, and advanced spatio-temporal (3D) filters must be used.

Most of the solutions available are motion adaptive and switch from a predominantly temporal to a predominantly spatial filter based on detecting the presence of motion.

The Ambarella A5 SoC uses motion compensation instead of being just motion adaptive and truly tracks the motion of the objects in the scene, therefore eliminating typical noise reduction-induced motion artifacts.