Sharper, brighter images thanks to ExwavePRO Technology

Unique to Sony’s fourth generation NVM cameras, ExwavePRO brings together several key innovations to significantly enhance image performance.

Complementary Colour Filter technology

In addition ExwavePRO also uses a new Complementary Colour Filter technology which results in approximately twice as much light reaching the CCD. Filtering light by colour is essential for a CCD to produce a colour image and normally Primary Colour Filters (Red, Green, Blue) are used, with each filter only passing a single primary colour – so for example, the Red Filter passes red light only.

Where Complementary Colour Filters are used, however, each filter passes multiple colours. Cyan passes green and blue; magenta passes red and blue; and yellow passes red and green. As a result, the complementary-colour filters pass more light, so that sensitivity is higher. A Complementary Colour Filter produces a normal looking video output but the higher luminance signal-to-noise ratio results in an image which can be twice as bright as one produced using a Primary Colour Filter.

The diagram below shows the 'Complementary Colour Filter' vs. 'Primary Colour Filter'. The left hand image is taking in twice the light of the right hand image.

ExwavePRO technology is a key feature of all of Sony’s fourth generation network cameras introduced in 2008, from the high resolution SNC-DS10, SNC-DS60 and SNC-CS20 to the Megapixel resolution cameras SNC-DM110, SNC-DM160 and SNC-CM120.

It’s a basic rule of CCD design that if the size of the image capture device is unchanged, then increasing the number of pixels will reduce the size of each pixel and consequently the amount of light each pixel receives is diminished and overall sensitivity reduced. For this reason, buying a conventional Megapixel camera comes with a hidden cost in terms of reduced performance in the lowlight conditions which are often most critical for security applications.

The below diagram illustrates the fact that if two images are the same size, increasing the number of pixels must reduce the photoreceptive area for each individual pixel.

The introduction of ExwavePRO technology, alongside the equally innovative Light Funnel system, means Sony’s Megapixel cameras deliver higher resolution imaging performance without hidden penalties.