In the past decade, the field of image processing (the processing of video and/or graphic images) and more specifically integrated circuits (ICs) for image processing, have changed dramatically.
The transition from SD to HD video content, the move to larger screen sizes and resolutions and the increasing use of compression technology has brought about new challenges and opportunities to merchant silicon providers.
Taking a Look Back
In the early 1990's the majority of flat panel TV (FPTV) manufacturing was taking place in Japan (Sharp, Sony, Panasonic, NEC, JVC, etc.) and these manufacturers were developing their display technologies and image processing solutions in-house.
At that time, manufacturers were able to take advantage of abundant internal fabrication (fab) capabilities, low tape-out costs and existing image processing solutions from other internal business units active in the flat panel computer monitor market.
Over time, the FPTV production base slowly made its way into Korea (LG & Samsung), as consumer demand for FPTV technology increased.. In many cases, in-house image processing solutions were not readily available and these manufacturers leveraged merchant image processing solutions developed primarily for the LCD computer monitor market.
During this same period, the LCD computer monitor market transitioned closer to a commodity space, encouraging many merchant monitor IC suppliers to changed course and enter the FPTV market. To be successful in the FPTV space, these merchant IC vendors needed to displace the widespread use of internal solutions. The strategy employed, was to offer a more 'cost effective' silicon solution through high levels of integration and 'good enough' image quality.
As the years progressed semiconductor processing technologies shrunk, fab NRE prices rose, and FPTV production spread across Asia. This increased the focus on better merchant image processing solutions. At that time At that time this merchant group consisted of Faroudja (latter acquired by Genesis), Genesis, Pixelworks, Silicon Image and Trident among others Faroudja dominated the pack with their DCDi technology, which is still regarded by some as the benchmark for SD image processing against which all other solutions are judged.. More recently Trident has gained strong momentum with a very good balance of integration, image quality and features.
Larger Screen Sizes and Higher Resolutions
In the early 2000's manufacturers began to introduce screen sizes greater than 50" and more recently introduced higher resolutions supporting full HDTV (1920x1080 pixels). These two factors, along with a lack of HDTV content made image artefacts (previously disguised by smaller sized displays and lower resolutions), much more apparent. This drove the need for better image processing quality!
To answer the call for better image quality, new entrants in the merchant semiconductor image processor space appeared such as Gennum offering VXP technology (migrating from their traditional broadcast market space, where the finest image quality is required), Silicon Optix with HQV, and Anchor Bay Technologies.
The main focus for this group of silicon providers was and is to provide better image quality and product differentiation through specialized functionality and processing.
The once broad image processing market has now been segmented. One group focuses on integration and lower cost (we call this the integration market) and the other group focuses on quality and differentiation, (we call this the specialization market).
What makes good image quality?
The simple answer is 'a lot of things' but there are certain areas of distinction such as de-interlacer performance, scaling performance, resolution (bit-depth), bandwidth, noise-reduction and frame rate conversion that sets image processors apart. Of course it goes without saying that there should be no compromise in image processing quality for both HD and SD content, as is the case with Gennum's VXP technology.
Creating an exceptional de-interlacer is somewhat like black magic. It requires a lot of time and effort to modify and tweak the algorithms over a number of silicon generations to get the right balance between sharpness and artefacts (jaggies, feathering, motion blur etc.). Figure 1 shows two images, one with proper pixel-by-pixel edge processing and one without. The difference is clearly visible!
Other areas for improvement include not only motion and edge adaptation but also speed adaptation. The concept is relatively straightforward, for video material with fast motion you want to employ a strict spatial interpolation method versus spatial-temporal processing for slower moving content. This minimizes temporal aliasing for faster moving content and preserves the maximum amount of detail for content with low or no motion.. Figure 2 shows speed adaptation in action on a vertically moving grid. With speed adaptive processing a sharp and clear grid is produced. Without speed adaptation the temporal alias can be seen as additional faint horizontal lines (in this case in the vertical direction).
