Faroudja

Active Color Management (ACM-3D)

Faroudja Active Color Management™ technology is designed to address the different color characteristics of the Liquid Crystal Display (LCD) and offer custom settings to produce a higher quality viewing experience.

ACM-3D supports a host of features to enable a TV manufacturer the most powerful and flexible color manipulation tools possible. The main characteristics of this technology are listed below:

• Color manipulation is in a cylindrical (tint,saturation, luminance) space.  This allows precise control over tint (color phase).
• Multiple, fully-independent, definable correction regions allow precision color control over the entire color space.
• Definable fade areas around correction regions prevent artifacts.
• Regional definition in luminance as well as in tint and saturation directions allow unprecedented control.
• Independent gain and offset control for hue, saturation and luminance.

   

A cylinder represents the color signal in the TV:  saturation increases out from the center, tint (or hue) changes around the center, and luminance changes up and down.

Independent gain and offset controls for hue, saturation and luminance enable a large amount of control over the color correction applied to an image. Increased flexibility allows for specific color adjustments such as flesh tone correction and global adjustments that can affect the entire image, such as increasing the overall color saturation.

This also allows for additional control for Themes that the TV manufacturer can offer.

ACM theme modes

Theme modes enable the end user to optimize the viewing experience by changing the corrections applied to an image based on the content or viewing conditions. For example, a sports theme mode might enhance blue and increase green saturation to better distinguish the action and players from the playing surface; a nature theme mode might increase the saturation on all colors to produce a more vibrant image. 

Adaptive Contrast Control (ACC)

Faroudja's adaptive contrast control provides algorithms and tools for the TV manufacturer to define and store automatic corrections to image contrast.  The ACC uses a predefined histogram of the incoming image and adjusts the levels (both color and brightness) to improve the contrast ratio while also ensuring no errors are introduced.

In the scene above, the image is dull, lacking in overall contrast.  In addition, details are lost in the shadows (trees).

With ACC active, the contrast is expanded, the colors enhanced, and the detail in the shadow near the trees is now visible. The bright areas (water) are bright without overdriving the display.

Some of the ACC features are:

• Multi-level histogram for improved contrast resolution
• Noise coring to reduce noise amplification
• Reduced image flicker during fade-ins and fade-outs
• Improved Y-C Link (Color-Luminanace). Provides for ability to affect the chrominance channel in the areas where the luminance is enhanced.
• Flesh tone detection
• Fast scene change detection
• Nonlinear saturation control with cross access to ACM3D
• Average scene brightness and scene change detector outputs
• Flexible calibration tool
• Settings can be stored as part of TV Themes

Color considerations

Whenever the colors or contrast of an image is enhanced there are certain factors to consider.

• Color enhancement versus color resolution

The color resolution is the number of different intensities that the display is able to reproduce.  When the contrast is increased the color resolution is decreased proportionally.

• Color enhancement versus linearity

The linearity is the smoothness of visible color variation as a function of the intended color variation. When the color hue or saturation is enhanced the linearity will be adversely affected. 

Reduction in color resolution or linearity may result in 'banding' or 'contouring' with images that contain smooth color gradients.