The following terms are commonly used when referring to illumination and display settings:
- System Mode - A flash structure that maps several types of look-up tables that are intended to be used together in order to achieve a desired image appearance. The tables within a System Mode are all designed for a specific:
- Frame Rate - The sequences are designed to match a specific input video frame rate
- RGB Duty Cycle - Percentage of sequence time allocated for red, green, and blue illumination
- Sequence - A table that controls the synchronization of DMD timing and illumination enable signals throughout a video frame time. Every sequence within a System Mode is designed for the same frame rate and RGB duty cycle. Each sequence is characterized by a specific DMD duty cycle. For example, one sequence may use a 70% (70/30) DMD duty cycle and another may use 50%, 50% (50/50) DMD duty cycle. This percentage is related to the maximum light output that the system can output.
- Illumination Bin - A table that controls the amount of time that illumination drive signals are active for a given sequence. This is used to provide coarse step control over the amount of light output in dimming use-cases. For applications that do not use dimming, illumination bins are designed to provide maximum sequence intensity.
- De-gamma Table - A de-gamma curve that controls the mapping of input pixel levels to output pixel brightness levels. These are generally used to compensate for gamma curves that are inherent to video content or to accentuate specific regions of pixel levels. The same de-gamma curves are used for each sequence so that every system brightness can use the same de-gamma curves.
The available sequences, illumination bins, and de-gamma tables are specified in the flash header file provided along with the flash binary file.
The host specifies a System Mode index, an Illumination Bin index, and a De-gamma index. The host never directly specifies a sequence index. This is explained by the example below.
Figure 10-1 uses an example
indexing to show the relationship between these tables. A System Mode contains a set
of Illumination Bins. The host specifies the system brightness by selecting the
desired illumination bin index within a System Mode. Each Illumination Bin is
designed for a specific sequence. When the host selects an illumination bin, the
main application will automatically select the one sequence that the illumination
bin is mapped to. The host never directly sets the sequence. Different Illumination
Bins can be mapped to the same sequence. This indicates the use of different
illumination percentages with the same DMD duty cycle to achieve a different total
brightness level. Each sequence maps to one or more de-gamma curves. The same set of
de-gamma curves is applied to all sequences. For example, de-gamma curve 0 could be
a simple linear mapping from input pixel to output pixel level (128 in = 128 out).
In that example, de-gamma 0 will be linear for all sequences.