SDA9410
Preliminary Data Sheet
Display processing
ASCENTLTI
Amplitude
00
01
10
11
0.5
1
2
4
Table 93
I²C Bus parameter ASCENTLTI
I²C Bus
Sub address
Description
parameter
THRESY
5Eh
5Eh
5Ch
Defines lower sensitivity threshold of DLTI
Defines upper sensitivity threshold of DLTI
Defines amplitude of correction signal
THRESY_UP
ASCENTLTI
Table 94
Output write I²C Bus parameters
5.12.3
Digital colour transition improvement
A new digital algorithm is implemented to improve horizontal transitions of the
chrominance signals resulting in a better picture sharpness. A correction signal
proportional to the slope of the detected horizontal transition of the input signal is added
to the original input signal. Different correction signals according to the bandwidth of the
input signal are selected. The amplitude of the correction signal is adjustable by the I²C
Bus parameter ASCENTCTI.
The exact position of a colour transition is calculated by detecting the corresponding zero
transition of the second derivative of both chrominance signals. Low pass filtering is
performed to avoid noise sensitivity. The I²C Bus parameter THRESC modifies the
sensitivity of the DCTI circuit. High values cause that only significant colour transitions
are improved. Small colour variations remain unchanged.
To eliminate “wrong colours” transitions, which are caused by over and undershoots at
the chroma transition, the sharpened chroma signals are limited to a proper value
automatically.
113
Micronas
MICRONAS [ MICRONAS ]
