Functional Description

STV9212

10/34

2.4

PictureBooST

The PictureBooST

™ function provides a picture enhancement effect for images with photographic

or moving video contents.

The function is activated whenever the level on pin PB is high (TTL) or the bit

PBINS is at 1, if the

general PictureBooST

™ enable bit PBGEN is at 1. By means of PB input signal toggling, the

function can take effect in a part of the screen, e.g. a window, or on the whole screen.

q

a content-sensitive peaking with slow restore (vivacity),

q

a contrast addition,

q

a brightness addition.

The vivacity amplitude depends on the slope height and steepness and on the status of bits

PBVIVAM[1:0]. The return to stabilized state is exponential with a time constant adjustable via bits

PBVIVTC[2:0]. Any undershoot below the video black level is clipped to a level close to black.

The PictureBooST

™ brightness is a DC offset superimposed on the video signal in the boosted

zone. Its value is selected by bits

PBBRIG[1:0]. The vivacity and PictureBooST

™ brightness are

both enabled by bit

PBVIVEN.

The PictureBooST

™ contrast component evenly increases the video amplitude in the boosted zone.

Its value is controlled by bits

PBCRST[1:0].

Figure 9: PictureBooST Action

PB brightness

H-sync

Video before

PB input

τ

viv

PB

contrast

PictureBooST

™

stage

Video after

PictureBooST

™

stage

clipping

A

A