HD49815TF Datasheet, PDF (13/22 Pages) Hitachi Semiconductor – Digital Camera Signal Processor

HD49815TF
Built-in Functions
1. Input line memory block
A/D input
10-bit
16
De-Knee
AGC
DL +
1HDL
16
Memory
control
1HDL
To the color-signal
processing block
To the luminance-signal
processing block
Figure 3 Input Line Memory Block
a. De-knee function
When the CDS/AGC IC at the pre-stage or the external circuit uses the knee circuit to expand the dynamic range
of the signal, the de-knee (inverse knee) circuit returns the signal converted by the knee circuit to the original
state.
The de-knee point can be set in State Data SP_A0 [1]. The gain of the high-luminance block is 1/2.
b. AGC function
A digital AGC circuit is provided. The AGC gain can be set in State Data SP_A0 [2] from 1 to 16 times.
c. 1H delay line (1HDL) function
This circuit obtains horizontal efficient pixels of the CCD output signal. The number of efficient pixels is set in
State Data SP_A0 [9, 10] and TM_A0 [14] MCSET.
2. Color-signal processing block
From
the input
line
memory
block
LINE
SW
C-
limit
+
Pre- RGB
Filter Matrix
+
RGB
Gain
Gamma
correc-
tion
C-G
RGB Setup
WB
YL
Matrix
Axis Base
conver- clipp-
sion ing
To
the zoom
function
Axis
conver-
sion
(WB)
To the luminance
To the AWB
signal processing block detection block
Figure 4 Color-Signal Processing Block
a. C-limit (complementary color clipping level) function
High clipping processing is performed on the complementary color signals independently. High clipping is set
in State Data SP_A2 [0 to 3].
The complementary color signal indicates Gb: (G + Cy), Wr: (Ye + Mg), Wb: (Mg + Cy), and Gr: (G + Ye).
b. RGB-matrix block
The three primary colors (red, green, and blue) are acquired in the RGB matrix by multiplying arbitrary
coefficients by the four complementary colors (Gb, Wr, Wb, and Gr) and taking the total of those results. The
RGB matrix is designed to support the minimum color moire and to enable free color reproduction. Arbitrary
coefficients are set in State Data SP_A2 [4 to 15]. The following shows the formula.
R KRa KRb KRc KRd
B = KBa KBb KBc KBd
G KGa KGb KGc KGd
Gb
Wr
Wb
Gr
State Data SP_A2 [4 to 15]
Rev.1.00 Jun 15, 2005 page 13 of 21