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Camera ISP Functional Description
) and another 32 programmable coefficients are available for the vertical direction
(registers
to
). The 32 programmable coefficients are arranged as either 4
taps and 8 phases for the resizing range of 1/2 ~ 4 (RSZ = 64 ~ 512), or 7 taps and 4 phases for a
resizing range of 1/4 ~1/2 (RSZ = 513 ~ 1024)(RSZ is either HRSZ or VRSZ).
shows the
arrangement of the 32 filter coefficients. Each tap is arranged in S10Q8 format.
Table 6-42. Camera ISP VPBE Resizer Arrangement of the Filter Coefficients
Filter Coefficient
0.5x to 4x
0.24x to ~0.5x
Phase
Tap
Phase
Tap
0
0
0
0
0
1
1
1
2
2
2
3
3
3
4
1
0
4
5
1
5
6
2
6
7
3
Not used
8
2
0
1
0
9
1
1
10
2
2
11
3
3
12
3
0
4
13
1
5
14
2
6
15
3
Not used
16
4
0
17
1
18
2
19
3
20
5
0
21
1
22
2
23
3
Not used
24
6
0
3
0
25
1
1
26
2
2
27
3
3
28
7
0
4
29
1
5
30
2
6
31
3
Not used
The indexing scheme of coefficients is oriented for dot-product (or inner product), rather than for impulse
response. In other words, the first data point contributing to a particular output is multiplied by the
coefficient associated with tap 0, and the last data point is multiplied by the coefficient associated with tap
3 or tap 6 (depending on whether it is 4-tap or 7-tap mode). The normal raster-scan order is used where
the upper-left corner gets the (0, 0) coordinate. Pixel 0 is the left-most column of pixels for horizontal
resizing, and the top-most row of pixels for vertical resizing.
shows an example of the
alignment of input pixels to tap coefficients using a simple 1:1 resize case (4-tap mode). In this example,
only one phase output is necessary.
shows the alignment of input pixels to tap coefficients.
1217
SWPU177N – December 2009 – Revised November 2010
Camera Image Signal Processor
Copyright © 2009–2010, Texas Instruments Incorporated
