lf3311 LOGIC Devices Incorporated, lf3311 Datasheet - Page 16

• Manufacturer Part Number: lf3311
• Description: Horizontal / Vertical Digital Image Filter
• Manufacturer: LOGIC Devices Incorporated

DEVICES INCORPORATED
Orthogonal Mode
LOGIC Devices Incorporated
Operating Modes
In Orthogonal Mode, the horizontal and vertical filters are used concurrently to implement an orthogonal
kernel on the input data (see Figure 16). The HV Filter can handle kernel sizes of 3-3, 5-5, and 7-7
(see Figure 17). Data delay elements at the input of the horizontal filter and the output of the vertical
filter are used to properly align data so that the orthogonal kernel is implemented correctly. The data
delays are automatically set to the correct lengths based on the programmed length of the line buffers
and the kernel size.
Kernel sizes of 3-3, 5-5, and 7-7 require that the horizontal filter’s output be delayed by LB – 2, 2(LB)
– 3, and 3(LB) – 4 clock cycles respectively before being added to the vertical filter’s output (LB is the
programmed line buffer length). The data delay at the input of the horizontal filter handles the LB, 2(LB),
and 3(LB) delays. The data delay at the output of the vertical filter handles the – 2, – 3, and – 4 delays.
For example, if the line buffers are programmed for a length of 720 and a 5–5 kernel is selected, the
horizontal filter input data delay will be 1440 clock cycles and the vertical filter output data delay will be
3 clock cycles.
It is important to note that the first 3, 5, or 7 multipliers of the horizontal and vertical filters must be used
in Orthogonal Mode. If other multipliers are used, data from the horizontal and vertical filters will not line
up correctly because the data delays are calculated assuming that the first 3, 5, or 7 multipliers are used.
Also, the ALUs in the horizontal filter should be configured to accept data from the forward I/D Register path
into ALU Input A and force ALU Input B to 0.
Figure 14. Orthogonal Mode
Figure 15. 3-3, 5-5, and 7-7 Orthagonal Kernels
DIN
11-0
H
1
HV
V
V
1
3
2
12
H
LINE BUFFER
LINE BUFFER
LINE BUFFER
LINE BUFFER
LINE BUFFER
LINE BUFFER
LINE BUFFER
3
H
1
16
H
DELAY
DATA
2
HV
V
V
V
V
1
2
4
5
3
H
4
Horizontal / Vertical Digital Image Filter
H
5
DELAY
DATA
H
1
H
2
HORIZONTAL FILTER
H
3
DOUT
12
HV
V
V
V
V
V
V
1
2
3
5
6
7
11-0
4
H
Improved Performance
5
H
Video Imaging Products
6
H
7
9/19/05 LDS.3311-C
LF3311