P0, P1, P2, P3, P4, P6, P7 and P8 represents the eight 8bit pixel inputs to the Sobel Module. The module consists of signed subtractors, shift registers and modulus operators. The output of the final adder block will be 11 bits (10 bits for the data as the maximum value of the adder output is 4*255 and the 11th bit as the sign bit). The output data is compared to limit the value to a maximum of 255 as the output image is also composed of 8-bit wide pixels. 32 Sobel modules are used in parallel. The limitation on the number of parallel Sobel operators that can be implemented is logic resources available in the target device.
The Sobel output for one group of pixels calculated as per |Gx| + |Gy| where Gx and Gy are calculated from the formula given in here.
The summary of the Sobel module showing the input output buses are shown above.
FPGA Statistics
A single Sobel operator logic consumes 149 four input lookup tables (LUT) which is 2% of the available FPGA resources.
SOBEL Project Status
Project File:
sobel.ise
Current State:
Synthesized
Module Name:
sobel
Errors:
No Errors
Target Device:
xc3s400-4tq144
Warnings:
4 Warnings (0 new, 0 filtered)
Product Version:
ISE, 8.1i
Updated:
Sat Feb 28 16:13:45 2009
Device Utilization Summary (estimated values)
Logic UtilizationUsedAvailableUtilization
Number of Slices
83
3584
2%
Number of Slice Flip Flops
30
7168
0%
Number of 4 input LUTs
149
7168
2%
Number of bonded IOBs
74
97
76%
Number of GCLKs
1
8
12%
Detailed Reports
Report NameStatusGenerated
ErrorsWarningsInfos
Synthesis ReportCurrentFri Feb 27 20:56:01 200904 Warnings (0 new, 0 filtered)0
Translation Report
Map Report
Place and Route Report
Static Timing Report
Bitgen Report
Sources
sobelcode.v
more »
Device Utilization Summary (estimated values)
Logic UtilizationUsedAvailableUtilization
Number of Slices
2890
3584
80%
Number of Slice Flip Flops
845
7168
11%
Number of 4 input LUTs
4989
7168
69%
Number of bonded IOBs
22
97
22%
Number of GCLKs
1
8
12%
Detailed Reports
Report NameStatusGenerated
ErrorsWarningsInfos
Synthesis ReportCurrentWed Apr 29 10:49:48 200903 Warnings (3 new, 0 filtered)5 Infos (5 new, 0 filtered)
Translation Report
Map Report
Place and Route Report
Static Timing Report
Bitgen Report
more »