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=== C code for Sobel Algorithm === | === C code for Sobel Algorithm === | ||
Source: Edge Detection Tutorial-Author: Bill Green (2002)[http://dasl.mem.drexel.edu/alumni/bGreen/www.pages.drexel.edu/_weg22/edge.html] |
Revision as of 05:17, 22 February 2012
Team Members
- Kevin Townsend
- Bhavani Satyanarayana Rao
- Chidvila Gaddam
Assignment1
Running the sample application with script files
- The runcp script located in the SampleAppVadd can be used to run the application in HW which sets the appropriate environment variables and runs the UserApp.exe export CNY_PDK_PROJ = ~/pdk_sample/cae_pers_vadd ./runcp
- The run script located in the SampleAppVadd can be used to run the application in SW
- The scripts above can be used to run the application on Simulator using the "-vsim" option which sets the environment variable CNY_CAE_EMULATOR to ./run_simulation ./runcp -vsim or ./run -vsim
Environment Variables | Software | ModelSim | Hardware |
---|---|---|---|
CNY_SIM_THREAD | libcpSimLib2.so | libcpSimLib2.so | unset |
CNY_CAE_EMULATOR | <location for CaeSimPers> | ./run_simulation | unset |
Changes made to run the application on ModelSim
- Setup as explained in here [[1]]
- Set the CNY_PDK_PROJ environment variable to the location of cae_pers_vadd export CNY_PDK_PROJ = ~/pdk_sample/cae_pers_vadd
- Copied Jones' my_makefile from the temp dir and replaced the makefile in CY_PDK_PROJ/testbench
- Add line to the makefile in testbench dir CNY_PDK_MODELSIM_USER_SIM_OPTIONS= -i -do "run -all"
- Modify the values of LIB_DIR and LDFLAGS from 32-bit to 64-bit as given below LIB_DIR = lib64 LDFLAGS = -m64
Error creating thumbnail: File missing
Extra Credit: Exploring gdb
- We invoked gdb using the gdb <programname> command or by using the run/runcp script files in with "-gdb" option gdb UserApp.exe or ./run -gdb Error creating thumbnail: File missing
- One can find different command classes on gdb by typing help.To get details on a particular command class/command, type help on gdb followed by the name of the command class/command Error creating thumbnail: File missing
- We explored some commands like run, start (to begin execution), stepi (for single instruction stepping into a file), kill (kill a running program) and quit on gdb Error creating thumbnail: File missing
Assignment2
About Sobel Algorithm
Sobel Algorithm is used for edge detection in image processing.The link[2] explains
- Why edge detection is important?
- How sobel algorithm uses the gradient method (jump in the pixel values along edges in the images compared to the pixels around it) to detect edges in images?
The Algorithm
- Use Sobel masks to find the gradient of a pixel w.r.t its 8 immediate neighboring pixel values. The Sobel masks are GX={(-1,0,+1),(-2,0,+2),(-1,0,+1)) which gives the gradient in the x direction and Gy={(+1,+2,+1),(0,0,0),(-1,-2,-1)} which gives the gradient in the x direction.
- Find the approximate magnitude of the gradient using the formula |G|=|Gx|+|Gy|
- Compare |G| against the threshold values (0 and 255 in our case). If (|G| > 255) then the pixel value is 0 in the output image. If (|G| < 0) then the pixel value is 255 in the output image.
- Repeat the above steps for all the pixels in the image
C code for Sobel Algorithm
Source: Edge Detection Tutorial-Author: Bill Green (2002)[3]