I have written some code in verilog for a median filter using a cumulative histogram method. When I try to synthesize my code in xilinx it's processing up to 1 hour and finally shows an error, "program ran out of memory".
My code is:
//***** MEDIAN FILTER BY USING CUMULATIVE HISTOGRAM METHOD******//
module medianfilter(median_out,clk,a1,a2,a3,a4,a5,a6,a7,a8,a9);
output median_out;
input [7:0]a1,a2,a3,a4,a5,a6,a7,a8,a9;
integer i,j;
reg[7:0]b[255:0];
reg [7:0]buff[0:8];
input clk;
reg [7:0]median_out;
always@(negedge clk)
begin
//**************************************************************************//
for(i=0;i<256;i=i+1) // initilize the memory bins with zeros
b[i]=0;
//*************************************************************************//
buff[0]=a1;
buff[1]=a2;
buff[2]=a3;
buff[3]=a4;
buff[4]=a5;
buff[5]=a6;
buff[6]=a7;
buff[7]=a8;
buff[8]=a9;
for(i=0;i<9;i=i+1) // this loop is for cumulative histogram method
begin
b[buff[i]]=b[buff[i]]+1; // incrementing the value in b[i]th memory address
for(j=0;j<256;j=j+1)
if(j>buff[i])
b[j]=b[j]+1; // incrementing the bins below b[i]th bin
end
//**************************************************************************//
for(i=0;i<256;i=i+1) // loop for finding the median
begin
if(b[i]>4) ///////// condition for checking median
begin
b[i]=1;
median_out=i;
i=256; // loop breaks here
end
end
//*************************************************************************//
end
endmodule
How can I make the code synthesizable?
How many adders are generated by your code? I see at least 2,100 8-bit adders which are working in the same cycle.
You should rethink your algorithm: A median filter needs an ordered list of pixel values, so at first you should think about efficient ordering of numbers on FPGAs.
A good approach are sorting networks like:
Sorting 9 numbers can't be done in one cycle so you need pipelining. (You can do it, but at very low clock speed.)
Our PoC-Library contains pipelined sorting networks,but I have never test these networks with a non-power of two input size!
Collected from the Internet
Please contact [email protected] to delete if infringement.
Comments