用verilog语言写SGM算法

SGM (Semi-Global Matching) 算法是一种用于计算立体匹配 (Stereo Matching) 的算法，其核心是计算每个像素点在左右两张图像中对应的像素点，从而得到深度图。下面是一个简单的 Verilog 实现 SGM 算法的例子：

module SGM (
  input clk,
  input rst,
  input [7:0] left_image,
  input [7:0] right_image,
  output [7:0] depth_map
);

parameter MAX_DISPARITY = 16;
parameter P1 = 10;
parameter P2 = 150;

reg [MAX_DISPARITY-1:0] cost[0:255];
reg [MAX_DISPARITY-1:0] min_cost[0:255];
reg [MAX_DISPARITY-1:0] dp[0:255];
reg [7:0] depth_map_reg;

// Cost computation
always @(posedge clk) begin
  if (rst) begin
    for (int i = 0; i < 256; i++) begin
      for (int j = 0; j < MAX_DISPARITY; j++) begin
        cost[i][j] = 0;
      end
    end
  end else begin
    for (int i = 0; i < 256; i++) begin
      for (int j = 0; j < MAX_DISPARITY; j++) begin
        int diff = left_image[i] - right_image[i-j];
        if (diff < 0) begin
          cost[i][j] = -P1 * diff - P2 * (diff - cost[i][j-1]);
        end else begin
          cost[i][j] = P1 * diff - P2 * (diff - cost[i][j-1]);
        end
      end
    end
  end
end

// Min-cost aggregation
always @(posedge clk) begin
  if (rst) begin
    for (int i = 0; i < 256; i++) begin
      min_cost[i] = cost[i][0];
    end
  end else begin
    for (int j = 1; j < MAX_DISPARITY; j++) begin
      for (int i = 0; i < 256; i++) begin
        int min_val = min_cost[i];
        if (i > 0 && min_cost[i-1] < min_val) begin
          min_val = min_cost[i-1];
        end
        if (i < 255 && min_cost[i+1] < min_val) begin
          min_val = min_cost[i+1];
        end
        dp[i] = cost[i][j] + min_val - min_cost[i];
      end
      for (int i = 0; i < 256; i++) begin
        min_cost[i] = dp[i];
      end
    end
  end
end

// Depth map calculation
assign depth_map = depth_map_reg;
always @(posedge clk) begin
  if (rst) begin
    depth_map_reg <= 0;
  end else begin
    int min_val = dp[0];
    int min_idx = 0;
    for (int i = 1; i < 256; i++) begin
      if (dp[i] < min_val) begin
        min_val = dp[i];
        min_idx = i;
      end
    end
    depth_map_reg <= min_idx;
  end
end

endmodule

这个例子中，我们使用了 Verilog 语言来实现 SGM 算法中的两个核心部分：Cost Computation 和 Min-cost Aggregation。我们通过不断地计算每个像素点的 cost 值，以及通过 DP 算法不断地更新每个像素点的 min_cost 值，最终得到深度图。