module filter_emboss #(

parameter DATA_WIDTH = 24

)(

input wire clk,

input wire reset_n,

// 3x3 Window (RGB)

input wire [DATA_WIDTH-1:0] rgb00, rgb01, rgb02,

input wire [DATA_WIDTH-1:0] rgb10, rgb11, rgb12,

input wire [DATA_WIDTH-1:0] rgb20, rgb21, rgb22,

// Output (Delayed by 2 clocks to match pipeline)

output reg [7:0] emboss_gray

);

// Internal Intensity (Gray) calculation macro

function [7:0] rgb2gray;

input [23:0] rgb;

begin

rgb2gray = (rgb[23:16] >> 2) + (rgb[15:8] >> 1) + (rgb[7:0] >> 2);

end

endfunction

// ==========================================

// Stage 1: Emboss Mask Calculation

// Emboss Mask (Diagonal):

// [ -2 -1 0 ]

// [ -1 1 1 ]

// [ 0 1 2 ]

// ==========================================

reg signed [12:0] emboss_sum;

always @(posedge clk or negedge reset_n) begin

if (!reset_n) begin

emboss_sum <= 0;

end else begin

// Positives: rgb11 + rgb12 + rgb21 + 2*rgb22

// Negatives: -2*rgb00 - rgb01 - rgb10

emboss_sum <=

(rgb2gray(rgb11) + rgb2gray(rgb12) + rgb2gray(rgb21) + (rgb2gray(rgb22) << 1)) -

((rgb2gray(rgb00) << 1) + rgb2gray(rgb01) + rgb2gray(rgb10));

end

end

// ==========================================

// Stage 2: Add neutral gray (128) and Clamp

// ==========================================

wire signed [13:0] emboss_result = emboss_sum + 13'd128; // Shift to visible range

always @(posedge clk or negedge reset_n) begin

if (!reset_n) begin

emboss_gray <= 8'd128;

end else begin

if (emboss_result[13]) begin

// Negative (underflow)

emboss_gray <= 8'd0;

end else if (emboss_result > 255) begin

// Positive (overflow)

emboss_gray <= 8'd255;

end else begin

// Normal range

emboss_gray <= emboss_result[7:0];

end

end

end