FPGA实现直方图统计
一、图像直方图统计原理
直方图的全称为灰度直方图，是对图像每一灰度间隔内像素个数的统计。即对一张图片中每隔二灰度值的像素数量做统计，然后以直方图的形式展现出来。图下的亮暗分布在直方图中就可以一目了然，直方图在图像前端和后端处理中都有广泛的应用，比如图像的直方图均衡、图像自动曝光控制和图像特征提取等。
二、基于寄存器（逻辑资源）的直方图统计系统框图
图片大小640x480，需要20bit的位宽来计像素的个数。i_img_vld为高时，输入图片数据i_img_data[7:0]有效，"256级灰度灰度值的像素计数"模块统计0~255中灰度级数的个数，"输入有效像素个数计数"模块用于计算i_mg_data已经输入了几个，"256级直方图统计结果分时输出"模块是输入256个灰度级的统计结果，需要256个时钟周期，每个周期输出一级灰度级的结果。
三、代码实现
这个代码简单而且暴力，主要是易于理解，占用较多的逻辑资源。因为这种统计方法，对于i_image_data来说有256个扇出，所以系统时钟频率不会跑的很高，时序很难收敛
verilog
`timescale 1ns/1ps
module m_histogram_reg#(
parameter P_IMAGE_WIDTH=640,
parameter P_IMAGE_HIGHT=480
)(
input i_clk,
input i_rst_n,
input i_image_vld,
input [7:0] i_image_data,
output reg o_result_rdy,
output reg [19:0] o_result_data
);
localparam P_IMAGE_SIZE = P_IMAGE_HIGHT*P_IMAGE_WIDTH;
reg [19:0] r_hist_cnt[255:0];//每个灰度值统计的计数器
//256个灰度值的直方图统计
always@(posedge i_clk)begin
if(!i_rst_n)begin
r_hist_cnt[0] <= 20'd0;
r_hist_cnt[1] <= 20'd0;
r_hist_cnt[2] <= 20'd0;
r_hist_cnt[3] <= 20'd0;
r_hist_cnt[4] <= 20'd0;
r_hist_cnt[5] <= 20'd0;
r_hist_cnt[6] <= 20'd0;
r_hist_cnt[7] <= 20'd0;
r_hist_cnt[8] <= 20'd0;
r_hist_cnt[9] <= 20'd0;
r_hist_cnt[10] <= 20'd0;
r_hist_cnt[11] <= 20'd0;
r_hist_cnt[12] <= 20'd0;
r_hist_cnt[13] <= 20'd0;
r_hist_cnt[14] <= 20'd0;
r_hist_cnt[15] <= 20'd0;
r_hist_cnt[16] <= 20'd0;
r_hist_cnt[17] <= 20'd0;
r_hist_cnt[18] <= 20'd0;
r_hist_cnt[19] <= 20'd0;
r_hist_cnt[20] <= 20'd0;
r_hist_cnt[21] <= 20'd0;
r_hist_cnt[22] <= 20'd0;
r_hist_cnt[23] <= 20'd0;
r_hist_cnt[24] <= 20'd0;
r_hist_cnt[25] <= 20'd0;
r_hist_cnt[26] <= 20'd0;
r_hist_cnt[27] <= 20'd0;
r_hist_cnt[28] <= 20'd0;
r_hist_cnt[29] <= 20'd0;
r_hist_cnt[30] <= 20'd0;
r_hist_cnt[31] <= 20'd0;
r_hist_cnt[32] <= 20'd0;
r_hist_cnt[33] <= 20'd0;
r_hist_cnt[34] <= 20'd0;
r_hist_cnt[35] <= 20'd0;
r_hist_cnt[36] <= 20'd0;
r_hist_cnt[37] <= 20'd0;
r_hist_cnt[38] <= 20'd0;
r_hist_cnt[39] <= 20'd0;
r_hist_cnt[40] <= 20'd0;
r_hist_cnt[41] <= 20'd0;
r_hist_cnt[42] <= 20'd0;
r_hist_cnt[43] <= 20'd0;
r_hist_cnt[44] <= 20'd0;
r_hist_cnt[45] <= 20'd0;
r_hist_cnt[46] <= 20'd0;
r_hist_cnt[47] <= 20'd0;
r_hist_cnt[48] <= 20'd0;
r_hist_cnt[49] <= 20'd0;
r_hist_cnt[50] <= 20'd0;
r_hist_cnt[51] <= 20'd0;
r_hist_cnt[52] <= 20'd0;
r_hist_cnt[53] <= 20'd0;
r_hist_cnt[54] <= 20'd0;
r_hist_cnt[55] <= 20'd0;
r_hist_cnt[56] <= 20'd0;
r_hist_cnt[57] <= 20'd0;
r_hist_cnt[58] <= 20'd0;
r_hist_cnt[59] <= 20'd0;
r_hist_cnt[60] <= 20'd0;
r_hist_cnt[61] <= 20'd0;
r_hist_cnt[62] <= 20'd0;
r_hist_cnt[63] <= 20'd0;
r_hist_cnt[64] <= 20'd0;
r_hist_cnt[65] <= 20'd0;
r_hist_cnt[66] <= 20'd0;
r_hist_cnt[67] <= 20'd0;
r_hist_cnt[68] <= 20'd0;
r_hist_cnt[69] <= 20'd0;
r_hist_cnt[70] <= 20'd0;
r_hist_cnt[71] <= 20'd0;
r_hist_cnt[72] <= 20'd0;
r_hist_cnt[73] <= 20'd0;
r_hist_cnt[74] <= 20'd0;
r_hist_cnt[75] <= 20'd0;
r_hist_cnt[76] <= 20'd0;
r_hist_cnt[77] <= 20'd0;
r_hist_cnt[78] <= 20'd0;
r_hist_cnt[79] <= 20'd0;
r_hist_cnt[80] <= 20'd0;
r_hist_cnt[81] <= 20'd0;
r_hist_cnt[82] <= 20'd0;
r_hist_cnt[83] <= 20'd0;
r_hist_cnt[84] <= 20'd0;
r_hist_cnt[85] <= 20'd0;
r_hist_cnt[86] <= 20'd0;
r_hist_cnt[87] <= 20'd0;
r_hist_cnt[88] <= 20'd0;
r_hist_cnt[89] <= 20'd0;
r_hist_cnt[90] <= 20'd0;
r_hist_cnt[91] <= 20'd0;
r_hist_cnt[92] <= 20'd0;
r_hist_cnt[93] <= 20'd0;
r_hist_cnt[94] <= 20'd0;
r_hist_cnt[95] <= 20'd0;
r_hist_cnt[96] <= 20'd0;
r_hist_cnt[97] <= 20'd0;
r_hist_cnt[98] <= 20'd0;
r_hist_cnt[99] <= 20'd0;
r_hist_cnt[100] <= 20'd0;
r_hist_cnt[101] <= 20'd0;
r_hist_cnt[102] <= 20'd0;
r_hist_cnt[103] <= 20'd0;
r_hist_cnt[104] <= 20'd0;
r_hist_cnt[105] <= 20'd0;
r_hist_cnt[106] <= 20'd0;
r_hist_cnt[107] <= 20'd0;
r_hist_cnt[108] <= 20'd0;
r_hist_cnt[109] <= 20'd0;
r_hist_cnt[110] <= 20'd0;
r_hist_cnt[111] <= 20'd0;
r_hist_cnt[112] <= 20'd0;
r_hist_cnt[113] <= 20'd0;
r_hist_cnt[114] <= 20'd0;
r_hist_cnt[115] <= 20'd0;
r_hist_cnt[116] <= 20'd0;
r_hist_cnt[117] <= 20'd0;
r_hist_cnt[118] <= 20'd0;
r_hist_cnt[119] <= 20'd0;
r_hist_cnt[120] <= 20'd0;
r_hist_cnt[121] <= 20'd0;
r_hist_cnt[122] <= 20'd0;
r_hist_cnt[123] <= 20'd0;
r_hist_cnt[124] <= 20'd0;
r_hist_cnt[125] <= 20'd0;
r_hist_cnt[126] <= 20'd0;
r_hist_cnt[127] <= 20'd0;
r_hist_cnt[128] <= 20'd0;
r_hist_cnt[129] <= 20'd0;
r_hist_cnt[130] <= 20'd0;
r_hist_cnt[131] <= 20'd0;
r_hist_cnt[132] <= 20'd0;
r_hist_cnt[133] <= 20'd0;
r_hist_cnt[134] <= 20'd0;
r_hist_cnt[135] <= 20'd0;
r_hist_cnt[136] <= 20'd0;
r_hist_cnt[137] <= 20'd0;
r_hist_cnt[138] <= 20'd0;
r_hist_cnt[139] <= 20'd0;
r_hist_cnt[140] <= 20'd0;
r_hist_cnt[141] <= 20'd0;
r_hist_cnt[142] <= 20'd0;
r_hist_cnt[143] <= 20'd0;
r_hist_cnt[144] <= 20'd0;
r_hist_cnt[145] <= 20'd0;
r_hist_cnt[146] <= 20'd0;
r_hist_cnt[147] <= 20'd0;
r_hist_cnt[148] <= 20'd0;
r_hist_cnt[149] <= 20'd0;
r_hist_cnt[150] <= 20'd0;
r_hist_cnt[151] <= 20'd0;
r_hist_cnt[152] <= 20'd0;
r_hist_cnt[153] <= 20'd0;
r_hist_cnt[154] <= 20'd0;
r_hist_cnt[155] <= 20'd0;
r_hist_cnt[156] <= 20'd0;
r_hist_cnt[157] <= 20'd0;
r_hist_cnt[158] <= 20'd0;
r_hist_cnt[159] <= 20'd0;
r_hist_cnt[160] <= 20'd0;
r_hist_cnt[161] <= 20'd0;
r_hist_cnt[162] <= 20'd0;
r_hist_cnt[163] <= 20'd0;
r_hist_cnt[164] <= 20'd0;
r_hist_cnt[165] <= 20'd0;
r_hist_cnt[166] <= 20'd0;
r_hist_cnt[167] <= 20'd0;
r_hist_cnt[168] <= 20'd0;
r_hist_cnt[169] <= 20'd0;
r_hist_cnt[170] <= 20'd0;
r_hist_cnt[171] <= 20'd0;
r_hist_cnt[172] <= 20'd0;
r_hist_cnt[173] <= 20'd0;
r_hist_cnt[174] <= 20'd0;
r_hist_cnt[175] <= 20'd0;
r_hist_cnt[176] <= 20'd0;
r_hist_cnt[177] <= 20'd0;
r_hist_cnt[178] <= 20'd0;
r_hist_cnt[179] <= 20'd0;
r_hist_cnt[180] <= 20'd0;
r_hist_cnt[181] <= 20'd0;
r_hist_cnt[182] <= 20'd0;
r_hist_cnt[183] <= 20'd0;
r_hist_cnt[184] <= 20'd0;
r_hist_cnt[185] <= 20'd0;
r_hist_cnt[186] <= 20'd0;
r_hist_cnt[187] <= 20'd0;
r_hist_cnt[188] <= 20'd0;
r_hist_cnt[189] <= 20'd0;
r_hist_cnt[190] <= 20'd0;
r_hist_cnt[191] <= 20'd0;
r_hist_cnt[192] <= 20'd0;
r_hist_cnt[193] <= 20'd0;
r_hist_cnt[194] <= 20'd0;
r_hist_cnt[195] <= 20'd0;
r_hist_cnt[196] <= 20'd0;
r_hist_cnt[197] <= 20'd0;
r_hist_cnt[198] <= 20'd0;
r_hist_cnt[199] <= 20'd0;
r_hist_cnt[200] <= 20'd0;
r_hist_cnt[201] <= 20'd0;
r_hist_cnt[202] <= 20'd0;
r_hist_cnt[203] <= 20'd0;
r_hist_cnt[204] <= 20'd0;
r_hist_cnt[205] <= 20'd0;
r_hist_cnt[206] <= 20'd0;
r_hist_cnt[207] <= 20'd0;
r_hist_cnt[208] <= 20'd0;
r_hist_cnt[209] <= 20'd0;
r_hist_cnt[210] <= 20'd0;
r_hist_cnt[211] <= 20'd0;
r_hist_cnt[212] <= 20'd0;
r_hist_cnt[213] <= 20'd0;
r_hist_cnt[214] <= 20'd0;
r_hist_cnt[215] <= 20'd0;
r_hist_cnt[216] <= 20'd0;
r_hist_cnt[217] <= 20'd0;
r_hist_cnt[218] <= 20'd0;
r_hist_cnt[219] <= 20'd0;
r_hist_cnt[220] <= 20'd0;
r_hist_cnt[221] <= 20'd0;
r_hist_cnt[222] <= 20'd0;
r_hist_cnt[223] <= 20'd0;
r_hist_cnt[224] <= 20'd0;
r_hist_cnt[225] <= 20'd0;
r_hist_cnt[226] <= 20'd0;
r_hist_cnt[227] <= 20'd0;
r_hist_cnt[228] <= 20'd0;
r_hist_cnt[229] <= 20'd0;
r_hist_cnt[230] <= 20'd0;
r_hist_cnt[231] <= 20'd0;
r_hist_cnt[232] <= 20'd0;
r_hist_cnt[233] <= 20'd0;
r_hist_cnt[234] <= 20'd0;
r_hist_cnt[235] <= 20'd0;
r_hist_cnt[236] <= 20'd0;
r_hist_cnt[237] <= 20'd0;
r_hist_cnt[238] <= 20'd0;
r_hist_cnt[239] <= 20'd0;
r_hist_cnt[240] <= 20'd0;
r_hist_cnt[241] <= 20'd0;
r_hist_cnt[242] <= 20'd0;
r_hist_cnt[243] <= 20'd0;
r_hist_cnt[244] <= 20'd0;
r_hist_cnt[245] <= 20'd0;
r_hist_cnt[246] <= 20'd0;
r_hist_cnt[247] <= 20'd0;
r_hist_cnt[248] <= 20'd0;
r_hist_cnt[249] <= 20'd0;
r_hist_cnt[250] <= 20'd0;
r_hist_cnt[251] <= 20'd0;
r_hist_cnt[252] <= 20'd0;
r_hist_cnt[253] <= 20'd0;
r_hist_cnt[254] <= 20'd0;
r_hist_cnt[255] <= 20'd0;
end
else if(i_image_vld)begin
case(i_image_data)
8'd0:r_hist_cnt[0] <=r_hist_cnt[0] + 1;
8'd1:r_hist_cnt[1] <=r_hist_cnt[1] + 1;
8'd2:r_hist_cnt[2] <=r_hist_cnt[2] + 1;
8'd3:r_hist_cnt[3] <=r_hist_cnt[3] + 1;
8'd4:r_hist_cnt[4] <=r_hist_cnt[4] + 1;
8'd5:r_hist_cnt[5] <=r_hist_cnt[5] + 1;
8'd6:r_hist_cnt[6] <=r_hist_cnt[6] + 1;
8'd7:r_hist_cnt[7] <=r_hist_cnt[7] + 1;
8'd8:r_hist_cnt[8] <=r_hist_cnt[8] + 1;
8'd9:r_hist_cnt[9] <=r_hist_cnt[9] + 1;
8'd10:r_hist_cnt[10] <=r_hist_cnt[10] + 1;
8'd11:r_hist_cnt[11] <=r_hist_cnt[11] + 1;
8'd12:r_hist_cnt[12] <=r_hist_cnt[12] + 1;
8'd13:r_hist_cnt[13] <=r_hist_cnt[13] + 1;
8'd14:r_hist_cnt[14] <=r_hist_cnt[14] + 1;
8'd15:r_hist_cnt[15] <=r_hist_cnt[15] + 1;
8'd16:r_hist_cnt[16] <=r_hist_cnt[16] + 1;
8'd17:r_hist_cnt[17] <=r_hist_cnt[17] + 1;
8'd18:r_hist_cnt[18] <=r_hist_cnt[18] + 1;
8'd19:r_hist_cnt[19] <=r_hist_cnt[19] + 1;
8'd20:r_hist_cnt[20] <=r_hist_cnt[20] + 1;
8'd21:r_hist_cnt[21] <=r_hist_cnt[21] + 1;
8'd22:r_hist_cnt[22] <=r_hist_cnt[22] + 1;
8'd23:r_hist_cnt[23] <=r_hist_cnt[23] + 1;
8'd24:r_hist_cnt[24] <=r_hist_cnt[24] + 1;
8'd25:r_hist_cnt[25] <=r_hist_cnt[25] + 1;
8'd26:r_hist_cnt[26] <=r_hist_cnt[26] + 1;
8'd27:r_hist_cnt[27] <=r_hist_cnt[27] + 1;
8'd28:r_hist_cnt[28] <=r_hist_cnt[28] + 1;
8'd29:r_hist_cnt[29] <=r_hist_cnt[29] + 1;
8'd30:r_hist_cnt[30] <=r_hist_cnt[30] + 1;
8'd31:r_hist_cnt[31] <=r_hist_cnt[31] + 1;
8'd32:r_hist_cnt[32] <=r_hist_cnt[32] + 1;
8'd33:r_hist_cnt[33] <=r_hist_cnt[33] + 1;
8'd34:r_hist_cnt[34] <=r_hist_cnt[34] + 1;
8'd35:r_hist_cnt[35] <=r_hist_cnt[35] + 1;
8'd36:r_hist_cnt[36] <=r_hist_cnt[36] + 1;
8'd37:r_hist_cnt[37] <=r_hist_cnt[37] + 1;
8'd38:r_hist_cnt[38] <=r_hist_cnt[38] + 1;
8'd39:r_hist_cnt[39] <=r_hist_cnt[39] + 1;
8'd40:r_hist_cnt[40] <=r_hist_cnt[40] + 1;
8'd41:r_hist_cnt[41] <=r_hist_cnt[41] + 1;
8'd42:r_hist_cnt[42] <=r_hist_cnt[42] + 1;
8'd43:r_hist_cnt[43] <=r_hist_cnt[43] + 1;
8'd44:r_hist_cnt[44] <=r_hist_cnt[44] + 1;
8'd45:r_hist_cnt[45] <=r_hist_cnt[45] + 1;
8'd46:r_hist_cnt[46] <=r_hist_cnt[46] + 1;
8'd47:r_hist_cnt[47] <=r_hist_cnt[47] + 1;
8'd48:r_hist_cnt[48] <=r_hist_cnt[48] + 1;
8'd49:r_hist_cnt[49] <=r_hist_cnt[49] + 1;
8'd50:r_hist_cnt[50] <=r_hist_cnt[50] + 1;
8'd51:r_hist_cnt[51] <=r_hist_cnt[51] + 1;
8'd52:r_hist_cnt[52] <=r_hist_cnt[52] + 1;
8'd53:r_hist_cnt[53] <=r_hist_cnt[53] + 1;
8'd54:r_hist_cnt[54] <=r_hist_cnt[54] + 1;
8'd55:r_hist_cnt[55] <=r_hist_cnt[55] + 1;
8'd56:r_hist_cnt[56] <=r_hist_cnt[56] + 1;
8'd57:r_hist_cnt[57] <=r_hist_cnt[57] + 1;
8'd58:r_hist_cnt[58] <=r_hist_cnt[58] + 1;
8'd59:r_hist_cnt[59] <=r_hist_cnt[59] + 1;
8'd60:r_hist_cnt[60] <=r_hist_cnt[60] + 1;
8'd61:r_hist_cnt[61] <=r_hist_cnt[61] + 1;
8'd62:r_hist_cnt[62] <=r_hist_cnt[62] + 1;
8'd63:r_hist_cnt[63] <=r_hist_cnt[63] + 1;
8'd64:r_hist_cnt[64] <=r_hist_cnt[64] + 1;
8'd65:r_hist_cnt[65] <=r_hist_cnt[65] + 1;
8'd66:r_hist_cnt[66] <=r_hist_cnt[66] + 1;
8'd67:r_hist_cnt[67] <=r_hist_cnt[67] + 1;
8'd68:r_hist_cnt[68] <=r_hist_cnt[68] + 1;
8'd69:r_hist_cnt[69] <=r_hist_cnt[69] + 1;
8'd70:r_hist_cnt[70] <=r_hist_cnt[70] + 1;
8'd71:r_hist_cnt[71] <=r_hist_cnt[71] + 1;
8'd72:r_hist_cnt[72] <=r_hist_cnt[72] + 1;
8'd73:r_hist_cnt[73] <=r_hist_cnt[73] + 1;
8'd74:r_hist_cnt[74] <=r_hist_cnt[74] + 1;
8'd75:r_hist_cnt[75] <=r_hist_cnt[75] + 1;
8'd76:r_hist_cnt[76] <=r_hist_cnt[76] + 1;
8'd77:r_hist_cnt[77] <=r_hist_cnt[77] + 1;
8'd78:r_hist_cnt[78] <=r_hist_cnt[78] + 1;
8'd79:r_hist_cnt[79] <=r_hist_cnt[79] + 1;
8'd80:r_hist_cnt[80] <=r_hist_cnt[80] + 1;
8'd81:r_hist_cnt[81] <=r_hist_cnt[81] + 1;
8'd82:r_hist_cnt[82] <=r_hist_cnt[82] + 1;
8'd83:r_hist_cnt[83] <=r_hist_cnt[83] + 1;
8'd84:r_hist_cnt[84] <=r_hist_cnt[84] + 1;
8'd85:r_hist_cnt[85] <=r_hist_cnt[85] + 1;
8'd86:r_hist_cnt[86] <=r_hist_cnt[86] + 1;
8'd87:r_hist_cnt[87] <=r_hist_cnt[87] + 1;
8'd88:r_hist_cnt[88] <=r_hist_cnt[88] + 1;
8'd89:r_hist_cnt[89] <=r_hist_cnt[89] + 1;
8'd90:r_hist_cnt[90] <=r_hist_cnt[90] + 1;
8'd91:r_hist_cnt[91] <=r_hist_cnt[91] + 1;
8'd92:r_hist_cnt[92] <=r_hist_cnt[92] + 1;
8'd93:r_hist_cnt[93] <=r_hist_cnt[93] + 1;
8'd94:r_hist_cnt[94] <=r_hist_cnt[94] + 1;
8'd95:r_hist_cnt[95] <=r_hist_cnt[95] + 1;
8'd96:r_hist_cnt[96] <=r_hist_cnt[96] + 1;
8'd97:r_hist_cnt[97] <=r_hist_cnt[97] + 1;
8'd98:r_hist_cnt[98] <=r_hist_cnt[98] + 1;
8'd99:r_hist_cnt[99] <=r_hist_cnt[99] + 1;
8'd100:r_hist_cnt[100] <=r_hist_cnt[100] + 1;
8'd101:r_hist_cnt[101] <=r_hist_cnt[101] + 1;
8'd102:r_hist_cnt[102] <=r_hist_cnt[102] + 1;
8'd103:r_hist_cnt[103] <=r_hist_cnt[103] + 1;
8'd104:r_hist_cnt[104] <=r_hist_cnt[104] + 1;
8'd105:r_hist_cnt[105] <=r_hist_cnt[105] + 1;
8'd106:r_hist_cnt[106] <=r_hist_cnt[106] + 1;
8'd107:r_hist_cnt[107] <=r_hist_cnt[107] + 1;
8'd108:r_hist_cnt[108] <=r_hist_cnt[108] + 1;
8'd109:r_hist_cnt[109] <=r_hist_cnt[109] + 1;
8'd110:r_hist_cnt[110] <=r_hist_cnt[110] + 1;
8'd111:r_hist_cnt[111] <=r_hist_cnt[111] + 1;
8'd112:r_hist_cnt[112] <=r_hist_cnt[112] + 1;
8'd113:r_hist_cnt[113] <=r_hist_cnt[113] + 1;
8'd114:r_hist_cnt[114] <=r_hist_cnt[114] + 1;
8'd115:r_hist_cnt[115] <=r_hist_cnt[115] + 1;
8'd116:r_hist_cnt[116] <=r_hist_cnt[116] + 1;
8'd117:r_hist_cnt[117] <=r_hist_cnt[117] + 1;
8'd118:r_hist_cnt[118] <=r_hist_cnt[118] + 1;
8'd119:r_hist_cnt[119] <=r_hist_cnt[119] + 1;
8'd120:r_hist_cnt[120] <=r_hist_cnt[120] + 1;
8'd121:r_hist_cnt[121] <=r_hist_cnt[121] + 1;
8'd122:r_hist_cnt[122] <=r_hist_cnt[122] + 1;
8'd123:r_hist_cnt[123] <=r_hist_cnt[123] + 1;
8'd124:r_hist_cnt[124] <=r_hist_cnt[124] + 1;
8'd125:r_hist_cnt[125] <=r_hist_cnt[125] + 1;
8'd126:r_hist_cnt[126] <=r_hist_cnt[126] + 1;
8'd127:r_hist_cnt[127] <=r_hist_cnt[127] + 1;
8'd128:r_hist_cnt[128] <=r_hist_cnt[128] + 1;
8'd129:r_hist_cnt[129] <=r_hist_cnt[129] + 1;
8'd130:r_hist_cnt[130] <=r_hist_cnt[130] + 1;
8'd131:r_hist_cnt[131] <=r_hist_cnt[131] + 1;
8'd132:r_hist_cnt[132] <=r_hist_cnt[132] + 1;
8'd133:r_hist_cnt[133] <=r_hist_cnt[133] + 1;
8'd134:r_hist_cnt[134] <=r_hist_cnt[134] + 1;
8'd135:r_hist_cnt[135] <=r_hist_cnt[135] + 1;
8'd136:r_hist_cnt[136] <=r_hist_cnt[136] + 1;
8'd137:r_hist_cnt[137] <=r_hist_cnt[137] + 1;
8'd138:r_hist_cnt[138] <=r_hist_cnt[138] + 1;
8'd139:r_hist_cnt[139] <=r_hist_cnt[139] + 1;
8'd140:r_hist_cnt[140] <=r_hist_cnt[140] + 1;
8'd141:r_hist_cnt[141] <=r_hist_cnt[141] + 1;
8'd142:r_hist_cnt[142] <=r_hist_cnt[142] + 1;
8'd143:r_hist_cnt[143] <=r_hist_cnt[143] + 1;
8'd144:r_hist_cnt[144] <=r_hist_cnt[144] + 1;
8'd145:r_hist_cnt[145] <=r_hist_cnt[145] + 1;
8'd146:r_hist_cnt[146] <=r_hist_cnt[146] + 1;
8'd147:r_hist_cnt[147] <=r_hist_cnt[147] + 1;
8'd148:r_hist_cnt[148] <=r_hist_cnt[148] + 1;
8'd149:r_hist_cnt[149] <=r_hist_cnt[149] + 1;
8'd150:r_hist_cnt[150] <=r_hist_cnt[150] + 1;
8'd151:r_hist_cnt[151] <=r_hist_cnt[151] + 1;
8'd152:r_hist_cnt[152] <=r_hist_cnt[152] + 1;
8'd153:r_hist_cnt[153] <=r_hist_cnt[153] + 1;
8'd154:r_hist_cnt[154] <=r_hist_cnt[154] + 1;
8'd155:r_hist_cnt[155] <=r_hist_cnt[155] + 1;
8'd156:r_hist_cnt[156] <=r_hist_cnt[156] + 1;
8'd157:r_hist_cnt[157] <=r_hist_cnt[157] + 1;
8'd158:r_hist_cnt[158] <=r_hist_cnt[158] + 1;
8'd159:r_hist_cnt[159] <=r_hist_cnt[159] + 1;
8'd160:r_hist_cnt[160] <=r_hist_cnt[160] + 1;
8'd161:r_hist_cnt[161] <=r_hist_cnt[161] + 1;
8'd162:r_hist_cnt[162] <=r_hist_cnt[162] + 1;
8'd163:r_hist_cnt[163] <=r_hist_cnt[163] + 1;
8'd164:r_hist_cnt[164] <=r_hist_cnt[164] + 1;
8'd165:r_hist_cnt[165] <=r_hist_cnt[165] + 1;
8'd166:r_hist_cnt[166] <=r_hist_cnt[166] + 1;
8'd167:r_hist_cnt[167] <=r_hist_cnt[167] + 1;
8'd168:r_hist_cnt[168] <=r_hist_cnt[168] + 1;
8'd169:r_hist_cnt[169] <=r_hist_cnt[169] + 1;
8'd170:r_hist_cnt[170] <=r_hist_cnt[170] + 1;
8'd171:r_hist_cnt[171] <=r_hist_cnt[171] + 1;
8'd172:r_hist_cnt[172] <=r_hist_cnt[172] + 1;
8'd173:r_hist_cnt[173] <=r_hist_cnt[173] + 1;
8'd174:r_hist_cnt[174] <=r_hist_cnt[174] + 1;
8'd175:r_hist_cnt[175] <=r_hist_cnt[175] + 1;
8'd176:r_hist_cnt[176] <=r_hist_cnt[176] + 1;
8'd177:r_hist_cnt[177] <=r_hist_cnt[177] + 1;
8'd178:r_hist_cnt[178] <=r_hist_cnt[178] + 1;
8'd179:r_hist_cnt[179] <=r_hist_cnt[179] + 1;
8'd180:r_hist_cnt[180] <=r_hist_cnt[180] + 1;
8'd181:r_hist_cnt[181] <=r_hist_cnt[181] + 1;
8'd182:r_hist_cnt[182] <=r_hist_cnt[182] + 1;
8'd183:r_hist_cnt[183] <=r_hist_cnt[183] + 1;
8'd184:r_hist_cnt[184] <=r_hist_cnt[184] + 1;
8'd185:r_hist_cnt[185] <=r_hist_cnt[185] + 1;
8'd186:r_hist_cnt[186] <=r_hist_cnt[186] + 1;
8'd187:r_hist_cnt[187] <=r_hist_cnt[187] + 1;
8'd188:r_hist_cnt[188] <=r_hist_cnt[188] + 1;
8'd189:r_hist_cnt[189] <=r_hist_cnt[189] + 1;
8'd190:r_hist_cnt[190] <=r_hist_cnt[190] + 1;
8'd191:r_hist_cnt[191] <=r_hist_cnt[191] + 1;
8'd192:r_hist_cnt[192] <=r_hist_cnt[192] + 1;
8'd193:r_hist_cnt[193] <=r_hist_cnt[193] + 1;
8'd194:r_hist_cnt[194] <=r_hist_cnt[194] + 1;
8'd195:r_hist_cnt[195] <=r_hist_cnt[195] + 1;
8'd196:r_hist_cnt[196] <=r_hist_cnt[196] + 1;
8'd197:r_hist_cnt[197] <=r_hist_cnt[197] + 1;
8'd198:r_hist_cnt[198] <=r_hist_cnt[198] + 1;
8'd199:r_hist_cnt[199] <=r_hist_cnt[199] + 1;
8'd200:r_hist_cnt[200] <=r_hist_cnt[200] + 1;
8'd201:r_hist_cnt[201] <=r_hist_cnt[201] + 1;
8'd202:r_hist_cnt[202] <=r_hist_cnt[202] + 1;
8'd203:r_hist_cnt[203] <=r_hist_cnt[203] + 1;
8'd204:r_hist_cnt[204] <=r_hist_cnt[204] + 1;
8'd205:r_hist_cnt[205] <=r_hist_cnt[205] + 1;
8'd206:r_hist_cnt[206] <=r_hist_cnt[206] + 1;
8'd207:r_hist_cnt[207] <=r_hist_cnt[207] + 1;
8'd208:r_hist_cnt[208] <=r_hist_cnt[208] + 1;
8'd209:r_hist_cnt[209] <=r_hist_cnt[209] + 1;
8'd210:r_hist_cnt[210] <=r_hist_cnt[210] + 1;
8'd211:r_hist_cnt[211] <=r_hist_cnt[211] + 1;
8'd212:r_hist_cnt[212] <=r_hist_cnt[212] + 1;
8'd213:r_hist_cnt[213] <=r_hist_cnt[213] + 1;
8'd214:r_hist_cnt[214] <=r_hist_cnt[214] + 1;
8'd215:r_hist_cnt[215] <=r_hist_cnt[215] + 1;
8'd216:r_hist_cnt[216] <=r_hist_cnt[216] + 1;
8'd217:r_hist_cnt[217] <=r_hist_cnt[217] + 1;
8'd218:r_hist_cnt[218] <=r_hist_cnt[218] + 1;
8'd219:r_hist_cnt[219] <=r_hist_cnt[219] + 1;
8'd220:r_hist_cnt[220] <=r_hist_cnt[220] + 1;
8'd221:r_hist_cnt[221] <=r_hist_cnt[221] + 1;
8'd222:r_hist_cnt[222] <=r_hist_cnt[222] + 1;
8'd223:r_hist_cnt[223] <=r_hist_cnt[223] + 1;
8'd224:r_hist_cnt[224] <=r_hist_cnt[224] + 1;
8'd225:r_hist_cnt[225] <=r_hist_cnt[225] + 1;
8'd226:r_hist_cnt[226] <=r_hist_cnt[226] + 1;
8'd227:r_hist_cnt[227] <=r_hist_cnt[227] + 1;
8'd228:r_hist_cnt[228] <=r_hist_cnt[228] + 1;
8'd229:r_hist_cnt[229] <=r_hist_cnt[229] + 1;
8'd230:r_hist_cnt[230] <=r_hist_cnt[230] + 1;
8'd231:r_hist_cnt[231] <=r_hist_cnt[231] + 1;
8'd232:r_hist_cnt[232] <=r_hist_cnt[232] + 1;
8'd233:r_hist_cnt[233] <=r_hist_cnt[233] + 1;
8'd234:r_hist_cnt[234] <=r_hist_cnt[234] + 1;
8'd235:r_hist_cnt[235] <=r_hist_cnt[235] + 1;
8'd236:r_hist_cnt[236] <=r_hist_cnt[236] + 1;
8'd237:r_hist_cnt[237] <=r_hist_cnt[237] + 1;
8'd238:r_hist_cnt[238] <=r_hist_cnt[238] + 1;
8'd239:r_hist_cnt[239] <=r_hist_cnt[239] + 1;
8'd240:r_hist_cnt[240] <=r_hist_cnt[240] + 1;
8'd241:r_hist_cnt[241] <=r_hist_cnt[241] + 1;
8'd242:r_hist_cnt[242] <=r_hist_cnt[242] + 1;
8'd243:r_hist_cnt[243] <=r_hist_cnt[243] + 1;
8'd244:r_hist_cnt[244] <=r_hist_cnt[244] + 1;
8'd245:r_hist_cnt[245] <=r_hist_cnt[245] + 1;
8'd246:r_hist_cnt[246] <=r_hist_cnt[246] + 1;
8'd247:r_hist_cnt[247] <=r_hist_cnt[247] + 1;
8'd248:r_hist_cnt[248] <=r_hist_cnt[248] + 1;
8'd249:r_hist_cnt[249] <=r_hist_cnt[249] + 1;
8'd250:r_hist_cnt[250] <=r_hist_cnt[250] + 1;
8'd251:r_hist_cnt[251] <=r_hist_cnt[251] + 1;
8'd252:r_hist_cnt[252] <=r_hist_cnt[252] + 1;
8'd253:r_hist_cnt[253] <=r_hist_cnt[253] + 1;
8'd254:r_hist_cnt[254] <=r_hist_cnt[254] + 1;
8'd255:r_hist_cnt[255] <=r_hist_cnt[255] + 1;
default:;
endcase
end
else;
end
//输入像素计数器,一张图片已经输入了多少个像素
reg[19:0] r_pix_cnt;
wire w_one_frame_done;//一帧图像处理完成标志
always@(posedge i_clk) begin
if(!i_rst_n)
r_pix_cnt <= 20'd0;
else if(w_one_frame_done)//计满一帧图像是，计数器清零。
r_pix_cnt <=0;
else if(i_image_vld)
r_pix_cnt <= r_pix_cnt + 1;
else;
end
assign w_one_frame_done = (r_pix_cnt==P_IMAGE_SIZE)?1:0;
//直方图统计结果输出计数
reg [8:0] r_result_cnt;
always@(posedge i_clk) begin
if(!i_rst_n)
r_result_cnt<=9'd0;
else if(w_one_frame_done)
r_result_cnt <= 9'd1;
else if( (r_result_cnt>9'd0) && (r_result_cnt<9'd256))
r_result_cnt <= r_result_cnt +1;
else
r_result_cnt<=9'd0;
end
//直方图统计结果的输出
//output reg o_result_rdy,
//output reg [19:0] o_result_data
always@(posedge i_clk) begin
if(!i_rst_n)
o_result_rdy <= 0;
else if(r_result_cnt !=9'd0)
o_result_rdy <= 1;
else
o_result_rdy <=0;
end
always@(posedge i_clk) begin
o_result_data <= r_hist_cnt[r_result_cnt-1];
end
endmodule直方图滤波的Matalb实现可以参考我另一篇博客，里面详细介绍了直方图滤波的原理：
MATLAB图像处理之【直方图均衡】 传送门
c
--晓凡 2024年4月28日于武汉书