在学习本节课之前需要一些预备知识：文章Verilog文件操作练习（1）BMP图像色彩替换中简单的介绍了BMP文件的格式，以及在文章图像色彩空间转换中学习RGB和YUV色彩空间的概念，在文章verilog 仿真工程应用-生成coe/mif 文件中学习如何通过文本文件或是二进制文件生成可以存储在RAM/ROM IP核中的coe/mif文件。本节课在使用BMP图像生成coe/mif文件的同时也练习使用了前面学过的Verilog文件操作等函数。结合以上的内容，就可以将一张BMP图像的RGB数据提取出来，经过YUV变换（可选），以相应的格式生成coe/mif文件，最终存储在FPGA的RAM/ROM IP核中，实验结构框图如下所示：
图1 实验结构
1. 从BMP图像中提取RGB纯数据
为了简化实验过程，突出实验目的，这里提供的BMP图像都是默认采用RGB24，并且宽度是4的整数倍（DWORD），不用padding。将RGB纯数据提取出来的Verilog代码如下图所示：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/test.bmp";
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
//建立了一个1920*1080的装24-bit RGB像素数据的矩阵
reg[23:0]rgb_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);
num = $fscanf(fpre,"%c",fbyte1);
num = $fscanf(fpre,"%c",fbyte2);
if(j < image_height )
begin
if(i < image_width)
begin
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
end
end
$fclose(fpre);
$display("\n ============= file closed... ============= ") ;
#100;
$stop;
end
endmodule
2. 调整RGB数据格式
在前面介绍BMP格式的文章中有说过，BMP中像素的排列顺序是从左到右，从下到上的，而大部分图片，视频输出显示的排列顺序一般是从左到右，从上到下的，如下图所示的对比。所以本实验为了适应大部分应用程序还需要调整RGB的数据格式。
图2 左为BMP格式中像素排列的方向，右为大部分图片，视频的像素排列方向
调整上文程序中的1920*1080的装24-bit RGB像素数据的矩阵rgb_byte中的行顺序代码如下：
reg[23:0]rgb_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
integer i;
integer j;
//这里只列出了颠倒RGB像素数据行顺序的部分代码
initial
begin
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
rgb_ordered[j][i] = rgb_byte[image_height -1 - j][i];
end
end
3. 变换RGB数据为YUV数据
文章图像色彩空间转换中详细说明了YUV色彩空间的概念，相比于RGB，YUV的优点是可以向下兼容黑白显示，以及根据人眼的视觉感知，调整图像的构成，使其便于后期压缩传输和还原。由YUV还可以扩展成YCbCr，YCbCr简单来说是在YUV的基础上做了偏移和缩放。RGB的构成是红色，绿色和蓝色分量组合，而YUV的构成是亮度（Y，Luminance）和色度（U和V，chrominance）。U表示蓝色投影，V表示红色投影。当U和V成分不存在时，Y单独可以输出到黑白电视上。
从RGB转换到YUV的公式如下所示，从公式中可以看出U和V成分是相对与Y成分的红，蓝投影（相对与Y来说，U和V不是告诉颜色有多少红/蓝，而是说明它比Y更红/蓝多少）。
- Y = 0.299R + 0.587G + 0.144B
- U = -0.147R – 0.289G + 0.436B = 0.492(B – Y)
- V = 0.615R – 0.515G – 0.100B = 0.877(R – Y)
注意：当RGB 取值范围在 0 — 255 之间时：
- Y 的范围： 0 — 255
- U的范围：-112 — +112
- V的范围：-157 — + 157
因为上述公式在实际转换过程中U，V的结果可能为负数，所以为了避免这种情况，将Y，U，V的范围都保证在[0, 255]内，一般会使用下列公式：
- Y = 0.257R + 0.504G + 0.098B + 16
- Cb = -0.148R – 0.291G + 0.439B + 128
- Cr = 0.439R – 0.368G – 0.071B + 128
YCbCr 与YUV的算法非常类似，这两者也经常会被混淆。 但YCbCr非常适合数值视频的存储（在YUV的基础上只是修改了矩阵的相关系数 + 偏移） 。 YCbCr 是ITU-R BT.601协议的一部分，在8-bit数字视频信号存储时：
- Y 的范围：16 — 235
- Cb（U）的范围：16 — 240
- Cr（V）的范围：16 — 240
在将RGB数据转换成YUV之后，这里同样颠倒了YUV数据的列顺序，实现的Verilog代码如下所示：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/test.bmp";
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
reg[23:0]yuv_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]yuv_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
real y,Cb,Cr;
reg[7:0] y_byte,u_byte,v_byte;
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);//****blue
num = $fscanf(fpre,"%c",fbyte1);//greeen
num = $fscanf(fpre,"%c",fbyte2);//****red
// *************** formula ******************
// Y = 0.257R + 0.504G + 0.098B + 16
// Cb = -0.148R - 0.291G + 0.439B + 128
// Cr = 0.439R - 0.368G - 0.071B + 128
y = 0.257*fbyte2 + 0.504*fbyte1 + 0.098*fbyte0 + 16;
Cb = -0.148*fbyte2 - 0.291*fbyte1 + 0.439*fbyte0 + 128;
Cr = 0.439*fbyte2 - 0.368*fbyte1 - 0.071*fbyte0 + 128 ;
//real number to integer number
y_byte = $rtoi( y ) ;
u_byte = $rtoi( Cb ) ;
v_byte = $rtoi( Cr ) ;
if(j < image_height)
begin
if(i < image_width)
begin
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
end
end
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
yuv_ordered[j][i] = yuv_byte[image_height -1 - j][i];
end
$fclose(fpre);
$display("\n ============= file closed... ============= ") ;
#100;
$stop;
end
endmodule
4. RGB/YUV数据生成coe/mif文件
对于在Verilog仿真工程中如何生成coe/mif文件，可以参考文章verilog 仿真工程应用-生成coe/mif 文件。这里在此基础上，将输入的input_data替换成RGB/YUV数据，实现的Verilog代码如下：
YUV数据生成coe文件：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/0207/test4.bmp";
// coe file
localparam FILE_COE = "D:/Files_import/2022/0207/coe_test.coe";
localparam INPUT_DATA_RADIX = 16; // 16, 10 , 2
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer fcoe;
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
reg[23:0]yuv_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]yuv_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
real y,Cb,Cr;
reg[7:0] y_byte,u_byte,v_byte;
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);//****blue
num = $fscanf(fpre,"%c",fbyte1);//greeen
num = $fscanf(fpre,"%c",fbyte2);//****red
//=================== formula ======================
// Y = 0.257R + 0.504G + 0.098B + 16
// Cb = -0.148R - 0.291G + 0.439B + 128
// Cr = 0.439R - 0.368G - 0.071B + 128
//==================================================
y = 0.257*fbyte2 + 0.504*fbyte1 + 0.098*fbyte0 + 16;
Cb = -0.148*fbyte2 - 0.291*fbyte1 + 0.439*fbyte0 + 128;
Cr = 0.439*fbyte2 - 0.368*fbyte1 - 0.071*fbyte0 + 128 ;
y_byte = $rtoi( y ) ;
u_byte = $rtoi( Cb ) ;
v_byte = $rtoi( Cr ) ;
if(j < image_height)
begin
if(i < image_width)
begin
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
end
end
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
yuv_ordered[j][i] = yuv_byte[image_height -1 - j][i];
end
$fclose(fpre);
$display("\n ============= file closed... ============= ") ;
//=============================== write coe file ===============================
i = 0;
j = 0;
fcoe = $fopen(FILE_COE, "w");
if(fcoe == 0)
begin
$display("$open coe file failed") ;
$stop;
end
$display("\n ============= coe file opened... ============= ") ;
// coe file
$fwrite(fcoe,"memory_initialization_radix = %0d;\n",INPUT_DATA_RADIX);
$fwrite(fcoe,"memory_initialization_vector = ");
#10;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
if( INPUT_DATA_RADIX == 16)
$fwrite(fcoe,"\n%h", yuv_ordered[j][i]);
if( INPUT_DATA_RADIX == 2)
$fwrite(fcoe,"\n%b",yuv_ordered[j][i]);
if( INPUT_DATA_RADIX == 10)
$fwrite(fcoe,"\n%d", yuv_ordered[j][i]);
#10;
end
$fwrite(fcoe,";");
#10;
$fclose(fcoe) ;
$display("\n ============= coe file closed... ============= ") ;
// =====================================================================
#100;
$stop;
end
endmodule
YUV数据生成mif文件：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/0207/test4.bmp";
localparam INPUT_DATA_RADIX = 16; // 16, 10 , 2
// mif file
localparam FILE_MIF = "D:/Files_import/2022/0207/mif_test.mif";
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer fmif;
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
reg[23:0]rgb_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]rgb_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]yuv_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]yuv_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
real y,Cb,Cr;
reg[7:0] y_byte,u_byte,v_byte;
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);//****blue
num = $fscanf(fpre,"%c",fbyte1);//greeen
num = $fscanf(fpre,"%c",fbyte2);//****red
//****************** formula ***********************
// Y = 0.257R + 0.504G + 0.098B + 16
// Cb = -0.148R - 0.291G + 0.439B + 128
// Cr = 0.439R - 0.368G - 0.071B + 128
y = 0.257*fbyte2 + 0.504*fbyte1 + 0.098*fbyte0 + 16;
Cb = -0.148*fbyte2 - 0.291*fbyte1 + 0.439*fbyte0 + 128;
Cr = 0.439*fbyte2 - 0.368*fbyte1 - 0.071*fbyte0 + 128 ;
y_byte = $rtoi( y ) ;
u_byte = $rtoi( Cb ) ;
v_byte = $rtoi( Cr ) ;
if(j < image_height)
begin
if(i < image_width)
begin
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
yuv_byte[j][ i ] = {y_byte,u_byte,v_byte};
i = i + 1;
end
end
end
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
yuv_ordered[j][i] = yuv_byte[image_height -1 - j][i];
end
$fclose(fpre);
$display("\n ============= file closed... ============= ") ;
// =====================================================================
// mif file
i = 0;
j = 0;
$display("\n ============= mif file opened... ============= ") ;
fmif = $fopen(FILE_MIF, "w");
if(fmif == 0)
begin
$display("$open mif file failed") ;
$stop;
end
$fwrite(fmif,"WIDTH=%0d;\n",24);//YUV data in 24-bits
$fwrite(fmif,"DEPTH=%0d;\n\n",image_height*image_width);
$fwrite(fmif,"ADDRESS_RADIX=UNS;\n");
if( INPUT_DATA_RADIX == 16)
$fwrite(fmif,"DATA_RADIX=HEX;\n\n");
if( INPUT_DATA_RADIX == 10)
$fwrite(fmif,"DATA_RADIX=DEC;\n\n");
if( INPUT_DATA_RADIX == 2)
$fwrite(fmif,"DATA_RADIX=BIN;\n\n");
$fwrite(fmif,"CONTENT BEGIN\n");
#10;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
if( INPUT_DATA_RADIX == 16)
$fwrite(fmif,"\n%h", yuv_ordered[j][i]);
if( INPUT_DATA_RADIX == 2)
$fwrite(fmif,"\n%b",yuv_ordered[j][i]);
if( INPUT_DATA_RADIX == 10)
$fwrite(fmif,"\n%d", yuv_ordered[j][i]);
#10;
end
$fwrite(fmif,"END;\n");
#10;
$fclose(fmif) ;
$display("\n ============= mif file closed... ============= ") ;
// =====================================================================
#100;
$stop;
end
endmodule
RGB数据生成coe文件：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/0207/test4.bmp";
// coe file
localparam FILE_COE = "D:/Files_import/2022/0207/coe_test.coe";
localparam INPUT_DATA_RADIX = 16; // 16, 10 , 2
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer fcoe;
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
reg[23:0]rgb_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]rgb_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);
num = $fscanf(fpre,"%c",fbyte1);
num = $fscanf(fpre,"%c",fbyte2);
if(j < image_height )
begin
if(i < image_width)
begin
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
end
end
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
//yuv_ordered[j][i] = yuv_byte[image_height -1 - j][i];
rgb_ordered[j][i] = rgb_byte[image_height -1 - j][i];
end
$fclose(fpre);
$display("\n ============= file closed... ============= ") ;
//=============================== write coe file ===============================
i = 0;
j = 0;
fcoe = $fopen(FILE_COE, "w");
if(fcoe == 0)
begin
$display("$open coe file failed") ;
$stop;
end
$display("\n ============= coe file opened... ============= ") ;
// coe file
$fwrite(fcoe,"memory_initialization_radix = %0d;\n",INPUT_DATA_RADIX);
$fwrite(fcoe,"memory_initialization_vector = ");
#10;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
if( INPUT_DATA_RADIX == 16)
$fwrite(fcoe,"\n%h", rgb_ordered[j][i]);
if( INPUT_DATA_RADIX == 2)
$fwrite(fcoe,"\n%b",rgb_ordered[j][i]);
if( INPUT_DATA_RADIX == 10)
$fwrite(fcoe,"\n%d", rgb_ordered[j][i]);
#10;
end
$fwrite(fcoe,";");
#10;
$fclose(fcoe) ;
$display("\n ============= coe file closed... ============= ") ;
// =====================================================================
#100;
$stop;
end
endmodule
RGB数据生成mif文件：
`timescale 1ns / 1ps
module bmp_1(
);
//original bmp file
localparam FILE_TXT = "D:/Files_import/2022/0207/test4.bmp";
localparam INPUT_DATA_RADIX = 16; // 16, 10 , 2
// mif file
localparam FILE_MIF = "D:/Files_import/2022/0207/mif_test.mif";
localparam WIDTH_PARAM = 1920;
localparam HEIGHT_PARAM = 1080;
integer fpre;//file
integer fmif;
integer ret;//param for $fseek
integer num;//param for $fread, $fscanf
reg[7:0]fbyte[3:0];//storing $fread reg
reg[7:0] fbyte0,fbyte1,fbyte2;
integer i = 0;//used for loop param
integer j = 0;//used for loop param
reg [31:0] image_width;//param for counting image width
reg [31:0] image_height;//param for counting image height
reg[23:0]rgb_byte [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
reg[23:0]rgb_ordered [HEIGHT_PARAM-1 : 0][WIDTH_PARAM-1 :0];
initial
begin
fpre = $fopen(FILE_TXT, "rb"); //binary read
if(fpre == 0)
begin
$display("$open file failed") ;
$stop;
end
$display("\n ============= file opened... ============= ") ;
ret = $fseek(fpre, 8'h12,0);//read from the start, offset set to image width and height
num = $fread(fbyte,fpre,0,4);
image_width = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image wdith is %d",image_width);
#10;
num = $fread(fbyte,fpre,0,4);
image_height = {fbyte[3],fbyte[2],fbyte[1],fbyte[0]};
$display ("The image height is %d",image_height);
ret = $fseek(fpre, 8'h36,0);//read from the start, offset set to pixel array
i = 0;
j = 0;
while($feof(fpre) != 1)
begin
num = $fscanf(fpre,"%c",fbyte0);
num = $fscanf(fpre,"%c",fbyte1);
num = $fscanf(fpre,"%c",fbyte2);
if(j < image_height )
begin
if(i < image_width)
begin
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
else
begin
j = j + 1;
i = 0;
rgb_byte[j][ i ] = {fbyte2,fbyte1,fbyte0}
i = i + 1;
end
end
end
i = 0;
j = 0;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
//yuv_ordered[j][i] = yuv_byte[image_height -1 - j][i];
rgb_ordered[j][i] = rgb_byte[image_height -1 - j][i];
end
$fclose(fpre);
// =====================================================================
// mif file
i = 0;
j = 0;
$display("\n ============= mif file opened... ============= ") ;
fmif = $fopen(FILE_MIF, "w");
if(fmif == 0)
begin
$display("$open mif file failed") ;
$stop;
end
$fwrite(fmif,"WIDTH=%0d;\n",24);//YUV data in 24-bits
$fwrite(fmif,"DEPTH=%0d;\n\n",image_height*image_width);
$fwrite(fmif,"ADDRESS_RADIX=UNS;\n");
if( INPUT_DATA_RADIX == 16)
$fwrite(fmif,"DATA_RADIX=HEX;\n\n");
if( INPUT_DATA_RADIX == 10)
$fwrite(fmif,"DATA_RADIX=DEC;\n\n");
if( INPUT_DATA_RADIX == 2)
$fwrite(fmif,"DATA_RADIX=BIN;\n\n");
$fwrite(fmif,"CONTENT BEGIN\n");
#10;
for(j = 0; j <image_height; j = j + 1)
begin
for(i = 0; i <image_width; i = i + 1)
if( INPUT_DATA_RADIX == 16)
$fwrite(fmif,"\n%h", rgb_ordered[j][i]);
if( INPUT_DATA_RADIX == 2)
$fwrite(fmif,"\n%b",rgb_ordered[j][i]);
if( INPUT_DATA_RADIX == 10)
$fwrite(fmif,"\n%d", rgb_ordered[j][i]);
#10;
end
$fwrite(fmif,"END;\n");
#10;
$fclose(fmif) ;
$display("\n ============= mif file closed... ============= ") ;
// =====================================================================
#100;
$stop;
end
endmodule
5.扩展
结合之前学习的HDMI图像显示，参见文章HDMI 图像显示 ，前面RGB数据生成的coe文件可以通过ADV7511图像显示工程在FII-PRX100-D FPGA开发板上跑起来，注意ADV7511图像显示工程中规定了图像的大小是480*270，实例将一张480*270的图像通过本文的RGB转coe文件工程，生成相应的coe文件，原图片和生成相应的coe文件如下：
[content_control]
[/content_control]
最后在屏幕上显示的效果如下：
图3 HDMI显示
从以上可知，使用Vivado仿真中的文件操作函数可以将一张图片转成coe文件，并通过HDMI显示在屏幕上。
