如何读取图像文件并将其转换为vhdl中的位
how to read image file and convert it to bits in vhdl
我正在尝试使用 vhdl 中的 textio 包读取图像文件。
如果我用记事本打开 .jpg，我会得到一些垃圾数据，但实际上它是 ASCII 数据。我在这里尝试读取这些 ascii 数据并将它们转换为字节。
下面是我的代码：
library ieee;
use ieee.std_logic_1164.all;
use std.textio.all;
use ieee.std_logic_textio.all;
entity file_io is
port (
clk: in std_logic;
Data: out std_logic_vector(7 downto 0)
);
end entity;
architecture behav of file_io is
signal test_data : std_logic_vector(7 downto 0);
use ieee.numeric_std.all;
use std.textio.all;
use ieee.std_logic_textio.all;
begin
File_reader:process(clk)
file f : text open read_mode is "C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg";
variable L: line;
variable var_int: integer:= 0;
variable var_char: character;
begin
if rising_edge(clk) then
while not endfile(f) loop
readline(f, L);
read(L, var_char);
var_int := character'pos(var_char);
test_data <= std_logic_vector(to_unsigned(var_int, test_data'length));
end loop;
end if;
Data <= test_data;
end process;
end architecture behav;
测试平台：
LIBRARY ieee;
use ieee.std_logic_1164.ALL;
use std.textio.all;
ENTITY file_io_test IS
END file_io_test;
ARCHITECTURE behavior OF file_io_test IS
use work.io.all;
signal clk: std_logic := '0';
signal Data: std_logic_vector(7 downto 0);
-- Clock period definitions
constant clk_period : time := 10 ns;
BEGIN
-- Instantiate the Unit Under Test (UUT)
UUT:
entity work.file_io(behav)
port map (
clk => clk,
Data => Data
);
-- Clock process definitions( clock with 50% duty cycle is generated here.
clk_process :process
begin
clk <= '1';
wait for clk_period/2; --for 5 ns signal is '1'.
clk <= '0';
wait for clk_period/2; --for next 5 ns signal is '0'.
end process;
end behavior;
我在波形中只得到一个字节。预期结果是：每个时钟周期都应读取新字符并获取新字节。
波形如下：
下面是我正在尝试阅读的图像：
您在流程的 rising_edge 部分内放置了一个 while 循环。发生的情况是，当第一个时钟边沿出现时，while 循环迭代直到文件末尾并为您提供输入图像的最后一个字节。
删除 while 循环语句应该可以解决您的问题。
这个问题有一个根本性的缺陷。您不能使用 textio 读取二进制值，它用于文本。
参见 IEEE Std 1076-2008 16.4 Package TEXTIO 第 3 段（部分）和第 4 段：
Procedures READLINE, WRITELINE, and TEE declared in package TEXTIO read and write entire lines of a file of type TEXT. Procedure READLINE causes the next line to be read from the file and returns as the value of parameter L an access value that designates an object representing that line. If parameter L contains a non-null access value at the start of the call, the procedure may deallocate the object designated by that value. The representation of the line does not contain the representation of the end of the line. ...
The language does not define the representation of the end of a line. An implementation shall allow all possible values of types CHARACTER and STRING to be written to a file. However, as an implementation is permitted to use certain values of types CHARACTER and STRING as line delimiters, it might not be possible to read these values from a TEXT file.
这可以用你的 Chrysanthemum.jpg 来证明：
在 VHDL 中可以一次读取一个原始字符（满足您的需要）。
参见 IEEE Std 1076-2008 5.5 文件类型：
所以我们所要做的就是声明一个文件类型，然后我们就可以隐式定义这些过程。
我们可以使用它们来调用原始读取，而不会出现由 textio 引起的任何行尾问题：
library ieee;
use ieee.std_logic_1164.all;
entity file_io is
port (
clk: in std_logic;
Data: out std_logic_vector(7 downto 0);
done: out boolean
);
end entity;
architecture foo of file_io is
use ieee.numeric_std.all;
begin
File_reader:
process (clk)
-- "C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg";
constant filename: string := "Chrysanthemum.jpg"; -- local to sim
variable char_val: character;
variable status: FILE_OPEN_STATUS;
variable openfile: boolean; -- FALSE by default
type f is file of character;
file ffile: f;
variable char_count: natural := 0;
begin
if rising_edge (clk) then
if not openfile then
file_open (status, ffile, filename, READ_MODE);
if status /= OPEN_OK then
report "FILE_OPEN_STATUS = " &
FILE_OPEN_STATUS'IMAGE(status)
severity FAILURE;
end if;
report "FILE_OPEN_STATUS = " & FILE_OPEN_STATUS'IMAGE(status);
openfile := TRUE;
else
if not endfile(ffile) then
read(ffile, char_val);
-- report "char_val = " & character'image(char_val);
char_count := char_count + 1;
Data <= std_logic_vector (
to_unsigned(character'pos(char_val),
Data'length) );
end if;
if endfile(ffile) then -- can occur after last character
report "ENDFILE, read " &
integer'image(char_count) & "characters";
done <= TRUE;
FILE_CLOSE(ffile);
end if;
end if;
end if;
end process;
end architecture foo;
library ieee;
use ieee.std_logic_1164.all;
entity file_io_test is
end file_io_test;
architecture behavior of file_io_test is
signal clk: std_logic := '0';
signal data: std_logic_vector(7 downto 0);
signal done: boolean;
constant clk_period: time := 10 ns;
begin
uut:
entity work.file_io(foo)
port map (
clk => clk,
data => data,
done => done
);
clk_process:
process
begin
if not done then
clk <= '1';
wait for clk_period/2;
clk <= '0';
wait for clk_period/2;
else
wait;
end if;
end process;
end architecture behavior;
现在我们可以在我们的阅读中显示所有可以分隔一行的字符：
请注意，包 std.textio 不会通过任何上下文项显示。
我正在尝试使用 vhdl 中的 textio 包读取图像文件。 如果我用记事本打开 .jpg，我会得到一些垃圾数据，但实际上它是 ASCII 数据。我在这里尝试读取这些 ascii 数据并将它们转换为字节。
下面是我的代码：
library ieee;
use ieee.std_logic_1164.all;
use std.textio.all;
use ieee.std_logic_textio.all;
entity file_io is
port (
clk: in std_logic;
Data: out std_logic_vector(7 downto 0)
);
end entity;
architecture behav of file_io is
signal test_data : std_logic_vector(7 downto 0);
use ieee.numeric_std.all;
use std.textio.all;
use ieee.std_logic_textio.all;
begin
File_reader:process(clk)
file f : text open read_mode is "C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg";
variable L: line;
variable var_int: integer:= 0;
variable var_char: character;
begin
if rising_edge(clk) then
while not endfile(f) loop
readline(f, L);
read(L, var_char);
var_int := character'pos(var_char);
test_data <= std_logic_vector(to_unsigned(var_int, test_data'length));
end loop;
end if;
Data <= test_data;
end process;
end architecture behav;
测试平台：
LIBRARY ieee;
use ieee.std_logic_1164.ALL;
use std.textio.all;
ENTITY file_io_test IS
END file_io_test;
ARCHITECTURE behavior OF file_io_test IS
use work.io.all;
signal clk: std_logic := '0';
signal Data: std_logic_vector(7 downto 0);
-- Clock period definitions
constant clk_period : time := 10 ns;
BEGIN
-- Instantiate the Unit Under Test (UUT)
UUT:
entity work.file_io(behav)
port map (
clk => clk,
Data => Data
);
-- Clock process definitions( clock with 50% duty cycle is generated here.
clk_process :process
begin
clk <= '1';
wait for clk_period/2; --for 5 ns signal is '1'.
clk <= '0';
wait for clk_period/2; --for next 5 ns signal is '0'.
end process;
end behavior;
我在波形中只得到一个字节。预期结果是：每个时钟周期都应读取新字符并获取新字节。
波形如下：
下面是我正在尝试阅读的图像：
您在流程的 rising_edge 部分内放置了一个 while 循环。发生的情况是，当第一个时钟边沿出现时，while 循环迭代直到文件末尾并为您提供输入图像的最后一个字节。
删除 while 循环语句应该可以解决您的问题。
这个问题有一个根本性的缺陷。您不能使用 textio 读取二进制值，它用于文本。
参见 IEEE Std 1076-2008 16.4 Package TEXTIO 第 3 段（部分）和第 4 段：
Procedures READLINE, WRITELINE, and TEE declared in package TEXTIO read and write entire lines of a file of type TEXT. Procedure READLINE causes the next line to be read from the file and returns as the value of parameter L an access value that designates an object representing that line. If parameter L contains a non-null access value at the start of the call, the procedure may deallocate the object designated by that value. The representation of the line does not contain the representation of the end of the line. ...
The language does not define the representation of the end of a line. An implementation shall allow all possible values of types CHARACTER and STRING to be written to a file. However, as an implementation is permitted to use certain values of types CHARACTER and STRING as line delimiters, it might not be possible to read these values from a TEXT file.
这可以用你的 Chrysanthemum.jpg 来证明：
在 VHDL 中可以一次读取一个原始字符（满足您的需要）。
参见 IEEE Std 1076-2008 5.5 文件类型：
所以我们所要做的就是声明一个文件类型，然后我们就可以隐式定义这些过程。
我们可以使用它们来调用原始读取，而不会出现由 textio 引起的任何行尾问题：
library ieee;
use ieee.std_logic_1164.all;
entity file_io is
port (
clk: in std_logic;
Data: out std_logic_vector(7 downto 0);
done: out boolean
);
end entity;
architecture foo of file_io is
use ieee.numeric_std.all;
begin
File_reader:
process (clk)
-- "C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg";
constant filename: string := "Chrysanthemum.jpg"; -- local to sim
variable char_val: character;
variable status: FILE_OPEN_STATUS;
variable openfile: boolean; -- FALSE by default
type f is file of character;
file ffile: f;
variable char_count: natural := 0;
begin
if rising_edge (clk) then
if not openfile then
file_open (status, ffile, filename, READ_MODE);
if status /= OPEN_OK then
report "FILE_OPEN_STATUS = " &
FILE_OPEN_STATUS'IMAGE(status)
severity FAILURE;
end if;
report "FILE_OPEN_STATUS = " & FILE_OPEN_STATUS'IMAGE(status);
openfile := TRUE;
else
if not endfile(ffile) then
read(ffile, char_val);
-- report "char_val = " & character'image(char_val);
char_count := char_count + 1;
Data <= std_logic_vector (
to_unsigned(character'pos(char_val),
Data'length) );
end if;
if endfile(ffile) then -- can occur after last character
report "ENDFILE, read " &
integer'image(char_count) & "characters";
done <= TRUE;
FILE_CLOSE(ffile);
end if;
end if;
end if;
end process;
end architecture foo;
library ieee;
use ieee.std_logic_1164.all;
entity file_io_test is
end file_io_test;
architecture behavior of file_io_test is
signal clk: std_logic := '0';
signal data: std_logic_vector(7 downto 0);
signal done: boolean;
constant clk_period: time := 10 ns;
begin
uut:
entity work.file_io(foo)
port map (
clk => clk,
data => data,
done => done
);
clk_process:
process
begin
if not done then
clk <= '1';
wait for clk_period/2;
clk <= '0';
wait for clk_period/2;
else
wait;
end if;
end process;
end architecture behavior;
现在我们可以在我们的阅读中显示所有可以分隔一行的字符：
请注意，包 std.textio 不会通过任何上下文项显示。