MATLAB：将 uint32（4 字节）值转换为相应的 IEEE 单精度浮点形式
在 MATLAB (r2009b) 中，我有一个包含值 2147484101 的 uint32 变量。
该数字（4 个字节）是在抓取过程中从数字机器视觉相机中提取的。据我了解，它保存了相机快门速度的单精度形式（应接近 1/260s = 3.8ms）。
如何使用 MATLAB 中提供的功能将此 32 位数字转换为其 IEEE 单精度浮点表示形式？
对于变量n中提到的值，我尝试使用nn=dec2hex(n,16)和hex2num(nn)的组合。但似乎 hex2num 期望十六进制编码是双精度的，而不是像这里一样是单精度的。至少我用这种方法得到了奇怪的数字。
有什么想法吗？
编辑：尝试了下面@Matt的答案：
typecast(uint32(2147484101),'single') %# without swapbytes
typecast(swapbytes(uint32(2147484101)),'single') %# with swapbytes
给出了：
ans =
-6.3478820e-043
ans =
-2.0640313e+003
我在http://www.h-schmidt.net/FloatApplet/IEEE754.html。
使用：
format hex
typecast(uint32(2147484101),'uint8') %# without swapbytes
typecast(swapbytes(uint32(2147484101)),'uint8') %# with swapbytes
给出
ans =
c5 01 00 80
ans =
80 00 01 c5
将这些字节输入小程序（十六进制）会得到与 MATLAB 相同的数字。
In MATLAB (r2009b) I have a uint32 variable containing the value 2147484101.
This number (its 4-bytes) has been extracted from a digital machine-vision camera in a grabbing process. According to what I understand it holds the single-precision form of the shutter-speed of the camera (should be close to 1/260s = 3.8ms).
How do I convert this 32-bit number to its IEEE single-precision floating-point representation - using what's available in MATLAB?
With mentioned value in variable n, I have tried using a combination of nn=dec2hex(n,16) and then hex2num(nn). But it seems that hex2num expects the hexadecimal coding to be double-precision and not single as it is here. Atleast I am getting weird numbers with this method.
Any ideas?
Edit: Tried @Matt's answer below:
typecast(uint32(2147484101),'single') %# without swapbytes
typecast(swapbytes(uint32(2147484101)),'single') %# with swapbytes
Which gives:
ans =
-6.3478820e-043
ans =
-2.0640313e+003
I tried the IEEE 754 converter (JAVA applet) at http://www.h-schmidt.net/FloatApplet/IEEE754.html.
Using:
format hex
typecast(uint32(2147484101),'uint8') %# without swapbytes
typecast(swapbytes(uint32(2147484101)),'uint8') %# with swapbytes
gives
ans =
c5 01 00 80
ans =
80 00 01 c5
Entering these bytes into the applet (hexadecimal) gives me the same numbers as MATLAB.
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我认为您所说的是底层位代表浮点数，但您已将其存储为 uint32。
如果是这种情况，您可以使用 typecast() 函数将其转换（即重新解释位）为单精度浮点数。
其中 a 是你的变量。
看：
http://www.mathworks.com/help/techdoc/ref/typecast.html
编辑：不是强制转换函数，而是强制转换函数...我很抱歉！
I think what you're saying is that the underlying bits represent a floating point number, but that you've got it stored as a uint32.
If that's that case, you can cast it (i.e. reinterpret the bits) as a single precision float using the typecast() function.
where a is your variable.
See:
http://www.mathworks.com/help/techdoc/ref/typecast.html
Edited: not the cast function, the typecast function... My apologies!
当您使用 fread() 读取数据时，您可以进行转换。
看看 precision 参数，您可以将其读取为 int32 数字并将其存储为单个
You could do the cast when you read the data in with fread().
Have a look for the precision argument, you could read it as the int32 number and store it as a single by doing