How to extract the reflectance from a remote sensing image?

holle all，

When I use the multibandread function to extract reflectance from a remote sensing image of .dat format, I encountered the following error. Could you please help me identify where the error occurred?

“error using ‘fread’

Invalid precision。

Error multibandread>getPixelInfo (line 455)

tmp = fread(fid, 1, info.precision);

Error multibandread>parseInputs (line 332)

info = getPixelInfo(fid,precision);

Error multibandread (line 111)

info = parseInputs(filename, dims,...

Error test (line 87)

data=multibandread(imgfilename,[lines,samples,9],precision,0,'bsq','ieee-le');”

In this context, 'precision' is as follows: precision=[];

switch datatype

case 1

precision='unit8=>unit8';

case 2

precision='int16=>int16';

case 12

precision='unit16=>unit16';

case 3

precision='int32=>int32';

case 13

precision='unit32=>unit32';

case 4

precision='float32=>float32';

case 5

precision='double=>double';

otherwise

precision='invalid type';

end

Answer 1

[Aditya Singh]

Hi,

To my understanding you want to know why the error is coming and how to fix,

I have taken the following code sample,

fileID = fopen('doubledata.bin');
precision = ['float32']
A = fread(fileID,[3 3],precision)

I was able to reproduce your issue as this, as with 'float32' it works just fine, but when with any values of "unit" (8,16 or 32), I get an error. Thus, it means that the unit values are not supported by the fread function. The supported type is "uint".

Thus, you should remove the "unit" types from you switch case and the code should work fine.

For more information you can refer to

Read data from binary file - MATLAB fread - MathWorks India

Hope it helps!