about the function "imwrite"

[Yaowang]

Dear Mr. /Ms

There is a problem about "imwrite", which I can not save my matrix what is the result of a image as follow:

octave:1> x=imread('1149.tiff')
octave:2> imshow(x)
octave:3> y=fft(x);
octave:4> imshow(y)
warning: imshow: only showing real part of complex image
octave:5> imwrite("1149.img",y)
error: Invalid call to imwrite.  Correct usage is:

 -- Function File:  imwrite (IMG, FILENAME, FMT, P1, V1, ...)
 -- Function File:  imwrite (IMG, MAP, FILENAME, FMT, P1, V1, ...)


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I also try with other ways, like that

imwrite('1149.tif', y)
error: Invalid call to imwrite.

octave:5> imwrite(y, "1149.tif")
error: invalid conversion from complex matrix to uint8 matrix
error: called from:
error:   /usr/share/octave/3.2.4/m/image/imwrite.m at line 109, column 13

octave:5> imwrite(y, "1149.tif",tif)
error: `tif' undefined near line 5 column 23
error: evaluating argument list element number 3
error: evaluating argument list element number 1

So could you tell me what is the problem and how to solve it? Thank you very much!

Yaowang

Leiden Institute of Chemistry