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HxLog

Synopsis

HxImageRep HxLog (HxImageRep img)

Input

HxImageRep img

The image you want to take the of.

Return value

HxImageRep

The of the input image.

Description

The function HxLog takes the logarithm of each pixel value. The logarithm of a vectro is defined by taking the logarithm of the components of the vector, i.e.

Remarks

Valid input images

Only image with values greater than zero are valid. If one of the values is less or equal than zero (or one of the components of a vector is less or equal than zero), the input image is not valid.

Examples

Taking the logarithm of an image.

#include "HxImageRepGlobalFuncs.h"
#include "HxImageRep.h"

HxImageRep HxLogExample1(HxImageRep img) {
   img = HxImageAsDouble(img);
   img = HxLog(img);
   img = HxContrastStretch(img, 255.0);
   img = HxImageAsByte(img);

   return img;
}

int main(int argc, char* argv[])
{
    HxImageRep img = HxMakeFromFile(argv[1]);
    img = HxLogExample1(img);
    HxWriteFile(img, argv[2]);

    return 0;
}

Input image for the HxLog example.

Output image of the HxLog example.

In this example we first convert the input image to a double valued image. We take the logarithm, after which we stretch the image to let it contain values ranging from 0.0 to 255.0 for visualization purposes.

See also

HxLog10, HxExp,

Keywords

Unary, Arithmetic,

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