Removal the DC Component of Gabor Filters
gabor filter formed a sine/cosine wave with a gaussian, where the center of frequency of the filter is specified by the frequency of sine-cosine and the band width of the filter is specified by the width of the gaussian (valid perfectly inside a certain range and outside it, attenuates the frequency). In other words, more than one gabor filter to cover the spectrum.
the gabor filter can be designed for a band-width of 1 octave maximum. 

you can find more details about gabor and log-gabor