code: public ColorImg getPowerSpectrumImg(){
  		this.recomputePowerChannel();
  		// get copy of power channel
  		ColorImg powerSpectrum = this.getDelegate().getChannelImage(ComplexImg.CHANNEL_POWER).copy();
  		// logarithmize values
  		powerSpectrum.forEach(px->px.setValue(0, Math.log(1+px.getValue(0))));
  		// normalize values
  		powerSpectrum.scaleChannelToUnitRange(0);
  		// copy 1st channel to others to retain grayscale
  		System.arraycopy(powerSpectrum.getData()[0], 0, powerSpectrum.getData()[1], 0, powerSpectrum.numValues());
  		System.arraycopy(powerSpectrum.getData()[0], 0, powerSpectrum.getData()[2], 0, powerSpectrum.numValues());
  		return powerSpectrum;
  	}
docs: Returns a {@link ColorImg} consisting of this ComplexImg's power channel
  log-scaled for display.
  Values are displayed in grayscale.
  @return image of power spectrum for display
  
  @see #getPhaseSpectrumImg()
  @see #getPowerPhaseSpectrumImg()