CombineZ5 incorporates a powerful set of DFT Filters. The two that will be used most often are Lowpass and Highpass. Lowpass is used for smoothing Depthmaps, and Highpass is for sharpening Frames and the Sum of the Stack in the Average and Sharpen method.
You should regard the filters as a separate section of the program with their own work areas and input and output locations. Information is transferred to and from these areas by the functions on the Filter menu, and commands are sent to the filtering routines via this menu.
Generally use the Normal setting. If you notice the ZV value on the Title Line get near to zero, you may need to use Brighten. Threshold is for specialist use.
Here you choose what it is you want to filter: the Active Frame, the Sum of the Stack, or the Depthmap. The default is the Active Frame. When you click on one of these items data is copied to the DFT input buffer, Filtered with any existing Filter and the output placed in Out. If you change the Active Frame, or Depthmap these changes will not be reflected in the Filter input buffer, you will need to press the appropriate Input menu option again.
Now is your chance to select the type of filter you wish to use, and begin the design process. When you first click on one of these items a representation of the current settings for this type of filter is produced. In the black and white rectangle, the upper left corner represents the lower frequency components of the filter and the lower right corner the high frequency components. Generally low frequencies represent large and/or out of focus features and high frequencies represent small or the sharp edges of larger features. Thus if you emphasize the higher frequencies, by making the lower right corner lighter, you will make a picture sharper. And if you increase the brightness of the upper left corner the picture will appear softer. Notice that there is no sudden change from black to white; if there were, you would get 'ringing' in the output picture.
Notice the information on the Title Line, especially the numbers in brackets and what immediately follows these. The numbers in brackets control the shape of the filter. After the close bracket is a single digit number that tells you which of these parameters you can alter. You can cycle through the available parameters by pressing the Up and Down Arrows. 1 means the left most param; the others are numbered towards the right. Next is a description of what the parameter does in words. If you wish to make a large change in the value press V and enter your desired number. If you wish to alter a value in small steps press the Right and Left Arrow keys. For larger steps use M and N as usual.
When you have the shape approximately right, or straight away if you like, press Return once. This brings you to the interactive stage of design. The input you specified above is filtered according to the current settings and displayed. You can still change the parameters that describe the filter at this stage, and see the result. When you are satisfied press return again.
The output from this last stage will be contained in Out.
Now if you change the Active Frame, you do not need to go through the design process again to filter it. To produce an output in Out use Input->Active Frame, or to Filter and replace the Active Frame use Filter Active Frame on this sub-menu. Filter All Frames uses the same Filter on all Frames and replaces them with the filtered output. Display Last Output simply copies the last filtered output to Out. And finally Last Output to Depthmap copies the filtered output to the Depthmap. Of course the last option only makes sense if the input was the Depthmap. Try that and notice the different colours. The actual Depthmap is Green and a filtered Depthmap is Blue so that you know what you are dealing with.
The DFT routines for a given Stack can take a while to set up on the first run, but on subsequent runs they should be faster because data is stored on disk.
These routines take up quite a lot of memory, you can release this back to the operating system by clicking on Free Memory.