There is a 'Through-focus MTF feature'. Is there a way to extract MTF50 through focus instead of modulation at a certain frequency through focus?
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Hi Anton,
The Through-Focus MTF plots do not provide a way to search for the spatial frequency which provides MTF50. Although, you could write a ZPL to do that search for you. For example, you could ask a ZPL to perform the following actions:
- Set the field and wavelength of interest
- Create a loop to cycle through multiple spatial frequencies
- Store the tangential and sagittal response to an array
- Use an IF statement to check for MTF50. If found, store the spatial frequency and focus shift data to a different array
I have set up a ZPL macro that will perform actions 1-3 for you. This macro will cycle through spatial frequency 0 to 70 and output the tangential and sagittal response for fiel = 1, wavelength = 1. You can add an IF statement before line 47 to run a check for MTF50. Here is what I have so far:
! Set up the location of the configuration file
lensFile$ = $FILEPATH()
fileNameLength = SLEN(lensFile$)
fileName$ = $LEFTSTRING(lensFile$, fileNameLength - 3)
cfgfile$ = fileName$ + 'CFG'
! Set up the Through Focus Analysis
field = 1 # Declare the field of interest
wave = 1 # Declare the wavelength of interest
MODIFYSETTINGS cfgfile$, TFM_FIELD, field # Change the settings to use the field of interest
MODIFYSETTINGS cfgfile$, TFM_WAVE, wave # Change the settings to use the wavelength of interest
numDataPoints = 201 # Each field will have 201 data points in the output
DECLARE tangent, double, 1, numDataPoints # Setup array to hold Tangential data
DECLARE sagit, double, 1, numDataPoints # Setup array to hold Sagittal data
! Extract data and write it to the arrays
! Cycle through multiple spatial frequency values
FOR freq, 0, 70, 5
PRINT 'Spatial Frequency: ', freq
MODIFYSETTINGS cfgfile$, TFM_FREQ, freq # Set new spatial frequency
A$ = $TEMPFILENAME()
GETTEXTFILE A$, Tfm # Extract Through Focus data
OPEN A$ # Open Through Focus data file and skip to numeric data
FOR i, 1, 14, 1
READSTRING B$
NEXT
FOR i, 1, numDataPoints, 1 # Write the data to the arrays
READNEXT shift, tanVal, sagVal
tangent(i) = tanVal
sagit(i) = sagVal
FORMAT 1.6
PRINT tangent(i), ' ', sagit(i) # Print the data for comparison
NEXT
DELETEFILE A$
CLOSE
PRINT
NEXT
lensFile$ = $FILEPATH()
fileNameLength = SLEN(lensFile$)
fileName$ = $LEFTSTRING(lensFile$, fileNameLength - 3)
cfgfile$ = fileName$ + 'CFG'
! Set up the Through Focus Analysis
field = 1 # Declare the field of interest
wave = 1 # Declare the wavelength of interest
MODIFYSETTINGS cfgfile$, TFM_FIELD, field # Change the settings to use the field of interest
MODIFYSETTINGS cfgfile$, TFM_WAVE, wave # Change the settings to use the wavelength of interest
numDataPoints = 201 # Each field will have 201 data points in the output
DECLARE tangent, double, 1, numDataPoints # Setup array to hold Tangential data
DECLARE sagit, double, 1, numDataPoints # Setup array to hold Sagittal data
! Extract data and write it to the arrays
! Cycle through multiple spatial frequency values
FOR freq, 0, 70, 5
PRINT 'Spatial Frequency: ', freq
MODIFYSETTINGS cfgfile$, TFM_FREQ, freq # Set new spatial frequency
A$ = $TEMPFILENAME()
GETTEXTFILE A$, Tfm # Extract Through Focus data
OPEN A$ # Open Through Focus data file and skip to numeric data
FOR i, 1, 14, 1
READSTRING B$
NEXT
FOR i, 1, numDataPoints, 1 # Write the data to the arrays
READNEXT shift, tanVal, sagVal
tangent(i) = tanVal
sagit(i) = sagVal
FORMAT 1.6
PRINT tangent(i), ' ', sagit(i) # Print the data for comparison
NEXT
DELETEFILE A$
CLOSE
NEXT
Each of the keywords I used are described in the Help System file 'The Programming Tab > About the ZPL > KEYWORDS (about the zpl).' Will this work for you? Let me know if you have any questions!
Best,
Allie
Hi Allie,
Thank you for the prompt response!
I think this is all I need. I will give it a try and post here if I have more questions.
Thank you
Anton
Hi Allie,
I am trying to run your code without modifications ans I am getting this error:
'ERROR in MODIFYSETTINGS: Cannot open settings file.
MODIFYSETTINGS CFGFILE$ , HFT_FIELD , FIELD'
Any chance you know how to fix this?
Thank you
Anton
Hi Anton,
This usually crops up when the wrong configuration file is provided. In the code I attached, the configuration file I used was
data$ = $DATAPATH()
cfgfile$ = data$ + '\Configs\TFM.CFG'
I have provided some guidance on identifying and using configuration files here:
Let me know if you have any other questions!
Best,
Allie
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