3 # calibcant - tools for thermally calibrating AFM cantilevers
5 # Copyright (C) 2007,2008, William Trevor King
7 # This program is free software; you can redistribute it and/or
8 # modify it under the terms of the GNU General Public License as
9 # published by the Free Software Foundation; either version 3 of the
10 # License, or (at your option) any later version.
12 # This program is distributed in the hope that it will be useful, but
13 # WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
15 # See the GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with this program; if not, write to the Free Software
19 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
22 # The author may be contacted at <wking@drexel.edu> on the Internet, or
23 # write to Trevor King, Drexel University, Physics Dept., 3141 Chestnut St.,
24 # Philadelphia PA 19104, USA.
27 Separate the more general bump_analyze() from the other bump_*()
28 functions in calibcant. Also provide a command line interface
29 for analyzing data acquired through other workflows.
31 The relevant physical quantities are :
32 Vzp_out Output z-piezo voltage (what we generate)
33 Vzp Applied z-piezo voltage (after external ZPGAIN)
34 Zp The z-piezo position
35 Zcant The cantilever vertical deflection
36 Vphoto The photodiode vertical deflection voltage (what we measure)
38 Which are related by the parameters :
40 zpSensitivity Zp / Vzp
41 photoSensitivity Vphoto / Zcant
43 photoSensitivity is measured by bumping the cantilever against the
44 surface, where Zp = Zcant (see calibrate.bump_aquire()). The measured
45 slope Vphoto/Vout is converted to photoSensitivity with bump_analyze().
52 from splittable_kwargs import splittableKwargsFunction, \
53 make_splittable_kwargs_function
59 @splittableKwargsFunction()
60 def Vzp_bits2nm(data_bits, zpGain=config.zpGain,
61 zpSensitivity=config.zpSensitivity,
62 Vzp_out2V=config.Vzp_out2V):
63 scale_Vzp_bits2V = Vzp_out2V(1) - Vzp_out2V(0)
64 data_V = data_bits / scale_Vzp_bits2V
66 data_nm = data_V * zpGain * zpSensitivity
69 @splittableKwargsFunction()
70 def Vphoto_bits2V(data_bits, Vphoto_in2V=config.Vphoto_in2V):
71 scale_Vphoto_bits2V = Vphoto_in2V(1) - Vphoto_in2V(0)
72 Vphoto_V = data_bits / scale_Vphoto_bits2V
76 @splittableKwargsFunction((Vzp_bits2nm, 'data_bits'),
77 (Vphoto_bits2V, 'data_bits'))
78 def slope_bitspbit2Vpnm(slope_bitspbit, **kwargs):
79 zp_kwargs,photo_kwargs = slope_bitspbit2Vpnm._splitargs(slope_bitspbit2Vpnm, kwargs)
81 Vphoto_bits = slope_bitspbit * Vzp_bits
82 return Vphoto_bits2V(Vphoto_bits, **photo_kwargs)/Vzp_bits2nm(Vzp_bits, **zp_kwargs)
84 #@splittableKwargsFunction((bump_fit, 'zpiezo_output_bits',
85 # 'deflection_input_bits'),
86 # (slope_bitspbit2Vpnm, 'slope_bitspbit'))
87 # Some of the child functions aren't yet defined, so postpone
88 # make-splittable until later in the module.
89 def bump_analyze(data, **kwargs) :
91 Return the slope of the bump ;).
93 data dictionary of data in DAC/ADC bits
94 Vzp_out2V function that converts output DAC bits to Volts
95 Vphoto_in2V function that converts input ADC bits to Volts
96 zpGain zpiezo applied voltage per output Volt
97 zpSensitivity nm zpiezo response per applied Volt
99 photoSensitivity (Vphoto/Zcant) in Volts/nm
100 Checks for strong correlation (r-value) and low randomness chance (p-value)
102 With the current implementation, the data is regressed in DAC/ADC bits
103 and THEN converted, so we're assuming that both conversions are LINEAR.
104 If they aren't, rewrite to convert before the regression.
106 bump_fit_kwargs,slope_bitspbit2Vpnm_kwargs = \
107 bump_analyze._splitargs(bump_analyze, kwargs)
108 Vphoto2Vzp_out_bit = bump_fit(data['Z piezo output'],
109 data['Deflection input'],
111 return slope_bitspbit2Vpnm(Vphoto2Vzp_out_bit, **slope_bitspbit2Vpnm_kwargs)
113 def limited_linear(x, params):
116 flat region (off-surface)
117 linear region (in-contact)
118 flat region (high-voltage-rail)
120 x_contact (x value for the surface-contact kink)
121 y_contact (y value for the surface-contact kink)
122 slope (dy/dx at the surface-contact kink)
124 high_voltage_rail = 2**16 - 1 # bits
125 x_contact,y_contact,slope = params
126 y = slope*(x-x_contact) + y_contact
127 y = numpy.clip(y, y_contact, high_voltage_rail)
130 def limited_linear_param_guess(x, y) :
132 Guess rough parameters for a limited_linear model. Assumes the
133 bump approaches (raising the deflection as it does so) first.
134 Retracting after the approach is optional. Approximates the contact
135 position and an on-surface (high) position by finding first crossings
136 of thresholds 0.3 and 0.7 of the y value's total range. Not the
137 most efficient algorithm, but it seems fairly robust.
139 y_contact = float(y.min())
140 y_max = float(y.max())
142 y_low = y_contact + 0.3 * (y_max-y_contact)
143 y_high = y_contact + 0.7 * (y_max-y_contact)
147 while y[i] < y_high :
150 x_contact = float(x[i_low])
151 x_high = float(x[i_high])
152 slope = (y_high - y_contact) / (x_high - x_contact)
153 return (x_contact, y_contact, slope)
155 def limited_linear_sensitivity(params):
157 Return the estimated sensitivity to small deflections according to
158 limited_linear fit parameters.
163 def limited_quadratic(x, params):
166 flat region (off-surface)
167 quadratic region (in-contact)
168 flat region (high-voltage-rail)
170 x_contact (x value for the surface-contact kink)
171 y_contact (y value for the surface-contact kink)
172 slope (dy/dx at the surface-contact kink)
173 quad (d**2 y / dx**2, allow decreasing sensitivity with increased x)
175 high_voltage_rail = 2**16 - 1 # bits
176 x_contact,y_contact,slope,quad = params
177 y = slope*(x-x_contact) + quad*(x-x_contact)**2+ y_contact
178 y = numpy.clip(y, y_contact, high_voltage_rail)
181 def limited_quadratic_param_guess(x, y) :
183 Guess rough parameters for a limited_quadratic model. Assumes the
184 bump approaches (raising the deflection as it does so) first.
185 Retracting after the approach is optional. Approximates the contact
186 position and an on-surface (high) position by finding first crossings
187 of thresholds 0.3 and 0.7 of the y value's total range. Not the
188 most efficient algorithm, but it seems fairly robust.
190 x_contact,y_contact,slope = limited_linear_param_guess(x,y)
192 return (x_contact, y_contact, slope, quad)
194 def limited_quadratic_sensitivity(params):
196 Return the estimated sensitivity to small deflections according to
197 limited_quadratic fit parameters.
202 @splittableKwargsFunction()
203 def bump_fit(zpiezo_output_bits, deflection_input_bits,
204 param_guesser=limited_quadratic_param_guess,
205 model=limited_quadratic,
206 sensitivity_from_fit_params=limited_quadratic_sensitivity,
208 x = zpiezo_output_bits
209 y = deflection_input_bits
210 def residual(p, y, x) :
211 return model(x, p) - y
212 param_guess = param_guesser(x, y)
213 p,cov,info,mesg,ier = \
214 scipy.optimize.leastsq(residual, param_guess, args=(y, x),
215 full_output=True, maxfev=int(10e3))
216 if config.TEXT_VERBOSE :
217 print "Fitted params:",p
218 print "Covariance mx:",cov
222 print "Solution converged"
224 print "Solution did not converge"
225 if plotVerbose or config.PYLAB_VERBOSE :
226 yguess = model(x, param_guess)
227 #yguess = None # Don't print the guess, since I'm convinced it's ok ;).
229 bump_plot(data={"Z piezo output":x, "Deflection input":y},
230 yguess=yguess, yfit=yfit, plotVerbose=plotVerbose)
231 return sensitivity_from_fit_params(p)
233 @splittableKwargsFunction()
234 def bump_save(data, log_dir=None) :
235 "Save the dictionary data, using data_logger.data_log()"
237 log = data_logger.data_log(log_dir, noclobber_logsubdir=False,
239 log.write_dict_of_arrays(data)
241 def bump_load(datafile) :
242 "Load the dictionary data, using data_logger.date_load()"
243 dl = data_logger.data_load()
244 data = dl.read_dict_of_arrays(datafile)
247 @splittableKwargsFunction()
248 def bump_plot(data, yguess=None, yfit=None, plotVerbose=False) :
249 "Plot the bump (Vphoto vs Vzp) if plotVerbose or PYLAB_VERBOSE == True"
250 if plotVerbose or config.PYLAB_VERBOSE :
251 common._import_pylab()
252 common._pylab.figure(config.BASE_FIGNUM)
253 if yfit != None: # two subplot figure
254 common._pylab.subplot(211)
255 common._pylab.hold(False)
256 common._pylab.plot(data["Z piezo output"], data["Deflection input"],
258 common._pylab.hold(True)
260 common._pylab.plot(data["Z piezo output"], yguess,
263 common._pylab.plot(data["Z piezo output"], yfit,
265 common._pylab.hold(False)
266 common._pylab.title("bump surface")
267 common._pylab.legend(loc='upper left')
268 common._pylab.xlabel("Z piezo output voltage (bits)")
269 common._pylab.ylabel("Photodiode input voltage (bits)")
271 # second subplot for residual
272 common._pylab.subplot(212)
273 common._pylab.plot(data["Z piezo output"],
274 data["Deflection input"] - yfit,
275 'r-', label='residual')
276 common._pylab.legend(loc='upper right')
277 common._pylab.xlabel("Z piezo output voltage (bits)")
278 common._pylab.ylabel("Photodiode input voltage (bits)")
281 make_splittable_kwargs_function(bump_analyze,
282 (bump_fit, 'zpiezo_output_bits',
283 'deflection_input_bits'),
284 (slope_bitspbit2Vpnm, 'slope_bitspbit'))
286 @splittableKwargsFunction((bump_analyze, 'data'))
287 def bump_load_analyze_tweaked(tweak_file, **kwargs):
288 "Load the output file of tweak_calib_bump.sh, return an array of slopes"
289 bump_analyze_kwargs, = \
290 bump_load_analyze_tweaked._splitargs(bump_load_analyze_tweaked, kwargs)
291 photoSensitivity = []
292 for line in file(tweak_file, 'r') :
293 parsed = line.split()
294 path = parsed[0].strip()
295 if path[0] == '#' : # a comment
297 if config.TEXT_VERBOSE :
298 print "Reading data from %s with ranges %s" % (path, parsed[1:])
300 full_data = bump_load(path)
301 if len(parsed) == 1 :
302 data = full_data # use whole bump
304 # use the listed sections
307 for rng in parsed[1:] :
311 zp.extend(full_data['Z piezo output'][starti:stopi])
312 df.extend(full_data['Deflection input'][starti:stopi])
313 data = {'Z piezo output': numpy.array(zp),
314 'Deflection input': numpy.array(df)}
315 pSi = bump_analyze(data, **bump_analyze_kwargs)
316 photoSensitivity.append(pSi)
317 return numpy.array(photoSensitivity, dtype=numpy.float)
319 # commandline interface functions
322 def read_data(ifile):
323 "ifile can be a filename string or open (seekable) file object"
324 if ifile == None : ifile = sys.stdin
325 unlabeled_data=scipy.io.read_array(ifile)
327 data['Z piezo output'] = unlabeled_data[:,0]
328 data['Deflection input'] = unlabeled_data[:,1]
331 def remove_further_than(data, zp_crit) :
333 ndata['Z piezo output'] = []
334 ndata['Deflection input'] = []
335 for zp,df in zip(data['Z piezo output'],data['Deflection input']) :
337 ndata['Z piezo output'].append(zp)
338 ndata['Deflection input'].append(df)
341 if __name__ == '__main__' :
342 # command line interface
343 from optparse import OptionParser
345 usage_string = ('%prog <input-file>\n'
346 '2008, W. Trevor King.\n'
348 'There are two operation modes, one to analyze a single bump file,\n'
349 'and one to analyze tweak files.\n'
351 'Single file mode (the default) :\n'
352 'Scales raw DAC/ADC bit data and fits a bounded quadratic.\n'
353 'Returns photodiode sensitivity Vphotodiode/Zcantilever in V/nm, determined by.\n'
354 'the slope at the kink between the non-contact region and the contact region.\n'
355 '<input-file> should be whitespace-delimited, 2 column ASCII\n'
356 'without a header line. e.g: "<zp_DAC>\\t<deflection_ADC>\\n"\n'
359 'Runs the same analysis as in single file mode for each bump in\n'
360 'a tweak file. Each line in the tweak file specifies a single bump.\n'
361 'Blank lines and those beginning with a pound sign (#) are ignored.\n'
362 'The format of a line is a series of whitespace-separated fields--\n'
363 'a base file path followed by optional point index ranges, e.g.:\n'
364 '20080919/20080919132500_bump_surface 10:651 1413:2047\n'
365 'which only discards all points outside the index ranges [10,651)\n'
366 'and [1413,2047) (indexing starts at 0).\n'
368 parser = OptionParser(usage=usage_string, version='%prog '+common.VERSION)
369 parser.add_option('-o', '--output-file', dest='ofilename',
370 help='write output to FILE (default stdout)',
371 type='string', metavar='FILE')
372 parser.add_option('-c', '--comma-out', dest='comma_out', action='store_true',
373 help='Output comma-seperated values (default %default)',
375 parser.add_option('-p', '--pylab', dest='pylab', action='store_true',
376 help='Produce pylab fit checks during execution',
378 parser.add_option('-t', '--tweak-mode', dest='tweakmode', action='store_true',
379 help='Run in tweak-file mode',
381 parser.add_option('-d', '--datalogger-mode', dest='datalogger_mode', action='store_true',
382 help='Run input files with datalogger.read_dict_of_arrays(). This is useful, for example, to test a single line from a tweakfile.',
384 parser.add_option('-q', '--disable-quadratic', dest='quadratic', action='store_false',
385 help='Disable quadratic term in fitting (i.e. use bounded linear fits).',
387 parser.add_option('-v', '--verbose', dest='verbose', action='store_true',
388 help='Print lots of debugging information',
391 options,args = parser.parse_args()
393 assert len(args) >= 1, "Need an input file"
397 if options.ofilename != None :
398 ofile = file(options.ofilename, 'w')
401 config.TEXT_VERBOSE = options.verbose
402 config.PYLAB_INTERACTIVE = False
403 config.PYLAB_VERBOSE = options.pylab
404 config.GNUPLOT_VERBOSE = False
405 if options.quadratic == True:
406 param_guesser = limited_quadratic_param_guess
407 model = limited_quadratic
408 sensitivity_from_fit_params = limited_quadratic_sensitivity
410 param_guesser = limited_linear_param_guess
411 model = limited_linear
412 sensitivity_from_fit_params = limited_linear_sensitivity
414 if options.tweakmode == False :
415 if options.datalogger_mode:
416 data = bump_load(ifilename)
418 data = read_data(ifilename)
419 photoSensitivity = bump_analyze(data,
420 param_guesser=param_guesser,
422 sensitivity_from_fit_params=sensitivity_from_fit_params)
424 print >> ofile, photoSensitivity
425 else : # tweak file mode
426 slopes = bump_load_analyze_tweaked(ifilename,
427 param_guesser=param_guesser,
429 sensitivity_from_fit_params=sensitivity_from_fit_params)
430 if options.comma_out :
434 common.write_array(ofile, slopes, sep)
436 if options.ofilename != None :