def sri_to_hdr(sri, data_type, data_format):
"""
Generates an X-Midas header file from the SRI information.
Inputs:
<sri> The BULKIO.StreamSRI object
<data_type> The X-Midas file type (1000, 2000, etc)
<data_format> The X-Midas data format (SD, SF, CF, etc)
Output:
Returns an X-Midas header file
"""
kwds = {}
kwds['xstart'] = sri.xstart
kwds['xdelta'] = sri.xdelta
kwds['xunits'] = sri.xunits
kwds['ystart'] = sri.ystart
kwds['ydelta'] = sri.ydelta
kwds['yunits'] = sri.yunits
kwds['format'] = data_format
kwds['type'] = data_type
ext_hdr = sri.keywords
if len(ext_hdr) > 0:
items = []
for item in ext_hdr:
items.append((item.id, item.value.value()))
kwds['ext_header'] = items
return bluefile.header(**kwds)
def sri_to_hdr(sri, data_type, data_format):
"""
Generates an X-Midas header file from the SRI information.
Inputs:
<sri> The BULKIO.StreamSRI object
<data_type> The X-Midas file type (1000, 2000, etc)
<data_format> The X-Midas data format (SD, SF, CF, etc)
Output:
Returns an X-Midas header file
"""
kwds = {}
kwds['xstart'] = sri.xstart
kwds['xdelta'] = sri.xdelta
kwds['xunits'] = sri.xunits
kwds['ystart'] = sri.ystart
kwds['ydelta'] = sri.ydelta
kwds['yunits'] = sri.yunits
kwds['format'] = data_format
kwds['type'] = data_type
ext_hdr = sri.keywords
if len(ext_hdr) > 0:
items = []
for item in ext_hdr:
items.append((item.id, item.value.value()))
kwds['ext_header'] = items
return bluefile.header(**kwds)
def make_midas_header(xfile, yfile, file_format):
hdr = bluefile.header(type=2000, format=file_format, subsize=xfile)
#hdr, data = bluefile.read('mydata_SL_500_1000.tmp')
hdr['xstart'] = 0
hdr['ystart'] = 0
hdr['xdelta'] = 1
hdr['ydelta'] = 1
#hdr['subsize']=xfile
#hdr['size']=yfile
# hdr['Version']="BLUE"
# hdr['head_rep']="EEEI"
# hdr['data_rep']="EEEI"
return hdr
def spectrogram(samprate, data, fftsize=2048, log_scale=True, overlap=0.0, removeDC=False):
epsilon = 1e-20
nsamp = len(data)
first_samp = 0
last_samp = fftsize
step = int(fftsize*(1.0-overlap))
samp_period = 1.0 / samprate
freqs = fftfreq(fftsize, samp_period)
hdr = bluefile.header(type=2000, format='SF')
hdr['xstart'] = freqs[0]
hdr['xdelta'] = freqs[1]-freqs[0]
hdr['ystart'] = 0.0
hdr['ydelta'] = step*samp_period
hdr['subsize'] = fftsize/2
frames = []
while last_samp < nsamp:
chunk = data[first_samp:last_samp]
if removeDC:
dc = float(sum(chunk))/len(chunk)
chunk = [x - dc for x in chunk]
if len(chunk) < fftsize:
chunk.extend([0.0]*(fftsize-len(chunk)))
chunk = fft(chunk)[:fftsize/2]
if log_scale:
try:
frame = array.array('f', [10*math.log((x*x.conj()).real+epsilon) for x in chunk])
except:
print x, x*x.conj()
raise
else:
frame = array.array('f', [(x*x.conj()).real for x in chunk])
frames.append(frame)
first_samp += step
last_samp = first_samp + fftsize
print len(frames), len(frames[0]), len(frames[-1])
return hdr, frames