def parse(self):
"""
Parse the leader file to create a header object
"""
try:
fp = open(self.file, 'rb')
except IOError as errs:
errno, strerr = errs
print("IOError: %s" % strerr)
return
# Leader record
self.leaderFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,
'risat/leader_file.xml'),
dataFile=fp)
self.leaderFDR.parse()
fp.seek(self.leaderFDR.getEndOfRecordPosition())
# pprint.pprint(self.leaderFDR.metadata)
# Scene Header
self.sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat/scene_record.xml'),
dataFile=fp)
self.sceneHeaderRecord.parse()
fp.seek(self.sceneHeaderRecord.getEndOfRecordPosition())
pprint.pprint(self.sceneHeaderRecord.metadata)
# Platform Position
self.platformPositionRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat/platform_position_record.xml'),
dataFile=fp)
self.platformPositionRecord.parse()
fp.seek(self.platformPositionRecord.getEndOfRecordPosition())
fp.close()
def parse(self):
"""
Parse the leader file to create a header object
"""
try:
fp = open(self.file,'rb')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
# Leader record
self.leaderFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos_slc/leader_file.xml'),dataFile=fp)
self.leaderFDR.parse()
fp.seek(self.leaderFDR.getEndOfRecordPosition())
# Scene Header
self.sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos_slc/scene_record.xml'),dataFile=fp)
self.sceneHeaderRecord.parse()
fp.seek(self.sceneHeaderRecord.getEndOfRecordPosition())
# Platform Position
self.platformPositionRecord = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos_slc/platform_position_record.xml'),dataFile=fp)
self.platformPositionRecord.parse()
fp.seek(self.platformPositionRecord.getEndOfRecordPosition())
# Spacecraft Attitude
# if (self.leaderFDR.metadata['Number of attitude data records'] == 1):
# self.platformAttitudeRecord = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos2_slc/attitude_record.xml'),dataFile=fp)
# self.platformAttitudeRecord.parse()
# fp.seek(self.platformAttitudeRecord.getEndOfRecordPosition())
# Radiometric Record
fp.seek(8192, 1)
self.radiometricRecord = CEOS.CEOSDB(xml=os.path.join(xmlPrefix, 'alos_slc/radiometric_record.xml'), dataFile=fp)
self.radiometricRecord.parse()
fp.seek(self.radiometricRecord.getEndOfRecordPosition())
# Data Quality Summary Record
self.dataQualitySummaryRecord = CEOS.CEOSDB(xml=os.path.join(xmlPrefix, 'alos_slc/data_quality_summary_record.xml'), dataFile=fp)
self.dataQualitySummaryRecord.parse()
fp.seek(self.dataQualitySummaryRecord.getEndOfRecordPosition())
# 1 File descriptor 720
# 2 Data set summary 4096
# 3 Map projection data 1620
# 4 Platform position data 4680
# 5 Attitude data 8192
# 6 Radiometric data 9860
# 7 Data quality summary 1620
# 8 Calibration data 13212
# 9 Facility related Variable
fp.close()
def readLeader(self):
'''
read meta data from leader
'''
try:
fp = open(self.leaderFile, 'rb')
except IOError as errs:
errno, strerr = errs
print("IOError: %s" % strerr)
return
# Leader record
leaderFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,
'alos2_slc/leader_file.xml'),
dataFile=fp)
leaderFDR.parse()
fp.seek(leaderFDR.getEndOfRecordPosition())
# Scene Header
sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/scene_record.xml'),
dataFile=fp)
sceneHeaderRecord.parse()
fp.seek(sceneHeaderRecord.getEndOfRecordPosition())
# Platform Position
platformPositionRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/platform_position_record.xml'),
dataFile=fp)
platformPositionRecord.parse()
fp.seek(platformPositionRecord.getEndOfRecordPosition())
#####Skip attitude information
fp.seek(16384, 1)
#####Skip radiometric information
fp.seek(9860, 1)
####Skip the data quality information
fp.seek(1620, 1)
####Skip facility 1-4
fp.seek(325000 + 511000 + 3072 + 728000, 1)
####Read facility 5
facilityRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/facility_record.xml'),
dataFile=fp)
facilityRecord.parse()
###close file
fp.close()
return (leaderFDR, sceneHeaderRecord, platformPositionRecord,
facilityRecord)
def read_param_for_checking_overlap(leader_file, image_file):
import os
import isce
from isceobj.Sensor import xmlPrefix
import isceobj.Sensor.CEOS as CEOS
#read from leader file
fsampConst = {
104: 1.047915957140240E+08,
52: 5.239579785701190E+07,
34: 3.493053190467460E+07,
17: 1.746526595233730E+07
}
fp = open(leader_file, 'rb')
leaderFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,
'alos2_slc/leader_file.xml'),
dataFile=fp)
leaderFDR.parse()
fp.seek(leaderFDR.getEndOfRecordPosition())
sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/scene_record.xml'),
dataFile=fp)
sceneHeaderRecord.parse()
fp.seek(sceneHeaderRecord.getEndOfRecordPosition())
fsamplookup = int(sceneHeaderRecord.metadata['Range sampling rate in MHz'])
rangeSamplingRate = fsampConst[fsamplookup]
fp.close()
#print('{}'.format(rangeSamplingRate))
#read from image file
fp = open(image_file, 'rb')
imageFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,
'alos2_slc/image_file.xml'),
dataFile=fp)
imageFDR.parse()
fp.seek(imageFDR.getEndOfRecordPosition())
imageData = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,
'alos2_slc/image_record.xml'),
dataFile=fp)
imageData.parseFast()
width = imageFDR.metadata['Number of pixels per line per SAR channel']
near_range = imageData.metadata['Slant range to 1st data sample']
fp.close()
#print('{}'.format(width))
#print('{}'.format(near_range))
return [rangeSamplingRate, width, near_range]
def parse(self):
"""
Parse the leader file to create a header object
"""
try:
fp = open(self.file, 'rb')
except IOError as errs:
errno, strerr = errs
print("IOError: %s" % strerr)
return
# Leader record
self.leaderFDR = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/leader_file.xml'),
dataFile=fp)
self.leaderFDR.parse()
fp.seek(self.leaderFDR.getEndOfRecordPosition())
# Scene Header
self.sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/scene_record.xml'),
dataFile=fp)
self.sceneHeaderRecord.parse()
fp.seek(self.sceneHeaderRecord.getEndOfRecordPosition())
# Platform Position
self.platformPositionRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/platform_position_record.xml'),
dataFile=fp)
self.platformPositionRecord.parse()
fp.seek(self.platformPositionRecord.getEndOfRecordPosition())
#####Skip attitude information
fp.seek(16384, 1)
#####Skip radiometric information
fp.seek(9860, 1)
####Skip the data quality information
fp.seek(1620, 1)
####Skip facility 1-4
fp.seek(325000 + 511000 + 3072 + 728000, 1)
####Read facility 5
self.facilityRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'alos2_slc/facility_record.xml'),
dataFile=fp)
self.facilityRecord.parse()
fp.close()
def extractImage(self, output=None):
"""
Extract I and Q channels from the image file
"""
if self.imageFDR is None:
self.parse()
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
dataLen = self.imageFDR.metadata['Number of pixels per line per SAR channel']
prf = self.parent.leaderFile.sceneHeaderRecord.metadata['Pulse Repetition Frequency in mHz']*1.0e-3
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
a = fp.tell()
imageData.parseFast()
msecs = imageData.metadata['Sensor acquisition milliseconds of day']
if line==0:
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata['Sensor acquisition milliseconds of day']
self.sensingStart = datetime.datetime(yr,1,1) + datetime.timedelta(days=(dys-1)) + datetime.timedelta(seconds = msecs*1e-3)
self.nearRange = imageData.metadata['Slant range to 1st data sample']
if line == (self.length-1):
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata['Sensor acquisition milliseconds of day']
IQLine = np.fromfile(fp, dtype='>f', count=2*dataLen)
self.writeRawData(output, IQLine)
self.width = dataLen
self.prf = prf
self.sensingStop = self.sensingStart + datetime.timedelta(seconds=(self.length-1)/self.prf)
transmitted_polarization_bool = imageData.metadata['Transmitted polarization']
received_polarization_bool = imageData.metadata['Received polarization']
transmitted_polarization = 'V' if transmitted_polarization_bool else 'H'
received_polarization = 'V' if received_polarization_bool else 'H'
self.current_polarization = transmitted_polarization + received_polarization
def parse(self):
try:
fp = open(self.file,'r')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
self.imageFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'jers/image_file.xml'), dataFile=fp)
self.imageFDR.parse()
fp.seek(self.imageFDR.getEndOfRecordPosition())
fp.close()
def parse(self):
try:
fp = open(self.file,'rb')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
volumeFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos_slc/volume_descriptor.xml'),dataFile=fp)
volumeFDR.parse()
fp.seek(volumeFDR.getEndOfRecordPosition())
fp.close()
def parse(self):
"""
Parse the leader file to create a header object
"""
try:
fp = open(self.file, 'rb')
except IOError as errs:
errno, strerr = errs
print("IOError: %s" % strerr)
return
# Leader record
self.leaderFDR = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/leader_file.xml'),
dataFile=fp)
self.leaderFDR.parse()
fp.seek(self.leaderFDR.getEndOfRecordPosition())
# Scene Header
self.sceneHeaderRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/scene_record.xml'),
dataFile=fp)
self.sceneHeaderRecord.parse()
fp.seek(self.sceneHeaderRecord.getEndOfRecordPosition())
#Data quality summary
qualityRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/data_quality_summary_record.xml'),
dataFile=fp)
qualityRecord.parse()
fp.seek(qualityRecord.getEndOfRecordPosition())
#Data histogram records
for ind in range(
self.leaderFDR.metadata['Number of data histograms records']):
histRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/data_histogram_record.xml'),
dataFile=fp)
histRecord.parse()
fp.seek(histRecord.getEndOfRecordPosition())
self.processingRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/detailed_processing_record.xml'),
dataFile=fp)
self.processingRecord.parse()
fp.seek(self.processingRecord.getEndOfRecordPosition())
# Platform Position
self.platformPositionRecord = CEOS.CEOSDB(xml=os.path.join(
xmlPrefix, 'risat_slc/platform_position_record.xml'),
dataFile=fp)
self.platformPositionRecord.parse()
fp.seek(self.platformPositionRecord.getEndOfRecordPosition())
fp.close()
def parse(self):
try:
fp = open(self.file,'r')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
volumeFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'jers/volume_descriptor.xml'),dataFile=fp)
volumeFDR.parse()
fp.seek(volumeFDR.getEndOfRecordPosition())
fp.close()
import pprint
pp = pprint.PrettyPrinter()
pp.pprint(volumeFDR.metadata)
def extractImage(self, output=None, dtype='short'):
"""
Extract I and Q channels from the image file
"""
if self.imageFDR is None:
self.parse()
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
prf = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Pulse Repetition Frequency']
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
dataLen = self.imageFDR.metadata[
'Number of pixels per line per SAR channel']
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
imageData.parseFast()
if line == 0:
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day'] + imageData.metadata[
'Acquisition time bias in ms']
self.sensingStart = datetime.datetime(
yr, 1, 1) + datetime.timedelta(days=(
dys - 1)) + datetime.timedelta(seconds=msecs * 1e-3)
self.nearRange = imageData.metadata['Slant range to 1st pixel']
self.farRange = imageData.metadata['Slant range to last pixel']
self.dopplerCoeff = [
imageData.metadata['First pixel Doppler centroid'],
imageData.metadata['Mid-pixel Doppler centroid'],
imageData.metadata['Last pixel Doppler centroid']
]
self.prf = imageData.metadata['PRF']
self.polarization = (
imageData.metadata['Transmitted polarization'],
imageData.metadata['Received polarization'])
if line == (self.length - 1):
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day'] + imageData.metadata[
'Acquisition time bias in ms']
self.sensingStop = datetime.datetime(
yr, 1, 1) + datetime.timedelta(days=(
dys - 1)) + datetime.timedelta(seconds=msecs * 1e-3)
if dtype == 'short':
IQLine = np.fromfile(fp, dtype='>i2', count=2 * dataLen)
else:
IQLine = np.fromfile(fp, dtype='>i4', count=2 * dataLen)
self.writeRawData(output, IQLine)
self.width = dataLen
def extractImage(self, output=None):
"""
Extract I and Q channels from the image file
"""
if self.imageFDR is None:
self.parse()
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
dataLen = self.imageFDR.metadata[
'Number of pixels per line per SAR channel']
delta = 0.0
prf = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Pulse Repetition Frequency in mHz'] * 1.0e-3
# print('LEADERFILE PRF: ', prf)
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
# pprint.pprint(imageData.metadata)
imageData.parseFast()
usecs = imageData.metadata[
'Sensor acquisition micro-seconds of day']
if line == 0:
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day']
self.sensingStart = datetime.datetime(
yr, 1, 1) + datetime.timedelta(days=(
dys - 1)) + datetime.timedelta(seconds=usecs * 1e-6)
self.nearRange = imageData.metadata[
'Slant range to 1st data sample']
prf1 = imageData.metadata['PRF'] * 1.0e-3
if line == (self.length - 1):
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day']
# self.sensingStop = datetime.datetime(yr,1,1) + datetime.timedelta(days=(dys-1)) + datetime.timedelta(seconds=usecs*1e-6)
if line > 0:
delta += (usecs - prevline)
prevline = usecs
IQLine = np.fromfile(fp, dtype='>f', count=2 * dataLen)
self.writeRawData(output, IQLine)
self.width = dataLen
prf2 = (self.length - 1) / (delta * 1.0e-6)
# print('TIME TAG PRF: ', prf2)
# print('LINE TAG PRF: ', prf1)
# print('Using Leaderfile PRF')
# self.prf = prf
#choose PRF according to operation mode. Cunren Liang, 2015
operationMode = "{}".format(
self.parent.leaderFile.sceneHeaderRecord.
metadata['Sensor ID and mode of operation for this channel'])
operationMode = operationMode[10:12]
if operationMode == '08' or operationMode == '09':
# Operation mode
# '00': Spotlight mode
# '01': Ultra-fine
# '02': High-sensitive
# '03': Fine
# '08': ScanSAR nominal mode
# '09': ScanSAR wide mode
# '18': Full (Quad.) pol./High-sensitive
# '19': Full (Quad.) pol./Fine
print('ScanSAR nominal mode, using PRF from the line header')
self.prf = prf1
else:
self.prf = prf
if operationMode == '08':
#adding burst information here. Cunren, 14-DEC-2015
sceneCenterIncidenceAngle = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Incidence angle at scene centre']
sarChannelId = imageData.metadata['SAR channel indicator']
scanId = imageData.metadata['Scan ID'] #Scan ID starts with 1
#if (sceneCenterIncidenceAngle > 39.032 - 5.0 and sceneCenterIncidenceAngle < 39.032 + 5.0) and (sarChannelId == 2):
if 1:
#burst parameters, currently only for the second, dual polarization, ScanSAR nominal mode
#that is the second WBD mode.
#p.25 and p.115 of ALOS-2/PALSAR-2 Level 1.1/1.5/2.1/3.1 CEOS SAR Product Format Description
#for the definations of wide swath mode
nbraw = [358, 470, 358, 355, 487]
ncraw = [2086.26, 2597.80, 1886.18, 1779.60, 2211.17]
self.parent.frame.nbraw = nbraw[scanId - 1]
self.parent.frame.ncraw = ncraw[scanId - 1]
#this is the prf fraction (total azimuth bandwith) used in extracting burst.
#here the total bandwith is 0.93 * prfs[3] for all subswaths, which is the following values:
#[0.7933, 0.6371, 0.8774, 0.9300, 0.7485]
prfs = [2661.847, 3314.512, 2406.568, 2270.575, 2821.225]
self.parent.frame.prffrac = 0.93 * prfs[3] / prfs[scanId - 1]
self.sensingStop = self.sensingStart + datetime.timedelta(
seconds=(self.length - 1) / self.prf)
def extractImage(self, output=None):
"""
Extract I and Q channels from the image file
"""
if self.imageFDR is None:
self.parse()
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
# pprint.pprint(self.imageFDR.metadata)
prf = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Pulse Repetition Frequency']
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
self.length = self.length - 1
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
imageData.parseFast()
if line == 0:
# pprint.pprint(imageData.metadata)
dataLen = imageData.metadata['Actual count of data pixels']
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day'] + imageData.metadata[
'Acquisition time bias in ms']
self.sensingStart = datetime.datetime(
yr, 1, 1) + datetime.timedelta(days=(
dys - 1)) + datetime.timedelta(seconds=msecs * 1e-3)
self.nearRange = imageData.metadata['Slant range to 1st pixel']
self.prf = imageData.metadata['PRF']
self.roll = imageData.metadata[
'Platform roll in micro degs'] * 1.0e-6
if line == (self.length - 1):
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day'] + imageData.metadata[
'Acquisition time bias in ms']
self.sensingStop = datetime.datetime(
yr, 1, 1) + datetime.timedelta(days=(
dys - 1)) + datetime.timedelta(seconds=msecs * 1e-3)
IQLine = np.fromfile(fp, dtype='>i1', count=2 * dataLen)
trailer = np.fromfile(fp, dtype='>i1', count=2)
self.writeRawData(output, IQLine)
###Read the replica and write it to file
imageData.parseFast()
chirpLength = imageData.metadata['Actual count of data pixels']
###Rewind to skip missing aux
fp.seek(-192, os.SEEK_CUR)
IQLine = np.fromfile(fp, dtype='>i1', count=2 * chirpLength)
IQLine.astype(np.float32).tofile('replica.bin')
# pprint.pprint(imageData.metadata)
self.chirpLength = imageData.metadata['Pulse length in ns'] * 1.0e-9
self.width = dataLen
def extractImage(self, output=None):
"""
Extract I and Q channels from the image file
"""
if self.imageFDR is None:
self.parse()
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
auxLength = self.parent.auxLength
prf = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Pulse Repetition Frequency']
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
firstRecTime = None
nominalPRF = None
nominalPulseLength = None
nominalRangeSamplingRate = None
nominalChirpSlope = None
nominalStartingRange = None
startUTC = None
lineCount = 0
lineWidth = 0
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
imageData.parseFast()
auxData = self.extractAUXinformation(fp)
# pprint.pprint(imageData.metadata)
#####Check length of current record
#######12 CEOS + 180 prefix + 50
dataLen = imageData.recordLength - self.imageFDR.metadata[
'Number of bytes of prefix data per record'] - auxLength - 12
recTime = auxData['Record Time']
if firstRecTime is None:
firstRecTime = recTime
nominalPRF = auxData['PRF']
nominalPulseLength = auxData['Pulse length']
nominalChirpSlope = auxData['Chirp slope']
nominalRangeSamplingRate = auxData['fsamp']
nominalStartingRange = auxData['Starting Range']
replicaLength = auxData['Replica length']
startUTC = datetime.datetime(
imageData.metadata['Sensor acquisition year'], 1,
1) + datetime.timedelta(
imageData.metadata['Sensor acquisition day of year'] -
1) + datetime.timedelta(seconds=auxData['Record Time'])
prevRecTime = recTime
# pprint.pprint(imageData.metadata)
if (auxData['hasReplica']):
lineWidth = dataLen - replicaLength
else:
lineWidth = dataLen
# pprint.pprint(auxData)
IQLine = np.fromfile(fp, dtype='B', count=dataLen)
if (recTime > (prevRecTime + 0.001)):
self.logger.debug('Time gap of %f sec at RecNum %d' %
(recTime - prevRecTime,
imageData.metadata['Record Number']))
if (auxData['hasReplica']):
# self.logger.debug("Removing replica from Line %s" % line)
IQLine[0:dataLen -
replicaLength] = IQLine[replicaLength:dataLen]
IQLine[dataLen - replicaLength:] = 16
dataLen = dataLen - replicaLength
# print('Line: ', line, dataLen, lineWidth, auxData['Replica length'])
if dataLen >= lineWidth:
IQout = IQLine
else:
IQout = 16 * np.ones(lineWidth, dtype='b')
IQout[:dataLen] = IQLine
lineGap = int(0.5 + (recTime - prevRecTime) * nominalPRF)
if ((lineGap == 1) or (line == 0)):
self.writeRawData(output, IQout[:lineWidth])
lineCount += 1
prevRecTime = recTime
elif ((lineGap > 1) and (lineGap < self.maxLineGap)):
for kk in range(lineGap):
self.writeRawData(output, IQout[:lineWidth])
lineCount += 1
prevRecTime = recTime + (lineGap - 1) * 8.0e-4
elif (lineGap >= self.maxLineGap):
raise Exception('Line Gap too big to be filled')
self.prf = nominalPRF
self.chirpSlope = nominalChirpSlope
self.rangeSamplingRate = nominalRangeSamplingRate
self.pulseLength = nominalPulseLength
self.startingRange = nominalStartingRange
self.sensingStart = startUTC
self.length = lineCount
self.width = lineWidth
def readImage(self):
'''
read image and get parameters
'''
try:
fp = open(self.imageFile,'rb')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
#read meta data
imageFDR = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos2_slc/image_file.xml'), dataFile=fp)
imageFDR.parse()
fp.seek(imageFDR.getEndOfRecordPosition())
#record length: header (544 bytes) + SAR data (width*8 bytes)
recordlength = imageFDR.metadata['SAR DATA record length']
width = imageFDR.metadata['Number of pixels per line per SAR channel']
length = imageFDR.metadata['Number of SAR DATA records']
#line header
imageData = CEOS.CEOSDB(xml=os.path.join(xmlPrefix,'alos2_slc/image_record.xml'), dataFile=fp)
imageData.parseFast()
#creat vrt and xml files for sar data
image = isceobj.createSlcImage()
image.setFilename(self.outputFile)
image.setWidth(width)
image.setLength(length)
image.renderHdr()
#sar data
fileHeaderBytes = 720
lineHeaderBytes = 544
if self.useVirtualFile:
#this overwrites the previous vrt
with open(self.outputFile+'.vrt', 'w') as fid:
fid.write('''<VRTDataset rasterXSize="{0}" rasterYSize="{1}">
<VRTRasterBand band="1" dataType="CFloat32" subClass="VRTRawRasterBand">
<SourceFilename relativeToVRT="0">{2}</SourceFilename>
<ByteOrder>MSB</ByteOrder>
<ImageOffset>{3}</ImageOffset>
<PixelOffset>8</PixelOffset>
<LineOffset>{4}</LineOffset>
</VRTRasterBand>
</VRTDataset>'''.format(width, length,
self.imageFile,
fileHeaderBytes + lineHeaderBytes,
width*8 + lineHeaderBytes))
else:
#read sar data line by line
try:
fp2 = open(self.outputFile,'wb')
except IOError as errs:
errno,strerr = errs
print("IOError: %s" % strerr)
return
fp.seek(-lineHeaderBytes, 1)
for line in range(length):
if (((line+1)%1000) == 0):
print("extracting line %6d of %6d" % (line+1, length), end='\r', flush=True)
fp.seek(lineHeaderBytes, 1)
IQLine = np.fromfile(fp, dtype='>f', count=2*width)
self.writeRawData(fp2, IQLine)
#IQLine.tofile(fp2)
print("extracting line %6d of %6d" % (length, length))
fp2.close()
#close input image file
fp.close()
return (imageFDR, imageData)
def extractImage(self, output=None, virtual=False):
"""
Extract I and Q channels from the image file
"""
if virtual:
output = output + '.vrt'
else:
try:
output = open(output, 'wb')
except IOError as strerr:
raise Exceptin("IOError: {0}".format(strerr))
if self.imageFDR is None:
self.parse()
###Open the image file for reading
try:
fp = open(self.file, 'rb')
except IOError as strerr:
self.logger.error(" IOError: %s" % strerr)
return
fp.seek(self.imageFDR.getEndOfRecordPosition(), os.SEEK_SET)
offsetAfterImageFDR = fp.tell()
dataLen = self.imageFDR.metadata[
'Number of pixels per line per SAR channel']
self.width = dataLen
##Leaderfile PRF
prf = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Pulse Repetition Frequency in mHz'] * 1.0e-3
#choose PRF according to operation mode. Cunren Liang, 2015
operationMode = "{}".format(
self.parent.leaderFile.sceneHeaderRecord.
metadata['Sensor ID and mode of operation for this channel'])
operationMode = operationMode[10:12]
if operationMode not in ['08', '09']:
# Operation mode
# '00': Spotlight mode
# '01': Ultra-fine
# '02': High-sensitive
# '03': Fine
# '08': ScanSAR nominal mode
# '09': ScanSAR wide mode
# '18': Full (Quad.) pol./High-sensitive
# '19': Full (Quad.) pol./Fine
print(
'This reader only supports ScanSAR full aperture data parsing.'
)
raise Exception('Use stripmap reader for other modes')
if operationMode != '08':
raise Exception('Only ScanSAR nominal mode is currently supported')
# Extract the I and Q channels
imageData = CEOS.CEOSDB(xml=self.image_record, dataFile=fp)
###If only a VRT needs to be written
for line in range(self.length):
if ((line % 1000) == 0):
self.logger.debug("Extracting line %s" % line)
imageData.parseFast()
###Always read the first line virtual / not
if line == 0:
offsetAfterFirstImageRecord = fp.tell()
yr = imageData.metadata['Sensor acquisition year']
dys = imageData.metadata['Sensor acquisition day of year']
msecs = imageData.metadata[
'Sensor acquisition milliseconds of day']
usecs = imageData.metadata[
'Sensor acquisition micro-seconds of day']
self.sensingStart = datetime.datetime(
yr, 1, 1) + datetime.timedelta(
days=(dys - 1)) + datetime.timedelta(
seconds=usecs * 1e-6)
self.nearRange = imageData.metadata[
'Slant range to 1st data sample']
self.prf = imageData.metadata['PRF'] * 1.0e-3
sceneCenterIncidenceAngle = self.parent.leaderFile.sceneHeaderRecord.metadata[
'Incidence angle at scene centre']
sarChannelId = imageData.metadata['SAR channel indicator']
scanId = imageData.metadata[
'Scan ID'] #Scan ID starts with 1
###Exit loop after first line if virtual
if virtual:
break
###Write line to file if not virtual
IQLine = np.fromfile(fp, dtype='>f', count=2 * dataLen)
self.writeRawData(output, IQLine)
fp.close()
####If virtual file was requested, create VRT here
if virtual:
##Close input file
with open(output, 'w') as fid:
fid.write('''<VRTDataset rasterXSize="{0}" rasterYSize="{1}">
<VRTRasterBand dataType="CFloat32" band="1" subClass="VRTRawRasterBand">
<SourceFilename relativeToVRT="0">{2}</SourceFilename>
<ByteOrder>MSB</ByteOrder>
<ImageOffset>{3}</ImageOffset>
<PixelOffset>8</PixelOffset>
<LineOffset>{4}</LineOffset>
</VRTRasterBand>
</VRTDataset>'''.format(
self.width, self.length, os.path.abspath(self.file),
offsetAfterFirstImageRecord, dataLen * 8 +
offsetAfterFirstImageRecord - offsetAfterImageFDR))
else:
##Close actual file on disk
output.close()
#burst parameters, currently only for the second, dual polarization, ScanSAR nominal mode
#that is the second WBD mode.
#p.25 and p.115 of ALOS-2/PALSAR-2 Level 1.1/1.5/2.1/3.1 CEOS SAR Product Format Description
#for the definations of wide swath mode
nbraw = [358, 470, 358, 355, 487]
ncraw = [2086.26, 2597.80, 1886.18, 1779.60, 2211.17]
self.parent.frame.nbraw = nbraw[scanId - 1]
self.parent.frame.ncraw = ncraw[scanId - 1]
#this is the prf fraction (total azimuth bandwith) used in extracting burst.
#here the total bandwith is 0.93 * prfs[3] for all subswaths, which is the following values:
#[0.7933, 0.6371, 0.8774, 0.9300, 0.7485]
prfs = [2661.847, 3314.512, 2406.568, 2270.575, 2821.225]
#Only needed for burst extraction. Skipping for now ....
#self.parent.frame.prffrac = 0.93 * prfs[3]/prfs[scanId-1]
self.sensingStop = self.sensingStart + datetime.timedelta(
seconds=(self.length - 1) / self.prf)
