Depth maps exporting

[Silvio_B]

Hi,

i am writing my master's thesis and would like to reconstruct 3d coordinates from images that I have collected with DJI Phantom 4 .

As I am using Agisoft Metashape to calculate elements of internal and external orientation I would like to write formulas to calculate X,Y,Z coordinates of selected pixel in one image using depth maps.

I came accros this topic

https://www.agisoft.com/forum/index.php?topic=11171.0

and would like to ask you to explain to me how can I get disparity from Agisoft depth maps, so I can include them in resection formulas .

Thans in advance

[tazzo]

They are in the project files, inside a zip file

[Silvio_B]

They are in the project files, inside a zip file

Thank for getting in touch.

I am aware that depth maps are in project file, but dont know what are the values (are they differences in pixels?) and
what I need to do with them ( do I need to determin the scale?).

Any help with these questions?

[Alexey Pasumansky]

Hello Silvio,

Please check the attached script that allows to export the depth maps in single band floating point format, where each pixel contains the distance information.
Note that the script requires numpy module installed.

Code: [Select]

import Metashape
from PySide2 import QtGui, QtCore, QtWidgets

global NUMPY
NUMPY = True

try:
import numpy
except ImportError:
NUMPY = False
print("numpy module not installed!")

class ExportDepthDlg(QtWidgets.QDialog):

def __init__ (self, parent):
QtWidgets.QDialog.__init__(self, parent)
self.setWindowTitle("Export depth maps")

self.btnQuit = QtWidgets.QPushButton("&Close")
self.btnP1 = QtWidgets.QPushButton("&Export")
self.pBar = QtWidgets.QProgressBar()
self.pBar.setTextVisible(False)

#self.selTxt =QtWidgets.QLabel()
#self.selTxt.setText("Apply to:")
self.radioBtn_all = QtWidgets.QRadioButton("Apply to all cameras")
self.radioBtn_sel = QtWidgets.QRadioButton("Apply to selected")
self.radioBtn_all.setChecked(True)
self.radioBtn_sel.setChecked(False)

self.formTxt = QtWidgets.QLabel()
self.formTxt.setText("Export format:")
self.formCmb = QtWidgets.QComboBox()
self.formCmb.addItem("1-band F32")
self.formCmb.addItem("Grayscale 8-bit")
self.formCmb.addItem("Grayscale 16-bit")

layout = QtWidgets.QGridLayout()   #creating layout
#layout.setSpacing(10)
layout.addWidget(self.radioBtn_all, 0, 1)
layout.addWidget(self.radioBtn_sel, 1, 1)
layout.addWidget(self.formTxt, 0, 2)
layout.addWidget(self.formCmb, 1, 2)
layout.addWidget(self.pBar, 2, 0)
layout.addWidget(self.btnP1, 2, 1)
layout.addWidget(self.btnQuit, 2, 2)
self.setLayout(layout) 

proc_depth = lambda : self.export_depth()
QtCore.QObject.connect(self.btnP1, QtCore.SIGNAL("clicked()"), proc_depth)
QtCore.QObject.connect(self.btnQuit, QtCore.SIGNAL("clicked()"), self, QtCore.SLOT("reject()"))

self.exec()


def export_depth(self):

global NUMPY
if not NUMPY:
Metashape.app.messageBox("Script aborted: numpy module is not installed.")
return 0

app = QtWidgets.QApplication.instance()
global doc
doc = Metashape.app.document
chunk = doc.chunk #active chunk

if self.formCmb.currentText() == "1-band F32":
F32 = True
elif self.formCmb.currentText() == "Grayscale 8-bit":
F32 = False
elif self.formCmb.currentText() == "Grayscale 16-bit":
F32 = False
else:
print("Script aborted: unexpected error.")
return 0

selected = False
camera_list = list()
if self.radioBtn_sel.isChecked():
selected = True
for camera in chunk.cameras:
if camera.selected and camera.transform and (camera.type == Metashape.Camera.Type.Regular):
camera_list.append(camera)
elif self.radioBtn_all.isChecked():
selected = False
camera_list = [camera for camera in chunk.cameras if (camera.transform and camera.type == Metashape.Camera.Type.Regular)]


if not len(camera_list):
print("Script aborted: nothing to export.")
return 0

output_folder = Metashape.app.getExistingDirectory("Specify the export folder:")
if not output_folder:
print("Script aborted: invalid output folder.")
return 0

print("Script started...")
app.processEvents()
if chunk.transform.scale:
scale = chunk.transform.scale
else:
scale = 1
count = 0

for camera in camera_list:
if camera in chunk.depth_maps.keys():
depth = chunk.depth_maps[camera].image()
if not F32:
img = numpy.frombuffer(depth.tostring(), dtype=numpy.float32)
depth_range = img.max() - img.min()
img = depth - img.min()
img = img * (1. / depth_range)
if self.formCmb.currentText() == "Grayscale 8-bit":
img = img.convert("RGB", "U8")
img = 255 - img
img = img - 255 * (img * (1 / 255))#normalized
img = img.convert("RGB", "U8")
elif self.formCmb.currentText() == "Grayscale 16-bit":
img = img.convert("RGB", "U16")
img = 65535 - img
img = img - 65535 * (img * (1 / 65535))#normalized
img = img.convert("RGB", "U16")
else:
img = depth * scale
img.save(output_folder + "/" + camera.label + ".tif")
print("Processed depth for " + camera.label)
count += 1
self.pBar.setValue(int(count / len(camera_list) * 100))
app.processEvents()
self.pBar.setValue(100)
print("Script finished. Total cameras processed: " + str(count))
print("Depth maps exported to:\n " + output_folder)
return 1


def export_depth_maps():

app = QtWidgets.QApplication.instance()
parent = app.activeWindow()
dlg = ExportDepthDlg(parent)

Metashape.app.addMenuItem("Custom menu/Export Depth Maps", export_depth_maps)


[Alexey Pasumansky]

Internally the depth maps are stored in some arbitrary coordinate system and require chunk.transform.scale value to be applied in order to get the real dimensions for referenced/scaled projects.