Calibration - Revision history

VMaslov: /* Step 2: Record calibration video */

2014-06-02T09:05:29Z

Step 2: Record calibration video

VMaslov: /* Step 2: Record calibration video */

2014-06-02T09:05:14Z

Step 2: Record calibration video

VMaslov: /* Step 2: Record calibration video */

2013-02-14T14:57:11Z

Step 2: Record calibration video

VMaslov: /* Step 5: process calibration video in iPi Mocap Studio */

2013-02-13T15:11:13Z

Step 5: process calibration video in iPi Mocap Studio

VMaslov: /* Step 5: process calibration video in iPi Mocap Studio */

2013-02-13T15:10:04Z

Step 5: process calibration video in iPi Mocap Studio

VMaslov: /* Step 5: process calibration video in iPi Mocap Studio */

2013-02-13T14:37:44Z

Step 5: process calibration video in iPi Mocap Studio

VMaslov: /* Step 3: stop recording and check recorded video */

2013-02-13T14:36:58Z

Step 3: stop recording and check recorded video

VMaslov: /* Step 2: Record calibration video */

2013-02-13T14:36:06Z

Step 2: Record calibration video

VMaslov: /* Step 2: Record calibration video */

2013-02-13T14:34:01Z

Step 2: Record calibration video

Andrew at 10:34, 10 September 2012

2012-09-10T10:34:36Z

← Older revision		Revision as of 09:05, 2 June 2014
Line 42:		Line 42:

	'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.		'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.
−

	'''Tip.''' For successful calibration, several hundred frames are sufficient. Much more frames (like several thousands) will not produce more accurate results, but instead will increase the processing time and possible number of marker detection errors. So generally it is not recommended to record calibration videos of more than 1 minute length.		'''Tip.''' For successful calibration, several hundred frames are sufficient. Much more frames (like several thousands) will not produce more accurate results, but instead will increase the processing time and possible number of marker detection errors. So generally it is not recommended to record calibration videos of more than 1 minute length.

← Older revision		Revision as of 09:05, 2 June 2014
Line 42:		Line 42:

	'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.		'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.
		+
		+
		+	'''Tip.''' For successful calibration, several hundred frames are sufficient. Much more frames (like several thousands) will not produce more accurate results, but instead will increase the processing time and possible number of marker detection errors. So generally it is not recommended to record calibration videos of more than 1 minute length.

	'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight arm away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.		'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight arm away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.

@@ Line 43: / Line 43: @@
 '''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.
-'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight hand away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.
+'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight arm away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.
 [[File:Calibration1.jpg]]

@@ Line 80: / Line 80: @@
 ** Uncheck “Auto detect initial camera positions” checkbox.
 ** Click “Calibrate” button. This will rerun calibration process, without recomputing marker positions.
 Follow video tutorial:
@@ Line 98: / Line 93: @@
 Red points designate misdetected marker positions.
 -20% of red points should be considered normal. Calibration is good if you have at least 70% of green points.
 === Step 6: Define ground plane ===

@@ Line 74: / Line 74: @@
 * '''Important.''' Adjust the Region of Interest to cover the part of video that contains the glowing marker.
 * Set the Diagonal Field of View (FOV) for your cameras on the “Scene” tab. If you use Sony PlayStation Eye or Logitech QuickCam 9000 cameras, leave the FOV value at the default 75 degrees.
-* Set initial positions of cameras. Move and rotate virtual cameras so that their positions and orientations very roughly correspond to real positions and orientations. Click “Calibrate” button on “Calibration” tab and wait while the system finishes calibration.
+* Go to “Calibration” tab. Check “Auto detect initial camera positions” checkbox. Click “Calibrate” button and wait while the system finishes calibration.
-* Calibration algorithm may occasionally fail to find correct camera position. In particular, this may happen if left and right cameras are swapped. If this happens, move virtual cameras using camera orbit control on “Scene” tab and click “Calibrate” again. This will cause calibration (but not marker tracking) to be repeated.
+* Calibration algorithm may occasionally fail to find correct camera positions. If this happens, you should manually adjust initial camera positions to roughly match your configuration. The main thing is the correct order of the cameras around the capture area, and their approximate view directions.
 Follow video tutorial:

@@ Line 72: / Line 72: @@
 To process calibration video please do the following:
 * Load your calibration video to [[iPi Mocap Studio]]
-* VERY IMPORTANT: Adjust the Region of Interest to cover the part of video that contains the glowing marker.
+* '''Important.''' Adjust the Region of Interest to cover the part of video that contains the glowing marker.
 * Set the Diagonal Field of View (FOV) for your cameras on the “Scene” tab. If you use Sony PlayStation Eye or Logitech QuickCam 9000 cameras, leave the FOV value at the default 75 degrees.
 * Set initial positions of cameras. Move and rotate virtual cameras so that their positions and orientations very roughly correspond to real positions and orientations. Click “Calibrate” button on “Calibration” tab and wait while the system finishes calibration.

@@ Line 59: / Line 59: @@
 === Step 3: stop recording and check recorded video ===
 * There is no significant motion blur (image of marker looks like a round spot rather than an ellipse or a luminescent line)
 * Most of the time marker is visible in at least 3 cameras and not completely obscured by human body

← Older revision		Revision as of 14:36, 13 February 2013
Line 42:		Line 42:

	'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.		'''Tip.''' The exact trajectory of the marker is not so important, just try to cover the whole capture volume, or at least its perimeter.
		+
	'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight hand away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.		'''Tip.''' You should make the marker visible to as much cameras as possible at all times. Hold the marker in the straight hand away from your body. In a circle configuration, when approaching the boundary of the capture area, position the marker inside the area, and your body outside.

@@ Line 38: / Line 38: @@
 Start video recording.
-First couple of seconds of calibration video should contain background only (no marker).
-Then move slowly the marker through your entire capture volume (front-top-right-bottom-left-back-top-right-bottom-left).  Start from top and move the marker in a descending spiral motion.
+Move the marker slowly through your entire capture volume (front-top-right-bottom-left-back-top-right-bottom-left).  Start from top and move the marker in a descending spiral motion.
 [[File:Calibration1.jpg]]
@@ Line 47: / Line 50: @@
 [[File:Calibration3.jpg]]
-Put the marker to the ground at each corner and at the center of capture volume.
+Put the marker to the ground at each corner and at the center of capture volume. At least 4-5 ground points are needed for the correct detection of the groundplane.
 [[File:Calibration_ground1.jpg]]

@@ Line 19: / Line 19: @@
 [[Image:Noname_flashlight.jpg|250px]]
-=== Step 1: Running iPi Recorder in calibration mode ===
+=== Step 1: Running [[iPi Recorder]] in calibration mode ===
-Run '''iPi Recorder''' and choose one of the darkening modes in "darkening for calibration" list (for Sony PS Eye cameras)
+Run [[iPi Recorder]] and choose one of the darkening modes in "darkening for calibration" list (for Sony PS Eye cameras)
 [[File:calibration-darkening.png]]
@@ Line 63: / Line 63: @@
 Take note of height of your first camera over the ground. You will need this parameter later. If you cannot measure this height accurately, then at least make a rough estimation.
-=== Step 5: process calibration video in iPiStudio ===
+=== Step 5: process calibration video in [[iPi Mocap Studio]] ===
 Strictly speaking, you can postpone processing calibration video until after you finished recording other videos (e.g. your action videos). However, it is a good idea to process your calibration video as soon as it was recorded because it helps you ensure that you have good calibration. (Later on, incorrectly recorded calibration video may affect your ability to process action videos. )
 To process calibration video please do the following:
-* Load your calibration video to iPiStudio
+* Load your calibration video to [[iPi Mocap Studio]]
 * VERY IMPORTANT: Adjust the Region of Interest to cover the part of video that contains the glowing marker.
 * Set the Diagonal Field of View (FOV) for your cameras on the “Scene” tab. If you use Sony PlayStation Eye or Logitech QuickCam 9000 cameras, leave the FOV value at the default 75 degrees.