Abstract book (pdf) - ICPR 2010

15:00-17:10, Paper MoBT8.7
Adaptive Image Projection Onto Non-Planar Screen using Projector-Camera Systems
Yamanaka, Takashi, Nagoya Inst. of Tech.
Sakaue, Fumihiko, Nagoya Inst. of Tech.
Sato, Jun, Nagoya Inst. of Tech.
In this paper, we propose a method for projecting images onto non-planar screens by using projector-camera systems eliminating
distortion in projected images. In this system, point-to-point correspondences in a projector image and a camera
image should be extracted. For finding correspondences, the epipolar geometry between a projector and a camera is used.
By using dynamic programming method on epipolar lines, correspondences between projector image and camera image
are obtained. Furthermore, in order to achieve faster and more robust matching, the non-planar screen is approximately
represented by a B-spline surface. The small number of parameters for the B-spline surface are estimated from corresponding
pixels on epipolar lines rapidly. Experimental results show the proposed method works well for projecting images
onto non-planar screens.
15:00-17:10, Paper MoBT8.8
Analysis and Adaptation of Integration Time in PMD Camera for Visual Servoing
Gil, Pablo, Univ. of Alicante
Pomares, Jorge, Univ. of Alicante
Torres, Fernando, Univ. of Alicante
The depth perception in the objects of a scene can be useful for tracking or applying visual servoing in mobile systems. 3D
time-of-flight (ToF) cameras provide range images which give measurements in real time to improve these types of tasks.
However, the distance computed from these range images is very changing with the integration time parameter. This paper
presents an analysis for the online adaptation of integration time of ToF cameras. This online adaptation is necessary in order
to capture the images in the best condition irrespective of the changes of distance (between camera and objects) caused by
its movement when the camera is mounted on a robotic arm.
15:00-17:10, Paper MoBT8.9
Detecting Paper Fibre Cross Sections in Microtomy Images
Kontschieder, Peter, Graz Univ. of Tech.
Donoser, Michael, Graz Univ. of Tech.
Kritzinger, Johannes, Graz Univ. of Tech.
Bauer, Wolfgang, Graz Univ. of Tech.
Bischof, Horst, Graz Univ. of Tech.
The goal of this work is the fully-automated detection of cellulose fibre cross sections in microtomy images. A lack of
significant appearance information makes edges the only reliable cue for detection. We present a novel and highly discriminative
edge fragment descriptor that represents angular relations between fragment points. We train a Random Forest
with a plurality of these descriptors including their respective center votes. In such a way, the Random Forest exploits the
knowledge about the object centroid for detection using a generalized Hough voting scheme. In the experiments we found
that our method is able to robustly detect fibre cross sections in microtomy images and can therefore serve as initialization
for successive fibre segmentation or tracking algorithms.
15:00-17:10, Paper MoBT8.10
Active Calibration of Camera-Projector Systems based on Planar Homography
Park, Soon-Yong, Kyungpook National Univ.
Park, Go Gwang, Kyungpook National Univ.
This paper presents a simple and active calibration technique of camera-projector systems based on planar homography.
From the camera image of a planar calibration pattern, we generate a projector image of the pattern through the homography
between the camera and the projector. To determine the coordinates of the pattern corners from the view of the projector,
we actively project a corner marker from the projector to align the marker with the printed pattern corners. Calibration is
done in two steps. First, four outer corners of the pattern are identified. Second, all other inner corners are identified. The
pattern image from the projector is then used to calibrate the projector. Experimental results of two types of camera-projector
systems show that the projection errors of both camera and projector are less than 1 pixel.
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