Accurate distortion correction is especially crucial for applications involving quantitative measurements such as on-orbit geometric positioning of remoting sensing cameras, depth measurement from ...stereoscopy, and target tracking and recognition from images. However, the conventional complicated correction methods and the unsatisfied results greatly limit their application prospects, especially in the aerospace field. In this paper, we propose an improved distortion correction method (IDCM) for large aperture infrared tracking cameras, addressing the distortion model and the principle point and distance with high-precision measurement points in the focal plane. Experimental results showed that the distortion errors corrected by the proposed method were 0.26 pixels in a near-infrared image and 0.19 pixels in a short-wavelength infrared image. These corrected distortion errors are better than that corrected by the two-dimensional Lagrange interpolation method (TDLIM) of 0.36 pixels in a near-infrared image and 0.29 pixels in a short-wavelength infrared image, and the conventional distortion model (CDM) of 0.54 pixels in a near-infrared image and 0.64 pixels in a short-wavelength infrared image, respectively.
There are potential pitfalls associated with the pursuit of accurate surgical navigation, such as vulnerability of the reference array to accidental dislodgment and damage or soiling of tracking ...arrays on tools. Additionally, there are hazards encountered when attempting accurate robotic screw placement in spine surgery, including skiving of the tool on bone, displacement of the robotic arm, or patient movement. Proven techniques are needed to address and mitigate these issues to ensure that navigation integrity is maintained and screw placement is accurate when using navigated robotic surgical guidance systems. The following research describes some potential hazards commonly encountered in robotic navigated screw placement, suggests techniques for overcoming these hazards, and provides examples of how these techniques have been incorporated into existing surgical robotic guidance systems.
Work analysis is one of critical tools for improving order picking efficiency in logistics centers. Traditionally, video analysis has been used to analyze work time for various tasks. However, video ...analysis generally requires a substantial amount of time and labor, which makes it too inefficient for real-time work improvement. To address this, a novel automatic work analysis method is proposed for analyzing the order picking process in logistics centers in this study. The automatic work analysis method can be divided into two parts: dynamic positioning and motion analysis. With the proposed method, an ultrasonic network and a tracking camera are used for measuring a worker’s real-time position while he/she is moving, and an acceleration sensor is used for checking the acceleration of the dominant working hand. Using the position and acceleration data, the worker’s motion is then estimated by an estimation model pre-tested for accuracy. To test the effectiveness of the proposed method, an experiment was conducted in which the measurement error of positioning was found to be approximately 0.01±0.19 m for the x-coordinate values and 0.03±0.45 m for the y-coordinate values. The total measurement error was confirmed to be within a one-step stride. The results of the motion analysis were more than 90% consistent with those obtained by traditional video analysis.
Gaze tracking is used for detecting the position that a user is looking at. In this research, a new gaze-tracking system and method are proposed to control a large-screen TV at a distance. This ...research is novel in the following four ways as compared to previous work: First, this is the first system for gaze tracking on a large-screen TV at a distance. Second, in order to increase convenience, the user's eye is captured by a remote gaze-tracking camera not requiring a user to wear any device. Third, without the complicated calibrations among the screen, the camera and the eye coordinates, the gaze position on the TV screen is obtained by using a simple 2D method based on a geometric transform with pupil center and four cornea specular reflections. Fourth, by using a near-infrared (NIR) passing filter on the camera and NIR illuminators, the pupil region becomes distinctive in the input image irrespective of the change in the environmental visible light. Experimental results showed that the proposed system could be used as a new interface for controlling a TV with a 60-inch-wide screen (16:9).
In order to capture an eye image of high quality in a gaze-tracking camera, an auto-focusing mechanism is used, which requires accurate focus assessment. Although there has been previous research on ...focus assessment in the spatial or wavelet domains, there are few previous studies that combine all of the methods of spatial and wavelet domains. Since all of the previous focus assessments in the spatial or wavelet domain methods have disadvantages, such as being affected by illumination variation, etc., we propose a new focus assessment method by combining the spatial and wavelet domain methods for the gaze-tracking camera. This research is novel in the following three ways, in comparison with the previous methods. First, the proposed focus assessment method combines the advantages of spatial and wavelet domain methods by using ε-support vector regression (SVR) with a symmetrical Gaussian radial basis function (RBF) kernel. In order to prevent the focus score from being affected by a change in image brightness, both linear and nonlinear normalizations are adopted in the focus score calculation. Second, based on the camera optics, we mathematically prove the reason for the increase in the focus score in the case of daytime images or a brighter illuminator compared to nighttime images or a darker illuminator. Third, we propose a new criterion to compare the accuracies of the focus measurement methods. This criterion is based on the ratio of relative overlapping amount (standard deviation of focus score) between two adjacent positions along the Z-axis to the entire range of focus score variety between these two points. Experimental results showed that the proposed method outperforms other methods.
Light projection function is a major area of interest within the field of designing ultra-wide angle cameras. In this paper, we introduce a novel ultra-wide angle projection function that is ...characterized by an angle-variant distortion model similar to that of human retina space-variant resolution. The projection peculiarities were compared with the classical equidistant fisheye projection function to illustrate the benefits of our projection model on real-time tracking and ultra-wide angle imaging applications. The new projection model produced an accurate result with uncomplicated distortion control using Zemax user-defined macro program. The inverted model is also successfully used in correcting such distorted image. The paper shows as well the design of an original 170° fast foveated fisheye lens that provides more than 52 % undistorted image with a high-resolution performance over the entire lens field of view.
Correlating chest surface motion to motion of the liver using epsilon-SVR--a porcine study Ernst, Floris; Martens, Volker; Schlichting, Stefan ...
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention,
2009, Letnik:
12, Številka:
Pt 2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In robotic radiosurgery, the compensation of motion of internal organs is vital. This is currently done in two phases: an external surrogate signal (usually active optical markers placed on the ...patient's chest) is recorded and subsequently correlated to an internal motion signal obtained using stereoscopic X-ray imaging. This internal signal is sampled very infrequently to minimise the patient's exposure to radiation. We have investigated the correlation of the external signal to the motion of the liver in a porcine study using epsilon-support vector regression. IR LEDs were placed on the swines' chest. Gold fiducials were placed in the swines' livers and were recorded using a two-plane X-ray system. The results show that a very good correlation model can be built using epsilon-SVR, in this test clearly outperforming traditional polynomial models by at least 45 and as much as 74%. Using multiple markers simultaneously can increase the new model's accuracy.
We propose a double-lens tracking-camera system composed of two lens-modules. One module is to take a wide view while the other is to track and magnify the target with its pan-tilt mechanism, which ...mimics the eye’s function of tracking and watching an object without losing wide whole view. We have developed a prototype of the camera and applied it two real-world applications, i.e., “fish-tracking” and “illegal-disposal-surveillance”, and had excellent results fundamentally in the applications.
This report describes a visual field tracking camera for laparoscopic surgery that allows the visual field to be changed without moving the laparoscope. We also report on our early experience with ...this camera for single-surgeon laparoscopic cholecystectomy.
The visual field tracking camera has a tracking mechanism (composed of a zoom lens and a charge-coupled device CCD slide mechanism) built into the camera head. The 80 degrees visual field observed with the laparoscope can be expanded using the zoom lens, and the field can be shifted by changing the size of the area being viewed by the CCD. This is accomplished by pushing a switch on the forceps or by verbal command. Cholecystectomy was carried out on 12 patients with gallstones using this camera. The operations were performed by either a single surgeon or two surgeons. Forceps held with a forceps holder were inserted through the right port to lift the fundus of the gallbladder. The single surgeon used the other two ports to resect the gallbladder by the two-handed technique.
In all cases, cholecystectomy was completed without any need to move the laparoscope at any point during the operation. Seven operations were performed by a single surgeon. Mainly for education purposes, five other operations were performed by a pair of surgeons. The mean time required for surgery was 76 +/- 17 min. This time did not differ from that of laparoscopic cholecystectomy performed during the same period on 22 patients by teams of three surgeons using conventional cameras.
Using the visual field tracking camera, laparoscopic cholecystectomy can be performed without any need to touch the laparoscope. This camera allowed laparoscopic cholecystectomy to be performed by a single surgeon.
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