Kimio Yamada

Performance of obstacle detection and collision warning system for civil helicopters

Some helicopters strike the power lines under the good weather conditions. Helicopter pilots sometimes have some difficulties to find such long and thin obstacles. We are developing an obstacle detection and collision warning system for civil helicopters in order to solve such problems. A color camera, an Infrared (IR) camera and a Millimeter Wave (MMW) radar are employed as sensors. This paper describes the results of different flight tests that show good enhancement of radar detection over 800m range for power lines. Additionally, we exhibit the processed fusion images that can assist the pilots in order to recognize the danger of the power lines.

Millimeter-Wave Radar for Rescue Helicopters

A collision avoidance and warning system for civil helicopters in Japan has been developed. A real-time warning method was applied using an image fused from a coloured video, an IR sensor data and mm-wave radar measurements. This paper focuses on the FM-CW mm-wave radar sensor and the associated antennas, working at 94 GHz. Flight tests were conducted in order to detect power lines. Thanks to two different antennas, power line response was measured in vertical and horizontal polarizations. Maximum detection ranges are of 800 and 600m respectively. This variation comes from the antenna gain difference. Radar resolution is limited by the allocated bandwidth at 94 GHz which is 200 MHz. Comparisons were conducted on the ground with an integrated FM-CW radar working at 77 GHz and achieving 500 MHz bandwidth

Image processing and fusion to detect navigation obstacles

Helicopters flying at low altitude in the visual flight rules often crash against obstacles such as a power transmission line. This paper describes the image sensors to detect obstacles and the several image processing techniques to derive and enhance the targets in the images. The images including obstacles were collected both on the ground and by air using an infrared (IR) camera and a color video camera in different backgrounds, distances, and weather conditions. Collected results revealed that IR images have an advantage over color images to detect obstacles in many environments. Several image processing techniques have been evaluated to improve the qualities of collected images. For example, fusion of IR and color images, several filters, such as the Median filter or the adaptive filter have been tested. Information that the target is thin and long, which characterizes the shape of power lines, has been introduced to derive power lines. It has been shown that these processes can greatly reduce the noise and enhance the contrast, no matter how the background is. It has also been demonstrated that there is a good prospect that these processes will help develop the algorithm for automatic obstacle detection and warning.

Obstacle detection for helicopter flights by infrared images

Helicopters often strike against obstacles such as a power line. To reduce such collisions, we are developing an obstacle detection and warning system for helicopters. This paper describes the techniques to detect wire-like obstacles by infrared (IR) images. Measurements were conducted to gather IR images and to investigate the sensor performance to detect obstacles in different environments. IR images proved that the use of IR cameras could greatly increase the possibility of detecting obstacles that could never be found by naked eyes. The performance to suppress sunlight noise by the 8-12 mm IR camera was also demonstrated. However, the target-to-background contrast of the original IR images was not enough as the advisory by which a pilot maneuvers his helicopter. There were cases that even IR cameras failed to detect obstacles in adverse weather and background conditions. Image processing techniques were then proposed to enhance the contrast of IR images and to improve the coverage in adverse conditions. An experimental millimeter wave (MMW) radar is now being developed to improve the detection performance and to add distance information on the enhanced images. The configuration of the MMW radar and the results of preliminary measurements by the radar were presented.

Optical sensing and image processing to detect a life raft

A system for maritime surveillance is presented. The system employs a high resolution IR camera and a color video camera to detect a very small object like a life raft. Several image processing techniques are presented to reduce noise in the data, identify targets and display them in an enhanced manner. Typical images obtained by the flight experiment are shown to demonstrate the validity of a series of procedures including these techniques. An example to enhance the visibility of the display is also presented.

A new color, IR, and radar data fusion for obstacle detection and collision warning

Helicopters often strike against obstacles such as power lines. We are developing an obstacle detection and warning system for civil helicopters to reduce such collisions. A color camera, an Infrared (IR) camera and a Millimeter Wave (MMW) radar are employed as its sensors. This paper describes an image and data fusion of color and infrared images with the millimeter wave information. An outline of the obstacle detection and warning system is described first. Then, we propose a newly developed on-board system based on a fast AD converter. A new algorithm is also proposed to identify the nearest target using the radar signal where there are other far large-RCS obstacles. As the result, the system can achieve 30 cycles per second of IR and color image acquisition, radar data processing, distance calculation, fusing all data and displaying them. Finally, we propose a future plan for flight experiments planned in this year.

Obstacle detection and warning for helicopter flight using infrared and millimeter wave

Helicopters often strike against thin obstacles such as power lines. To prevent such collisions,we are developing an obstacle detection and warning system for helicopters. An Infrared (IR)camera,a color camera and a Millimeter Wave (MMW)radar are employed as its sensor components.This paper describes the performance of the system. 94GHz FMCW radar has been developed for this system. The Vivaldi antenna has been fabricated for the radar. The range accuracy of the radar is tested by the measurements. The radiation pattern of the Vivaldi antenna is measured in the anechoic chamber. The validity of the IR camera to detect obstacles is evaluated by the flight measurements.IR images, collected by the measurements are employed to analyze the effect of the background brightness and to develop new rendering techniques to enhance obstacles. The results show that the accuracy of the FMCW radar is within 5%. The Vivaldi antenna has good characteristics but its transition circuit deforms the total antenna pattern. It is shown that IR camera greatly increases the possibility to detect obstacles even in poor visibility. The normal distribution in the IR spectrum proves to be enough to analyze the image and to derive the obstacle information. The IR image rendered by the pseudo color method is effective to enhance obstacles.

PED Interference Reporting System in Japan

This paper describes the EMI reports submitted voluntarily by Japanese operators when they face interference events suspected to be caused by Portable Electronic Devices (PEDs) in aircraft. The reports are classified and analyzed in terms of aircraft types, victim aircraft sub systems, details of the events and flight phases. Suspected sources of events are investigated by noting the correlation between occurrence of events and PED use. A suspected source of events other than PED is also studied. 204 reports collected in 1993 - 2006 have shown that about one third of total events have some relationships with the use of PEDs and that anomalies relating to Auto Pilot have been increasing. Cell phones have been suspected most as the source of interference events. Probability of interference has become higher at lower altitude than at higher altitude, which means that some events may have been caused by the radio waves from the ground.