JPS6152954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of detecting obstacles in a passage using ultrasonic waves, and more particularly to a method of detecting obstacles for use as a walking aid for blind people. be.

Frequency sweep methods, pulse reflection methods, and pulse reflection phase difference methods have already been proposed as devices that use ultrasonic waves to detect obstacles for the purpose of assisting blind people in walking. However, these methods have problems such as poor resolution and learning and training required to infer the direction of an obstacle from a sound image.Also, no matter how sharp the directivity is, there are the following drawbacks. That is, for example, in the pulse reflection method, as shown in FIG.
When obstacles T _{L and TR} exist at symmetrical positions on both sides of the central axis of body B, the reflected pulse reflected by the obstacle T _L will be different from the oscillation pulse, as shown in Figure 2. After ₁ hour t, it is detected as a received pulse in the geophone _RL , and further, after ₂ hours t with respect to the reflected pulse oscillation pulse, it is detected as a received pulse in the geophone _RR . In addition, the reflected pulse at the obstacle T _R is detected as a received pulse at the geophone R _R after t ₁ hour with respect to the oscillation pulse, and is detected as a received pulse on the geophone R _L after t ₂ hours with respect to the oscillation pulse.
It is detected as a received pulse at . Therefore,
The reflected pulses are simultaneously received by the geophones R _L and R _R after t ₁ hour, and the obstacle T is erroneously recognized as if it were present on the central axis of the vessel B in FIG. 1.

In this way, the creation of a virtual image of an obstacle on the central axis of the oscillator S is a very serious hindrance for blind people who often have the opportunity to pass between two pillars lined up on the left and right.

In addition, when presenting information about obstacles to blind people, conventionally it has been customary to use sound images or single-point tactile stimulation, but it is also possible to maximize the use of hearing for conversation and emergency warnings. It should not be exclusively used for presenting obstacle information, etc.; from this perspective, it is effective and appropriate to present information such as direction and distance using a tactile stimulation device that is designed to convey a large amount of information. .

In view of the above, in the present invention, the obstacle detection area by ultrasonic waves is divided into left and right areas that include the central axis of the instrument body, and obstacles in both areas are sequentially detected. Therefore, it is an object of the present invention to provide an obstacle detection method in which the direction and distance of an obstacle can be detected reliably, and a virtual image generated on the central axis of a vessel is not mistakenly recognized as an obstacle.

Further, the present invention uses a plurality of tactile sensors on a tactile matrix board to detect the distance of the obstacle obtained as described above and the direction detected depending on whether the obstacle is detected in one or both of the left and right regions. The object of the present invention is to provide a method that displays information in correspondence with the vertical and horizontal positions of a stimulation element, thereby making it possible to accurately transmit information on direction and distance without using the sense of hearing.

The method of the present invention will be explained in more detail below with reference to the drawings.

As shown in FIG. 3, obstacle detection based on the present invention uses an ultrasonic oscillator S and left and right geophones R _L1 and R _R1 located symmetrically on both sides of its central axis. Exploration area on the left including the central axis A _L
Obstacle T _L is detected for. To detect this obstacle T _L , a directional oscillator S emits an ultrasonic pulse toward the left exploration area A _L , and the reflected pulse from the obstacle T _L is sent to the left and right receivers R _L1 and R _{R .}
Receive vibration at ₁ . In this case, even if the receivers R _L1 and R _R1 are given directivity to receive the reflected waves of the ultrasonic waves emitted from the oscillator S over a wide range by obstacles, or the oscillator and the receiver There is no problem even if both have directionality. Therefore, the distance to the obstacle is determined by the oscillation from the oscillator S and the receiver R.
It can be detected by the time difference between the reception pulses at _L1 or R _R1 , and the direction of the obstacle can also be detected by the time difference or phase difference between the reception pulses at the left and right geophones R _L1 and R _R1 . Since a certain oscillator or geophone is used, it is possible to detect the direction of the obstacle at least in the left, right, and center ranges, as will be described later. The method of detecting the distance to the obstacle is not limited to the pulse reflection method described above, and various conventionally known methods can be used.

If such an obstacle is detected, the device B
It is possible to detect the presence or absence of an obstacle in the left search area A _L including the central axis of , and if there is an obstacle, the distance to it.

Next, in _the same manner _, as shown in FIG. Using geophones R _L2 and R _R2 , the presence or absence of an obstacle and the distance to the obstacle are detected.

Further, when continuously detecting obstacles, the above-mentioned obstacle search for the left and right regions is repeated.

In this way, by dividing the exploration area into left and right exploration areas that include the central axis of body B, and sequentially detecting obstacles in both areas,
The orientation of the obstacle can be detected depending on whether the obstacle is detected in one or both of the left and right regions. That is, if an obstacle is detected in either the left or right area, it is obvious that there is an obstacle within the detected area, and if it is detected in both the left and right areas, it is obvious that the obstacle is within the detected area. ,
It is detected that an obstacle exists on both regions or on the central axis of the vessel B included in both regions. In particular, obstacles T _L , as shown in FIGS. 3 and 4,
If T _R occurs, a received pulse as shown in Figure 5a will be obtained, but even if t ₁ = t ₄ and t ₂ = t ₅ , the received pulse will be generated by two oscillations. Since the image is divided into two parts, there is no possibility of creating the aforementioned virtual image.

That is, in processing the received pulses in each geophone, as shown in Figure 5a, an ultrasonic wave is first oscillated in the left exploration area A _L , and the reflected pulses from the obstacle T _L are received by the left and right receivers. t ₁ in the devices R _L1 and R _R1
and t When the received vibration is received after ₂ hours, the received image is held electronically, and an ultrasonic wave is further emitted in the right exploration area A _R , and the reflected pulse from the obstacle T _R is sent to the left and right geophones R _L2. , R _R2 after t ₅ and t ₄ hours, the received images are held electronically in the same way, and after searching for the presence of obstacles in these left and right areas, the above two received images are combined. . In this synthesis, the received pulses of the geophones R _L1 and R _L2 and the geophones R _R1 and R _R2 are synthesized as shown in Figure 5b, using the oscillation pulses to the left and right search areas as a reference. The presence of two pulses in each signal indicates that an obstacle exists in each area on the left and right sides, and when one pulse each occurs at the same position in both composite signals, it indicates that there is an obstacle in the left and right regions.
An obstacle exists on the central axis of

The direction and distance of the obstacle thus detected are presented by a tactile matrix board 1 as shown in FIG. This tactile matrix board 1 has a large number of tactile stimulation elements 2 arranged vertically and horizontally, and the vertical and horizontal positions of the tactile stimulation elements correspond to the direction and distance of an obstacle, respectively. ~2z correspond to left, center, and right directions, and element arrays 2a to 2g correspond to distances.

Thus, when an obstacle is detected as described above, the tactile stimulation element corresponding to the direction and distance is operated based on the signals of the direction and distance. For the operation of the tactile stimulation element, any means such as electrical stimulation, mechanical vibration of a vibrator, protrusion of a protrusion, etc. can be employed.

FIG. 7 shows an example of the configuration of a device that displays the direction and distance of an obstacle on the tactile matrix board 1 based on the reception signal of the geophone that detects the presence or absence of an obstacle. The operations of _L1 , R _R1 , and R _L2 , R _R2 are controlled by timing pulses generated in a control device, and the received signal from the geophone is amplified in an amplifier and then sent to a decoder from the control device. The tactile stimulation element 2 on the tactile matrix plate 1 is operated by the direction signal and distance signal obtained thereby.

As is clear from the detailed description above, according to the method of the present invention, it is possible to reliably detect the direction and distance of obstacles, and to detect obstacles on both sides of the central axis of the device. There is no possibility that the obstacle will be mistakenly recognized as being on a line, and the tactile matrix board can clearly display the direction and distance of the obstacle.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional obstacle detection method, FIG. 2 is an explanatory diagram showing the relationship between oscillation pulses and received pulses in that method, and FIGS. 3 and 4 are obstacle detection methods based on the present invention. Figures 5a and 5b are explanatory diagrams showing the relationship between the oscillation pulse and the received pulse in that method and the processing method thereof. Figure 6 is a plan view of the tactile matrix board.
The figure is a block diagram of an apparatus for implementing the present invention. 1... Tactile matrix board, 2... Tactile stimulation element, S... Ultrasonic oscillator, B... Instrument body, R _L1 , R
_R1 , R _L2 , R _R2 ... Geophone.

Claims (1)

[Claims] 1. In a method in which the reflection of ultrasonic waves emitted from an oscillator by an obstacle is received by a receiver and the obstacle is detected based on the time difference between the above-mentioned oscillation and reception, the search area is set to the left and right sides that include the central axis of the instrument body, respectively. The distance to the obstacle is detected in both regions sequentially using a directional oscillator or geophone, and the distance to the obstacle is detected depending on whether the obstacle is detected in one or both of the left and right regions. Detects the orientation of an object and uses it on a tactile matrix board with a large number of tactile stimulation elements arranged vertically and horizontally.
The vertical and horizontal positions of the tactile stimulation elements are respectively made to correspond to the direction and distance of the obstacle, and the corresponding tactile stimulation elements are operated based on the detected direction and distance signals of the obstacle. Obstacle detection method using sound waves.