JPS62140079A - Apparatus for detecting position of object - Google Patents

Abstract

PURPOSE:To make it possible to detect the position of an object with a high visual field and high accuracy, by constituting the titled apparatus so that the detection wave group generated from a detection wave generator of which frequency is variable contains a dense frequency detection wave group small in frequency difference and a rough frequency detection wave group large in frequency difference. CONSTITUTION:A wave receiver group is constituted of three stages of a 3X3 wave receiver group A consisting of wave receivers 11-19, a 3X3 wave receiver group B consisting of wave receivers 20-23, 15, 24-27 and a 3X3 wave receiver group C consisting of wave receivers 28-31, 15, 33-36. The position of an object is detected on the whole using the receiving signal obtained by a detection wave group dense in frequency difference and the wave receiver group A dense in an arrangement interval and the position of the object is locally detected using receiving signals successively obtained on the basis of the detection result by a detection wave group rough in frequency difference and the wave receiver groups B, C rough in an arrangement interval. As mentioned above, the estimation process of the position of the object is made stepwise and the approximate position of the matter is estimated at the initial stage and accuracy is made higher while a visual field is successively made narrow and the position of the object is finally detected with high resolving power to enable the detection of the position of the object with a high visual field and high accuracy.

Description

[Detailed Description of the Invention] Summary of the Invention A detection wave group sequentially transmitted toward a detected object includes a detection wave group with a dense two-frequency difference and a detection wave group with a sparse frequency difference, The arrangement of the wave receiving element group that receives the detected waves from the object is configured so that there are dense parts and sparse parts, and first, the one frequency difference is created by forming the detection wave group with a dense detection wave group and the wave receiving element group with a dense arrangement interval. The position of the object is detected globally using the received signal obtained, and based on this result, the received signal obtained by a group of detected waves with a sparse one frequency difference and a group of receivers with a sparse arrangement interval is sequentially determined. 1. An object position detection device characterized in that the position of an object is locally detected using.

[Technical Field] The present invention relates to an object position detection device that detects the position of an object by holography using detection waves such as ultrasonic waves and electromagnetic waves, and particularly relates to a three-dimensional type object position detection device.

[Description of Prior Art] FIG. 1 shows a schematic configuration of a conventionally proposed object position detection device η. This device sequentially irradiates an object with detection waves having a plurality of different frequencies with the same frequency difference, and receives the reflected waves reflected from the object using a large number of receiver groups arranged at equal intervals. The object position is estimated by arithmetic processing based on this received signal. Hereinafter, a case will be described in which an ultrasonic wave is used as the detection wave, the number of types of one frequency is 5, and the wave receiver group is 5×5 channels.

First, an ultrasonic signal transmitted from the ultrasonic transmitter 2 toward the object 7 is reflected by the object 7, and is reflected by the ultrasonic receiver group 3.
The wave is received at After passing through the amplifier circuit group 4, the amplitude and phase of these received signals are measured in the phase detection circuit group 5 and recorded in the memory 6 of the computer. This data is so-called hologram data. Hologram data is collected by changing 1 frequency and 5
This is done sequentially using ultrasound waves with two different frequencies.

Using an ultrasonic signal with a frequency If, coordinates (x', y')
If the received signal is observed at , the hologram data h(x', y', r) is expressed as follows.

b (x', y') = (1) where f' (x, y, z) is the reflectance of the object 7, and C is the speed of sound.

(t is the distance between the wave transmitter 2 and the object 7, (r is the distance between the wave receiver and the object 7.) Such hologram data is measured for all frequencies and the wave receiver, and the reproduction calculation shown in The reproduced image 1 (x, y, z) is reproduced according to the process.

1 (x, y, z) = ... (2) Here, ff1t' is the distance between the transmitter and the reproduction point, (r'
is the distance between the receiver and the reproduction point.

By the way, in such an imaging system, assuming that the object exists in the Fresnel region, the horizontal resolution Δr and the field of view g and the vertical resolution Δ2 and the field of view g are respectively expressed as follows.

λZ.

Δ"-□ ... (3) λ ... (6) gz'" 2Δf Here, λ is the wavelength of the ultrasonic wave at the center frequency fo, Zo
is the distance from the hologram surface to the object surface.

P is the arrangement interval of the wave receivers, L is the aperture width of the wave receivers, and f is the difference between the maximum frequency and the minimum frequency (for convenience, this will be referred to as the frequency aperture width hereinafter).

However, such object position detection devices that apply holography techniques have the following problems. In other words, in order to accurately measure the position of an object in the X and Y directions,
From equation (3), it is necessary to increase the aperture width, and from equation (4), it is necessary to reduce the receiver spacing P in order to widen the detection area. In other words, in order to accurately detect the position of an object in the x and y directions over a wide field of view, it is necessary to arrange the wave receiver group densely and in an extremely large number of wave receivers. Furthermore, in the Z direction as well, in order to accurately detect the position of an object in the Z direction over a wide field of view, it is necessary to prepare an extremely large number of different frequencies of detection waves with small frequency differences. For this reason, electronic processing circuits such as oscillation circuits, amplifier circuits, and single-phase detection circuits have become large-scale, making it difficult to implement them.In addition, the amount of data required to fill the data is small, and the memory capacity and calculation processing time of computers have increased significantly. There was a drawback.

[Object of the Invention] The object of the invention is to provide an object position detection device that can accurately detect the position of an object over a wide field of view even when using a detection wave group with a small number of frequency types and a wave receiver group with a small number of wave receivers. Our goal is to provide the following.

[Configuration and Effects of the Invention] The present invention provides an object in which a group of wave receivers sequentially receives detection waves of a plurality of different frequencies propagating from an object, and obtains hologram data regarding the position of the object from the received signals. In a position detection device, the wave receiving element group is arranged so that there are a densely arranged part where the spacing between adjacent wave receiving elements is narrow and a sparsely arranged part where the spacing between the wave receiving elements is wide, and detects a detection wave with one frequency variable. The detection wave group generated from the generator includes a dense frequency difference detection wave group with a small one-frequency difference and a wire scrap wave number difference detection wave group with a large frequency difference.

First, the position of the object is detected globally using the received signals obtained by a group of detection waves with a close one-frequency difference and a group of receivers with a close arrangement interval, and based on this result.

The position of the object is locally detected using received signals obtained by a group of detection waves having a sparse one frequency difference and a group of receivers having a sparse arrangement interval.

As described above, in the present invention, the process of estimating the position of the object is performed in stages, and in the initial stage, a wide field of view detection area is set to estimate the approximate position of the object.

The accuracy is gradually increased while narrowing the field of view, and the object position is finally detected with high resolution. Therefore, as a result, the position of an object can be detected over a wide field of view and with high precision using a detection wave group with a small number of types of frequencies and a wave receiver group with a small number of wave receivers.

[Description of Embodiments] FIG. 2 shows an example of the arrangement of the wave receiver group used in the present invention. This receiver group has a three-stage configuration,
Receiving wave element 11, 12, 13, 14° 15.16, 17.1
8.19 The 3×3 wave receiver group is a wave receiver group arranged so that the mutual spacing is the closest,
Let P be the interval between adjacent wave receivers (this wave receiver group is hereinafter referred to as wave receiver group A). Next, the 3×
In the receiver group 3, the receiver spacing is the aperture width 2P of receiver group A.
(hereinafter referred to as wave receiver group B). Furthermore, receivers 28, 29,
30, 31° 15.33, 34, 35.36, the receiver spacing is the receiver group B.
(hereinafter referred to as wave receiver group C) arranged so as to be equal to the aperture width 4P of (hereinafter referred to as wave receiver group C).

Furthermore, the detection wave group is also configured in three stages, with one frequency f=f
, a group of detected waves composed of detected waves of fo±Δf is,
The dense layer wave number detection wave group having the smallest detected wave frequency difference is called the detection wave group A'. next.

Let B' be a detected wave group composed of frequencies ff and fo±2Δf, and C' be a detected wave group composed of frequencies ff and f±4fo. The detection wave group C' is a line waste wave number difference detection wave group selected so that the frequency difference thereof is the largest.

Next, a method for estimating the position of an object using such a receiver group and a detection wave group will be described. The hardware configuration of the processing circuit is the same as that shown in FIG. First, the object region is reconstructed using hologram data obtained by a combination of the receiver group A and the detection wave group A'. This combination has a receiving wave element spacing P, receiving/receiving wave opening/opening 0 width 1 frequency difference Δ
Since f1 frequency aperture width f=2Δf is both small, the (3rd
) to formula (6), reproduced images with low resolution but high field of view can be obtained.In other words, as shown in Fig. 3, each area obtained by equally dividing the reproduction area into 3 x 3 x 3 areas. An image with 1 pixel is obtained.Now, the target object is 1 pixel.
Suppose that this is detected in the reproduced pixel S. However, at this stage, it is only known that the object is somewhere within the reproduced pixel S, and the more accurate position cannot be recognized.

Next, based on this result, the reproduced pixel S is further divided into 3×3×3 regions (pixels) using the hologram data obtained by the combination of the receiving wave element group B and the detected wave group B'. At this time, since the receiver spacing 2P of the receiver 14B is equal to the aperture width 2P of the receiver group A, equations (3) and (4)
), the field of view in the X and Y directions reproduced by the receiver group B is equal to the resolution in the X and Y directions reproduced by the receiver group A. Furthermore, since a similar relationship holds for the detected wave group, the field of view in the Z direction reproduced by the detected wave group B' is equal to the resolution in the Z direction reproduced by the detected wave group A'. Therefore, at this stage, a reproduced image as shown in FIG. 4 is obtained, and it is possible to detect, for example, that the position of the object is included in the pixel T. Similarly, based on this result, the reproduced pixel T is divided into 3×3×3 regions as shown in FIG. 5 using the hologram data obtained by the combination of the receiver group C and the detected wave group C'.
The final object position (pixel) U is detected.

As described above, according to the present invention, the process of estimating the position of an object is performed globally at first, and then locally by gradually narrowing the field of view. It is also possible to detect the three-dimensional position of an object with a wide field of view and high precision. Therefore, the electronic processing circuit is not so large, the memory capacity of the computer is small, and the calculation processing time can be shortened.

For example, in the above embodiment, 9X3X3-81 hologram data are obtained by a combination of detection wave groups of 7 types of frequencies and a wave receiver group consisting of 25 wave receivers, and this is used to perform position detection. I explained about
In order to achieve position detection with the same precision in the same field of view using a conventional device, a detection wave group with nine different frequencies and a wave receiver group with 9 x 9 wave receivers, that is, 9 x 9 x 9 = 729 holograms. Requires data. The effects of this invention are clear from this comparison.

[Other Examples] In the above embodiment, the detection wave group and the receiver group are configured in three stages, each stage has three types of frequency elements, and the number of receiver elements is 3×3. and the number of elements may be arbitrarily selected depending on the purpose. The same effect can also be obtained by using electromagnetic waves instead of ultrasonic waves. Furthermore, although the wave receiver group is arranged in a square shape in FIG. 2, it may be arranged in another arrangement, for example, in a circular shape (concentric circles).

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a conventional object position detection device.
FIG. 2 is a diagram showing an example of the arrangement of a wave receiver group in the object position detection device according to the present invention, and FIGS. 3 to 5 are explanatory diagrams for explaining the position detection process of the object position detection device according to the present invention. It is. 1... High frequency oscillator, 2... Wave transmitter. 3... Wave receiver group, 4... Amplifier circuit group. 5... Phase detection circuit group, 6... Computer memory. 7...Object, 11-36...Receiver. that's all

Claims (1)

[Claims] An object position detection device in which a group of wave receivers sequentially receives detection waves of a plurality of different frequencies propagating from an object and obtains hologram data regarding the position of the object from the received signals, The wave receiver group is arranged so that there are densely arranged parts where the spacing between adjacent wave receivers is narrow and sparsely arranged parts where the spacing between the wave receivers is wide. The detected wave group is
An object position detection device comprising: a fine frequency difference detection wave group with a small frequency difference and a sparse frequency difference detection wave group with a large frequency difference.