JPS5841719B2 - 4 channel pan pot stake position detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stick position detection method for a 4-channel panpot, and relates to the inclination angle and direction of a stick that is rotatable with one end as a fulcrum and the other end tracing a hemispherical trajectory. When detecting and extracting the amount of change corresponding to the distance as a change in distance from the origin in two-dimensional orthogonal coordinates where the origin is defined when the stick is perpendicular to the horizontal plane, if the distance is divided into n and displayed, For example, by making the divided section near the origin more narrow than the other divided sections, a 4-channel pan pot can stably maintain the localization of the sound image at the origin even if there is camera shake due to stick operation or noise is mixed in. The purpose of this invention is to provide a stick position detection method.

Conventionally, it has been known that a four-channel stereo reproduction device localizes a sound image at a position corresponding to the movement of a stick of a four-channel panpot.

However, the conventional method for localizing a sound image is called a level difference localization method in which the sound image is localized by relatively varying only the levels of the audio signals supplied to the four speakers.

Therefore, the output signal of the 4-channel panpot is only a univariate parameter signal for relatively varying the level of the 4-channel audio signal and distributing it to the front left and right or the rear left and right.

However, in the level difference localization method described above, the position of the sound image is limited to the range between each speaker, and it is not possible to localize the sound image outside of each speaker.

On the other hand, in recent years, as a method for obtaining clear and natural sound images outside each speaker, for example,
Pages 455 to 46 of the NHK Technology Monthly Report, December 2009 issue
On page 1, a method called the so-called ΔP-Δφ method was proposed.

According to this ΔP-Δφ method, for example, in the case of two-channel stereo, a natural sound image can be created even right next to the listener using the natural sound image localization device shown in FIG.

In FIG. 6, the audio signal input to the input terminal 21 is supplied to a low-pass filter 22, bandpass filters 23, 24, and 25, respectively, and divided into four bands, and then passed to a phase shifter 26.
Husband will be provided on 27.28 and 29.

The phase shifter 26 converts the band-divided signal from the low-pass filter 23 into 2
Desired phase shift difference θ for both human power signals that are branched and supplied
For example, one human input signal is set to θ so that 1 is given relatively.
Shifts the phase by one.

Of the two output signals of the phase shifter 26, one output signal whose phase is shifted is adjusted to a desired level by a variable resistor 31a and supplied to the mixer 33, and the other output signal whose phase is not shifted is supplied to a variable resistor 30a. The signal is adjusted to a desired level and supplied to the mixer 34.

Here, the variable resistor 31a provides a signal level lower than Xl relative to the variable resistor 30a.

Similarly, θ2,
Each of the two output signals given a phase difference of θ3 and θ4 is connected to variable resistors 30b and 31b, 30c and 31c, and 30d.
and 31d to mixers 32 and 33.

The output signal of the mixer 32 is sent to the right speaker R of the listener 34.
The output signal of the mixer 33 is supplied to the left speaker L.
supplied to

Here, if the signal applied to speaker L is xejθ and the signal applied to speaker R is 1.0, then X is (level of input signal of speaker R)/(level of input signal of speaker R). is the level ratio expressed, and θ is the relative phase difference between both speaker input signals.

Now, the sound pressure PL at the left and right ear canal entrances of the listener 34
.

pR is It is expressed as

However, in the above equation, τ is the delay time due to head diffraction, γ is the attenuation coefficient due to head diffraction, and Po is the reference sound and pressure.

Also, the interaural level difference △P is 201oglPR/PL
l, the interaural phase difference △φ is Arg(PR)−Arg(P
L).

According to the ΔP-Δφ method, a natural sound image that is equal in quality to the actual sound source can be created outside the two speakers.

In the case of 4-channel stereo, one more stage of the apparatus shown in FIG. 6 is sufficient.

Here, it is necessary for the phase shifters 26, 27, 28 and 29 to vary the phase shift according to the desired sound image localization position, and for this purpose, the phase shift amount is configured to be varied by the angle identification signal.

On the other hand, the resistance values of the variable resistors 30a to 30d and 31a to 31d must be varied according to the desired sound image localization position, and for this purpose, the resistance values are configured to be varied by the distance identification signal.

The present invention particularly relates to a stick position detection system capable of generating the above-mentioned angle identification signal and distance identification signal depending on the stick position of a four-channel panpot.

Here, in two-dimensional orthogonal coordinates where the origin is defined when the stick is perpendicular to the horizontal plane, when detecting the distance from the origin of the stick position, the detection distance is divided into n pieces, and If the stick is divided into equal parts and distributed, if the stick approaches the origin from a certain direction, even a slight change in the stick position information will change as it approaches the origin, as will be described later, making it impossible to stably detect the origin.

Therefore, the present invention solves the above problems,
An embodiment will be described below with reference to the drawings.

FIG. 1 shows a schematic side view of an example of a four-channel panpot.

1 is a stick, one end 1a of which is rotatably supported, and by freely rotating the stick 1 with this one end 1a as a fulcrum, the other end 1b draws a hemispherical trajectory.

The resistance values of the rotary variable resistors VR1 and VB2 are configured to change in accordance with the amount of change in the movement of the stick 1.

By the way, in the method of the present invention, the resistance value of the variable resistor is changed in response to the movement of the stick 1 in order to express the mapping of the stick 1 to the horizontal plane as a position within coordinates with this horizontal plane as two-dimensional orthogonal coordinates. Furthermore, the rotary variable resistors VR1 and VB2 are constructed as shown in FIG.

In the figure, VRl is stick 1 at the X coordinate of the horizontal plane.
VB2 is a rotary variable resistor that indicates the position of the stick 1 in the Y coordinate of the horizontal plane.

One ends of the rotary variable resistors vR1 and VB2 are connected to the positive DC power supply voltage B input terminal, while the other ends are respectively connected to the negative DC power supply voltage -B input terminal.

The origin (Olo) of the above two-dimensional orthogonal coordinates of X and Y is defined as the mapping position of the stick 1 when the stick 1 is perpendicular to the horizontal plane, and at this time, the rotary variable resistor VR
The sliders 1 and R2 are set to be located at their respective midpoints.

Therefore, when the stick 1 is perpendicular to the horizontal plane, the DC voltages led from the sliders of the rotary variable resistors vR1 and VR2 to the output terminals 2 and 3 are both OV.

Movements other than the vertical position of stick 1 are as described above in X and Y02.
The resistance values of the rotary variable resistors vR1 and VR2 are changed to be expressed as a change in the mapping position in the dimensional orthogonal coordinates,
A signal with a corresponding level and polarity is extracted.

Based on this signal, the movement of the stick 1 is determined by the distance r (=a) from the origin of the mapping of the stick 1 in the above-mentioned X, Y two-dimensional orthogonal coordinates, and the angle 1z with respect to a certain direction.

It is detected as degree θ(-jan-).

The detection signal of the distance r from the mapping origin of the stick 1 of the channel pan pot is used as a distance identification signal, and the detection signal of the angle θ with respect to a certain direction is used as an angle identification signal. By being supplied to a system-equipped 4-channel natural sound image localization device, the sound image in the 4-channel stereo sound field can be moved to a location according to the movement of the stick 1, or localized to a fixed location. be.

Here, when detecting and displaying the position of the stick 1 in both coordinates (x, y) in proportion to the distance from the origin, for example, the distance is 0, 0.5.1.0.2.0, etc. , ■ to obtain the (x, y) position proportional to the inclination angle and direction of the stick 1. If you divide these n distance divisions into equal parts, for example, near the origin If you use stick 1 frequently, in other words, if you bring stick 1 to the origin of the (x, y) coordinates, even a slight change in stick 1 will cause the position information obtained by stick 1 to change due to this slight movement of stick 1. , the origin display changes and lacks stability in the origin display.

That is, when approaching the vicinity of the origin from a certain direction, the direction of the stick 1 will change even if there is a slight change when approaching the origin.

This situation is shown in FIG. 4 by a curved line connecting X marks.

Therefore, the method of the present invention divides the distance that was previously divided into n into equal parts into n + 2, and at the same time gives a width to an important point, such as the origin, so that the distance can be adjusted even if there is slight fluctuation of the hand. To prevent direction reversal in the vicinity, n+
Assign three of the two divided sections to the origin, maintain the detection of the origin even if the distance changes from the origin to one division distance n + 2, and then divide the distance equally according to the amount of change of -n + 2. It is designed to perform detection.

FIG. 3A is a side view showing the movement of the stick 1, and FIG. 3B shows an embodiment of the distance detection section according to the present invention.

Normally, the stick 1 is configured to be freely rotated within a range of ±45° with respect to the vertical origin (0,0), as shown in FIG. 3A.

Therefore, when dividing this 45° into n equal parts of the distance R on the horizontal plane, n+i (i is a positive integer smaller than n; however, in this embodiment, i=2).

). As a result, the angle of the stick 45°1 per unit distance division becomes as shown in Figure 3A.

n+2 Also, the length per unit of each divided distance section is as shown in Figure B.

Here, R is the radius of the circle formed by the locus of the mapping of the stick 1 to the horizontal plane when the Stison n+2 stick 1 is rotated at 45 degrees to the vertical plane.

R The three divided distance sections from the origin are the distance r for displaying the origin, as shown by hatching in Figure 3 n+2B.
.

(− distance detection interval), and from the fourth distance detection interval detected as distance r1 to the n + second distance detection interval detected as distance rn-1, the interval is equally spaced.
Assigned to each.

n+2 As a result, the resolution decreases when stick 1 is near the origin, so even a slight change will not be judged as a change in the direction of stick 1, regardless of camera shake caused by stick operation, noise, or inaccurate origin display. First, the origin can be detected stably.

This state is shown by the broken line in FIG. Furthermore, when trying to bring the stick 1 closest to the origin and fix it at the angle θ, there is a possibility that the angle θ may change or reverse due to minute movements near the origin and be detected in the opposite quadrant. I don't get it.

In other words, as shown in FIG. 5, even if the stick 1 that has moved to point a changes slightly to point b or 0 after detecting the position of point a, it will be weighted near the origin as described above. , so the sound image does not move.

In this way, the origin display and the direction when closest to the origin are detected so as not to change even if the origin of the stick is inaccurately displayed by a human, or even if there is some fluctuation of the hand.

As described above, the stick position detection method of the 4-channel pan pot according to the present invention is a 4-channel pan pot that is configured to be rotatable with one end of the stick as a fulcrum and the other end to draw a hemispherical trajectory. The output of a variable resistor whose resistance value is varied by movement of the stick so as to be expressed as a change in the stick mapping position within a two-dimensional orthogonal coordinate whose origin is defined when the stick is perpendicular to the horizontal plane. When detecting and outputting a signal representing the distance from the origin of the stick in the orthogonal coordinates, the distance in the orthogonal coordinates from the origin to the maximum rotational position of the stick is divided by n + i (n is a positive number). (integer, i is a positive integer less than or equal to n)) Among the divided distance sections obtained, the distance range (1
+i) divided distance intervals are one distance detection interval, and the other (n-1) divided distance intervals are each (n-1)
Because the distance detection section has been set to 1, it is possible to detect distance ranges that are frequently used, or ranges where minute changes in stick movement may be a problem due to operator hand shake or noise, etc.
For example, by using the origin and its vicinity as one distance detection section, the origin can be stably detected even if the position of the stick changes slightly due to slight camera shake or noise.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an example of a 4-channel panpot to which the method of the present invention can be applied, Fig. 2 is a circuit diagram of an example of a rotary variable resistor used in the method of the present invention, and Figs. 3A and B 4 is a side view showing the movement of the stick and a diagram showing the distance detection section for explaining one embodiment of the method of the present invention, and FIG. 4 schematically shows the detection state of the stick movement in the conventional method and the method of the present invention. 5 is a schematic diagram for explaining the detection operation of the method of the present invention when the stick is brought closest to the origin, and FIG. 6 is a block system diagram showing an example of a natural sound image localization device. 1...Stick, VRl, vR2...
・Rotating variable resistor.

Claims (1)

[Claims] 1 A two-dimensional system whose origin is defined when the stick of a 4-channel panpot, which is rotatable with one end of the stick as a fulcrum and the other end drawing a hemispherical trajectory, is perpendicular to a horizontal plane. Detects and outputs a signal representing the distance of the stick from the origin in the orthogonal coordinates from the output signal of a variable resistor whose resistance value is varied in conjunction with the movement of the stick, in order to express it as a change in the stick mapping position in the orthogonal coordinates. When doing so, divide the distance in the above orthogonal coordinates from the origin to the maximum rotational position of the stick by n+i (n is a positive integer, i is a positive integer less than or equal to n)
Among the divided distance sections obtained, (1+1) divided distance sections within a desired distance range from the origin are regarded as one distance detection section, and the other (n-1) divided distance sections are defined as one distance detection section. A stick position detection method for a four-channel panpot, characterized in that each section has (n-1) distance detection sections.