JP2002290240A - Data interpolation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data interpolation method that obtains an output interpolation value of target point by respectively obtaining a plurality of interpolation values at a target point on the basis of values of a plurality of points where at least one point differs from other points, multiplying the plurality of interpolation values by weights different from each other and summing the products. SOLUTION: The data interpolation method includes a step 220 of obtaining a 1st preliminary interpolation value as a mean value or a median of two points apart before and after a target point by a time (a), respectively, a step 230 of obtaining a 2nd preliminary interpolation value as a mean value of two points apart before and after the target point by a time (b) (>a), respectively, a step 240 of obtaining a 3rd preliminary interpolation value as a mean value of two points apart before and after the target point from a time (c) (>b), respectively, and a step 250 of multiplying the 1st, 2nd and 3rd preliminary interpolation values by weights p, q, r as correction values and summing the products to obtain an interpolation value at the target point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a data interpolation method, and more particularly, to a plurality of interpolated values at a target point based on values of a plurality of points at least one of which is different. The present invention relates to a data interpolation method of multiplying and adding different weights to obtain an output interpolation value of a target point.

[0002]

2. Description of the Related Art
Sound information processing, image information processing, and the like are generally performed using a computer. Originally, audio information and image information are analog signals, and the audio information and image information must be converted into digital signals sampled at predetermined intervals in order to be processed by a computer. At this time, if the sampling interval is small, information closer to the original analog signal can be obtained as a digital signal. However, when the sampling interval is reduced, the amount of data increases, so that the memory for recording data increases, and the load on the processor that processes the data also increases. Therefore, determining the sampling interval is closely related to the trade-off with the cost of the system.

[0003] On the other hand, audio information and image information digitized to be processed by a computer are converted into analog signals again in order to be visualized and visualized. Since conversion to an analog signal is performed based on sampled digital data, even if the digital signal is not processed, unsampled data cannot be obtained as an analog signal. As described above, by being sampled and generated, it is necessary to interpolate the data in order to make the data in which the unsampled portion is missing closer to the original data.

A general method of interpolating data between two points of one-dimensional data such as digitized voice information by using two points of the one-dimensional data is to obtain an average of the data values of the two points. That is, the data value at the intermediate point.
In performing such interpolation, if the distance between two points used for obtaining the interpolation value is short, a value close to the original data is obtained as the interpolation value. In this case, as a result, although the accuracy of the data is high, there is a problem in that non-smooth data having discrete states of digital data remaining is obtained.

When the distance between two points used for interpolation is long, a value far from the original data is obtained as an interpolation value. In this case, as a result, there is a problem that data which is smooth but has low accuracy is obtained without leaving discrete states of digital data.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and a plurality of interpolated values at a target point are obtained based on values of a plurality of points at least one of which is different. It is an object of the present invention to propose a data interpolation method in which an output interpolated value of a target point is obtained by multiplying and adding different weights.

[0007]

According to a first aspect of the present invention, a first preliminary interpolated value at a target point is obtained by using at least two or more values. A second preliminary interpolation value at the target point is obtained using at least two or more values that are different from each other by at least one point, and a correction value is added to at least the first preliminary interpolation value and the second preliminary interpolation value. And a data interpolation method for obtaining an interpolation value at the target point by multiplying and adding.

[0008] Each of the first and second preliminary interpolation values may be obtained by averaging at least two values.
Further, the correction value may be set to a larger value as the interval having the maximum length is shorter among the mutual intervals of the at least two or more points.

As described above, according to the first aspect of the present invention,
A first preliminary interpolation value at a target point is obtained using at least two or more values, and a second preliminary interpolation at the target point is obtained using at least two or more values different from the two points by at least one point. A value is obtained, and an interpolation value at the target point is obtained by multiplying at least the first preliminary interpolation value and the second preliminary interpolation value by respective correction values and adding them. As a result, the data has both accuracy and smoothness, and the audio information and the image information obtained by this method are compared with the case where the first and second interpolation values are used as interpolation values alone. As a result, sound quality and image quality are improved.

[0010]

FIG. 1 shows an embodiment in which a data interpolation circuit 26 of the present invention is applied to a compact disk reproducing apparatus 100.

An optical pickup 14 for reading information of the compact disc 10 set in the compact disc reproducing apparatus 100 has an RF (Radio Freq).
uency) amplifier 20, digital signal processing circuit 22,
Also, a servo circuit 28 is connected. The servo circuit 28 for controlling various servos unique to the optical disk is also connected to the motor 12 for rotating the compact disk 10.

An RF amplifier 20 connected to the optical pickup 14 for generating a focus error signal, etc.
It is also connected to the digital signal processing circuit 22. The digital signal processing circuit 22 that performs various digital signal processing
/ A converter 24. The D / A converter 24 for converting a digital signal into an analog signal is connected to a data interpolation circuit 26 which is a feature of the present invention. A system control 30 for controlling the digital signal processing circuit 22 and the servo circuit 28 is connected to the digital signal processing circuit 22 and the servo circuit 28.

The servo circuit 28 controlled by the system controller 30 includes a compact disk reproducing device 10
In order to read the information of the compact disc 10 set to 0, the motor 12 for rotating the compact disc 10 and the optical pickup 14 are operated. The RF amplifier 20 generates a focus error signal based on the data transmitted by the optical pickup 14. The digital signal processing circuit 22 performs digital signal processing based on the data generated by the RF amplifier 20 and the data read by the optical pickup 14.

The D / A converter 24 converts the digital signal processed by the digital signal processing circuit 22 and subjected to digital signal processing into an analog signal. The analog signal is subjected to data interpolation by the data interpolation circuit 26, and is output as audio information via a speaker (not shown) or the like.

Next, a first embodiment of the data interpolation processing executed by the data interpolation circuit 26 of the present invention will be described with reference to FIGS.

An analog signal on which data interpolation is performed is represented by a function x (t) using time t as a variable, and is indicated by a broken line in FIG. The processing routine is started at step 200 in FIG. In step 210, a target point t = n to be subjected to data interpolation is determined. In step 220, the first preliminary interpolated value is determined by equation (1).

Y ₁ = (x (na) + x (n + a)) / 2 (1) Here, it is assumed that a is an arbitrary positive value. That is, the first preliminary interpolation value is obtained as an average value or an intermediate value of two points separated by a time before and after the target point.

Similarly, at step 230, a second preliminary interpolated value is determined by equation (2).

Y ₂ = (x (n−b) + x (n + b)) / 2 (2) where b is an arbitrary positive value larger than a.
That is, the second preliminary interpolation value is obtained as an average value or an intermediate value of two points that are separated by a time b (> a) before and after the target point.

In step 240, a third preliminary interpolated value is obtained by equation (3).

Y ₃ = (x (n−c) + x (n + c)) / 2 (3) where c is any positive value greater than b.
That is, the third preliminary interpolation value is obtained as an average value or an intermediate value of two points that are separated by a time c (> b) before and after the target point.

In step 250, an interpolation value is obtained from the weighted average value shown in equation (4).

I (n) = (p · y ₁ + q · y ₂ + r · y ₃ ) / (p + q + r) (4) That is, the first, second, and third preliminary interpolated values are weighted p as correction values. , Q, and r. The division by p + q + r is for scaling. here,
p, q, and r are the distances 2a, 2b, and 2c between the data of the two points used in obtaining the first, second, and third preliminary interpolation values.
It is determined according to (2a <2b <2c), and becomes larger as the distance between the two points becomes smaller, and is set so that p>q> r.

At step 260, it is determined whether or not there is a next target point for obtaining an interpolation value.
Steps 250 to 250 are repeated. If it is determined that there is no next target point, the process proceeds to step 270, and the process ends at step 270.

FIG. 3 shows the result of this processing routine. The first, second and third preliminary interpolation values are particularly extreme values (for example, t =
9 to 23). The first preliminary interpolated value indicates a value closest to the original analog signal, but lacks smoothness. The third preliminary interpolated value is the smoothest, but indicates a value far from the analog signal. Here, the interpolation value i (t) indicated by the solid line indicates a value close to the original analog signal and is a smooth curve.

As described above, the first preliminary interpolation value at the target point is obtained by using at least two points, and the target preliminary value is obtained by using at least two points at least different from the two points. Determine a second preliminary interpolation value at the point;
By obtaining an interpolation value at the target point by multiplying at least the first preliminary interpolation value and the second preliminary interpolation value by respective correction values and adding the corrected values, the advantage of each interpolation value is obtained. It is possible to acquire data having both characteristics and smoothness, and it is possible to improve the sound quality of the sound reproduced by the output data.

Next, a second embodiment of the data interpolation processing executed by the data interpolation circuit 26 of the present invention will be described with reference to FIGS.

Since the first embodiment and the second embodiment are the same except for steps 220 to 250, only steps 220 to 250 will be described here.

In step 220, a first preliminary interpolated value is determined using equation (5).

Y ₁ = (x (na) + x (n + a)) / 2 (5) Here, a is an arbitrary positive value. That is, the first preliminary interpolation value is obtained as an average value of two points separated by a time a before and after the target point.

Similarly, at step 230, a second preliminary interpolated value is determined using equation (6).

Y ₂ = (x (n−2a) + x (na) + x (n + a) + x (n + 2a)) / 4 (6) That is, the second preliminary interpolated value is calculated at time a before and after the target point. And the average value of four points 2a apart from each other.

In step 240, a third preliminary interpolated value is determined using equation (7).

Y ₃ = (x (n−3a) + x (n−2a) + x (na) + x (n + a) + x (n + 2a) + x (n + 3a)) / 6 (7) That is, the third preliminary interpolation The value is obtained as an average value of six points separated by time a, 2a and 3a before and after the target point, respectively.

In step 250, an interpolation value is obtained from the weighted average value shown in equation (8).

I (n) = (p · y ₁ + q · y ₂ + r · y ₃ ) / (p + q + r) (8) That is, the first, second, and third preliminary interpolated values are weighted p as correction values. , Q, and r. The division by p + q + r is for scaling. here,
p, q, and r are the maximum distances 2a, 4a, and 6 between the plurality of points used in obtaining the first, second, and third preliminary interpolation values.
a (2a <4a <6a). That is, the smaller the interval having the maximum length among the mutual intervals of the plurality of points, the larger the value is set. In this case, the value is set so that p>q> r.

FIG. 4 shows the result of this processing routine. Similarly to the result of the first embodiment shown in FIG. 3, the first, second, and third preliminary interpolation values are particularly extreme values (for example, t = 9 to 2).
The feature is clear in 3). The first preliminary interpolation value indicates a value closest to the original analog signal,
Lack of smoothness. The third preliminary interpolated value is the smoothest, but indicates a value far from the analog signal. Here, the interpolation value i (t) indicated by the solid line indicates a value close to the original analog signal and is a smooth curve.

As described above, in the second embodiment, as in the first embodiment, the first preliminary interpolation value at the target point is obtained by using at least two or more values. A second preliminary interpolation value at the target point is obtained by using at least two or more points having different points, and at least the first preliminary interpolation value and the second preliminary interpolation value are multiplied by correction values and added. By calculating the interpolation value at the target point, it is possible to obtain output data having both data accuracy and smoothness, which are advantages of each interpolation value. It is possible to improve the sound quality of the sound to be performed.

Next, a third embodiment of the data interpolation processing executed by the data interpolation circuit 26 of the present invention will be described with reference to FIGS.

The first, second and third embodiments are different from each other in that
Since steps other than steps 220 to 250 are the same, steps 220 to 250 will be described here.

In step 220, a first preliminary interpolation value is obtained by using equation (9).

Y ₁ = (b × x (n−a) + a × x (n + b)) / (a + b) (9) Here, it is assumed that a and b are arbitrary positive values. That is, the first preliminary interpolation value is obtained according to the distance from the two points that are two times apart from the target point by time a and then by time b.

Similarly, in step 230, the second preliminary interpolation value is obtained by the equation (10).

[0044] Here, it is assumed that a and c are arbitrary positive values. That is, the second preliminary interpolation value is obtained according to the distance from the target point using two points separated by time a and time c before the target point.

In step 240, a third preliminary interpolated value is obtained using equation (11).

[0046] Here, it is assumed that a and d are arbitrary positive values. That is, the third preliminary interpolation value is obtained according to the distance from the two points, using two points separated by a time a before the target point and a time d after the target point.

In step 250, an interpolation value is obtained from the weighted average value shown in equation (12).

I (n) = (p · y ₁ + r · y ₂ + q · y ₃ ) / (p + r + q) (12) That is, the first, second, and third preliminary interpolated values are weighted p as correction values. , R, and q. It is divided by p + q + r for scaling. Where p, q,
r is the distance a + b, a + c, a + d (b <c) between the two points used in obtaining the first, second, and third preliminary interpolation values.
The value is determined according to <d), and becomes larger as the distance between the two points becomes shorter, and is set so that p>q> r.

FIG. 5 shows the result of this processing routine. As a result of the first embodiment shown in FIG. 3, the second embodiment shown in FIG.
Similarly to the result of the embodiment, the characteristics of the first, second, and third preliminary interpolated values are apparent particularly at extreme values (for example, t = 9 to 23). The first preliminary interpolated value indicates a value closest to the original analog signal, but lacks smoothness.
The third preliminary interpolated value is the smoothest, but indicates a value far from the analog signal. Here, the interpolation value i (t) indicates a value close to the original analog signal and has a smooth curve.

As described above, in the third embodiment, similarly to the first and second embodiments, the first preliminary interpolation value at the target point is obtained by using at least two or more values, and Obtains a second preliminary interpolation value at the target point using at least two or more values that are different from each other by at least one point, and assigns a correction value to at least the first preliminary interpolation value and the second preliminary interpolation value. By obtaining the interpolated value at the target point by multiplying and adding, it is possible to obtain output data having both the accuracy of data and the smoothness, which are the advantages of each interpolated value. The sound quality of the sound reproduced by the data can be improved.

In the above embodiment, the first through third
Although the correction value is obtained using the preliminary interpolation values of the above, the present invention is not limited to this, and the preliminary interpolation values may be any two or more types.
Further, the method of obtaining the first to third preliminary interpolation values is not limited to the method described in the above embodiment, and any known method may be used.

Further, in the above embodiment, the correction value is set to a larger value as the interval having the maximum length is shorter among the mutual intervals of at least two points, but the present invention is not limited to this. For example, in a case where smoothness is emphasized rather than data accuracy, a smaller value may be set as the interval having the maximum length among the intervals between at least two or more points is shorter. The correction value may be set arbitrarily, or may be determined by learning using a neuron network or the like.

In the above embodiment, the data interpolation of the present invention is applied to a compact disc reproducing apparatus. However, the present invention is not limited to this. , May be applied in other devices. In the present invention, since the data interpolation is applied to the compact disc reproducing apparatus, the first to third preliminary interpolation values are obtained based on the data arranged one-dimensionally. For example, the present invention is applied to an image information processing apparatus. When applied, the first to third preliminary interpolation values may be obtained based on data arranged in two dimensions or three dimensions.

In the above embodiment, the digital signal is converted to an analog signal, and data interpolation is performed on the analog signal before the analog signal is output as audio information. However, the present invention is not limited to this. Instead, data interpolation may be performed at any point in the signal processing. Further, data interpolation may be performed on the digital signal.

[0055]

According to the first aspect of the present invention, at least 2
A first preliminary interpolation value at the target point is obtained by using a value equal to or more than the point, and a second preliminary interpolation value at the target point is calculated using at least two or more values that are different from the two points by at least one point. At least the first preliminary interpolation value and the second
The interpolation value at the target point is obtained by multiplying each of the preliminary interpolation values by the respective correction values and adding the correction values. Thus, both the accuracy of data and the smoothness, which are advantages of each interpolation value, are obtained. The output data can be obtained, and the sound quality of the sound reproduced by the output data can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a compact disk reproducing apparatus having a data interpolation circuit according to the present invention.

FIG. 2 shows a flow chart of the first, second and third embodiments of the present invention.

FIG. 3 is a graph showing a processing result of the first example of the present invention.

FIG. 4 is a graph showing a processing result of the second example of the present invention.

FIG. 5 is a graph showing a processing result of the third example of the present invention.

[Explanation of symbols]

 100 Compact disk player 26 Data interpolation circuit

Claims (3)

[Claims] 1. A first preliminary interpolation value at a target point is obtained by using at least two or more points, and at least one point different from the two points is calculated by using at least two points or more. A data interpolation method for obtaining a second preliminary interpolation value, multiplying at least the first preliminary interpolation value and the second preliminary interpolation value by respective correction values, and adding the multiplied correction values at the target point. 2. The data interpolation method according to claim 1, wherein each of the first and second preliminary interpolation values is obtained by averaging at least two values. 3. The data interpolation according to claim 1, wherein the correction value is set to a larger value as an interval having a maximum length is shorter among mutual intervals between the at least two points. Method.