JP3408330B2 - Signal judgment method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal determination method for performing an inspection using an analog measurement signal output from a sensor or the like, and more particularly, to a signal determination method suitable for tracking inspection of an optical disk. The present invention relates to a signal determination method. 2. Description of the Related Art Conventionally, the following typical inspection methods have been known for inspecting tracks of a video disk. In the first inspection method, a deviation amount of a video disk to be inspected from a track reference position is measured by a tracking inspection device. The waveform of the analog electric signal continuously output as a measurement result is displayed on an oscilloscope, and the inspector visually inspects the displayed waveform. The abnormality / normal judgment criterion is abnormal when the maximum value indicated by the waveform exceeds a threshold value. A second inspection method detects a maximum voltage of the analog electric signal in a certain time range, compares the maximum voltage with a reference voltage for a reference value by a comparator, and automatically detects the measurement signal. This is an automatic inspection for detecting a portion which becomes an abnormal signal in the above, and has an advantage that the inspection can be performed uniformly. [0004] When a plurality of video disk track inspections are performed and statistically examined, the probability that the second inspection method recognizes an abnormality is higher than that of the first inspection method. Has turned out to be high. Therefore, when image information of a video disk to be inspected is transferred onto a CRT screen and image inspection is performed in a situation where the video disk is actually used, a waveform of an electric signal which is a first inspection method is displayed on an oscilloscope. As a result, it has been found that a method in which an inspector visually inspects a displayed waveform is more practical than the second inspection method, but the reason is not well understood. As described above, the first inspection method is practical, but requires personnel for the inspection, and it is difficult to always expect a uniform inspection. An object of the present invention is to provide a method of determining a measurement signal that can easily and automatically determine whether a measurement signal includes an abnormal signal in view of the above points. The gist of the present invention is to divide a signal value to be continuously measured into N (N is an integral multiple of 10), and to obtain N measured values extracted from each section. , A representative value is determined according to the following procedure, and the representative value is compared with a predetermined reference value to determine the quality of the signal in that section. Procedure for determining representative values First step for continuously measuring N signal values Second step for rearranging the measured values obtained in the first step in ascending order Two adjacent two of the rearranged measured values The third step of retrieving the difference value of the values The fourth step of rearranging the difference values in descending order The fifth step of extracting (0.3N) difference values from the maximum value of the rearranged difference values is obtained in the third step. From the beginning of the difference value (0.4N)
Sixth step of extracting the difference values The first determination is made as to whether or not all the values of the difference values extracted in the fifth step are present in the value group extracted in the sixth step. (1) As a result of the primary determination, if any, the representative value of the N measurement values is determined by [(0.4N) +
1] -th numerical value. (2) As a result of the primary discrimination, if there is no primary discrimination, the (0.1N) th numerical value in the fifth step is:
The second is to determine whether the value is present in the value group in the sixth step.
(2) -1: as a result of the second discrimination, if it exists, the position number at the beginning of the value group in the sixth step is M,
The (M + 1) th numerical value of the measured values in the second step is determined as a representative value of the N measured values. (2) -2: As a result of the secondary discrimination, if there is no secondary value, the (0.1N) th numerical value of the measured value in the second step is determined as a representative value of the N measured values. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a system configuration of a video disk track inspection apparatus to which the present invention is applied. FIG. 2 shows a flow of processing of the sampled measurement signal, and FIG. 3 shows a process of determining a representative value from the measurement signal. FIG. 4 shows a distribution example of sampled data. In FIG. 1, the amount of positional deviation of a track on a video disk 10 is measured by a position measuring device 11. A well-known track position measuring device 11 can be used. The result of the position measuring device 11 is sent to the maximum value holding circuit 12. The maximum value holding circuit 12 holds the maximum value at a predetermined interval, and outputs the maximum value to an A / D (analog / digital) converter 13 in the form of an analog signal. The digital signal converted by the A / D converter 13 is sent to a RAM (random access memory) 1 by a CPU (central processing unit) 15.
4 is stored. The CPU 15 functions as an information processing circuit (procedure) of the present invention by processing the data stored in the RAM 14 in accordance with the control procedures shown in FIGS. Perform judgment of abnormal / normal. At this time, data used in the arithmetic processing is temporarily stored in the RAM 14. The representative value of the measurement is displayed on the display 17, and when an abnormality determination is obtained in the CPU 15, a warning is displayed by a display lamp (LED) 18. FIG. 2 shows a method of determining a measurement signal according to the present invention.
This will be described with reference to FIGS. The control procedures of FIGS. 2 and 3 are actually described in a program language that can be executed by the CPU 15, but for convenience of description, FIGS. 2 and 3 functionally express processing contents. The measured value held by the maximum value holding circuit 12 is taken into the CPU 15 as described above. In this embodiment, the maximum value holding circuit 12 holds the maximum value at 0.1 second intervals, and the measured value obtained by digitally converting the maximum value from the A / D converter 13 is taken into the CPU 15. Referring to FIG. This system measures the sampling interval of 0.1 second by the internal timer (S1
0), when the sampling timing comes (S20), A
The maximum value of the measurement signal divided at intervals of 0.1 seconds is taken in from the / D converter 13 as a measurement value (S30). The taken measurement value is stored in the RAM 14. The points of the input measurement values are added, and thereafter, a certain number (N) ｛(first step)
In the present embodiment, the above-described sampling processing (first step) is repeated until N = 10, 1 second interval｝. (S1
0-S55 loop processing). When 10 measured values are taken in, the CPU 15
Executes a process (second step) of rearranging the measured values in descending order of the value as a pre-process for examining the correlation of the sampling signals, that is, a so-called sorting process (S6).
0). Here, dat is used in order from the largest measured value.
1, dat2,... Next, the CPU 15 calculates a difference value between two adjacent measured values among the measured values dat1 to dat10 (third step) (S70). For example, if a difference value between dat1 and dat2 is expressed as Delta1, Delta1 is obtained by the following equation. Delta1 = data1-data2 In this way, the nine difference values Delta1 to Delta are obtained.
When 9 is obtained, the CPU 15 performs the sorting process again on these difference values, and rearranges them in ascending order of value (fourth step) (S80). The rearranged difference values are represented as del1, del2,..., Del9 in descending order. The CPU 15 executes the data del1,
del2, del3, Delta1, Delta2, D
The correlation between delta3 and delta4, specifically, the magnitude relationship is investigated, and a representative value used for determining the presence or absence of a track abnormality is determined from dat1 to dat9 in accordance with the result of the investigation (S90). The method for determining the representative value will be described later. The determined representative value is compared with a predetermined reference value (threshold) (S100). When the representative value is larger than the reference value, it is determined that the track is abnormal, the LED 18 is turned on by the instruction of the CPU 15, and the representative value at that time is displayed on the display 17 (S100 → S).
120). On the other hand, when the determined representative value is smaller than the reference value, the representative value is displayed on the display 17. In this way, one representative value is determined from the 10 sampled measurement values, and when the presence / absence determination is performed on the representative value, one track inspection is completed. Continue inspection. The procedure for determining the representative value (S90) will be specifically described with reference to FIG. The process of S210 → S220 determines whether all the values (del1) to (del3) extracted in the fifth step are present in (Delta1 to Delta4) extracted in the sixth step. Perform primary determination. If there is a result of the primary determination, the representative value is determined to be (dat5). The distribution pattern of measured values in this case corresponds to, for example, FIGS. In addition, *
The marks indicate the determined representative values. The processing of S210 → S230 → S240 will be specifically described. As a result of the primary determination as to whether or not all the values of (del1) to (del3) exist in (Delta1 to Delta4), in the case of no, (del1) exists in (Delta1 to Delta4) A second determination is made as to whether or not to perform. If present, (del1) becomes (Delt)
An and n are the first position number in the value group of 1 to 4), M, and Dat (M + 1) as the representative value. FIG. 4F, for example, corresponds to the pattern of the measured values. The processing of S210 → S230 → S250 will be specifically described. As a result of the primary determination as to whether or not all the values of (del1) to (del3) exist in (Delta1 to Delta4), in the case of no, (del1) exists in (Delta1 to Delta4) A second determination is made as to whether or not to perform. If no, the representative value is (del1). The pattern of the measured values in this case is shown in FIG.
(B), (C), etc. correspond. Using the 20 video disks, the video disk track inspection apparatus shown in FIG. 1 using the signal determination method of the present invention is compared with the visual image inspection in which the waveform of an analog electric signal is displayed on an oscilloscope. did. By visual image inspection, the same video disk as the video disk determined to be defective was also determined to be abnormal by the track inspection apparatus using the signal determination method of the present invention. According to the track inspection apparatus for a video disk using the signal judgment method of the present invention, the same result as that of the visual image inspection can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a system configuration of a video disk track inspection apparatus to which the present invention is applied. FIG. 2 is a diagram showing a flow of processing of a sampled measurement signal. FIG. 3 is a diagram illustrating a process of determining a representative value from measurement signals. FIG. 4 is a diagram illustrating a distribution example of sampled data; [Description of Signs] 10 Video disk 11 Position inspection device 12 Maximum value holding circuit 13 A / D converter 14 RAM 15 CPU 16 ROM 17 Display 18 LED

Claims (1)

(57) [Claims 1] A signal value to be continuously measured is divided into N (N is an integral multiple of 10), and N is extracted from each section.
A signal determination method for determining a representative value from the measured values according to the following procedure, and comparing the representative value with a predetermined reference value to determine the quality of a signal in that section. Procedure for determining a representative value First step for continuously measuring N signal values Second step for rearranging the measured values obtained in the first step in descending order Difference between two adjacent values of the rearranged measured values The fourth step in which the values are sorted in descending order of the difference value The fourth step in which the difference values obtained in the fifth step and the third step in which (0.3N) difference values are extracted from the maximum value of the sorted difference values From the beginning (0.4N)
Sixth step of extracting the difference values The first determination is made as to whether or not all the values of the difference values extracted in the fifth step are present in the value group extracted in the sixth step. (1) As a result of the primary determination, if any, the representative value of the N measurement values is determined by [(0.4N) +
1] -th numerical value. (2) If the result of the primary determination does not exist, a secondary determination is made as to whether the (0.1N) th numerical value in the fifth step exists in the value group in the sixth step, (2) -1: As a result of the second discrimination, if it exists, the position number that first exists in the value group in the sixth step is M,
The (M + 1) th numerical value of the measured values in the second step is determined as a representative value of the N measured values. (2) -2: As a result of the secondary determination, if there is no secondary determination, the (0.1N) th numerical value of the measured value in the second step is determined as a representative value of the N measured values.