JP3102071B2 - Video tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video tape recorder (hereinafter, referred to as "VTR") having a function of retrieving information recorded on a magnetic tape, and more particularly to identifying a plurality of magnetic tapes. This is effective when managing and retrieving information recorded on a magnetic tape.

[0002]

2. Description of the Related Art Conventionally, as a first means for retrieving information recorded on a magnetic tape in a VTR, a method of recording a cue signal by duty-modulating a servo control signal at the beginning of information to be taken out from a magnetic tape. There is. V, the mainstream of so-called home 1 / 2-inch VTRs
This is called a VISS search function of the HS standard, and detects a cue signal (VISS signal) in a fast forward / rewind (hereinafter, referred to as FF / REW) state and shifts to a stop state or a reproduction state.

A second means is a counter search function using a linear time counter function for displaying a count value of a servo control signal. The counter search function corresponds to the beginning of information to be taken out from the magnetic tape in the FF / REW state. When the count value is reached, the state is shifted to the stop or reproduction state.

[0004]

However, in the video tape recorder as described above, a problem in retrieving information recorded on a magnetic tape is that, first, in any case, the current absolute position of the magnetic tape is unknown. For this reason, the magnetic tape must be rewound to the beginning before the search, and the information to be searched cannot be obtained quickly. Secondly, in order to remember what was recorded on the magnetic tape, index information such as a title and the count value in the case of the counter search function are stored, or the magnetic tape is stored in a label or the like. Must be attached to a cassette. Furthermore, in order to avoid forgetting to read or erroneously erasing the information recorded for the above reasons, only one piece of information is often recorded on one tape, which has reduced the use efficiency of the tape.

[0005] In order to solve the above-mentioned problems, a function of writing / reading a cue signal to / from a magnetic tape and cueing information recorded on the magnetic tape is provided.
Cassette identification means for identifying an inserted cassette; information acquisition means for inputting or collecting index information on information to be recorded; remaining amount detection means for detecting remaining amount information of a magnetic tape stored in the cassette; Memory means for storing information from the identification means, information acquisition means, and remaining amount detection means; writing means for writing the information to the memory means at the start or end of recording; and cassette identification information from the cassette identification means. Reading means for reading out the index information and the remaining tape information from the memory means based on the information; signal processing means for converting the index information read by the reading means into a video signal and outputting it to a monitor; Program selection means for selecting information to be reproduced; Comparing the current residual tape amount information detected by the tape remaining amount information and the remaining amount detecting means corresponding to the selected information by means, fast-forward on the basis of the result /
A VTR having a program search means for performing rewinding or cueing and a reproduction means for reproducing recorded information on a magnetic tape and outputting it to a monitor when a cue signal is detected by this program search means have already been proposed. Although automatic reading using a bar code is conceivable as cassette identification means, the insertion speed of the cassette into the VTR is unstable due to variations in mechanical load, differences in mass between various cassettes, and the effects of human operations. Therefore, it is difficult to read a barcode, and at present, a method of manually inputting a cassette number to a user when a cassette is inserted is generally used.

However, not only is it extremely difficult to use from the viewpoint of operability, but there is a high risk that the data will not be registered in the memory means due to an input error or forgetting to be input, or the stored data will be destroyed. There was such a problem.

[0007]

In order to solve this problem, a video tape recorder according to the present invention employs a first bar code of a specific pattern and a second bar code in which a cassette number for identifying a cassette is encoded. Is attached to the cassette, and the first bar code is attached to the wall of the cassette insertion slot.
A first sensor for detecting a bar code, a second sensor for detecting a second bar code, and cassette identification means for identifying a cassette inserted based on output signals of the two sensors. .

[0008]

According to the present invention, a highly reliable cassette number can be identified by reading the second bar code based on the first bar code even if the speed of inserting the cassette into the VTR is unstable. This makes it possible to improve the disadvantage of random access, which has been the biggest problem of the conventional VTR in management and retrieval of a plurality of pieces of information recorded on a plurality of cassette tapes.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a video tape recorder according to the present invention.
And a rotary drum 3 for driving a rotary head (not shown) for recording and reproducing information on and from a magnetic tape 2
And a supply reel (hereinafter, referred to as an S reel) 4 for sending out the magnetic tape 2 at the time of reproduction or fast-forward, and a take-up reel (hereinafter, referred to as S reel) at which the magnetic tape 2 is wound at the time of reproduction or fast-forward.
A supply reel rotation speed detector (hereinafter, referred to as an S reel rotation speed detector) 6 for detecting the rotation speed of the S reel 4, and a winding for detecting the rotation speed of the T reel 5. A side reel rotation speed detector (hereinafter, referred to as a T reel rotation speed detector) 7, a control head 8 for recording and reproducing servo control signals, and two types of barcodes for identifying cassette numbers are printed. A bar code label 9, two photo sensors 10 and 11 for reading the two bar codes, a control signal recording / reproducing circuit 12 for writing and reading a cue signal to / from the magnetic tape 2 via a control head 8, a VTR, F
A tape drive circuit 13 for driving a capstan motor (not shown) or a reel motor (not shown) for transferring the magnetic tape 2 according to the F / REW state or the reproduction state; A key input device 14 for operating a VTR or the like;
A static random access memory (hereinafter referred to as SRAM) 15 which stores index information and remaining tape information relating to information to be recorded together with the barcode information detected in 1 and is backed up by a battery (not shown) at the time of power failure; An on-screen display circuit (hereinafter referred to as an OSD circuit) 16 for displaying index information stored in the SRAM 15 when necessary, a video signal processing circuit 17, a monitor 18, and a microcomputer 19 for controlling the above system And the whole is constituted.

FIG. 2 is a schematic diagram showing a state in which the cassette 1 is inserted into the VTR main body 20. When the magnetic tape 2, ie, the cassette 1 is inserted into the VTR main body 20, the cassette 1 is inserted.
The two barcodes printed on the barcode label 9 affixed to the upper surface of each of the two photosensors 10,
By reading by the microcomputer 11, the microcomputer 19 first recognizes which cassette has been inserted. In other words, since the cassette 1 has the bar code label 9 in which the cassette number is coded, the cassette can be specified by decoding the bar code.

FIG. 3 is a pattern diagram of two barcodes printed on the barcode label 9, which is composed of two types of bars, wide and narrow. The first barcode 91 is a reference barcode having a fixed pattern, and has a continuous pattern of narrow bars. Second bar code 9
Reference numeral 2 denotes a data barcode, which is composed of a start bit (section a), a data bit (section b) in which a cassette number is encoded, and a stop bit (section c).
The start bit and the stop bit are each "000
The fixed patterns are "0" and "100". The data bits consist of 10 bits each consisting of five black bars and five white bars, which encode an integer from "00" to "99" in decimal. That is, the tenth digit is encoded by the black bar, and the first digit (Table 1) is encoded by the white bar (Table 1).

[0013]

[Table 1]

As shown in (Table 1), two of the five data bits are always wide, ie, "1", in black and white. In the case of FIG. 3, since the black bar in the data bit section is “01010”, the tenth digit is “9”, and the white bar is “00110”, so the first digit is “0”. Means “90”.

The reason why the reference barcode is provided as shown in FIG. 3 is that, unlike a normal barcode reader, the relative speed change between the barcode and the sensor is very large. That is, as shown in FIG.
When the cassette 1 is inserted into the cassette 1, the human hand intervenes, and the force applied to the cassette 1 and the insertion speed at that time vary widely. The cassette insertion speed is greatly changed by the load, the difference in the mass of the cassette due to various tapes, and the friction or the catch between the cassette and the cassette insertion slot. Therefore, by providing the reference barcode, the insertion speed of the cassette, that is, the relative speed between the barcode and the sensor can be detected, and the wide / narrow discrimination of the data barcode is performed based on the detection result.

FIG. 4 is a flowchart of a software program incorporated in the microcomputer 19 for detecting the bar code and reading the cassette number. The second bar code 92, that is, the second photo sensor for reading the data bar code is shown in FIG. A first external interrupt routine (FIG. 4 (a)) activated by the output signal of FIG.
A second external interrupt routine (FIG. 4B) activated by an output signal of the first photo sensor 10 for reading the first bar code 91, that is, the reference bar code, and a second external interrupt routine built in the microcomputer 19 The timer interrupt routine (FIG. 4C) is started by the overflow of a timer (not shown).

FIGS. 5 and 6 are timing charts for explaining the operation of the software program.
FIG. 6 is a timing chart for explaining a period detection method for decoding the second bar code by measuring the period of the output signals of the two photo sensors 10 and 11. FIG. 6 shows one bit of the output signal of the second photo sensor. FIG. 5 is a timing chart illustrating an edge counting method of decoding a second barcode by counting edges of an output signal of a first photosensor that occurs between the first and second photosensors. The cassette identification means of this embodiment, that is, a method of reading a barcode will be described with reference to FIGS.

FIGS. 5A and 5D respectively show the output signal of the first photosensor reading the first bar code and the second output signal.
5B is an output signal of the second photo sensor which reads the bar code of FIG. 5, and FIG. 5B is built in the microcomputer 19 for measuring a half cycle (multiplication cycle) of the output signal of the first photo sensor. The count operation of the first timer is represented in an analog manner, and FIG. 5E is built in the microcomputer 19 for measuring a half cycle (multiplication cycle) of the output signal of the second photosensor. FIG. 5C shows the count operation of the second timer in an analog manner. C in FIG. 5 is a bit count value obtained by counting the edges of the output signal (D in FIG. 5) of the second photosensor.
Sections a, b, and c of FIG. 5 correspond to a, b, and c of FIG. In this embodiment, the reference bar code has the same width as the narrow bar of the data bar code as shown in FIG. 3, and the ratio of the wide bar to the narrow bar of the data bar code is 5: 2.
In the normal case, every time an edge of the output signal of the first photosensor occurs, a value obtained by multiplying the detected half cycle by 1.5 times is obtained as a threshold value, and the wide bar of the data bar code is obtained. And narrow bars. For example, one of the reference barcodes measured at point r9 in FIG.
The bit period, that is, the count value n9 of the timer 1 is set to α (=
1.5) The multiplied threshold value is obtained, and the magnitude of the 1-bit cycle of the data barcode measured when the next edge of the output signal of the second photosensor occurs and the threshold value obtained earlier are determined. That is, a 0/1 judgment is made.

As described above, 0/1 judgment is performed for all the bits of the data barcode, and the data bits are decoded after checking the start bit and the stop bit. The above is the basic algorithm of the cycle detection method.

Next, the edge counting method will be described with reference to FIG. A, C, and D in FIG. 6 are the same signals as A, C, and D in FIG. 5, and A 'and D' in FIG.
When the bit count value of “7” and “14”, that is, d7
It is a partial enlarged view of A and D at point d14. I in FIG.
Is an edge count value obtained by counting the edges of the first sensor output signal existing between the edges (1 bit) of the second sensor output signal, provided that the section indicated by the oblique lines A 'and D' in FIG. T0 [m from the edge of the second sensor output signal
During the period up to S], the above counting is prohibited. This is because the edge positions of the two sensor output signals are shifted back and forth due to variations in the mounting positions of the photosensors 10 and 11 and printing displacement of the two barcodes. By providing this prohibition period, in the case of the barcode of the present embodiment, the edge count value of the narrow bar becomes only “0” or “1”,
Since the edge count value of the wide bar is always "2" or "3", 0/1 determination is possible. The rest is the same as the above-described cycle detection method, and the description is omitted.

Next, the flowchart of the software program incorporated in the microcomputer 19 shown in FIG. 4 will be described first with reference to the second external interrupt routine shown in FIG. 4B.

This routine is started at the output signal edge of the first photo sensor 10 for reading the first bar code 91, that is, the reference bar code. First, in the processing block 37, as shown in FIG. After the count value of the first timer is fetched, it is cleared.
Therefore, the captured count value corresponds to a cycle between edges of the first photosensor output signal, that is, a multiplication cycle. Next, in the branch 38, it is determined whether or not the count value of the first timer is larger than a preset count value t1. If it is smaller, the process proceeds to a processing block 39. As a threshold, the count value of the first timer fetched in the processing block 37 is multiplied by a coefficient value (= 1.5). The count value of the first timer fetched in the processing block 37 is used as the threshold value. That is, the fact that the count value of the first timer is larger than the predetermined value t1 means that the insertion of the cassette is stopped for a moment for some reason, and the stop period is just offset with respect to the two bar codes. That is, the coefficient value approaches “1”.

In this embodiment, the predetermined value t1 is divided into two cases. However, in order to further improve the accuracy, it is easily analogized that the cases may be divided into three or more cases and the coefficient values may be set stepwise. it can. Next, in the branch 41, the current count value of the first timer that measures a half cycle (multiplied cycle) of the output signal of the second photosensor 11 for reading the data barcode by the cycle detection method is set in advance. The magnitude is discriminated from the set count value t0, and if it is larger, the process proceeds to the processing block 42, and the edge count value is incremented by "1", but if it is smaller, the edge count value is not incremented. This corresponds to A 'and D' in FIG.
And the description is omitted.

The second external interrupt routine is completed as described above. Here, the calculation of the threshold value in the cycle detection method and the edge counting operation of the reference barcode in the edge counting method are performed.

Next, the first external interrupt routine shown in FIG. 4A will be described. This routine is started at the output signal edge of the second photo sensor 11 for reading the second bar code 92, that is, the data bar code.
After taking in the count value of the second timer as shown in E of FIG.

Therefore, the fetched count value corresponds to a cycle between edges of the second photosensor output signal, that is, a multiplication cycle.

Next, in the branch 23, it is determined whether the measured bar code is a black bar or a white bar. Wide / narrow determination, that is, 0/1 determination is performed based on the threshold value obtained in the processing block 39 or 40 of the second interrupt processing routine. Then, in the processing block 25, the wide / narrow determination, that is, the 0/1 determination is performed based on the edge count value counted in the processing block 42 of the second interrupt processing routine by the edge counting method.

In the case of a white bar in the branch 23, the processing shifts to the processing block 26, where the count value detected in the processing block 22 by the cycle detection method and the threshold value obtained in the processing block 39 or 40 of the second interrupt processing routine. , A wide / narrow determination, that is, a 0/1 determination is performed. Then, in a processing block 27, a wide / narrow determination, that is, a 0/1 determination is performed by the edge counting method based on the edge count value counted in the processing block 42 of the second interrupt processing routine. That is, the processing block 24 and the processing block 25 separately determine the bit of the black bar, and the processing block 26 and the processing block 27 separately determine the bit of the white bar.

Then, in the processing block 28, the bit count value is incremented by "1" as shown in FIG. 5 and FIG. 6C, and it is checked in the branch 29 whether the bit count value is "18". If "18"
If all bits have been input, branch 3
In 0 and the branch 31, the start bit and the stop bit shown in F of FIG. 5 are checked. Here, it is sufficient that at least one of the discrimination results by the two methods of the cycle detection method and the edge counting method is “OK”.

In the processing block 32, data bits are firstly decoded by the period detection method based on (Table 1), and if an error occurs, the data bits are decoded by the edge count method. As a result, even if data bits cannot be detected properly by the cycle detection method that is weak against the cassette insertion speed fluctuation, backup is performed by the edge count method that is strong against the cassette insertion speed fluctuation.

Then, the bit count value is cleared in the processing block 33 to prepare for the next input.
Finally, in the processing block 34, the edge count value of the edge count method is cleared to complete the first external interrupt routine.

Finally, the second timer interrupt routine configured in FIG. 4C will be described. This routine is built in the microcomputer 19 and is started by an overflow of a second timer for measuring a period between edges of the second photosensor output signal, that is, a multiplication period. It is cleared and the barcode header is detected.

As described with reference to the timing charts of FIGS. 5 and 6 and the flowchart of FIG. 4, the present invention improves the recognition rate by reading a bar code by using two methods, a period detection method and an edge counting method. Is being planned.

The operation of the VTR constructed as shown in FIG. 1 on the basis of the cassette number thus identified will be described in detail below.

First, at the time of recording, the microcomputer 1
Reference numeral 9 denotes index information on information to be recorded and remaining tape information at the start of recording together with the identified cassette number.
It is stored in the RAM 15. The index information is information that allows the content of information to be stored, such as the recording date, recording start time, channel number of the tuner, and title name, to be recognized later. The tape remaining amount information is for storing where information to be recorded is recorded on the tape. For example, by measuring the rotation period of the S reel 4 and the rotation period of the T reel 5, for example, This is the remaining time of the tape from the recording start position to the end of the tape.

Further, the microcomputer 19 controls the control signal recording / reproducing circuit 1 shown in FIG.
The start signal so-called VISS signal obtained by duty-modulating the control signal by the control signal 2 is recorded on the magnetic tape 2.

The above operation is performed for each series of recording operations, that is, the cassette number, index information, and remaining tape information are stored in the SRAM 15 for each program (hereinafter, referred to as a program), and the cue signal is output. The information is recorded on the magnetic tape 2. Of course, if another cassette is inserted,
A cassette number corresponding to the bar code attached to the cassette is stored.

The case where the tape recorded as described above is reproduced will be described below. First, insert the cassette 1 into the VTR 20
As described above, the microcomputer 19 first recognizes which cassette has been inserted by reading the bar code label 9 attached to the side surface of the cassette 1 with the two bar code readers 10 and 11 as described above. Then, the index information corresponding to the detected cassette number is read out from the SRAM 15, and the OSD circuit 16
Monitor screen 18 by video signal processing circuit 17 through
Display above.

FIG. 7 shows an example of the display.
The cassette number of the cassette inserted in R is "5", and a total of five programs (programs) are currently recorded on this tape. For example, the program of program number 1 is 9 pm on October 20. It is a 6-channel Western movie theater recorded at that time, and the program of program number 2 is a 10-channel drama recorded at 7:00 pm on October 25.

The monitor screen 1 is operated by the operation keys 14.
When the VTR is set to the reproduction mode after selecting the program number on 8, the program selected by the software program incorporated in the microcomputer 19 is searched, and then the reproduction mode is automatically set. Also,
When the cassette is not inserted or when it is desired to search the contents of the cassette different from the inserted one, the cassette identification information is inputted from the outside by the key input device 14 or the like, and the index information corresponding to the cassette identification information is obtained. When the cassette 1 is inserted after the program is displayed on the monitor screen 18 and the program is selected in the same manner as in FIG. 7, the selected program is searched for by the software program incorporated in the microcomputer 19, and the reproduction state is automatically set. Become.

[0041]

As is clear from the above description, the video tape recorder of the present invention comprises two barcodes of reference and data, and two barcode detecting means having different characteristics of a period detecting method and an edge counting method. Adopting this makes it possible to identify cassettes with a high recognition rate, dramatically reducing the drawback of random access, which was the biggest problem of conventional VTRs in managing and searching for multiple pieces of information recorded on multiple cassette tapes. In addition to the improvement, it is also possible to improve the use efficiency of the magnetic tape.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a video tape recorder of the present invention.

FIG. 2 is a schematic view showing a state where a cassette is inserted into the VTR main body of the embodiment.

FIG. 3 is a pattern diagram of a barcode printed on a barcode label of the embodiment.

FIG. 4 is a flowchart of a software program incorporated in a microcomputer for detecting a barcode and reading a cassette number according to the embodiment.

FIG. 5 is a timing chart illustrating a period detection method according to the embodiment.

FIG. 6 is a timing chart for explaining an edge counting method according to the embodiment;

FIG. 7 is a display screen diagram showing a monitor screen display example of the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cassette 2 magnetic tape 3 rotating drum 4 supply reel 5 take-up reel 6 supply-side reel rotation speed detector 7 take-up reel rotation speed detector 8 control head 9 barcode label 10 first photosensor 11 second Photosensor 12 Control signal recording / reproducing device 13 Tape drive circuit 14 Key input device 15 SRAM memory 16 On-screen display circuit 17 Video signal processing circuit 18 Monitor 91 First barcode 92 Second barcode

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-237244 (JP, A) JP-A-62-200477 (JP, A) JP-A-55-145470 (JP, A) 122982 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 27/10 G11B 15/07 G11B 23/30

Claims (3)

(57) [Claims] 1. A first barcode having a fixed pattern and a second barcode in which a cassette number for identifying a cassette is encoded are attached to the cassette, and attached to a wall of an insertion port of the cassette. A first sensor for detecting the first barcode, a second sensor for detecting the second barcode, and a video tape for identifying a cassette inserted based on output signals of the two sensors
In the recorder, a half rotation of the output signal of the first sensor
First period detecting means for detecting a period, and the second sensor
Second period detecting means for detecting a half period of the output signal of
A first half-period information output from the first period detecting means;
The first half-period information is changed by a coefficient according to the
Reference value generating means for outputting the multiplied first reference value;
Output from a first reference value and the second cycle detection means
The size of the second bar code is determined by comparing with the second half cycle information.
The first card for decoding the cassette number encoded in the code
A video tape recorder comprising: set identification means. 2. A fixed pattern first bar code, comprising:
The cassette number for identifying the set is encoded.
2 is attached to the cassette, and the cassette
The first bar code attached to the wall of the
And a second sensor for detecting the second bar code.
A second sensor to be detected and output signals of the two sensors
Video tape identifying the cassette inserted based on
In the recorder, the edge of the output signal of the second sensor is
The first period occurring during a half cycle except for a predetermined period after the arrival
Counting means for counting the edges of the output signal of the sensor
And the edge count value and a second reference value preset
Is discriminated, and is encoded into the second barcode.
Second cassette identification means for decoding the cassette number
Video tape recorder. 3. A first bar code having a fixed pattern, and a first bar code having a fixed pattern.
The cassette number for identifying the set is encoded.
2 is attached to the cassette, and the cassette
The first bar code attached to the wall of the
And a second sensor for detecting the second bar code.
A second sensor to be detected and output signals of the two sensors
Video tape identifying the cassette inserted based on
In the recorder, a half rotation of the output signal of the first sensor
First period detecting means for detecting a period, and the second sensor
Second period detecting means for detecting a half period of the output signal of
A first half-period information output from the first period detecting means;
The first half-period information is changed by a coefficient according to the
Reference value generating means for outputting the multiplied first reference value;
Output from a first reference value and the second cycle detection means
The size of the second bar code is determined by comparing with the second half cycle information.
The first card for decoding the cassette number encoded in the code
Set identification means, and an edge of an output signal of the second sensor.
The first period occurring during a half cycle except for a predetermined period after the arrival
Counting means for counting the edges of the output signal of the sensor
And the edge count value and a second reference value preset
Is discriminated, and is encoded into the second barcode.
Second cassette identification means for decoding the cassette number
Wherein the first cassette identification means
If the second cassette is not detected,
Specially, use the cassette number obtained from the identification means.
Video tape recorder.