JP3082914B2 - Signal processing device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a signal processing device, and more particularly to a device for processing a signal with a dropout. [Prior Art] Conventionally, a signal with a dropout (lack of signal) such as a signal like a video signal reproduced from a magnetic recording medium such as a magnetic disk or a magnetic tape is once used.
An apparatus has been developed which stores the image data in an image memory and then transmits the image data using a telephone line or the like. In such an apparatus, when it is detected that a dropout has occurred using, for example, an IH delay line by using the correlation of the image in order to compensate for the above-mentioned dropout, the missing part is automatically replaced with the previous line. Some were being replaced with signals. [Problems to be Solved by the Invention] However, in the above-described apparatus, when the degree of dropout is large, for example, when an image of two lines is dropped out, good compensation cannot be performed. There is a problem in that the image signal is deteriorated by performing the operation. SUMMARY OF THE INVENTION It is an object of the present invention to provide a signal processing apparatus which solves such a problem and prevents image information from deteriorating due to the current state of dropout compensation. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides an apparatus for processing an input image signal, wherein a storage means capable of storing at least one screen of the input image signal; Detecting means for detecting an unreproducible portion in the input image signal, output means for performing predetermined processing on the image signal stored in the storage means and outputting the processed signal to the outside of the apparatus, And control means for controlling whether or not the output means outputs the image signal stored in the storage means to the outside of the apparatus on a screen-by-screen basis. [Operation] With this configuration, the output of the image signal is controlled for each screen according to the unreproducible portion in the input image signal. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a circuit when the method of the present invention is applied to a still image transmission device. On the magnetic sheet 10, video signals in units of one field are recorded in the form of concentric tracks. The magnetic sheet 10 is driven to rotate by a motor 15 controlled by a motor drive circuit 14. Motor drive circuit
14 is also controlled by the CPU 12. Reference numerals 16A and 16B denote reproduction heads, which are, for example, in-line heads for performing field reproduction or frame reproduction. The playback head 16A is connected to the A terminal of the switch 18, and the playback head 16B is connected to the switch 1
8 terminal B. The switch 18 is switched by a switching signal from the CPU 12. The output of the switch 18 is supplied to a reproduction process circuit 22 via a reproduction amplifier 20, and the reproduction process circuit 22 generates a reproduction luminance signal (Y) 24, a line-sequential color signal (R / B) 26, and a horizontal synchronization signal (HS). 28, vertical sync signal (V
S) 30, a dropout pulse (DOP) 32 generated in response to the lack of a playback envelope, and a signal 34 indicating whether the playback video signal is color or black and white. The reproduction luminance signal 24 and the line-sequential color signal 26 from the reproduction process circuit 22 are temporarily stored in a memory circuit 36, and the reproduction luminance signal 24 is supplied to a monitor device 40 via an adder 38 for monitoring an image. Is also supplied. The adder 38 includes a monitor device
In order to superimpose the display such as the track number on the video at 40,
A font pattern signal 44 is supplied from a character generator 42. This character generator
42 is the font of the designated character under the control of the CPU 12.
The pattern signal 44 is output. Further, the memory circuit 36 is provided with two field memories M ₀ and M ₁ as shown in Table 1 described later. The horizontal synchronization signal 28, the vertical synchronization signal 30, and the dropout pulse 32 are supplied from the reproduction process circuit 22 to the memory control circuit 46 for controlling the memory circuit 36. 48 is an address bus, 50 is a data bus, and 52 is a control line. A magnetic piece (not shown) is fixed to the magnetic sheet 10 for detecting a rotation phase, and is read by a magnetic head 54. Amplifier
Reference numeral 56 amplifies the output signal (PG pulse) of the magnetic head 54, and the output of the amplifier 56 is used to feed back to the motor drive circuit 14 to control the rotation phase of the magnetic sheet 10, but the memory control circuit 46 And is used for controlling the memory circuit 36. The memory control circuit 46 also includes a control line 58, a data bus 60
And to the CPU 12 via the address bus 62. The playback video signal written from the playback process circuit 22 to the memory circuit 36 is taken into the CPU 12 via the data bus 50, the memory control circuit 46, and the data bus 60, and the CPU 12 sends the video data to the transmission circuit 64. I do. The transmission circuit 64 is a signal form suitable for transmitting the input video data (AM, FM, etc.)
, And sends it out of the output terminal 66 to the transmission path. Various switches for specifying the operation of the CPU 12 are connected to the CPU 12. The up switch 68 instructs the reproducing heads 16A and 16B to move in the increasing direction of the track number, and the down switch 70 instructs it to move in the decreasing direction. Reference numeral 72 denotes a start switch of a transmission operation for transmitting the reproduced video signal written in the memory circuit 36 from the output terminal 66. Reference numeral 74 denotes a transmission stop switch for stopping transmission during transmission. Reference numerals 76, 78, and 80 denote switches for designating the transmission mode. Closing switch 76 designates monochrome field transmission, closing switch 78 designates monochrome frame transmission, and closing switch 80. Specifies color field transmission. Switch 76,78,80
Should be closed only one of them. The switch 82 is used to select a playback mode (field playback or frame playback), and the CPU 12
The switch 18 is continuously connected to either the A terminal or the B terminal, or alternately switched every one field.
Of course, some of these switches 68-82 may be replaced by corresponding flag variables under program control. Reference numeral 84 denotes an LED for indicating that the video signal is being transmitted from the transmission circuit 64. The LED 84 is also used for giving a warning when there is a lot of dropout. FIG. 2 shows an overall routine for starting and ending the head feeding and transmission operation. When the power is turned on,
The transmission flag TX.FLG is reset to "0", and the lighting of the LED 84 is stopped (S2-1). The transmission flag TX.FLG is “1” during transmission, and is “0” when not transmitting. When the up switch 68 is pressed (S2-2), the heads 16A and 16B are sent in the direction of increasing the track number (S2-4), and the CPU
Increment the track number held in 12 (S2
-5). At this time, either the field reproduction or the frame reproduction is selected as the reproduction mode according to the mode selection switch 82. Also, in response to the increment of the track number in step S2-5, the display track number data of the character generator 42 is also changed in order to update the display of the track number on the monitor device 40. If the up switch 68 is not closed in step S2-2, then it is checked whether the down switch 70 is closed (S2-3). If the down switch 70 is closed, step S2 is performed.
Conversely to -4 and S2-5, the head is sent in the direction of decreasing the track number (S2-6), and the track number of the CPU 12 is decremented by 1 (S2-7). The display track number data of the character generator 42 is also changed according to the decrement of the track number. Next, the state of the transmission flag TX.FLG is determined in step S2-8, and if "0", that is, in the non-transmission state, the flow branches to step S2-9 and below. If "1", that is, in the transmission state, step S2-8. Branch to 15 or less. In step S2-9, it is checked whether the transmission start switch 72 has been pressed, and if it has been pressed, the reproduction mode switch 72 has been pressed.
Playback mode and transmission mode switches 76, 78,
According to the transmission mode selected by 80, each signal is frozen (written) to the memory circuit 36 in the section shown in Table 1.
The memory circuit 36 has two field memories M ₀ and M ₁
And has a capacity of 640 pixels in the horizontal direction and 256 scanning lines. Basically, the memory M ₀ is accommodated luminance signal Y, the memory M ₁ the luminance signal or the color line sequential signals R / B are housed. If the playback mode switch 82 specifies a field reproduction, the luminance signal Y is received in the memory M _0, the color only in the memory M ₁ when the transmission mode is the color field mode (switch 80) A line-sequential signal R / B is accommodated. Further, when a case where the reproduction signal is mono reproduction mode is a field monochrome frame mode (switch 78) is specified, it accommodates only the luminance signal of one field worth in the memory M _0. Also when the actual reproduction signal is set at a spite color field transmission mode monochrome does not write anything to the memory M ₁ containing only the luminance signal Y to the memory M _0. If the playback mode switch 82 specifies frame playback, the odd field and the even field are played back repeatedly for each field, but in the example shown, the field that appears after the transmission start switch 72 is pressed is It is being taken in. FIGS. 3 and 4 schematically show how the field memories M ₀ and M ₁ accommodate video signals. Fig. 3 shows color
FIG. 4 shows a state in which field signals are stored, and FIG. 4 shows a state in which luminance signals for two fields of the frame signal are stored. When a video signal is stored in the field memories M ₀ and M ₁ , the memory control circuit 46 directly outputs a drop-out signal from the CPU 12 in accordance with the generation timing of the drop-out signal 32 supplied from the reproduction process circuit 22.
DMA (Direct Memory Access) control of the flag memory. FIG. 5 shows the configuration of the drop-out flag memory in the CPU 12. Flags are assigned to each one bit corresponding to the pixel configuration of the memory circuit 36. The 640th column (the hatched portion in FIG. 5) is provided to increase the retrieval speed of the dropout position. When even one dropout exists in the line, the flag of the 640th column is set. The memory control circuit 46 sets the flag of the corresponding location to "1" in response to the occurrence of the dropout, and sets the bit of the 640th column corresponding to the line where the dropout exists to "1". Returning to FIG. 2, when the memory freeze operation is completed in step S2-10, the dropout compensation routine (S2-11)
go to. FIG. 6 shows a detailed flowchart of this dropout compensation routine. In FIG. 6, first, the number of dropouts generated during the freeze in the dropout number counting routine shown in FIG. 9 is counted from the dropout flag memory in the CPU 12 (S6-1). Next, the dropout number counting routine is described in ninth embodiment.
This will be described with reference to the drawings. In FIG. 9, first, the dropout counter value CNT is reset to 0 (S9-0), the number of vertical lines Y is reset to 0 (S9-1), and X is checked to check for the presence of a dropout in the line. 640 (S9-2) It is checked whether the flag F (X, Y) in FIG. 5 is "1" or "0" (S9-3). If it has been reset, the process branches to step S9-9. If it has been set, X is reset to 0 (S9-9) to retrieve the position of the dropout in the line. Check whether X, Y) is “1” or “0” (S9-1)
0). If "0", the process proceeds to step S9-7. If "1", the dropout counter CNT is incremented by one (S
9-6). Next, X is incremented by 1 (S9−
7) The above operation is repeated until the last horizontal address 639 (S9-8). When compensation for one line is completed, Y is incremented by 1 (S9-9), and step 9-2 is performed until the last line 255 is reached.
Steps 9-9 are repeated (S9-10). In this way, when the number of dropouts on the memory is counted in step S6-1, it is determined whether or not the count value CNT is equal to or more than a certain number (S6-2). If it is below a certain level,
The process branches to S6-7. At this time, the fixed number may be appropriately determined, for example, a value corresponding to the length of two lines. In step S6-3 and subsequent steps, it is determined that the number of dropouts is larger than a constant, that is, a low-quality image signal.
Performs a warning action by blinking the BUSY LED84 (S
6-3). Next, the timer is started (S6-4),
If the transmission start switch 72 is turned on again within a predetermined time (S6-5), the flow branches to step S6-7 to perform the dropout compensation operation described in detail in FIG. Wait (S6-6). Therefore, even if there are many dropouts, the transmission operation can be performed if the user turns on the transmission start switch 72 with priority given to the transmission operation. If the transmission start switch 72 is not pressed even after the lapse of the predetermined time, the flow returns to step S2-1 to be in the initial state. If the dropout is less than the predetermined number in step S6-2, dropout compensation is automatically performed (S6-7) and the transmission operation starts. FIG. 10 is a detailed flowchart for explaining the dropout compensation operation in step S8-6 in FIG. In FIG. 10, first, the vertical position variable Y is reset to 0 (S10-1), and the horizontal position variable X is set to 640 (S10-2) to check for the presence of a dropout in the line. It is checked whether the indicated flag F (X, Y) is "1" or "0" (S10-3). Step S10 if reset
The process branches to -9, and if set, X is reset to 0 (S10-9) to search for the position of the dropout in the line, and the flag F (X, Y) at that time is set to "1". Or "0" (S10-10). If “0”, step S10
If “1” is set to −7, the average value of the data of the upper and lower lines ΔM (X, Y−1) + M (X, Y +
1) Calculate｝ / 2 and rewrite it as the corresponding address data M (X, Y) of the memory circuit 6 as compensation data (S
10-6). The compensation operation is not limited to this, and another interpolation method may be used. Next, the horizontal position variable X is set to 1
The above operation is repeated until the last horizontal address 639 (S10-8). When the compensation of one line is completed, Y is incremented by 1 (S10-9), and the step S10 is performed until the last line 255 is reached.
The operation of step S10-9 is repeated to -2 (S10-10). When such an operation is performed for all the 256 lines, the process proceeds to step S2-12 in FIG. In step 2-12, a parameter I for deciding whether or not to transmit two fields of data as a transmission mode, and other variables are initialized. As shown in Table 1, when sending only data D ₀ is when sending _{I = 0, D 0, D} 1 to I = 1. Further, the variable i for starting transmission from the first field is cleared to zero. Further, the address (X, Y) for reading data from the field memory is reset to (0, 0). X is a horizontal pixel column number from 0 to 639, and Y is a vertical pixel row number from 0 to 255. After initializing the transmission parameters, set the transmission flag TX.FLG (S2-13), clear the flag IRQ.MSK to disable transmission interrupts to start transmission, enable interrupt acceptance, and turn on the LED84. , Indicating that transmission is in progress (S2-14). On the other hand, if TX.FLG is set in step S2-8 to indicate that transmission is in progress, the transmission stop switch 74 is set.
It is checked whether or not is pressed (S2-15). If it is not pressed, the process goes to step S2-2. If it is pressed, IRQ and MSK are set, and the subsequent interrupts are disabled (S2-16), TX.FLG is cleared, and the lighting of the LED 84 is stopped (S2-16). −17), Step S2
Return to -2. FIG. 7 shows a flowchart of an interrupt routine for transmission. When the interrupt is started, the transmission data Di (X,
Y) is formed from the memories M ₀ and M ₁ (S7-1). i is 0 or 1, and as shown in Table 1, D ₀ is the luminance signal or G signal at the time of field transmission, or the first signal at the time of frame transmission.
A field luminance signal Y _0, D ₁ is the color field transmission mode of the RB signal, or frame transmission mode the second time
This is the field luminance signal YE. Incidentally, Table 1 of M 'is obtained by the pseudo-frame to extend the frame luminance signal reproduced field, even in exactly the same contents as the memory M _0, it may be an average of about 2 lines. FIG. 8 shows how signals are accommodated in the transmission mode of the color field mode. In particular, the R and B signals are time-division-transmitted by 1H as shown in FIG. 8 (b). M ₁ ′ is obtained by converting the line-sequential color signal stored in the memory M ₁ for time division transmission. R / 2 and B / 2 are obtained by thinning out the signal data of the line where R and B exist as shown in FIG.
R ′ / 2 and B ′ / 2 are obtained by interpolating the R signal thinned out line-sequentially by some method and similarly thinning out the R signal every other pixel. Interpolation methods include pre-value interpolation that makes them exactly the same as R and B, average interpolation of upper and lower R and B lines, and the like. M ₀ , M ₁ → G in Table ₁ indicates that a G signal is calculated from Y, R / B, and can be obtained by G = (Y−0.30R−0.11B) /0.59. The missing R signal or B signal in the line sequence may be obtained by some interpolation method. When the transmission data Di (X, Y) is obtained in this way, it is supplied to the transmission circuit 64. (S7-2), converted into a transmission signal form, and output from the output terminal 66. When the transmission of one data is completed, the horizontal address X is incremented by 1 (S7-3). If the result is equal to or smaller than the maximum horizontal address value 639 (S7-4), the interrupt is terminated. If it is larger than 639, it means that data transmission for one line has been completed, so X is reset to 0 (S7-5) and the vertical address Y
Is incremented by 1 (S7-6). If Y is the last line number, that is, 255 or less, the interrupt is terminated (S7
-7) If it is larger, Y is reset (S7-8), and the variable i representing the number of transmission fields is incremented by 1 (S7-9). The variable i is compared with a parameter I representing the number of transmission fields (S7-10). If it is less than I, the interrupt is terminated, and if it is larger than I, the transmission of the predetermined field has been completed. To disable the subsequent interrupts (S7-11), and reset the transmitting flag TX.FLG to 0 (S7-12). In the above-described embodiment, if it is determined in step S6-2 that there is a dropout exceeding a predetermined amount, a warning is immediately issued in step 6-2. However, the dropout count operation performed in step 6-1 is performed a predetermined number of times. The warning operation may be performed only after the execution. That is, not only the recording sheet but also various recording media such as an optical recording medium causes a dropout due to a change in the distance between the head and the medium or dust or jitter on the medium. May change. Therefore, even if the freeze-out operation of writing the video signal for one screen to the memory is performed once, even if the drop-out often occurs, the degree of the drop-out occurring in the next freeze operation can be sufficiently reduced. obtain. Therefore, repeating the freeze operation a predetermined number of times as described above is very effective in practice. Next, an embodiment for performing such an operation will be described with reference to FIG. FIG. 11 shows a flow chart that replaces FIG. In FIG. 11, steps performing the same operations as those shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, step S2-- shown in FIG.
A step is provided between 9 and S2-10 to reset the counter K. If there is more than a predetermined number of dropouts in step S6-2, the counter K is incremented in step S6-10, and the value of the counter K is incremented by a predetermined number, for example, five.
It is determined whether or not it indicates that the freeze operation has been tried (S6-10).
After waiting only for TA (S6-9), the process returns to step S2-10 to perform the freeze operation again. The reason for waiting for a predetermined time is to avoid the previous freeze as much as possible since the previous freeze may have been adversely affected by the jitter of the magnetic sheet reproducing unit. If the dropout does not disappear even after the predetermined number of freezes in step S6-8, it is determined that the magnetic sheet is defective, and the TX BU
The SY LED 14 blinks and a warning is displayed (S6-3). In the above embodiment, the transmission data is the G, R / B signal in the case of the color signal field transmission, but is not limited to this, and may be the Y and (RY) / (BY) color difference signals. The present invention is applicable. Further, in the present embodiment, the number of dropouts is simply counted by the flow shown in FIG. 9, but if any dropout having a predetermined length or more is present, a warning is issued because it is visually significant. You may do. Further, even when a dropout occurs in an adjacent line, a warning may be issued because interpolation from upper and lower lines is impossible. In the present embodiment, in the embodiment shown in FIG. 6, a warning is issued by executing steps S6-5 and S6-6, and if the transmission start switch 72 is pressed again within a predetermined time, the transmission is performed. However, the transmission is not limited to this. If the dropout is larger than a predetermined amount, the transmission may be automatically performed if the transmission stop switch 74 is not pressed within a predetermined time. Transmission may not be possible once a warning is issued. Also, in this embodiment, when a warning is issued when a lot of dropouts occur during a freeze, the TX BUSY LED 84 indicating that transmission is being performed is blinked, so a special display is provided for such a warning. The structure can be simplified without using an element. Further, in the embodiment described above, the dropout of the video signal reproduced from the recording medium is detected. However, the present invention is not limited to this, and any apparatus that processes a signal accompanied by a dropout can be applied. [Effects of the Invention] As described above, according to the present invention, an output operation of an image signal is controlled in units of a screen according to a non-reproducible portion in an input image signal, so that an unsightly screen image signal is output. Can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an image transmission apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart of a basic algorithm of a transmission sequence of the apparatus of FIG. 1, FIG. FIG. 4 is a diagram showing the data storage state in the image memory, FIG. 5 is a diagram showing the storage state of the dropout flag memory, FIG. 6 is a flowchart of the dropout detection / compensation routine, and FIG. FIG. 8 is a diagram showing a transmission mode in the color field mode, FIG. 9 is a diagram showing details of the dropout number counting routine shown in FIG. 6, and FIG. 10 is a diagram in FIG. 11 is a diagram for explaining the dropout compensation operation shown in FIG. 11, and FIG. 11 is a diagram showing another example of FIG. 10 ... magnetic sheet, 12 ... CPU, 15 ... motor, 16A, 16B ... reproduction head, 18 ... switch, 22 ... reproduction process circuit, 24 ... reproduction luminance signal (Y), 26 ... line Sequential color signal (R / B), 28 Horizontal sync signal (HS), 30 Vertical sync signal (VS), 32 Drop-out pulse (DOP), 44 Font pattern signal, 48 Address bus, 50: Data bus, 52: Control line, 58: Control line, 60: Data bus 60, 62: Address bus, 66: Output terminal, 68: Up switch , 70 …… Down switch, 72 …… Transmission start switch, 74 …… Transmission stop switch, 76 …… Monochrome field transmission designation switch, 78 …… Monochrome frame transmission designation switch, 80 …… Color field transmission Designated switch, 82: Playback mode selection switch, 84: L ED.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-120378 (JP, A) JP-A-61-61580 (JP, A) JP-A-58-109954 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G11B 20/02 H04N 5/94

Claims (1)

(57) [Claims] An apparatus for processing an input image signal, a storage unit capable of storing at least one screen of the input image signal, a detection unit configured to detect a non-reproducible portion in the input image signal, and an image signal stored in the storage unit An output unit that performs predetermined processing on the image data and outputs the image signal to the outside of the device. And a control means for controlling the control on a screen-by-screen basis. 2. The signal processing device according to claim 1, wherein the input image signal is an image signal reproduced from a recording medium. 3. The control means outputs the image signal stored in the storage means when the number of pixels corresponding to an unreproducible image signal in one screen in the input image signal is smaller than a predetermined number, and The signal processing device according to claim 1, wherein the output unit is controlled so as to prohibit the output of the image signal stored in the storage unit in the case described above. 4. An apparatus for processing an input image signal, comprising: a storage unit capable of storing at least one screen of the input image signal; a detection unit configured to detect a ratio of a non-reproducible portion in the input image signal in units of one screen; Control means for controlling whether or not the image signal stored in the storage means is output to the outside of the apparatus in units of one screen according to the output of the detection means. 5. The control unit, when the number of pixels corresponding to an unreproducible image signal in one screen in the input image signal is smaller than a predetermined number, permits the output of the image signal stored in the storage unit. The signal processing device according to claim 4, wherein output of the image signal stored in the storage unit is prohibited when the number is equal to or more than a predetermined number.