JP2564820B2 - Dropout information management method and image data processing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dropout information management method and an image data processing device for efficiently managing dropout information in order to compensate for dropouts occurring in image data. .

[Conventional technology]

A device that temporarily stores a reproduced signal in a field memory or a frame memory for various image signal processing as a device for recording image data on a magnetic tape, a magnetic disk, an optical disk, etc., and reproducing as needed becomes widespread. Is proposed, and a method of performing drop-out compensation of an image signal in the state where the image signal for one screen is accommodated in the memory is also proposed.

As one of such drop-out compensation methods,
The following applicant has applied for a patent for the following method by the same applicant as this application. That is, a flag memory indicating whether or not a dropout has occurred for each horizontal line of the image signal is added to the image memory capable of accommodating the image signal for one field or one frame, and all of them are first detected by the dropout detection routine. The presence / absence of dropout is detected for the horizontal line of, and for the line where dropout is detected, the corresponding storage location of the flag memory is set, and specific data (for example, "F
F ") is then embedded, and in the next dropout compensation routine, the set state of the flag memory is checked, the pixel of the specific data of the line in which the flag is set is searched, and the pixel in the line above or below or adjacent to that pixel is detected. Alternate data is selected and formed by the other pixels that perform the dropout compensation.

[Problems to be solved by the invention]

However, in this compensation method, more specifically, in the method of storing and managing the information indicating the dropout pixel, in the dropout compensation routine, first, after finding the line in which the dropout flag is set, In order to know the pixel in which the actual drop-out has occurred, it is necessary to search only the number of constituent pixels of one line at the maximum to find the specific data. For example, if a dropout occurred in the last pixel of one line,
Since the presence or absence of the specific data is checked for all the pixels for one line, it takes a very long time to actually perform the dropout compensation.

Therefore, it is an object of the present invention to provide a dropout information management method and an image data processing device capable of efficiently discovering pixel data in which dropout occurs when executing dropout compensation of image data. To do.

[Means for solving problems]

The management method of dropout information according to the present invention is m
An image to be input by dividing image data for one screen composed of (m is a positive integer) pixel data for each n (n is a positive integer of n <m) pixel data and inputting The data is stored in the memory, and it is detected for each of the n pixel data that constitutes the input image data whether or not a dropout has occurred in the n pixel data, and the detection result is displayed. Generate the dropout information data shown,
The image data is stored in an area other than the area in which the image data is stored.

The image data processing apparatus according to the present invention is capable of converting image data for one screen constituted by m (m is a positive integer) pixel data for every n (n is a positive integer of n <m) pixel data. An image data inputting unit for dividing and inputting the image data, and a first storing the image data input by the image data inputting unit
With respect to the image data input by the memory means and the image data input means, is there a dropout in the n pixel data for each of the n pixel data forming the image data? Dropout detection means for detecting whether or not the dropout information data is generated, and second memory means for storing the dropout information data generated by the dropout detection means. Characterize.

[Action]

With the above-mentioned means, it is possible to quickly know where n pixel data in the input image data has the dropout based on the content of the dropout information data. As a result, the time required to detect pixel data in which dropout has occurred can be shortened, and dropout compensation can be speeded up as a whole.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment in which the present invention is applied to a reproducing system of image data recorded on a magnetic sheet according to the present invention.

In FIG. 1, the image signal reproduced by the reproducing head 102 from the magnetic sheet 100 is supplied to the reproducing process circuit 106 via the reproducing amplifier 104. Regeneration process circuit 106
Performs a known signal reproduction process on the input image signal according to the recording signal format and the output signal format thereof, and outputs various video signals such as a luminance signal, a color difference signal, and a chromaticity signal. In the following description, it is generically called a reproduced video signal. Regeneration process circuit
The 106 also separates and outputs a horizontal sync signal H _sync and a vertical sync signal V _sync from the input signal, and generates a dropout pulse for pixels in which dropout has occurred. Dropout can be detected, for example, from the envelope of the input signal. Reference numeral 108 denotes a clock circuit that generates a reference clock that defines the operation timing of the illustrated circuit.

Reference numeral 110 denotes an A / D converter that converts a reproduced video signal that is an analog signal into a digital signal, and 112 generates specific data (hexadecimal FF in the illustrated example) as a mark of a pixel in which dropout has occurred. Fixed data generator, 11
Reference numeral 4 is a memory for accommodating a digital video signal for one field (or one screen). In this embodiment, the video data is 640 pixels in the horizontal direction and 256 pixels in the vertical direction, as shown in FIG. , And an area 114B (hatched portion) for accommodating the dropout information for each horizontal line. Reference numeral 116 is an address generation circuit that generates an address of the memory 114, and 118 is a circuit that generates dropout information for each horizontal line of a video signal for one screen. A specific example of the dropout information generation circuit 118 is shown in FIG. Reference numeral 120 denotes a switch for replacing the corresponding pixel data with the above-described specific mark data when a dropout occurs, and 122 a switch for supplying dropout information of each horizontal line to the dropout information accommodating area of the memory 114. Is.

In the present embodiment, 640 pixels in the horizontal direction are divided into 8 sections, and a section in which a dropout occurs is indicated by which bit of 8 bits D _{0 to} D ₇ is set. ing. In other words, 8 bits for dropout information
When D _{0 to} D ₇ are allocated and the dropout occurs in the 1st to 80th pixels of the 640 pixels on the corresponding line, the LSB bit D ₀ is used to detect the 81st to 160th pixels. In this case, use bit D ₁ and then every 80 pixels
Use D _{2 to} D ₇ . For example, dropout information area 11
That bit D ₃ of 4A has been set, indicating that the drop-out occurs in the portion of the first 241-320 pixels on corresponding line.

The operation of the circuit of FIG. 1 will be described. Normally, switch 12
0 and 122 are connected so as to lead the output of the A / D converter 110 to the memory 114. The A / D converter 110 receives the playback video signal from the playback process circuit 106 at the freeze clock timing.
After A / D conversion, the address circuit 116 increments the logical horizontal address value to the memory 114 according to the freeze clock. Of course, at this time, the memory 114 is in the write operation state. When a dropout occurs in the reproduced video signal, the switch 120 is switched by the dropout pulse from the reproduction process circuit 106, and the specific mark data from the fixed data generator 112 is sent to the memory 114. The dropout pulse is also sent to the dropout information generation circuit 118, and the bit of the corresponding section in the horizontal direction is set.

At the stage when one horizontal line (that is, 640 pixels) is completed, the dropout information generation circuit 118 is 1 byte indicating which of the eight sections of the one horizontal line the dropout has occurred. Holds (8 bits) data. After the end of one horizontal line, the dropout information generation circuit 118 switches the switch 122 to send the held dropout information to the memory 114. At this time, the address generating circuit 116 outputs the horizontal address value indicated by the hatched portion in FIG. After that, the horizontal sync signal H _sync causes the dropout information generation circuit 118 to clear the dropout information and switch the switch 122 to the switch 120.
Then, the address generator 116 clears the horizontal address and increments the vertical address.

In this way, video data and dropout information are stored in the memory 114 for all 256 horizontal lines for one screen.
When it is accommodated in, the dropout is used to perform processing such as dropout compensation, as will be described later.
The address generation circuit 116 clears the horizontal address and the vertical address according to the vertical synchronizing signal V _sync .

Next, the dropout information generation circuit 118 will be described more specifically with reference to FIG. Reference numeral 124 is a counter for counting the freeze clock. When the count value is ₀ to 79, the output A ₀ is output, when the count value is 80 to 159, the output A ₁ is output, and when the count value is 160 to 239, the output A ₂ is output. Output A ₃ between -319, output A ₄ between 320-399, output A ₅ between 400-479, output 480-559
The A _6, during the 560 to 639 to the output A ₇ to High. Then, when the count value is 640, the output A _{8 is set} to High and the switching signal of the switch 122 is generated. Each output of counter 124 A ₀ , A ₁ , A ₂ , A ₃ , A ₄ ,
A ₅ , A ₆ , and A ₇ are applied to the clock inputs of D flip-flops (D-FF) 142 to 156 via AND gates 126 to 140. AND gates 126-140 are regeneration process circuits
Opened by a dropout pulse from 106.
Therefore, a clock signal is applied to the D-FFs 142 to 156 corresponding to the section to which the pixel in which the dropout has occurred, out of the eight sections in the horizontal direction, and the output Q thereof becomes High.
In the illustrated example, the D-FFs 142 to 156 are of the falling trigger type so that the data can be latched in the D-FFs 142 to 156 even when the dropout occurs in all the pixels in the section.

When the count value of the freeze clock of the counter 124 reaches 640, the dropout information of the horizontal line is latched in the D-FFs 142 to 156, and the switch 122 is switched to the switch 120 side by the switching signal of the output A _8. To D-FF142 ~ 1
By switching to the output side of 56, this dropout information is stored in the storage area 114B of the memory 114.

Next, the operation of compensating for the dropout of the video data in the memory 114 will be described. However, since this compensation operation can be easily realized by program control, it will be described with reference to the flowchart shown in FIG. 4, but it can also be easily realized by hardware. In FIG. 4, a dropout counter (DOPC) is a variable for counting the number of lines in which a dropout is occurring in the information of one screen. First, this DOPC is 0, and the vertical position (address) variable of the memory 114. Set Y to 0 (S4-1, S4-2) and set the horizontal position (address) to check for dropout in the line.
The variable X is set to 640 (S4-3) and the memory value M (X, Y) is 0.
It is checked whether or not (S4-4). If the memory value M (X, Y) is 0, it means that no dropout has occurred for the horizontal line, and the process branches to step S4-18.

When the memory value M (X, Y) is not 0, the DOPC is incremented (S4-5), and when the DOPC is a predetermined value (for example, 10) or more, an LED (not shown) blinks,
Warns the operator of a defective playback system or transmission system (S4-
6, S4-7). Next, 1 is assigned to variables A and B (S4-8),
The logical product of the memory value M (X, Y) and the variable A is calculated (S4−
9). Variable A is which bit of the dropout information is High
The variable B is a variable indicating which of the eight horizontal sections is being investigated. If the result M of the logical product in step S4-9 is 0, pixel 0
Since there is no dropout in the first horizontal section of ~ 79, go to step S4-11. On the contrary, if M is 1, there is a dropout in the horizontal section, the minimum horizontal position X of the horizontal section is calculated (S4-13), and thereafter, X is incremented by 1 and the memory value is increased. It is checked whether or not M (X, Y) is specific mark data (S4-14, S4-15), and if it is specific mark data, it is rewritten with the average value of upper and lower pixel data (S4-16). Then, when all the pixel data of the horizontal section are checked (S4-17), the process goes to step S4-11.

In step S4-11, it is checked whether B is 8 (that is, whether or not all the horizontal sections have been examined), and if it has not reached 8, B is incremented and A is doubled to obtain step S4-1. Return to 9. If B is 8, Y is incremented (S4-18), and if Y is 255 or less, the process returns to step S4-3 to check the next line. If Y becomes 256, it means that all the lines of one screen have been examined, and the compensation routine is ended.

In the above embodiment, 8 bits are prepared as the storage area for the dropout information, the horizontal line of the video signal is divided into 8 sections, and the section is identified by the 8-bit dropout information signal. Is not limited to this, and may be 2 bits or 8 bits or more. In the illustrated embodiment,
Dropout information logically video data storage area 114A
However, the dropout information may be placed in another memory or at a distant address. Of course, adopting the logical arrangement of FIG. 3 simplifies the hardware configuration.

FIG. 5 shows an example of a circuit when the method of the present invention is applied to a still image transmission device. Reference numeral 10 is a magnetic sheet 10, 14 on which a video signal of one field unit is recorded by forming concentric tracks, and 15 is a motor drive circuit, and 15 is a motor. The motor drive circuit 14 is controlled by the CPU 12. 16A and 16B are reproducing heads, which are, for example, in-line heads and perform field reproduction or frame reproduction. The reproducing heads 16A and 16B are selected by a switch 18 which is switched by a switching signal from the CPU 12. The output of the switch 18 is supplied to the reproduction process circuit 22 via the reproduction amplifier 20, which reproduces the reproduction luminance signal (Y) 24, the line sequential color signal (R / B) 26, and the horizontal synchronization signal (HS). 28 、 Vertical sync signal (V
S) 30, a dropout pulse (DOP) 32 resulting from the lack of a playback envelope, and a signal 34 indicating whether the playback video signal is color or black and white.

The head drive mechanism 19 follows the instruction from the CPU 12 to move the head 1
6A and 16B are moved to the target track position on the magnetic sheet 10.

The reproduction luminance signal 24 and the line-sequential color signal 26 from the reproduction process circuit 22 are temporarily stored in the memory circuit 36, and the reproduction luminance signal 24 is also supplied to the monitor device 40 via the adder 38 for monitoring. To be done. A font pattern signal 44 is supplied from the character generator 42 to the adder 38 in order to superimpose a display such as a track number on the image on the monitor device 40. Also, the NTSC encoder 41 uses an adder 38
Output and the line sequential color signal (R /
B) 26, and outputs the NTSC signal to the output terminal 43 under the ON / OFF control signal of the CPU 12.

The memory control circuit 46 controls the memory circuit 36 according to the horizontal synchronizing signal 28, the vertical synchronizing signal 30, the dropout pulse 32 from the reproduction process circuit 22 and a PG pulse described later. 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 the rotational phase, and the magnetic head 54 reads it. The amplifier 56 amplifies the output signal (PG pulse) of the magnetic head 54, and the output of the amplifier 56 is used for feedback to the motor drive circuit 14 to control the rotational phase of the magnetic sheet 10.

The memory control circuit 46 also includes a control line 58, a data bus 60.
Also, it is connected to the CPU 12 via the address bus 62. The reproduced video signal written from the reproduction 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. To do. The transmission circuit 64 is a signal form (AM, FM, etc.) suitable for transmitting the input video data.
Is converted to the output terminal 66 and sent to the transmission line.

Various switches that specify the operation of the CPU 12 are connected to the CPU 12. The up switch 68 is a playback head 16A, 16B
Is instructed to move in the increasing direction of the track number, and the down switch 70 in reverse instructs to move in the decreasing direction. Reference numeral 72 is a start switch for transmission operation, and 74 is a transmission stop switch for stopping transmission during transmission. 7
6,78,80 are switches for designating transmission modes such as monochrome field transmission, monochrome frame transmission, and color field transmission. Only one of the switches 76, 78 and 80 is closed. The switch 82 is for selecting the reproduction mode (field reproduction or frame reproduction), and the CPU 12 accordingly continuously connects the switch 18 to either the A terminal or the B terminal, or 1
Alternate every field. Switch 83 is NTSC
This is a switch for turning on / off the operation of the encoder 41.

Reference numeral 84 is a light emitting diode (hereinafter referred to as transmission busy LED) that indicates that the video data is being sent to the transmission path via the transmission circuit 64, and 86 is the step S4-7 in FIG. The dropout warning LED described.

Operations such as reproduction head feeding and start / end of transmission operation by the circuit of FIG. 5 will be briefly described. When the power is turned on, the transmission flag TX.FLG is reset to "0". The transmission flag TX.FLG is "1" during transmission and "0" when not transmitting. Then, during transmission, the transmission busy LED 84, which is turned on, is turned off, and the warning LED 86 is turned off. Although not shown in FIG. 5, whether or not the magnetic sheet 10 is loaded is detected from the output of a known loading detection device that detects whether or not the magnetic sheet 10 is loaded. -Set the flag IN.FLG to "1". When IN.FLG is set, since the magnetic sheet 10 has been taken out once, the heads 16A and 16B are once moved to the innermost or outermost reference position and the heads 16A and 16B are repositioned.

Depending on the operation of the up switch 68 or the down switch 70, the head increases or decreases in the track number direction.
16A and 16B are sent to increment or decrement the track number held in the CPU 12. The reproduction mode at this time depends on the mode selection switch 82. In order to update the display of the track number on the monitor device 40 in response to the increment or decrement of the track number, the character
The display track number data of the generator 42 is also changed.

If the NTSC switch 83 is on, the NTSC encoder
41 is activated, and if it is off, it is deactivated.

When the transmission start switch 72 is pressed, the reproduction signal is frozen (written) in the memory circuit 36 in accordance with the reproduction mode determined by the reproduction mode switch 82 and the transmission mode selected by the transmission mode switches 76, 78, 80. To do. The memory circuit 36 is composed of two field memories M ₀ and M ₁ .
Each has the capacity shown in FIG. Basically, the memory M ₀ stores the luminance signal Y, and the memory M ₁ stores the luminance signal or the color line sequential signal R / B. At the time of this freeze, the memory circuit 36 and the memory control circuit 46 make the first reproduction signal for each reproduction signal.
The dropout information described in the figure is formed and stored in the memory, and the dropout compensation is performed according to the dropout information.

When the reproduction mode switch 82 specifies field reproduction, the luminance signal Y is stored in the memory M ₀ , and the color is stored in the memory M ₁ only when the transmission mode is the color field mode (switch 80). A line sequential signal R / B is accommodated. However, even though the actual playback signal is monochrome, monochrome frame mode (switch 78)
When is designated, only the luminance signal for one field is stored in the memory M ₀ . When the color field transmission mode is set, only the luminance signal Y is stored in the memory M ₀ .

Playback mode switch 82 after dropout compensation operation
In the format determined by the transmission mode switches 76, 78 and 80, the video data of the memory circuit 36 is sequentially sent out to the transmission path via the transmission circuit 64 by the interrupt processing. During transmission, the transmission flag TX.FLG is set and the transmission busy LE
Turn on D84.

When the transmission stop switch 74 is pressed during data transmission, the transmission interrupt is prohibited and the transmission is stopped.

In the above embodiments, the device for processing an image signal is targeted, but the present invention can be applied to a device for processing an audio signal, for example, and is not limited to an image signal.

〔The invention's effect〕

As described above, according to the present invention, when performing dropout compensation of image data, it is possible to efficiently find pixel data in which dropout has occurred, and perform dropout compensation quickly. A dropout information management method and an image data processing device that can be executed can be presented.

[Brief description of drawings]

FIG. 1 is a structural example of a circuit for carrying out the method according to the present invention,
FIG. 2 is a configuration example of the dropout information generation circuit 118 of FIG. 1, FIG. 3 is an example of a memory arrangement of a video signal and dropout information, and FIG. 4 is a dropout compensation using the dropout information of the present invention. A flowchart, FIG. 5 is a block diagram of an image transmission apparatus as a specific example to which the present invention is applied. 10 …… Magnetic sheet, 15 …… Motor, 24 …… Playback luminance signal (Y), 26 …… Line sequential color signal (R / B), 28 …… Horizontal sync signal (HS), 30 …… Vertical sync signal (VS), 32 ... Dropout pulse (DOP), 44 ... Font pattern signal, 48,62 ... Address bus, 50,60 ... Data bus, 52,58 ... Control line, 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 designation switch, 82 …… Playback mode selection switch, 10
0 …… Magnetic sheet, 102 …… Reproduction head, 104 …… Reproduction amplifier, 106 …… Reproduction process circuit, 108 …… Clock circuit, 110 …… A / D converter, 112 …… Fixed data generation circuit, 1
14 ... Memory, 116 ... Address generation circuit, 118 ... Dropout information generation circuit, 120,122 ... Switch, 124 ...
… Counter, 126-140… And Gate, 142-156…
... D flip-flops

Front Page Continuation (72) Inventor Kazuhiko Ito 770 Shimonoge, Takatsu-ku, Kawasaki City, Inc., Tamagawa Plant, Canon Inc. (56) Reference JP 62-82887 (JP, A) )

Claims (3)

(57) [Claims] 1. Image data for one screen composed of m (m is a positive integer) pieces of pixel data is divided and input for every n (n is a positive integer of n <m) pixel data. Then, the input image data is stored in the memory, and it is detected whether or not a dropout has occurred in the n pixel data for each of the n pixel data forming the input image data. Then, the dropout information data indicating the detection result is generated and stored in an area other than the area of the memory in which the image data is stored. 2. An image for one screen indicated by the image data is
Each has p (p is p = m / k) scanning lines, each of which is composed of k (k is an integer of n <k <m) pixels, and pixel data corresponding to each scanning line. The dropout information management method according to claim (1), wherein k / n bits of dropout information data are generated and stored for each. 3. Image data for one screen composed of m (m is a positive integer) pixel data is divided into n (n is a positive integer of n <m) pixel data and input. Image data inputting means, first memory means for storing image data input by the image data inputting means, and image data inputting by the image data inputting means. Dropout detection means for detecting whether or not a dropout has occurred in the n pixel data for each of the n pixel data that are present, and generating dropout information data indicating the detection result, and the dropout. A second memory means for storing the dropout information data generated by the detecting means.