JP3158681B2 - Video signal recording device - 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 signal recording apparatus having a recording function linked to a shutter operation.

[0002]

2. Description of the Related Art As a device for recording a video signal on a recording medium, for example, a magnetic recording medium, for example, a so-called electronic still camera using a so-called still video floppy, a video tape recorder using a magnetic tape, and the like are known.

Specifically, for example, in a so-called 8 mm video tape recorder (hereinafter referred to as an 8 mm VTR), a magnetic tape is wound around a so-called rotating head drum at an angle of 211 degrees, and a pair of heads (hereinafter referred to as a rotating head) at an interval of 180 degrees. The head performs a helical scan on the magnetic tape, thereby forming an oblique track 81 on the magnetic tape 80 as shown in FIG. A video area 82 corresponding to 180 degrees of the rotating head drum of each track 81
Has a luminance signal FM-modulated, a carrier chrominance signal converted to a low frequency, an audio signal FM-modulated, and a tracking signal for tracking servo, for example, a so-called ATF (Au).
tomatic Track Finding) is recorded by being frequency-multiplexed with a pilot signal for control. The remaining rotating head drum of each track 81 is about 3
In a PCM audio area 83 corresponding to 0 degrees, a digital audio signal of 8 bits / sample that has been non-linearly quantized is subjected to a so-called cross interleave code processing for error correction, and then a synchronization signal, parity, ID Are added and recorded. On both sides of the magnetic tape 80, a fixed head scans the cue track 84 and the audio track 85, respectively.
Is formed. The cue track 84 records a cue signal to be used for, for example, the address of a recorded content or the beginning of a recorded content.
ter recording) audio signal is recorded.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-164383, it is necessary to superimpose a title, cast, description, and the like on a moving image recorded in a video area 82 so as to be superimposed. In addition, there is known a technique of photographing a still image such as character information and recording (after-recording) in the PCM audio area 83. Further, the applicant of the present application has disclosed in Japanese Patent Application No. 2-46816 an 8 mm VT.
A proposal has been made in which a digital video signal of one field or one frame is recorded as a still image in the R PCM audio area.

In an 8 mm VTR in which a digital video signal is recorded as a still image in a PCM audio area, various photographing modes can be considered. For example, each time a so-called recording key operation (shutter operation) is performed, one still image data, that is, one image or one frame of a still image to be converted into a digital signal from a video signal for one field or one frame from the image sensor and recorded in the PCM audio area. A shot imaging mode or a still image continuous recording mode in which video signals of a plurality of still images are continuously recorded from the first shutter operation to the second shutter operation, for example, can be considered. Further, in the one-shot imaging mode of the still image, the continuous recording mode, and the like, while recording a still image, an analog video signal continuously obtained from the imaging device is recorded as a video signal of a moving image in a video area. A simultaneous shooting mode of a still image and a moving image in which a digital video signal of a still image is recorded in a PCM audio area can be considered.

[0006]

By the way, in an 8 mm VTR in which a digital video signal is recorded as a still image in a PCM audio area, a PCM audio in which a digital audio signal having a quantization number of 8 bits is recorded at a transmission rate of 500 kbps. When a digital video signal of a still image is recorded in an area, if the digital video signal for one frame is, for example, 7.6 Mbits of a luminance signal and a color difference signal, this 7.6 Mbit digital video signal is used as it is. Recording at a transmission rate of 500 kbps requires 7600/500 = 15.2 seconds (about 900 tracks). Also, the above 7.6 Mbit digital video signal is compressed to 1/4 1.9 Mbit and 500 k
To record at a transmission rate of bps, 1900/500
= 3.8 seconds (about 220 tracks). Further, the 7.6 Mbit digital video signal is converted into 1/6 1.
It takes 1300/500 = 2.6 seconds (approximately 150 tracks) to record at a transmission rate of 500 kbps after compressing to 3 Mbit.

As described above, the time required for recording can be shortened by compressing the digital video signal,
Although a large number of still images can be recorded in the PCM audio area, the image quality deteriorates with the compression rate.
In addition, by recording the digital video signal in an uncompressed state, high image quality can be ensured, but the time required for recording becomes long.

[0008] In addition, since the recording operation of a still image in various image pickup modes is performed in conjunction with the shutter operation,
The shutter operation has to be performed for each photo opportunity, and there is a possibility that the photo opportunity is missed. In addition, by performing the imaging operation in the simultaneous shooting mode of the still image and the moving image,
Even when a photo opportunity is missed, an analog video signal recorded in the video area can be reproduced as a still image, but a high-quality still image cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to reliably record a high-quality still image without missing a photo opportunity by performing a shutter operation at a photo opportunity.

[0010]

In order to solve the above-mentioned problems, a video signal recording apparatus according to the present invention comprises an A / D converter for digitizing an input video signal, and a digital signal converted by the A / D converter. A storage unit for storing the obtained digital video signal, a first signal processing unit for performing signal processing for obtaining a first image quality on the digital video signal read from the storage unit, and a readout from the storage unit. A second signal processing unit for performing signal processing for obtaining a second image quality on the digital video signal obtained, a switching unit for switching the output of the first and second signal processing units, a storage unit and a switching unit And a control unit for controlling the operation of the digital video signal in the first video signal imaging mode, wherein the digital video signal is fetched into the storage unit at predetermined intervals and the first signal processing unit Output Controls the switching unit so that-option,
In the second video signal imaging mode, when a shutter operation is performed, a digital video signal is taken into the storage unit in accordance with the shutter operation, and the second video signal is captured.
The switching unit is controlled so as to select the output of the signal processing unit, and the second image quality is higher than the first image quality.

[0011]

[0012]

In the video signal recording apparatus according to the present invention, the digital video signal read from the storage section is subjected to signal processing for obtaining the first image quality by the first signal processing section. The signal processing unit performs signal processing for obtaining higher quality than the first image quality and obtaining second image quality. In the first video signal imaging mode, the control unit captures the digital video signal into the storage unit at predetermined intervals, controls the switching unit to select the output of the first signal processing unit, and controls the second In the video signal imaging mode, when a shutter operation is performed, a digital video signal is taken into the storage unit in accordance with the shutter operation, and
The switching section is controlled so as to select the output of the second signal processing section.

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a video signal recording apparatus according to the present invention will be described below with reference to the drawings.

In this embodiment, the present invention is applied to a so-called camera-integrated 8 mm VTR (hereinafter simply referred to as VTR). FIG. 1 is a block diagram showing a circuit configuration of a recording system of the VTR.

As shown in FIG. 1, the recording system of the VTR includes an imaging unit 10 for imaging a subject, a moving image video signal processing unit 20 and a still image video signal processing unit 30 connected to the imaging unit 10, It comprises a recording section 40 connected to the moving picture video signal processing section 20 and the still picture video signal processing section 30, and a control section 50 for controlling the operation of these sections.

The image pickup section 10 comprises a CCD image sensor 11, a sample and hold circuit 12A / D converter 13, and a camera process circuit 14. An image output signal from the CCD image sensor 11 is supplied to an A / D converter 13 via a sample and hold circuit 12, and the A / D converter 13
The camera process 1 which is digitized by the D converter 13
4 is supplied. The camera process circuit 14 performs signal processing such as knee and gamma processing on the digital imaging output signal obtained by the A / D converter 13. And
The digital imaging output signal obtained by the imaging unit 10 is supplied to the moving image video signal processing unit 20 and the still image video signal processing unit 30.

The moving picture video signal processing section 20 comprises a moving picture video processing circuit 21 and a D / A converter 22.

The moving picture video process circuit 21 generates a digital video signal compliant with the NTSC system by subjecting the digital image pickup output signal supplied from the image pickup section 10 to a process process compliant with the NTSC system, for example. The digital video signal generated by the video processing circuit 21 is converted into an analog signal by the D / A converter 22. Then, the analog video signal obtained by the D / A converter 22 is supplied to the recording unit 40 as a moving image video signal.

Further, the still image / video signal processing unit 30
Is composed of an image memory 31, a compression processing circuit 32, a changeover switch 33, a still image video processing circuit 34, and a PCM processing circuit 35.

The image memory 31 is a frame memory whose writing / reading is controlled by the memory controller 51 of the control unit 50. The image memory 31 stores one frame of the digital output image signal supplied from the image pickup unit 10 as a still image. It is temporarily stored as a video signal.

The compression processing circuit 32 performs a compression process for compressing the digital video signal for one frame read from the image memory 31 to, for example, a デ ー タ data amount. The compression processing in the compression processing circuit 32 is performed using, for example, a strong correlation between video signals in space and time. When an image is divided into blocks, the dynamic range of the video signal included in each block is reduced by local correlation. Therefore, adaptive dynamic range coding (ADR) in which the number of bits is assigned according to the dynamic range of each block to perform data compression.
C: Adaptive Dyanmic Range Coding) is adopted.

The changeover switch 33 is controlled by a changeover control section 52 of the control section 50. The changeover switch 33 switches between the digital video signal read from the image memory 31 and the digital video signal subjected to the compression processing by the compression processing circuit 32, and selects the digital video signal by the still picture video processing circuit 34. Supply.

The still picture video processing circuit 34 generates still picture data by adding a synchronizing signal, an error correction code and an ID to the digital video signal supplied via the changeover switch 33.

The PCM process circuit 35 performs PCM process processing on the still image data supplied from the still image video process circuit 34 in accordance with the 8 mm video standard to generate PCM data. Then, the PCM data obtained by the PCM process circuit 35 is supplied to the recording unit 40 as a still image video signal.

Further, the recording section 40 comprises a changeover switch 41, a recording amplifier 42 and a rotating magnetic head 43.

The changeover switch 41 is connected to the control unit 50.
Are controlled by the area controller 53 of the first embodiment. The changeover switch 41 is supplied from the D / A converter 22 of the moving picture video signal processing unit 20, that is, the moving picture video signal and the PCM process circuit 35 of the still picture video signal processing unit 30. PCM data, that is, a still image video signal, and selectively supplies it to the rotating magnetic head 43 via the recording amplifier 42.

The magnetic tape 45 has the same tape format as the magnetic tape 80 shown in FIG.
The track formed obliquely on the magnetic tape 45 by the helical scanning is divided into a video area and a PCM audio area, a moving image is recorded as an analog video signal in the video area, and a still image is recorded as a digital video signal in the PCM audio area. Be recorded.

The control unit 50 includes the memory controller 51, the switching control unit 52, the area controller 5
3 and a system controller 54 for controlling them.

The system controller 54 determines that V
A controller of the entire system of the TR, which receives an operation input by operating various operation buttons (not shown) and controls various operation modes such as a recording mode and a reproduction mode.

The system controller 54 controls the V
The recording system of the TR is operated as follows in the simultaneous shooting mode of the still image and the moving image in the recording mode.

That is, normally, the compression processing circuit 32
The digital video signal for one frame is fetched into the image memory 31 every period corresponding to the recording period of the still image data for one frame which has been subjected to the compression process, and the digital video signal is sequentially read out and read out by the compression processing circuit. 3
The writing / reading of the image memory 31 is controlled by the memory controller 51 of the control unit 50 so as to supply the data to the image memory 31. Further, the switching control section 52 controls the switch 33 so that the digital video signal subjected to the compression processing by the compression processing circuit 32 is supplied to the still image video processing circuit 34. That is, the still image video signal processing unit 30 is operated in the still image continuous imaging mode.

The changeover switch 41 of the recording section 50 is controlled by the area controller 53,
The analog video signal supplied from the moving picture video signal processing section 20 and the video area of the magnetic tape 45 are sequentially recorded, and the still picture video signal processing section 30 converts the still picture digital video signal to the video data of the magnetic tape 45. The information is sequentially recorded in the area.

When the stem controller 54 receives a shutter operation input by operating the shutter button 58, the system controller fetches one frame of digital video signal into the image memory 31 in conjunction with the shutter operation.
The writing / reading of the image memory 31 is controlled by the memory controller 51 of the control unit 50 so that the digital video signals are sequentially read. Further, the changeover control unit 52 controls the changeover switch 3 so that the uncompressed digital image signal read from the image memory 51 is supplied to the still image video processing circuit 34.
3 is controlled. That is, the still image video signal processing unit 3
0 is operated in a one-shot imaging mode for a still image.

Then, the changeover switch 41 of the recording section 50 is controlled by the area controller 53,
The analog video signal supplied from the moving picture video signal processing section 20 and the video area of the magnetic tape 45 are sequentially recorded, and the still picture video signal processing section 30 converts the still picture digital video signal into the PCM of the magnetic tape 45. Record in the area.

That is, the stem controller 54
For example, as shown in the flowchart of FIG. 2, a digital video signal for one frame is fetched into the image memory 31 (step 1), the digital video signal is subjected to compression processing by the compression processing circuit 32, and After recording in the 45 PCM area (step 2), it is determined whether or not a shutter operation input has been received (step 3). If the result of the determination in step 3 is "NO", the process returns to step 1 to fetch the next one frame of digital video signal into the image memory 31, thereby capturing a still image in the continuous imaging mode. It is recorded in the PCM area of the magnetic tape 45. On the other hand, if the decision result in the above step 3 is "YES", the process shifts to step 4 to fetch the next one frame of digital video signal into the image memory 31 and read the uncompressed uncompressed image data from the image memory 31. The digital video signal is transferred to the magnetic tape 45 in a one-shot mode.
(Step 5), and returns to step 1 to perform the control operation in the continuous imaging mode.

The still images of each frame recorded in the PCM area of the magnetic tape 45 are divided by guard bands as shown in FIG.

Here, in the control operation shown in the flowchart of FIG. 2, the process in progress is not interrupted for the shutter operation, and the uncompressed still image digital video signal is uncompressed. The digital video signal of the still image is switched and recorded, but as shown in the flowchart of FIG. 4, the recording operation of the digital video signal of the still image subjected to the compression processing by the compression processing circuit 32 (step 2) When the shutter operation is received during the operation, as shown in FIG. 5, the recording operation of the digital video signal of the still image subjected to the compression processing is immediately stopped, and the stop code is recorded (step 3). A digital video signal for one frame is fetched into the image memory 31 (step 4), and an uncompressed digital signal read from the image memory 31 is read. Recording the PCM area of the magnetic tape 45 to the image signal by one shot imaging mode (Step 5)
Then, returning to step 1, the digital video signal for the next one frame may be fetched into the image memory 31, and the control operation in the continuous imaging mode may be performed.

[0039]

As is apparent from the above description, in the video signal recording apparatus according to the present invention, in the first video signal imaging mode, the control section captures the digital video signal into the storage section at predetermined intervals. And controlling the switching unit so as to select the output of the first signal processing unit for performing the signal processing for obtaining the first image quality. When the shutter operation is performed in the second video signal imaging mode, Is a second signal processing unit that fetches a digital video signal into the storage unit in response to the shutter operation and performs signal processing for obtaining a second image quality that is higher in quality than the first image quality. Since the switching unit is controlled so as to select the output of (1), a high-quality still image can be recorded by performing a shutter operation at a photo opportunity.

Therefore, according to the present invention, by performing a shutter operation at a photo opportunity, a high quality still image can be reliably recorded without missing a photo opportunity.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a recording system of a camera-integrated 8 mm video tape recorder to which the present invention is applied.

FIG. 2 is a flowchart showing an operation of the recording system.

FIG. 3 is a diagram showing a recording state of a magnetic tape by the operation of the recording system according to the flowchart of FIG. 2;

FIG. 4 is a flowchart illustrating an operation example of the recording system.

FIG. 5 is a diagram showing a recording state of a magnetic tape by an operation of the recording system according to the flowchart of FIG. 4;

FIG. 6 is a diagram showing a tape format of a magnetic tape used in an 8 mm video tape recorder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Image pick-up part 13 ... A / D converter 20 ... Video image signal processing part 30 ... Still image video signal processing part 31 ... Image memory 32 ... Compression processing circuit 33 ... · Changeover switch 34 ··· Still image process circuit 35 ··· PCM process circuit 40 ··· Recording unit 45 ··· Magnetic tape 50 ··· Control unit 51 ··· Memory controller 52 ··· Switching control unit 53 ... Area controller 54 ... System controller 58 ... Shutter button

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-369983 (JP, A) JP-A-3-249887 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/91-5/956 G11B 20/00

Claims (1)

(57) [Claims] An A / D for digitizing an input video signal
A conversion unit; a storage unit for storing the digital video signal digitized by the A / D conversion unit; and a first digital video signal read from the storage unit.
A first signal processing unit for performing signal processing for obtaining an image quality of the digital image signal read from the storage unit;
A second signal processing unit for performing signal processing for obtaining image quality of the image, a switching unit for switching the outputs of the first and second signal processing units, and a control unit for controlling operations of the storage unit and the switching unit. In the first video signal imaging mode, the control unit captures the digital video signal into the storage unit at predetermined intervals, and selects the output of the first signal processing unit. Controlling a switching unit, in a second video signal imaging mode, when a shutter operation is performed, fetching a digital video signal into the storage unit according to the shutter operation; The video signal recording device, wherein the switching unit is controlled so as to select the output of the video signal, and the second image quality is higher than the first image quality.