JP3449746B2 - Video camera - 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 camera.

[0002]

2. Description of the Related Art 60 Hz or 60 fields per second,
2: 1 (interlaced) format high-definition video equipment (for example, equipment that meets the so-called SMPTE240M standard)
Is now well known and widely used. However, if you later try to distribute the material in the form of high-definition video, motion picture film is still a very good way to capture the material. This not only has the advantage of expressing the material on film, but the film camera is easier to carry than the high-definition video cameras of the current generation.
This is because a film camera can obtain a good slow motion by imaging at a high frame rate.

A previously proposed apparatus for video post-processing of material that is to be filmed or video distributed after being filmed is illustrated schematically in FIG. In the example of the figure, the film material 10 of 24 Hz 1: 1 format
Is converted into a 60 Hz 2: 1 format video signal by a high definition (HD) film scanner 12 (for non-real time operation) or a high definition telecine machine (not shown, for real time operation). For example, conversion from the 24 Hz 1: 1 format to the 60 Hz 2: 1 format is performed by 3
232 pulldown technique. The 3232 pulldown technique scans each film frame
It produces two or three interlaced video fields from every other film frame (see FIG. 2). This technique is currently used in the United States and Japan to convert film material into broadcast video signals.

The 60 Hz 2: 1 format HD video signal output that is 3232 pulled down by the HD film scanner 12 is subsequently sent to various HD post-processing units (shown as a single unit) 14 for post-processing. . After post-processing, the 60Hz 2: 1 format HD video signal may be downgraded to standard definition format (using a down (downgrade) converter 16) for later distribution, or left at HD60Hz 2: 1 format. Alternatively, it may be returned to the film format. 32 when returning to film format
The third (phantom) video field generated from every other film frame in the 32 pulldown format is discarded by the field reduction unit 18. The remaining two corresponding to each original film frame
Two interlaced fields, electron beam recorder (EBR)
22 recomposes into one frame of 24 Hz film 20. 60H at various points in the device of FIG.
HD video tape recorder (VT)
R) 24.

The video signal generated by the HD film scanner 12 is electrically distinguished from the normal 60Hz 2: 1 HD video signal (eg, the video signal directly generated by a conventional 60Hz 2: 1 (interlaced) HD video camera). Although not possible, it can be clearly seen from the state of the motion of the image drawn by the signal that the signal is obtained by the 3232 pulldown, during reproduction. 3232
When the video signal generated by pulldown is mixed with the 2: 1 interlace signal obtained conventionally (during post-processing), the difference in motion in the video can be subjectively disturbing to the viewer. The HD post-processing unit 14 can also be modified in view that the phantom fields (during mixing operations such as wipes and fades) are later discarded by the field reduction unit 18. Therefore, any other signal that seeks to be mixed in with the 3232 pulldown signal desirably has motion delineation characteristics similar to the 3232 pulldown signal.

FIG. 1 illustrates a previously proposed method of providing another video signal having a 3232 pulldown format for mixing with material obtained by film scanner 12. The conventional 60 Hz 2: 1 video signal obtained from the HD video camera 26 is HD-VT.
After being recorded in R24, it is processed by the motion compensation system converter 28 and converted into a 24 Hz 1: 1 HD video signal. This 24 Hz 1: 1 video signal, or a similarly formatted signal generated by computer graphics machine 30, is provided to 3232 pulldown unit 32. 3232 pull-down unit 32 is 3232
To generate a pull-down format signal, a buffer memory is used to periodically repeat the fields of the same polarity from each frame of the input 24 Hz 1: 1 video signal, thereby appropriately providing 3 or 2 interlaced videos. Generate a field. 3232 pull-down unit 32
Is output to the HD post-processing unit 14 as needed.

[0007]

Problems to be Solved by the Invention HD camera 26, HD
The device described above, including the VTR 24, motion compensation converter 28 and 3232 pull-down unit 32, is a suitable 3
Although it provides a video signal in the 232 pulldown format, it has some drawbacks. One is that it cannot operate in real time because it is a troublesome multi-stage process (using the current generation motion compensation converter). Secondly, a suitable motion compensation converter operating in HD format is not currently commercially available and can only be used as an experimental device. Therefore, the object of the present invention is to
As a real-time and commercially usable device, for example, 3
To obtain a video camera capable of generating a video signal containing a periodic fake video field such as the H.232 pulldown format.

[0008] The present invention relates to a video camera for generating a video signal including a video field of the periodic saw Sekake, as the output of the video camera body, two from each exposure
Odd video field, even video
Charge storage type interlace that sequentially generates deofield
Image capturing element and the above-mentioned charge storage type interlaced image capturing device.
Capture element to the video signal between the odd video fields
Periodically less than 1/2 the field rate of
Shutter for exposure to light and the above charge storage type interlaced image
Of the video fields generated sequentially by the image capture element
Of which will later be selected as a fake video field
One video file that stores an exponent as updatable periodically
The storage means of the field storage capacity and the video camera body
Video field in the output video signal
In order to insert a fake video field in the position,
Periodically read / select one video field from memory
Read out / selection means for
It

The video camera according to the present invention can be used to generate a video signal containing spurious video fields and field pairs in a single exposure. This allows the camera to generate an interlaced video signal in real time with the motion characteristics of the signal in, for example, 3232 pulldown format. This signal can be mixed with similar format video signals derived from film material during video post-processing. Thus, the camera can easily generate a suitable video signal for post-processing, eliminating the potentially expensive non-real-time motion compensation conversion of previously obtained video material.

The video camera of the present invention is also useful, for artistic reasons, when a broadcast television program is desired to be video but film-like. That is, by producing and broadcasting a television program in the form of a 3232 pull-down format video signal, it is possible to make the viewer think that the program is derived from the film material. Previously, such effects would not have been obtained without the use of non-real time system converters.

In the preferred embodiment, the shutter exposes the imager four times during the ten video fields of the video signal, and the video camera produces an output video signal in the 3232 pulldown format. Also in the preferred embodiment, the storage means comprises an analog-to-digital converter and a digital video memory.

The video camera may have means for responding to the synchronization information about the video field generated by the image pickup device and means for controlling the storage means, the selection means and the shutter in response to the synchronization information.

Although various types of shutter mechanisms can be used, a rotary type shutter is preferable. The imaging device may be a frame-line transfer charge coupled device.

To prevent the image sensor from leaving any stray charge before exposure, the video camera should include means for discharging the image sensor before each exposure by the shutter.

[0015]

The present invention, in yet another aspect, provides a method of generating a video signal that includes a periodic spurious video field. The method consists of two video fields , an odd video field and an even video field, from each exposure.
Sequentially field, a charge storage interlaced video capturing element for generating, in less than 1/2 rate field rate of the video <br/> O signals between the odd video field
A step of periodic exposing, by the video capture device
Sequentially, one of the generated Ru video field, Miseka after
Cyclically what should be selected as the video field
Steps to store 1 video field for renewal
And the apparent video field position in the above video signal .
In order to insert a video field disguised as a location, currently stored
And a step of periodically reading and selecting the video field being.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 2 shows a video signal generated by the 3232 pulldown technique. Since the horizontal axis represents time, the figure shows the temporal correspondence between film frames and video fields. The video signal has 60 2: 1 interlaced fields per second and the film has 24 frames per second. Film frame 1 has video fields 1 and 2
Film frame 2 is used to create video fields 3, 4 and 5. Video field 5 is known as the sham field and is identical to the previous odd video field (video field 3) obtained from film frame 2. In this way, five film fields of odd-even-odd-even-odd are provided from two film frames. In order to maintain the required odd / even alternation in the video field, the next resulting sequence of 5 fields must start with an even field. There, film frame 3 is used to create video fields 6 and 7, and film frame 4 is used to create video fields 8, 9 and 10. Here, the video field 10 is identical to the previous even video field (video field 8) obtained from the film frame 4 in the sham field. By repeating the order of these 10 fields, the required odd / even alternation is given.

As described with reference to FIG. 1, when video post-processing is performed on video material obtained by a film scanner or telecine using 3232 pulldown, all video material to be added during the post-processing is 323.
A 2-pulldown format is preferred. Figure 3 shows 60Hz in 3232 pulldown format
1 illustrates a video camera 40 according to the present invention that produces a 2: 1 output video signal.

In FIG. 3, the video camera 40 has a camera body 42 including an image pickup device 43, a shutter mechanism 44, an objective lens 46 and a repeating field generator 48.
The repetitive field generator 48 operates as described later to provide a necessary pseudo field as a 3232 pulldown format video signal and controls the operation of the shutter mechanism 44. Iterative field generator 48
May be built into the camera body 42 or made as a separate part.

The image sensor 43 used in the camera 40 is a frame-line transfer charge coupled device that operates in the so-called "frame" mode. Charge is stored on the array of photosensitive cells during the recording period (part of the active field period). During the field blanking period, charge is transferred from one set of alternating lines of photosensitive cells corresponding to the field to the array of storage cells via the corresponding interline storage cells. The charge is then read from the storage cell in the next active field period. The next field comes from another set of alternating lines of photosensitive cells. Generation of a video field by the image sensor is controlled by a field synchronization signal. This signal may be generated by a sync generator in the camera body 42 or received from an external sync generator via input line 49.

Now, referring to FIG. 4, the video camera 4
The operation of 0 will be described. FIG. 4 illustrates diagrammatically the sequence of 10 consecutive fields (or 1/6 second) of the output video signal produced by the video camera 40. In FIG. 2, the video field is displayed along a long time axis.
In, the increasing time is represented by clockwise rotation from the reference point 60. This makes it clear that the sequence of consecutive 10 fields is repeated.

FIG. 4 can be considered as comprising a series of annular portions 62, 64, 66 and 68. Annular portion 62
Is divided into four 90 ° zones, each zone corresponding to the equivalent duration of a 24 Hz film frame. This is to facilitate the comparison of the operation shown in FIG. 4 with the film frame to video field relationship of FIG. Annular part 64
Is divided into ten 36 ° areas, each area corresponding to one video field of the output video signal. The annular portion 66 is
It includes a fixed number of shaded portions representing the field blanking period between each field shown in the annular portion 64. Previously proposed S using 1125 lines for each video frame
In the MPTE240M system, the field blanking period consists of 40 lines at the beginning of each video field and 5 lines at the end of each video field. The final annular portion 68 has four shaded portions that indicate the time T (including T ₁ ) that the shutter mechanism 44 exposes the image sensor 43. These exposures are performed every 1/24 seconds.

At a reference point 60 corresponding to the beginning of the active field period for video field 1 (ie, the end of the field blanking period between video field 1 and the preceding field), shutter mechanism 44 allows time T. Exposure is performed. During exposure, charge corresponding to incident light is accumulated in the photosensitive cells arranged in a line corresponding to odd and even interlaced fields (ie, video fields 1 and 2). However, the charge corresponding to the video field 1 is read out for the first time in the field blanking period at the end of the video field 1. Since the image sensor 43 is shielded by the shutter mechanism 44 during the entire charge accumulation period corresponding to the video field 2, the charge read at the end of the active field period of the video field 2 is the video field 1.
Accumulated during the time T at. In this way, using the charge accumulated during one exposure time T,
Two interlaced video fields are created. These two video fields 1 and 2 will therefore have exactly the same characteristics in terms of motion depiction, as if they were obtained by scanning one film frame.

At the beginning of the active field period of the video field 3, all the charge stored in the image sensor 43 is read out, so that all photosensitive cells are (at least theoretically) in a discharged state. A cell reset signal is applied to the image sensor 43 in order to completely discharge the photosensitive cells. When the shutter mechanism 44 exposes the image sensor 43 for time T ₁ , the photosensitive cell remains in the discharged state up to about the middle of the video field 3. During this exposure, the photosensitive cells corresponding to video fields 3 (odd) and 4 (even) are also charged. The exposure time T ₁ ends at the end of the active field period for video field 3. During the field blanking period at the end of video field 3, the charge from the photosensitive cell corresponding to the odd interlaced field is read. The image sensor 43 is also shielded from light during the next even field of the video field 4, and the charges read from the image sensor 43 during the field blanking period at the end of the video field 4 are accumulated during the previous exposure by the shutter mechanism 44. It has been done.

At the beginning of the active field period of video field 5, all photosensitive cells are in a discharged state. Also,
During the video field 5, the image sensor 43 is shielded from light by the shutter mechanism 44, so that no further charge is stored. Video field 5 is the actual spurious field and must be the same as the preceding odd field (video field 3) in the 3232 pulldown format. In effect, the repeating field generator 48 replaces the video signal read from the image sensor 43 with a stored or delayed copy of the video field 3 during the field blanking period at the end of the video field 5 (see below). .

Both video fields 1 and 2 of FIG.
It is generated from only one exposure of the image sensor 43 performed during the video field 1. In terms of motion depiction by a video signal, this is equivalent to two video fields 1 and 2 being derived in the film scanner from only one film frame. Similarly, video fields 3, 4 and 5 of FIG. 4 all result from a single exposure of imager 43 during video field 3. Video fields 3 and 5 are identical (video field 5 is a stored or delayed copy of video field 3). Similarly, in terms of motion depiction, this is equivalent to three video fields 3, 4 and 5 derived from only one film frame. The shutter exposure times T (including the exposure time represented by T ₁ ) are all the same length. Comparing the 5 video fields 1-5 of FIG. 4 with the like-numbered video fields of FIG. 2, the 5 video fields 1-5 thus generated are described in FIG.
It will be appreciated that it conforms to the 32 pulldown format.

The same operation is performed for the next five video fields 6-10. That is, the shutter mechanism 44
2 separate exposures by 4 video fields 6-9
The phantom video field 10 is generated by the repeat field generator 48 using a stored copy of the video field 8.

As described above, it has been described that the video camera 40 of FIG. 3 can be used to generate a video signal equivalent to the video signal obtained by pulling down the film material 3232 in terms of motion depiction. The equivalent film camera shutter angle (the ratio of the film camera shutter open to each film frame in degrees) can be changed by changing the exposure time T in FIG. In order for the video camera 40 to generate groups of exactly two or three video fields from a single exposure, the exposure by the shutter mechanism 44 should not exceed one active video field. That is, there is an upper limit on the period of time T for a given video system. Each 60 Hz video field is 562.
It consists of 5 lines, 45 of which are field
In the blanking period, the maximum value of the time T is 1/60 seconds × (517.5 / 562.5) = 0.015.
3 seconds. In FIG. 4, the length of the exposure time T may be represented by an equivalent film camera / shutter angle. Figure 4
The start and end points of time T ₁ of are calculated as deviations from the reference point 60. 24 Hz 1 frame ≡1 / 24 seconds × number of lines / second ≡1 / 24 × (30 × 1125) lines = 1406.25 lines Start point of time T ₁ = 140.25 lines from reference point 60 End point of time T ₁ = From the reference point 60 (3 fields-45 lines) = (3 x 562.5) -45 lines = 1642.5 lines ∴ T ₁ length = (1642.5-1406.25) lines = 236.25 lines ∴ Equivalent film camera / shutter angle = (236.25 lines / 1406.25 lines) × 360 ° = 60.48 °

FIG. 5 schematically shows a rotary shutter 80 suitable for use in the shutter mechanism 44. The rotary shutter 80 comprises a generally disk-shaped element 80 that rotates 24 times per second during operation. The element 80 has a cutout 82 that allows light to pass through. The active area of the image sensor 43 is defined by a broken-line rectangle 8.
4 shows. As the element 80 rotates, the active area of the image sensor 43 is exposed for a time T every 1/24 second. Time T
Is determined by the angular width of the cutout 82. The shutter mechanism 44 also uses means (not shown) for synchronizing the rotation of the element 80 with the active field period of the video field. To this end, a shutter sync signal is provided from the repeat field generator 48 to the shutter mechanism.

FIG. 6 illustrates the iterative field generator 48 of FIG.
It is a block diagram showing an example of. Iterative field generator 4
8 receives a video signal from the image sensor 43 of FIG. 3 as an input, and receives two outputs, that is, a 60 Hz 2: 1 (interlaced) video signal of 3232 pulldown format and a synchronization signal for controlling the synchronization of the shutter mechanism 44. Supply.

An input video signal from the image pickup device 43 is digitized by an analog / digital (A / D) converter 90. The digitized video signal is sent from the A / D converter 90 to the data selector 92 and the field memory 9
4 is supplied.

The video signal from the image sensor 43 is also supplied to the sync separator 96, which extracts the field sync information from the video signal and sends the information to the timing generator 98. The timing generator 98 supplies a shutter synchronization signal to the shutter mechanism 44 based on the sent synchronization information. The timing generator 98 has three other outputs,
That is, reading / writing (R
/ W) signal, a control signal to the address generator 100, and a control signal to the data selector 92.

The R / W signal supplied from the timing generator 98 to the field memory 94 controls the field memory which stores the digitized versions of the video fields 3 and 8 of FIG. These stored data are later used by the data selector 92 which performs the permutation to give the spurious video fields 5 and 10. The field memory 94 is controlled by an address generator 100 which generates read and write addresses within the memory 94 during read or write operations. During video fields 5 and 10 (phantom video fields), the timing generator 98 controls the field memory 94 to read the stored fields (by the R / W signal) and controls the data selector 92. A / D converter 90
The output of the field memory 94 is selected instead of the direct output of. Thus, video fields 3 and 8
Respectively stored data is substituted or inserted into the output video signal of the camera, and the spurious fields 5 and 10
Is given.

While the embodiment described above produced a high quality 3232 pulldown video signal, other embodiments of the present invention include video containing a periodic spurious field in accordance with other formats and definition standards. It can also be configured to generate a signal.

[0035]

As is apparent from the above description, according to the present invention, a signal including a periodic fake video field, such as a 3232 pulldown format, can be generated in real time and for commercial use. You can get a video camera.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional example of an apparatus for post-processing video material recorded on film.

FIG. 2 is an illustration showing a video signal generated by the 3232 pulldown technique.

3 is a block diagram showing an embodiment of a video camera of the present invention which generates the video signal of FIG.

4 is an explanatory diagram showing continuous 10 fields of a video signal generated by the video camera of FIG.

FIG. 5 is an explanatory view showing a rotary shutter suitable for the present invention.

6 is a block diagram illustrating an example of the iterative field generator of FIG.

[Explanation of symbols]

40 video camera 43 Image capturing (imaging) device 44,80 Shutter (rotary shutter) 48, (90, 94) storage means 48,92 selection means 90 analog / digital converter 94 Digital Video (Field) Memory 98 Selection means and means for controlling shutter

Continuation of the front page (56) Reference JP-A-1-256880 (JP, A) JP-A-63-102580 (JP, A) JP-A-61-18939 (JP, A) JP-A-58-202668 (JP , A) JP-A-4-37846 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 5/222-5/257 G03B 19/18-19/26

Claims (8)

(57) [Claims] 1. A video camera for generating a video signal including a periodic phantom video field, wherein two video signals from each exposure are output from the video camera body.
Off-field odd video field, even video
Field sequential, and charge storage interlaced video capture device that generates, the charge storage interlaced video capture device, less than 1/2 of the field rate of the video signal during said odd <br/> video field Shutter, which periodically exposes at a rate, and the charge storage type interlaced image capturing element ,
Among of the generated Ru video field, bidet pretense after
Periodically update what should be selected as an offfield
A storage Hand <br/> stage of one video field memory capacity for storing as variable, viewed in the video signal output from said video camera body
A video camera having a reading / selecting means for periodically reading / selecting one video field from the storage means so as to insert a pseudo-video field at the position of the pseudo video field . 2. The shutter is configured to operate the video signal of 10 times.
The charge storage type interlaced image capturing element is exposed four times for each video field,
The video camera of claim 1, which is operative to generate an output video signal in a pull-down format. Wherein the upper Kiki憶means, according to claim 1 or 2 having an analog-to-digital converter and a digital video memory
Video camera. 4. A means for responding to synchronization information about a video field generated by the charge storage type interlaced image capturing element, and controlling the storage means, the reading / selecting means and the shutter according to the synchronization information. The video camera according to claim 1, further comprising: 5. The video camera according to claim 1, wherein the shutter is a rotary shutter. 6. The video camera according to claim 1, wherein the charge storage type interlaced image capturing device is a frame-line transfer charge coupled device. 7. The voltage is applied before each exposure by the shutter.
7. The video camera of claim 6 further comprising means for discharging the load storage interlaced image capture device. 8. A method of generating a video signal containing a periodic spurious video field, wherein two video fields from each exposure are odd video fields.
A charge storage type interlaced image capturing device for sequentially generating a field and an even video field is provided with a field rate of 1 of the video signal between the odd video fields.
/ A step 2 periodically exposed at smaller rate, sequentially by the video capture device, among the generated Ru video field, selecting a video field guise after
One video fee that can be updated periodically.
Field component, a step of storing, in order to insert the <br/> Sekake video field seen pretense video field position in the video signal, is currently stored
A method for generating a video signal , which comprises the step of periodically reading and selecting an existing video field.