JP2007325302A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of remarkably reducing flicker and improving image quality. <P>SOLUTION: The present invention relates to the imaging apparatus in which a 24p imaging signal due to a progressive scanning system of a frame frequency 24 Hz is converted into a 60i signal due to an interlaced scanning system of a field frequency 60 Hz that is a standard television system, by 2:3 pull-down processing, comprising: an imaging unit which outputs 24p imaging signals for one frame for (1/30) sec at the interval of (1/24)_sec synchronously with a vertical synchronizing signal of the 24p imaging signal; a memory unit in which a vertical band of the 24p imaging signals for one frame output from the imaging unit is limited and written in a storage region for (1/30)_sec and a so-called 2:3 pull-down signal resulting from converting two frames of the vertical band limited 24p imaging signals into 60i signals of five fields by 2:3 pull-down processing is output at the interval of (1/60)_sec synchronously with the vertical synchronizing signal of the 60i signal; a recording unit which records on a recording medium the 2:3 pull-down signal from the memory unit; and a display unit which displays thereon the 2:3 pull-down signal from the memory unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention can generate an image pickup signal by a progressive scanning method with a frame frequency of 24 Hz used for movies and the like, and use this image pickup signal with an interlaced scanning method by a field frequency of 60 Hz which is a standard television method. The present invention relates to an imaging device capable of converting into an image.

  With the development of HD (High Definition) broadcasting equipment in recent years, in VTR-integrated imaging devices, so-called camcorders, an image whose vertical resolution is about twice as high as that of an interlace scanning method with a field frequency of 60 Hz, which is a standard television method, is obtained. I was able to do it. As described above, in response to the fact that a high-quality image can be obtained in the VTR integrated imaging apparatus, movements such as movie shooting using the VTR integrated imaging apparatus have been activated.

  Such an image pickup apparatus such as a VTR integrated image pickup apparatus is configured to take an image by a progressive scanning method with a frame frequency of 24 Hz so that a still image of 24 frames / second can be taken like a 24-frame film camera. (For example, refer to Patent Document 1).

  In addition, such an image pickup apparatus performs a 2: 3 pull-down process on an image pickup signal (hereinafter referred to as a 24p image pickup signal) using a progressive scan method with a frame frequency of 24 Hz, and an interlace scan method with a field frequency of 60 Hz, which is a standard television method. Is converted into an image signal (hereinafter referred to as a 60i signal) and recorded on a video tape. This is because the recording unit can be configured with a conventional one by converting to a 60i signal, and a display unit such as a VF (view finder) or an external monitor for confirming the recorded image on the spot. This is because it can be configured with a conventional one, so that it is not necessary to develop a progressive scan type and the price can be reduced. A so-called 2: 3 pull-down signal converted into a 60i signal by the 2: 3 pull-down process can be converted into a signal by a progressive scanning method with a frame frequency of 24 Hz by performing a so-called reverse 2: 3 pull-down process.

  Hereinafter, an imaging device capable of recording a conventional 24p imaging signal will be described. FIG. 15 is a block diagram illustrating a configuration of the imaging apparatus.

  In FIG. 15, reference numeral 1 denotes an optical system lens and a lens unit including an optical aperture and a mechanical shutter, and 2 denotes an imaging unit constituted by a CCD (Charge Coupled Device), which transfers accumulated charges by sequential scanning (1/24). A 24p imaging signal is output every second.

  Reference numeral 3 denotes a memory unit that performs 24: 3 pull-down processing on the 24p image signal and converts it into a standard television 60i signal, and outputs a so-called 2: 3 pull-down signal. The interlace signal is output every (1/60) second. Odd line (odd) and even line (even) are output alternately.

A recording unit 4 generates a video signal obtained by adding a 60i signal vertical synchronizing signal (60i-SYNC) to the 2: 3 pull-down signal from the memory unit 3 and records the video signal on a recording medium such as a video tape.

Reference numeral 5 denotes a display unit such as a VF that generates and displays a display signal obtained by adding a 60i signal vertical synchronization signal (60i-SYNC) to the 2: 3 pull-down signal from the memory unit 3.

  6 is a synchronizing signal generator for generating a vertical synchronizing signal for a 24p imaging signal (hereinafter referred to as a 24p vertical synchronizing signal) and a vertical synchronizing signal for a 60i signal (hereinafter referred to as a 60i vertical synchronizing signal); This is a captured image state detection unit that detects the state of the captured image and outputs a control signal to the lens unit 1 and the image capturing unit 2.

  The operation of the imaging apparatus configured as described above will be described with reference to FIGS. 15 and 16. FIG. 16 is a diagram for explaining the operation of the imaging apparatus, and shows the signal states and operations of (a) to (d) and (f) to (k) shown in FIG.

  The optical image input through the lens unit 1 is output by the imaging unit 2 as a 24p imaging signal. As illustrated in FIG. 16A, the imaging unit 2 outputs a 24p imaging signal every (1/24) second in synchronization with the 24p vertical synchronization signal. As a signal output method, as shown in FIG. 16 (b), it takes a time of (1/24) seconds to output, and as shown in FIG. 16 (c), it is shorter than (1/24) seconds. There is a method to output intermittently in time. Note that the numbers shown in FIGS. 16B and 16C indicate the frame numbers of the 24p imaging signal. Further, the hatched portion shown in FIG. 16C indicates a signal non-output period (blanking period).

  The method shown in FIG. 16C is applied to an imaging apparatus using a CCD (Charge Coupled Device). This is because when a CCD is used, the image quality deteriorates drastically when the transfer time of accumulated charges becomes long, and it is desirable to output (transfer) in a time of (1/30) seconds or less. Hereinafter, a case in which a 24p imaging signal is output every (1/24) seconds over (1/30) seconds by the method shown in FIG.

  The captured image state detection unit 7 detects a captured image state such as an average or a peak value of a luminance signal and a color difference signal for each frame from the 24p imaging signal output from the imaging unit 2 (see FIG. 16F). Based on the data, necessary control data (control signal) is output to the lens unit 1 and the imaging unit 2 (see FIG. 16G).

  The memory unit 3 performs the write operation and the read operation shown in FIGS. That is, a 24p imaging signal is written in a storage area (not shown) over a period of (1/30) seconds, and a 2: 3 pull-down process is performed to convert 2 frames of the 24p imaging signal into 5 fields of 60i signals. Then, in synchronization with the 60i vertical synchronization signal, the odd line (odd) and the even line (even) of the interlace signal are alternately read every (1/60) seconds, and the recording unit 4 and the display unit are output as a 2: 3 pull-down signal. Output to 5. That is, for example, frames 1 and 2 of a 24p imaging signal are 1-odd (hereinafter, “odd” is simply referred to as “o”), 1-even (hereinafter, “even” is simply referred to as “e”), 2-o, 2 of 60i signal. -E, converted into 2-o and output.

  The synchronization signal generation unit 6 outputs a 24p vertical synchronization signal (see FIG. 16D) and a 60i vertical synchronization signal (see FIG. 16H) for the imaging apparatus to perform the above operation to each unit.

However, in the conventional imaging apparatus, when a 24p imaging signal having a high vertical band that is approximately twice as high as an image signal by an interlace scanning method with a field frequency of 60 Hz, which is a standard television system, is converted into a 60i signal. Since the vertical band of the folded signal of the 60i signal is wide, there is a problem that flicker increases and the screen flickers and is difficult to see.

The problem with 2: 3 pull-down is that there is a bias in the reproduction of each frame of the 24p image signal, and the movement is jerky. This is because 2 frames of a 24p imaging signal are converted into 5 fields of a 60i signal. For example, the same field is used as (2-o, 2-e), (2-o, 3-e). This is because the frame is displayed.
Japanese Patent Laid-Open No. 2002-152569

In view of the above problems, the present invention significantly reduces flicker and improves image quality by limiting the vertical band of the 24p imaging signal and narrowing the vertical band of the folding signal of the 2: 3 pull-down signal (60i signal). An object of the present invention is to provide an imaging device that can be made to operate.

  Also, the 2: 3 pulldown signal is converted into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal frame from which the fifth field converted by the 2: 3 pulldown process is removed, and the interval between the frames. By generating a display signal in which black level signals are inserted so as to be evenly spaced, the jerky feeling of movement, which is a problem of 2: 3 pull-down, is suppressed, and a mechanical shutter such as that taken with a film camera is used. An object of the present invention is to provide an imaging device that reproduces flickering.

  The imaging apparatus according to claim 1 of the present invention converts a 24p imaging signal by a progressive scanning method with a frame frequency of 24 Hz into a 60i signal by an interlace scanning method with a field frequency of 60 Hz, which is a standard television system, by 2: 3 pull-down processing. An imaging unit that outputs a 24p imaging signal for one frame over (1/30) second every (1/24) second in synchronization with a vertical synchronization signal of the 24p imaging signal; The 24p imaging signal for which the vertical band of the 24p imaging signal for one frame output from the imaging unit is limited, is written to the storage area in (1/30) seconds, and this vertical band is limited by 2: 3 pull-down processing. The so-called 2: 3 pull-down signal obtained by converting the 2 frames of 5 into a 60i signal of 5 fields is synchronized with the vertical synchronization signal of the 60i signal. A memory unit that outputs every (1/60) second, a recording unit that records the 2: 3 pull-down signal from the memory unit on a recording medium, and a display that displays the 2: 3 pull-down signal from the memory unit And a section.

  The imaging device according to claim 2 of the present invention is the imaging device according to claim 1, wherein the memory unit limits the vertical band by adding two adjacent vertical lines of the 24p imaging signal. Features.

  An imaging apparatus according to a third aspect of the present invention is the imaging apparatus according to the first or second aspect, wherein the memory unit performs a 2: 3 pull-down process after limiting a vertical band of a 24p imaging signal. The obtained 2: 3 pull-down signal and the 2: 3 pull-down signal obtained by performing the 2: 3 pull-down process without limitation on the vertical band can be output, and the latter 2: 3 pull-down signal is output to the recording unit. And the former 2: 3 pull-down signal is output to the display unit.

An imaging device according to a fourth aspect of the present invention is the imaging device according to the first or second aspect, wherein the memory unit limits a vertical band of a 24p imaging signal to be written to the storage area. And a circuit for switching between them.

An imaging device according to a fifth aspect of the present invention is the imaging device according to any one of the first to fourth aspects, wherein the display unit outputs the 2: 3 pull-down signal from the memory unit to a fifth Converts to a frame of 60i signal that has a one-to-one correspondence with the original 24p imaging signal frame with the field removed, and generates a display signal with black level signals inserted so that the frames are equally spaced It is characterized by displaying.

  The imaging apparatus according to claim 6 of the present invention converts a 24p imaging signal by a progressive scanning method with a frame frequency of 24 Hz into a 60i signal by an interlace scanning method with a field frequency of 60 Hz, which is a standard television system, by 2: 3 pull-down processing. An imaging unit that outputs a 24p imaging signal for one frame over (1/30) second every (1/24) second in synchronization with a vertical synchronization signal of the 24p imaging signal; The so-called 24p imaging signal for one frame output from the imaging unit is written to the storage area in (1/30) seconds, and 2 frames of the 24p imaging signal are converted into 60i signals of 5 fields by 2: 3 pull-down processing. A memory unit that outputs a 2: 3 pull-down signal every (1/60) second in synchronization with a vertical synchronization signal of a 60i signal; A recording unit that records the 2: 3 pull-down signal from the memory unit on a recording medium, and the frame of the original 24p imaging signal from which the 2: 3 pull-down signal from the memory unit is removed from the fifth field and 1 And a display section that generates and displays a display signal in which a black level signal is inserted so that the frame is converted into a 60i signal frame corresponding to one-to-one correspondence and the interval between the frames is equal. To do.

As described above, according to the present invention, the vertical band of the 24p imaging signal is limited to narrow the vertical band of the folding signal of the 2: 3 pull-down signal (60i signal), thereby greatly reducing flicker and improving the image quality. It becomes possible to improve.

  Also, the 2: 3 pulldown signal is converted into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal frame from which the fifth field converted by the 2: 3 pulldown process is removed, and the interval between the frames. By generating a display signal with black level signals inserted at equal intervals, it becomes possible to suppress the jerky feeling of motion, which is a problem of 2: 3 pull-down, and it seems that the image was taken with a film camera. The flicker of a mechanical shutter can be reproduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, embodiment shown here is an example to the last, Comprising: It is not necessarily limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 1 of the present invention. In addition, the same code | symbol is attached | subjected to the member corresponding to the member demonstrated based on FIG. 15, and description is abbreviate | omitted.

  In FIG. 1, 1 is an optical system lens and a lens unit comprising an optical aperture and a mechanical shutter, and 2 is an imaging unit composed of a CCD (Charge Coupled Device), which transfers accumulated charges in sequential scanning (1/24). A 24p imaging signal is output every second.

  3 is a memory unit for writing a 24p imaging signal in a storage area (not shown) over (1/30) seconds, converting it into a standard television 60i signal by performing 2: 3 pulldown processing, and outputting a so-called 2: 3 pulldown signal The odd lines (odd) and even lines (even) of the interlace signal are alternately output every (1/60) seconds.

4 2 from the memory unit 3: generates the 3 video signal obtained by adding a pull-down signal to the 6 0i vertical synchronizing signal (60i-SYNC), which is a recording unit for recording on a recording medium such as a video tape.

5 2 from the memory unit 3: a display unit such as 3 pull-down signal to the 6 0i vertical synchronizing signal VF for generating and displaying a display signal obtained by adding (60i-SYNC).

6 2 4p vertical synchronizing signal and a 6 0i synchronizing signal generator for generating a vertical synchronizing signal, 7 captured image state detecting unit which detects a state of the captured image, and outputs a control signal to the lens unit 1 and the imaging section 2, Reference numeral 8 denotes a delay unit that delays the 24p imaging signal from the imaging unit 2 and outputs the delayed signal to the memory unit 3.

  In addition to displaying the image being photographed on the display unit, the image being photographed may be displayed on an external monitor or the like, and the 60i signal recorded on the recording medium is reproduced to be externally displayed. You may enable it to output to.

  The difference between the first embodiment and the conventional example is that a delay unit 8 is provided, and the other parts are substantially the same, and the operation is similar.

  The operation of the imaging apparatus according to the first embodiment configured as described above will be described with reference to FIGS. FIG. 2 is a diagram for explaining the operation of the imaging apparatus, and shows the signal states and operations (a) to (k) shown in FIG.

  The optical image input through the lens unit 1 is output by the imaging unit 2 as a 24p imaging signal. As shown in FIG. 2A, the imaging unit 2 outputs a 24p imaging signal every (1/24) second in synchronization with the 24p vertical synchronization signal. As a signal output method, as in the conventional example, a method of outputting over (1/24) seconds (see FIG. 2B) and intermittent in a time shorter than (1/24) seconds. There is a method of outputting automatically (see FIG. 2C). Note that the numbers shown in FIGS. 2B and 2C indicate the frame numbers of the 24p imaging signal. Further, the hatched portion shown in FIG. 2C indicates a signal non-output period (blanking period). Also in the first embodiment, as in the conventional example, a 24p imaging signal is output every (1/24) seconds over (1/30) seconds by the method shown in FIG. 2 (c). The case will be described.

  The delay unit 8 delays the 24p imaging signal from the imaging unit 2 when the phases of the 24p vertical synchronization signal (see FIG. 2D) and the 60i vertical synchronization signal (see FIG. 2H) match. If it does not match, the 60i signal is delayed by (1/2) field scanning and output. That is, when the 24p imaging signal is output from the imaging unit 2 at the timing coincident with the 60i vertical synchronization signal, the 24p imaging signal is output as it is, and when it does not coincide, the writing to the memory unit 3 is performed at the timing coincident with the 60i vertical synchronization signal. The output is delayed so as to be started (see FIGS. 2E and 2I).

  As a result, the signal shown in FIG. 2E is output to the memory unit 3 and the captured image state detection unit 7 (in FIG. 2E, the horizontal line portion is a delay period). The captured image state detection unit 7 detects the captured image state at the same timing as the 60i vertical synchronization signal (see FIG. 2 (f)), as shown in FIG. 2 (g). Necessary control data (control signal) is output to the lens unit 1 and the imaging unit 2 at a timing coincident with the vertical synchronization signal.

  The memory unit 3 performs the write operation and the read operation shown in FIGS. That is, for the 24p imaging signal output from the imaging unit 2 at a timing that does not coincide with the 60i vertical synchronization signal, the delay unit 8 gives a delay corresponding to the time during which the 60i signal is (1/2) field scanned, Writing to the memory unit 3 is started at a timing that coincides with the 60i vertical synchronization signal.

  As shown in FIG. 2 (k), a 2: 3 pull-down signal is output to the recording unit 4 and the display unit 5 as in the conventional example.

  As described above, the processing of the delay unit 8 causes the captured image state detection unit 7 to perform the captured image state detection process and the control signal output, and the writing operation of the memory unit 3 in synchronization with the vertical synchronization signal of the 60i signal. Can do.

  The delay unit 8 detects the 24p vertical synchronization signal and the 60i vertical synchronization signal from the synchronization signal generation unit 6, and determines whether or not the phases of the 24p vertical synchronization signal and the 60i vertical synchronization signal match. It is determined whether or not to delay the 24p imaging signal.

  As described above, according to the first embodiment, the captured image state detection process and the control signal output by the captured image state detection unit 7 can be performed in synchronization with the vertical synchronization signal of the 60i signal. Even when the detection unit is designed based on the captured image state detection processing for the 60i signal, the captured image detection processing of the 24p captured signal using the captured image state detection processing circuit for the 60i signal is not complicated. Therefore, it is not necessary to add a circuit for the 24p imaging signal.

  In addition, since the write operation of the memory unit 3 can be performed in synchronization with the vertical synchronization signal of the 60i signal, it is possible to prevent a difference in signal level of each circuit in the memory unit. Thereby, it is possible to avoid the occurrence of horizontal stripes near the (1/2) field display position, that is, near the center of the screen, and to prevent image quality deterioration.

(Embodiment 2)
FIG. 3 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member corresponding to the member demonstrated based on FIG. 1, 15, and description is abbreviate | omitted.

  The difference between the second embodiment, the first embodiment, and the conventional example is that the delay unit is not provided, and the output timing of the 24p imaging signal can be delayed in the imaging unit 9, and the other units are described. The operation is generally the same, and the operation is similar.

  FIG. 4 is a block diagram showing an example of the internal configuration of the imaging unit 9. Reference numeral 10 denotes an imaging signal driving circuit installed inside the imaging unit 9, 11 is a 24p vertical synchronization signal, and 60i vertical synchronization signal. An imaging signal drive pulse generation circuit capable of outputting a readout pulse and transfer pulses 1 to 3 to be described later, 12 is a switching circuit for switching and outputting transfer pulses 1, 2, and 3 output from the imaging signal drive pulse generation circuit 11; Is a synchronization signal phase determination circuit that determines the phase relationship between the 24p vertical synchronization signal and the 60i vertical synchronization signal and controls the switching circuit 12.

The operation of the imaging apparatus according to the second embodiment configured as described above will be described with reference to FIGS. 3, 4, and 5. FIG. 5 is a diagram for explaining the operation of the imaging apparatus, and shows the signal states and operations of (a) to (e) and (h) shown in FIGS. Since operations other than the imaging unit are the same as those in the first embodiment, description thereof is omitted.

  The imaging signal drive pulse generation circuit 11 generates a 24p imaging signal based on the 24p vertical synchronization signal (see FIG. 5D) and the 60i vertical synchronization signal (see FIG. 5H) from the synchronization signal generation circuit 6. Read pulse (see FIG. 5 (a)) and transfer pulse 1 (see FIG. 5 (b)) for transferring the 24p imaging signal over a period of (1/24) seconds. ), Or transfer pulse 2 for transfer over a period of (1/30 seconds) (see FIG. 5C), and further, the transfer start of transfer pulse 2 is indicated by the 60i signal in the (1/2) field. The transfer pulse 3 (not shown) delayed by the scanning time can be output, and the switching circuit 12 switches and outputs the transfer pulses 1 to 3 according to the determination result of the synchronization signal phase determination circuit 13. In the present embodiment, the transfer pulses 2 and 3 are switched and output.

  The synchronization signal phase determination circuit 13 detects the phases of the 24p vertical synchronization signal and the 60i vertical synchronization signal from the synchronization signal generation circuit 6, and when the 24p vertical synchronization signal matches the phase of the 60i vertical synchronization signal, the switching circuit 12 outputs a control signal for selecting the transfer pulse 2, and if they do not match, the switching circuit 12 outputs a control signal for selecting the transfer pulse 3.

  With the above operation, the 24p imaging signal output from the imaging unit 9 is as shown in FIG. That is, the 24p imaging signal can be output at the timing synchronized with the 60i vertical synchronization signal, and the same effect as in the first embodiment can be obtained without the delay unit as in the first embodiment.

  That is, since the captured image state detection process and the control signal output by the captured image state detection unit 7 can be performed in synchronization with the vertical synchronization signal of the 60i signal, the captured image state detection unit performs the captured image state detection process for the 60i signal. Even in the case of basic design, the captured image detection process of the 24p captured signal using the captured image state detection processing circuit for the 60i signal does not become complicated, and therefore it is necessary to add a circuit for the 24p captured signal. Also disappear.

  In addition, since the write operation of the memory unit 3 can be performed in synchronization with the vertical synchronization signal of the 60i signal, it is possible to prevent a difference in signal level of each circuit in the memory unit. Thereby, it is possible to avoid the occurrence of horizontal stripes near the (1/2) field display position, that is, near the center of the screen, and to prevent image quality deterioration.

  In addition, since it is not necessary to provide a delay unit, the circuit scale can be made smaller than in the first embodiment, and the cost can be reduced.

(Embodiment 3)
FIG. 6 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member corresponding to the member demonstrated based on FIG. 1, 15, and description is abbreviate | omitted.

  The difference between the third embodiment, the first embodiment, and the conventional example is that the memory unit 14 converts the fifth field of the 2: 3 pull-down signal (two frames of the 24p imaging signal into five fields of the 60i signal). The last field) is replaced by a mixed signal obtained by mixing the frame (60i signal) around the fifth field (including the fifth field), and the other parts are substantially the same. There is a similar operation.

  FIG. 7 is a block diagram showing an example of the internal configuration of the memory unit 14. Reference numeral 15 denotes a 2: 3 pull-down signal that performs a 2: 3 pull-down process on the 24p image signal and converts it to a 60i signal to output a so-called 2: 3 pull-down signal. A conversion circuit 16 mixes an arbitrary frame of the 60i signal to generate a signal (mix signal) of one field of the 60i signal, and 17 mixes with the 2: 3 pulldown signal from the 2: 3 pulldown conversion circuit 15 A switching circuit 18 that switches and outputs the mix signal from the circuit 16, and a switching control circuit 18 that controls the switching circuit 17.

  The operation of the imaging apparatus according to the third embodiment configured as described above will be described with reference to FIGS. 6, 7, and 8. FIG. 8 is a diagram for explaining the operation of the imaging apparatus, and shows the signal states and operations of (a) to (k1) and (k2) shown in FIGS. Note that the operations and signal states from (a) to (j) are the same as those in the first embodiment, and a description thereof will be omitted.

When the signal shown in FIG. 8E is input to the memory unit 14, the 2: 3 pull-down conversion circuit 15 performs the write operation and the read shown in FIGS. 8I and 8J, as in the first embodiment. Operates and outputs a 2: 3 pull-down signal. The mix circuit 16 adds 60i signals corresponding to a plurality of consecutive frames of the original 24p imaging signal, for example, (2-e, 2-o), (3-e, 3-o) frame signals, and mixes them. Output a signal. At this time, a mix signal having the same phase as the phase of the fifth field of the 2: 3 pull-down signal to be replaced is output. For example, an arithmetic filter is selected according to whether the field to be replaced is an odd line or an even line, and addition is performed.

  The switching circuit 17 switches and outputs the output of the 2: 3 pull-down conversion circuit 15 and the output of the mix circuit 16 under the control of the switching control circuit 18. The switching control circuit 18 controls the switching circuit 17 so that the fifth field of the 2: 3 pull-down signal is replaced with the mix signal generated by the mix circuit 16 (see FIG. 8 (k2)). Note that in the signal shown in FIG. 8 (k2), the delay due to the calculation is omitted.

  As described above, according to the third embodiment, 60i signal frames corresponding to a plurality of frames of the original 24p imaging signal are added, and the fields before and after the fifth field of the 2: 3 pull-down signal are interpolated. By generating a field (mixed signal) and replacing it with the fifth field, the problem of 2: 3 pull-down that the movement becomes jerky can be reduced.

  Note that the mix circuit may only add the frame including the fifth field and the next frame, for example, as long as the jerky feeling can be reduced without using signals for a plurality of frames.

(Embodiment 4)
FIG. 9 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the member corresponding to the member demonstrated based on FIG. 15, and description is abbreviate | omitted.

  The difference between the fourth embodiment and the conventional example is that the synchronization signal generation unit 6 generates a display-specific vertical synchronization signal (60i-SYNC2), and the display unit 19 receives an input from the memory unit 3. A pair of the 2: 3 pull-down signal and the frame of the original 24p image signal obtained by removing the fifth field of the 2: 3 pull-down signal (the last field obtained by converting 2 frames of the 24p image signal into 5 fields of the 60i signal). The frame is converted into a 60i signal frame corresponding to 1, and an arbitrary level signal is inserted between the frames so that the intervals of the frames are equal. The other parts are generally the same, and the operation is similar.

  FIG. 10 is a block diagram showing an example of the internal configuration of the display unit 19. Reference numeral 20 denotes a 2: 3 pull-down signal input from the memory unit 3, and a 60i signal for (1/2) field scanning time. A delay circuit for delaying, 21 is a 2: 3 pull-down signal input from the memory unit 3, a signal from the delay circuit 20, and a switching circuit for switching and outputting a signal of an arbitrary level, and 22 is an output signal from the switching circuit 21 An addition circuit for adding a display-specific vertical synchronization signal (60i-SYNC2), and 23 is a timing pulse generation time for controlling the switching operation of the switching circuit 21.

The operation of the imaging apparatus according to the fourth embodiment configured as described above will be described with reference to FIGS. 9, 10, and 11. FIG. 11 is a diagram for explaining the operation of the imaging apparatus. FIGS. 9 and 10 show (a), (c), (d), (k1) to (k4), (h1), and (h2). The signal states and operations are shown. The operations other than the synchronization signal generation unit and the display unit are the same as those in the conventional example, and thus description thereof is omitted.

  A 2: 3 pull-down signal shown in FIG. 11 (k1) is input to the display unit 19 and the recording unit 4 from the memory unit 3. Here, the display unit 19 converts this signal as follows. First, the 2: 3 pull-down signal is delayed by the delay circuit 20 by the time for which the 60i signal is (1/2) field-scanned (see FIG. 11 (k2)). The switching circuit 21 switches the original 2: 3 pull-down signal, the delayed signal, and an arbitrary level (for example, black level) signal, and outputs the signal shown in FIG. 11 (k3). That is, the 2: 3 pull-down signal is converted into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal frame from which the fifth field of the 2: 3 pull-down signal is removed, and the frame interval is equal. The signals are switched so as to be a signal in which a signal of an arbitrary level is inserted so as to have an interval.

  The timing pulse generation circuit 23 controls the switching circuit 21 by generating a predetermined switching pulse so that the signal shown in FIG. 11 (k3) is output. That is, based on a 60i vertical synchronization signal 1 (see FIG. 11 (h1)) and a signal obtained by delaying the 60i vertical synchronization signal 1 by the time that the 60i signal is scanned by (1/2) field, A switching pulse is generated.

  The adder circuit 22 is a display element, such as a cathode ray tube, and the 60i vertical synchronization signal 2 shown in FIG. 11 (h2) so that the output signal of the switching circuit 21 (signal shown in FIG. 11 (k3)) is displayed appropriately. Is added to the output signal of the switching circuit 21. The 60i vertical synchronization signal 2 is obtained by shortening the vertical scanning period of the 60i vertical synchronization signal so as to match the length of a signal period of an arbitrary level inserted so that the frame interval is equal. .

  As described above, according to the fourth embodiment, the 2: 3 pull-down signal is converted into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal obtained by removing the fifth field of the 2: 3 pull-down signal. In addition, by making the intervals of the frames equal, it is possible to form a signal having a one-to-one correspondence with the frame of the original 24p imaging signal and the same signal interval, and the movement becomes jerky. : The problem of 3 pull-down can be reduced. Further, if a black level signal is used as an arbitrary level signal, mechanical shutter flickering (black level) can be reproduced as in the case of shooting with a film camera.

  In the fourth embodiment, the delay circuit 20, the switching circuit 21, and the timing pulse generation circuit 23 are used to convert the 2: 3 pull-down signal into a 60i signal that corresponds to the original 24p imaging signal. However, the present invention is not limited to this example as long as the operation is similar.

(Embodiment 5)
FIG. 12 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 5 of the present invention. In addition, the same code | symbol is attached | subjected to the member corresponding to the member demonstrated based on FIG . 1, FIG. 15, and description is abbreviate | omitted.

  The difference between the fifth embodiment, the first embodiment, and the conventional example is that an LPF (low pass filter) for limiting the vertical band of the 24p imaging signal is provided in the memory unit 24, and the vertical of the input 24p imaging signal is provided. The 2: 3 pull-down process is performed after the bandwidth is limited, and the other parts are substantially the same, and the operation is similar.

  FIG. 13 is a block diagram showing an example of the internal configuration of the memory unit 24, 25 is a vertical LPF circuit (vertical band limiting low-pass filter) for limiting the vertical band of the 24p imaging signal, and 26 is an input source. A switching circuit 27 that switches between the 24p imaging signal and the output signal from the vertical LPF circuit 25 and outputs the so-called 2: 3 pulldown signal by subjecting the 24p imaging signal to 2: 3 pulldown processing and converting it to a 60i signal. A 2: 3 pull-down conversion circuit 28 is a switching control circuit that controls the switching circuit 26.

  The operation of the imaging apparatus according to the fifth embodiment configured as described above will be described with reference to FIGS. 12, 13, and 14. FIG. 14 is a diagram for explaining the vertical band limitation of the 24p imaging signal by the vertical LPF circuit 25.

When the vertical resolution of the 24p imaging signal is about twice that of the image signal obtained by the interlace scanning method of the standard television system, the vertical band characteristic of the 24p imaging signal is improved as shown in (1) of FIG. . When a 24p image signal having a high vertical band is sampled at a vertical scanning frequency (960 TV lines) twice that of the standard television system, aliasing noise is generated as indicated by the hatched portion.

  The 2: 3 pull-down signal (60i signal) obtained by performing the 2: 3 pull-down process on the 24p imaging signal in which the vertical band is high and the aliasing signal is generated in this way is 480 TV vertical scanning frequencies of the standard television system. As shown by the dotted line in FIG. 14 (a), the folded signal when sampled by is a signal having a high vertical band and a wide band.

  Usually, the aliasing signal when a standard television system signal is sampled at a frequency of 480 TV lines has a phase difference for each field, so that it is canceled by the monitor and the human eye. However, when a signal with a high vertical band is sampled, the vertical band becomes wide, so that the return signal is detected as flicker, and the screen flickers and is difficult to see.

  Therefore, when a 60i signal obtained by performing 2: 3 pull-down processing on a 24p imaging signal whose vertical resolution is approximately twice that of the standard television system is displayed, the folding signal is detected as flicker as described above, and the screen flickers. The problem becomes difficult.

Therefore, in the fifth embodiment, as shown in (3) of FIG. 14C, a vertical LPF circuit for limiting the vertical band is provided, and the vertical band of the 24p imaging signal is limited by this vertical LPF circuit. : Perform 3 pull-down processing. That is, as shown in FIG. 14B, the vertical band of the 24p imaging signal is limited from ( 1) to (2) , and the 2: 3 pull-down process is performed after the aliasing noise is not generated. Specifically, for example, by adding two adjacent vertical lines of the 24p imaging signal, the vertical band of the 24p imaging signal can be limited from ( 1) to (2) .

If the vertical band is limited in this way so that aliasing noise does not occur, the vertical band of the aliasing signal of the 60i signal obtained by the 2: 3 pull-down process is appropriately set as shown by the dotted line in FIG. it is possible to narrow to significantly can reduce the flicker, it is possible to improve the image quality.

  The switching circuit 26 switches between the original 24p image pickup signal and the signal subjected to the vertical band restriction and outputs it to the 2: 3 pull-down conversion circuit 27. The 2: 3 pull-down conversion circuit 27 converts the 24p imaging signal into a 60i signal and outputs it to the recording unit 4 and the display unit 5 as in the other embodiments.

  Note that the switching circuit 26 may be controlled so that only the 2: 3 pull-down signal output to the display unit 5 or the external monitor becomes a signal subjected to vertical band limitation. In addition, when the 60i signal recorded on the recording medium is used for an external device having a function of returning the 2: 3 pull-down signal to the progressive signal by inverse 2: 3 pull-down conversion, a wide band without vertical band limitation is applied. The switching circuit 26 may be controlled so as to record a 2: 3 pull-down signal having a vertical band characteristic as follows on the recording medium. When the 60i signal recorded on the recording medium is used as it is, the vertical band limitation is performed. The switching circuit 26 may be controlled so as to record the 2: 3 pull-down signal subjected to. Needless to say, switching may be freely selected as appropriate.

  As described above, according to the fifth embodiment, it is possible to reduce flicker caused by converting a 24p image pickup signal into a 60i signal by performing 2: 3 pull-down processing, thereby reducing image quality degradation and flickering in the display unit. Can be suppressed.

  The image pickup apparatus according to the present invention significantly reduces flicker, improves image quality, suppresses the jerky feeling of movement, which is a problem of 2: 3 pull-down, and is a mechanical shutter that is photographed with a film camera. Flicker can be reproduced, and an image signal can be generated by a progressive scanning method with a frame frequency of 24 Hz used for movies and the like, and the image signal is interlaced with a field frequency of 60 Hz which is a standard television method. This is useful for an imaging device that can convert to an interlace signal by a scanning method.

1 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 1 of the present invention. The figure for demonstrating operation | movement of the imaging device by Embodiment 1 of this invention. FIG. 3 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 2 of the present invention. The block diagram which shows an example of an internal structure of the imaging part of the imaging device by Embodiment 2 of this invention The figure for demonstrating operation | movement of the imaging device by Embodiment 2 of this invention. FIG. 5 is a block diagram showing a configuration of an imaging apparatus according to Embodiment 3 of the present invention. The block diagram which shows an example of the internal structure of the memory part of the imaging device by Embodiment 3 of this invention The figure for demonstrating operation | movement of the imaging device by Embodiment 3 of this invention. Block diagram showing the configuration of an imaging apparatus according to Embodiment 4 of the present invention The block diagram which shows an example of the internal structure of the display part of the imaging device by Embodiment 4 of this invention The figure for demonstrating operation | movement of the imaging device by Embodiment 4 of this invention. Block diagram showing the configuration of an imaging apparatus according to Embodiment 5 of the present invention FIG. 9 is a block diagram showing an example of an internal configuration of a memory unit of an imaging apparatus according to Embodiment 5 of the present invention. The figure for demonstrating the vertical band restriction | limiting of the vertical LPF circuit of the imaging device by Embodiment 5 of this invention Block diagram showing the configuration of a conventional imaging device The figure for demonstrating operation | movement of the conventional imaging device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens 2, 9 Imaging part 3, 14, 24 Memory part 4 Recording part 5, 19 Display part 6 Synchronization signal generation part 7 Captured image state detection part 8 Delay part 10 Imaging signal drive circuit 11 Imaging signal drive pulse generation circuit 12 Switching Circuit 13 Sync signal phase determination circuit 15, 27 2: 3 pull-down conversion circuit 16 Mix circuit 17 Switching circuit 18 Switching control circuit 20 Delay circuit 21 Switching circuit 22 Adder circuit 23 Timing pulse generation circuit 25 Vertical LPF circuit 26 Switching circuit 28 Switching control circuit

Claims (6)

An imaging apparatus that converts a 24p imaging signal by a progressive scanning method with a frame frequency of 24 Hz into a 60i signal by an interlace scanning method with a field frequency of 60 Hz, which is a standard television system, by 2: 3 pull-down processing,
An imaging unit that outputs a 24p imaging signal for one frame over (1/30) second every (1/24) second in synchronization with the vertical synchronization signal of the 24p imaging signal;
The 24p imaging signal for which the vertical band of the 24p imaging signal for one frame output from the imaging unit is limited, is written to the storage area in (1/30) seconds, and this vertical band is limited by 2: 3 pull-down processing. A memory unit that outputs a so-called 2: 3 pull-down signal obtained by converting 2 frames of 5 into a 60i signal of 5 fields in synchronization with a vertical synchronization signal of the 60i signal every (1/60) second;
A recording unit for recording the 2: 3 pull-down signal from the memory unit on a recording medium;
An image pickup apparatus comprising: a display unit that displays the 2: 3 pull-down signal from the memory unit.   The imaging apparatus according to claim 1, wherein the memory unit limits a vertical band by adding two adjacent vertical lines of a 24p imaging signal.   3. The imaging device according to claim 1, wherein the memory unit includes a 2: 3 pull-down signal obtained by performing 2: 3 pull-down processing after limiting a vertical band of a 24p imaging signal, and a vertical band. It is possible to output the 2: 3 pull-down signal obtained by performing the 2: 3 pull-down process without limitation, the latter 2: 3 pull-down signal is output to the recording unit, and the former 2 is output to the display unit. An image pickup apparatus that outputs 3 pull-down signals. The imaging apparatus according to claim 1, wherein the memory unit includes a circuit that switches whether to limit a vertical band of a 24p imaging signal written to the storage area. The display unit converts the 2: 3 pull-down signal from the memory unit into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal frame from which the fifth field has been removed. 5. The image pickup apparatus according to claim 1, wherein a display signal in which a black level signal is inserted is generated and displayed so that the frame intervals are equal. An imaging apparatus that converts a 24p imaging signal by a progressive scanning method with a frame frequency of 24 Hz into a 60i signal by an interlace scanning method with a field frequency of 60 Hz, which is a standard television system, by 2: 3 pull-down processing,
An imaging unit that outputs a 24p imaging signal for one frame over (1/30) second every (1/24) second in synchronization with the vertical synchronization signal of the 24p imaging signal;
The so-called 24p imaging signal for one frame output from the imaging unit is written to the storage area in (1/30) seconds, and 2 frames of the 24p imaging signal are converted into 60i signals of 5 fields by 2: 3 pull-down processing. A memory unit that outputs a 2: 3 pull-down signal every (1/60) second in synchronization with a vertical synchronization signal of a 60i signal;
A recording unit for recording the 2: 3 pull-down signal from the memory unit on a recording medium;
The 2: 3 pull-down signal from the memory unit is converted into a 60i signal frame that has a one-to-one correspondence with the original 24p imaging signal frame from which the fifth field is removed, and the interval between the frames is equal. An image pickup apparatus comprising: a display unit that generates and displays a display signal in which a black level signal is inserted so as to have an interval.

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