JPH04259171A - Portable vtr with stereo microphone - Google Patents

Abstract

PURPOSE:To attain a comfortable video image pickup by changing the directivity of a stereo microphone in response to the moving vector of detected plural representative points so as to set the directivity of the stereo microphone automatically. CONSTITUTION:An image pickup signal obtained by a lens 1 and a solid-state image pickup element CCD 2 is inputted to an image pickup signal processing circuit 3, and then digitized by an A/D converter 4 and stored in a field memory 5, and inputted to a moving vector detection section 6. On the other hand, a voice signal collected by an non-directional microphone 8 and a two-directional microphone 9 is mixed in mixing circuits 10, 11 while the collected voice signals are inverted at a prescribed rate and the microphones are used as a stereo microphone. The detection section 6 sets plural detection areas in a fetched pattern to detect a secular moving vector of a representative point in the detection area and a microcomputer 21 adjusts the directivity of the stereo microphone in response to the moving vector. Thus, the video image pickup in response to the movement of an object with full of presence is attained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a portable VT equipped with a stereo microphone that can automatically adjust the directional characteristics and perform stereo recording.
Regarding R.

0002

[Prior Art] Conventional portable VTR (Video Ta
pe Recorder), the subject is captured by the imaging unit (
The image is captured by a video camera), and the image captured by this imaging unit is recorded on a videotape by a recording unit, and it is generally equipped with a built-in microphone to record surrounding sounds at the same time as the image is captured. Here, as a portable VTR, there are those in which an imaging section and a recording section are separated and connected by a cable, and those in which these are integrated. Further, as a microphone, a stereo microphone is often used, which provides a higher sense of realism than a monaural microphone. Furthermore, there are also devices in which the directional characteristics of the microphone are variable and linked to zooming. This means that when the zoom lens is set to telephoto or wide-angle, the directional characteristics of the microphone are narrowed or widened.In such portable VTRs, when zooming in on a distant subject, the subject is unaffected by surrounding noise. It is possible to record the sound clearly.

0003

However, in a portable VTR in which the directional characteristics of the microphone are variable in conjunction with the zoom, the directional characteristics of the microphone do not change if the zoom is constant. Therefore, if you want to change the sound effect depending on the subject you are photographing, that is, the picture, for example, a scene where trains are passing by on the left and right sides of the screen, or children playing in the center of the screen. Even in scenes that moved across the screen, the microphone's directivity remained constant, resulting in a lack of realism. In such cases, you can improve the sense of presence by connecting an external microphone to the external input terminal that comes with the video camera and adjusting the directional characteristics of the microphone by changing the direction of the external microphone. can be done.

However, connecting an external microphone and changing its direction depending on the picture is complicated and also impairs the mobility of the portable VTR. Furthermore,
Even though the built-in microphone's directional characteristics could be changed by zooming, it did not change automatically. The present invention has been made in view of the above-mentioned prior art, and provides a portable VTR with a stereo microphone that allows comfortable video shooting by automatically setting the directional characteristics of the stereo microphone according to the movement of the subject being photographed. The purpose is to provide the following.

[0005]

[Means for Solving the Problems] The configuration of the present invention that achieves the above object includes an imaging unit for imaging a subject, a stereo microphone for recording audio, and an image captured by the imaging unit and recorded by the stereo microphone. In a portable VTR equipped with a recording section for recording the recorded audio on a videotape,
a motion vector detection section that sets a plurality of detection regions within the screen where the subject is captured by the imaging section, and detects a motion vector over time of a representative point within the detection region; The present invention is characterized by further comprising a control circuit that varies the directivity characteristics of the stereo microphone according to motion vectors of a plurality of representative points.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments shown in the drawings. 1 to 4 show the circuit configuration of a portable VTR with a stereo microphone according to an embodiment of the present invention. As shown in the figure, an imaging signal obtained by a lens 1 and a solid-state imaging device (hereinafter referred to as CCD) 2, which is an imaging unit for imaging a subject, is input to an imaging signal processing circuit 3, and then an A/ The signal is digitized by the D converter 4 and stored in the field memory 5, while being input to the motion vector detection section 6. The data stored in the field memory 5 is then read out, converted into an analog signal by the D/A converter 7, and outputted as a Y output, an RY output, and a BY output.

On the other hand, the omnidirectional microphone 8 and the figure-directional microphone 9 send audio signals recorded by them to the mix circuit 1.
By mixing by reversing the positive and negative at a predetermined ratio at 0 and 11,
Used as a stereo microphone. mix circuit 1
Level controllers 0 and 11 have built-in level controllers, and the mixing ratio thereof is adjusted by a microcomputer (hereinafter referred to as microcomputer) 21, which is a control circuit. The audio signals output from the mix circuits 10 and 11 are
Digitized by A/D converter 12 and stored in audio memory 1
3, the signal is read out, converted into an analog signal by a D/A converter 14, and outputted as a left channel audio signal and a right channel audio signal.

These left channel audio signals and right channel audio signals are the aforementioned Y output, RY output,
It is recorded on videotape in the recording unit along with the BY output, but this recording unit is similar to a general portable VTR, so
I will omit the explanation here.

As shown in FIG. 2, the motion vector detection section 6 includes a representative point memory 15, a correlation calculation section 16, a correlation value memory 17, a minimum value detection section 18, and a controller 19 for controlling these. It is connected to microcomputer 21. Here, the screen of CCD2 is shown in FIG. 3(a).
As shown in the figure, it is divided into 35 blocks of 5 rows x 6 columns (horizontal x vertical), and a total of 6 blocks among these blocks are set as detection areas (shown in black in the figure). In this embodiment, the block is divided into 35 blocks, but it can be divided into any number of blocks, and the number of detection ranges may be arbitrary. Here, each detection area is composed of a large number of correlation points. For example, as shown in Fig. 3(b), the detection area K is composed of multiple correlation points S(Xk
-i, Yk-j), and images of the real-time field are sequentially taken into the field memory 5. Further, as shown in FIG. 3(c), a representative point D (Xk, Yk) is set at the center position of each detection range and is stored in the representative point memory 15. The correlation calculation unit 16 calculates the representative point D(Xk
, Yk ) and multiple correlation points S(
The correlation value with Xk-i, Yk-j) is sequentially calculated for each correlation point. That is, N− stored in the representative point memory 15
The representative point Dn-1 (Xk, Yk) of one field and the correlation point Sn which is (i, j) away from the representative point (Xk, Yk) of N fields stored in the field memory 5.
The absolute value of the difference between (Xk-i, Yk-j) is determined as follows and is used as a correlation value. Correlation value = |Dn-1 (Xk, Yk)-Sn (X
k-i, Yk-j) |

[0010] Such a correlation value is calculated from all (i, j) distant correlation points S within the detection range K.
n is calculated and stored in the correlation value memory 17. The point with the lowest correlation value is the point where the representative point has moved over time in the real-time field. The minimum value detection unit 18 determines the coordinates to which the representative point has moved, that is, the coordinates (Xk, Yk) of the correlation point with the smallest correlation value within the detection range K stored in the correlation value memory 17, as follows. (X, Y)=MIN {|Dn-1 (Xk, Yk
)-Sn (Xk-i, Yk-j) |

0011
] These coordinates (X, Y) become the movement vector for the representative point (Xk, Yk). The coordinates (X, Y) calculated as this movement vector are output to the microcomputer 21, and the microcomputer 21 synthesizes the plurality of movement vectors obtained in each detection area and determines the direction of the object's movement within the screen. Understand the speed. The microcomputer 21 then adjusts the level controllers of the mix circuits 10 and 11 according to the movement of the subject to adjust the directional characteristics of the stereo microphone. For example, if it is detected from a movement vector that a plurality of children who were at the center of the screen are dispersing around the screen, the directional characteristics of the stereo microphone may be made omnidirectional. On the other hand, if the children who were scattered around the screen are concentrating on the center, it is better to use a unidirectional display. Furthermore, when a train moves across the screen, it is preferable to swing the unidirectionality left and right to follow the progress of the train.

Furthermore, in this embodiment, special effects can be added to the audio signal depending on the movement of the subject. That is, the memory controller 22 controls the audio memory 13 in accordance with the movement of the subject detected by the microcomputer 21, and adds special effects such as echo to the audio signal.

Portable VTR of this embodiment having the above configuration
Then, the directional characteristics of the stereo microphone are automatically adjusted as shown in FIG. 4 according to the movement of the subject to be imaged. First, as shown in the figure, when the imaging signal begins to be written as N fields to the field memory 5 via the lens 1, CCD 2, imaging signal processing circuit 3, and A/D converter 4, each detected signal is stored in the representative point memory 15. While the representative points of the range are stored, the correlation calculation unit 16 stores the representative points D(X
k, Yk) and the correlation point S(Xk
-i, Yk-j) are sequentially calculated,
It is stored in the correlation value memory 17 as a correlation value. When the writing of N fields is completed, the minimum value detection unit 18 detects the minimum correlation value among the correlation values stored in the correlation memory 17, and calculates it as a motion vector. Microcomputer 21
Then, the motion of the subject is determined from the motion vector calculated by the minimum value detection unit 18, and the mixing ratio of the mix circuits 10 and 11 is adjusted according to the subject to change the directional characteristics of the microphone. Further, when a special effect is to be applied by the microcomputer 21, the audio memory 13 is adjusted via the memory controller 22.

As described above, in this embodiment, the directional characteristics of the microphone are automatically and precisely changed in accordance with the movement of the subject to be imaged, so that it is possible to take a video with a sense of realism. Therefore, there is no need to connect an external microphone, making handling extremely easy. Additionally, special effects can be added to the audio, which in combination with the directional characteristics of the microphone allows for even more effective recording.

In the above embodiment, a combination of an omnidirectional microphone and a bidirectional microphone is used as a stereo microphone, but a general stereo microphone may also be used. Furthermore, the directionality may be adjusted by mechanically moving the direction of the microphone instead of adjusting the mixing ratio of the omnidirectional microphone and the bidirectional microphone.

[0016]

[Effects of the Invention] As described above in detail based on the embodiments, the present invention enables comfortable video shooting by automatically setting the directional characteristics of the stereo microphone according to the movement of the subject being photographed. . This eliminates the need for an external microphone,
The mobility of a portable VTR can be improved. The present invention is applicable not only to a VTR with an integrated camera, but also to a separate VTR separated from a camera.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing a portable VTR with a stereo microphone according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a motion vector detection section used in the embodiment shown in FIG. 1;

[Fig. 3] Regarding the screen, Fig. 3 (a) is an explanatory diagram showing the division of the entire screen into blocks, Fig. 3 (b) is an explanatory diagram showing the correlation points of the detection range, and Fig. 3 (c) is an explanatory diagram showing the division of the entire screen into blocks. It is an explanatory diagram showing representative points.

FIG. 4 is a flowchart showing calculation of a motion vector and adjustment of microphone directivity characteristics in the above embodiment.

[Explanation of symbols]

1 Lens 2 CCD 3 Imaging signal processing circuit 4 A/D converter 5 Field memory 6 Motion vector calculation unit 7 D/A converter 8 Omnidirectional microphone 9 Bidirectional microphone 10 Mix circuit 11 Mix circuit 12 A/D converter 13 Voice memory 14 D/A converter 15 Representative point memory 16 Correlation calculation section 17 Correlation value memory 18 Minimum value detection section 19 Controller 20　SSG 21 Microcomputer 22 Memory controller

Claims (1)

[Claims] [Claim 1] An imaging unit that captures an image of a subject, a stereo microphone that records audio, and a recording unit that records the image captured by the imaging unit and the audio recorded by the stereo microphone on a videotape. In a portable VTR, a motion vector detection section sets a plurality of detection regions within a screen where a subject is captured by the imaging section, and detects a motion vector over time of a representative point within the detection region; 1. A portable VTR with a stereo microphone, comprising: a control circuit that varies the directivity characteristics of the stereo microphone according to motion vectors of a plurality of representative points detected by the stereo microphone.