JP4661222B2 - Video camera - Google Patents

Description

  The present invention relates to a video camera used for a broadcast site such as television broadcasting or studio photography.

  As a format of a high-definition television signal used in a television broadcasting station or the like, the 1080 / 60i system or 720 / 60p system of SMPTE (Society of Motion Picture and Television Engineers) is generally adopted.

  The 1080 / 60i system television signal is an interlace system in which the number of pixels in the horizontal direction is 1920 dots and the number of lines in the vertical direction is 1080 lines, and the system is a television signal system in which the transmission rate is 60 fields / second.

  The 720 / 60p television signal is a progressive method in which the number of pixels in the horizontal direction is 720 dots, the number of lines in the vertical direction is 1080 lines, and the transmission signal has a transmission rate of 60 frames per second.

  Recent video cameras for studios can support both 1080 / 60i system and 720 / 60p system television signals. There are several methods for supporting both the 1080 / 60i method and the 720 / 60p method, as described below, but each has its own drawbacks.

--First method--
The first method uses a CCD (Charge Coupled Device) driven by the 1080 / 60i system, and when outputting a 1080 / 60i system television signal, the image signal obtained from the CCD is used as it is. When a 60p television signal is output, the 1080 / 60i image signal is converted into a 720 / 60p television signal. A disadvantage of the first method is that when a 720 / 60p television signal is output, the horizontal conversion is from a large number of pixels to a small number, so there is no problem in image quality. Since the conversion is an interlace to progressive conversion, the image quality itself is inferior compared to the case where the image sensor itself uses an image sensor that operates in the 720 / 60p system.

--Second method--
The second method is a method of increasing the number of image sensors in the vertical direction and changing the combination to obtain the number of scanning lines corresponding to each method. The second method is not practical because it is possible to obtain an optimal vertical pixel, but the optical filter characteristic in front of the image sensor required by each method changes.

  The present invention solves the above-described problems, and can output both 1080 / 60i system and 720 / 60p system television signals, and the television signals of either system have high image quality. The purpose is to provide a video camera.

The video camera according to the present invention captures a subject, is a progressive method in which the number of pixels in the horizontal direction is 1920 dots and the number of lines in the vertical direction is 1080 lines, or the number of pixels in the horizontal direction is 1920 dots and the number of lines in the vertical direction. Is an image sensor that outputs an interlaced image signal of 1080 lines, a drive pulse generator that generates a vertical sync pulse and a horizontal sync pulse to control the drive of the image sensor, and an image output from the image sensor Image processing means for performing predetermined processing on the signal, and format conversion means for converting the image signal output from the image processing means into a television signal of a predetermined moving image format, and the drive pulse generating means Is an output terminal for outputting a positive differential signal of the vertical synchronization pulse, and a negative difference of the vertical synchronization pulse. An output amplifier having an output terminal for outputting a signal, between the output terminal for outputting the output terminal and the negative differential signal to output a positive differential signal of the output amplifier, LC filter connected The LC filter is of a progressive type in which the transmission characteristic of the differential transmission path between the output amplifier and the image sensor is 1920 dots in the horizontal direction and 1080 lines in the vertical direction. The frequency conversion is performed so that the frequency characteristics are set so as to have two resonance points of frequencies corresponding to the interlace method with the corresponding frequency, the number of pixels in the horizontal direction of 1920 dots, and the number of lines in the vertical direction of 1080 lines. In this example, a progressive image signal with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction is input. An interlaced television signal with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction, or 1280 dots in the horizontal direction and 720 lines in the vertical direction. When generating an interlaced television signal with a horizontal pixel count of 1920 dots and a vertical line count of 1080 lines, the above-mentioned drive pulse is generated. The image pickup device is driven and controlled so as to output an interlaced image signal having 1920 pixels in the horizontal direction and 1080 lines in the vertical direction by means, and predetermined processing is performed by the image processing means. An image signal is output, the number of pixels in the horizontal direction is 1280 dots, and the vertical direction When a progressive television signal having a number of 720 lines is output, the drive pulse generator outputs a progressive image signal having 1920 pixels in the horizontal direction and 1080 lines in the vertical direction. The image pickup device is driven and controlled, and a television signal converted into a moving image format by the format conversion means is output.

In the video camera according to the present invention described above, when outputting an interlaced television signal having 1920 pixels in the horizontal direction and 1080 lines in the vertical direction, the number of pixels in the horizontal direction is set by the drive pulse generator. The image pickup device is driven and controlled so as to output an interlaced image signal having 1920 dots and 1080 lines in the vertical direction, and an image signal obtained by performing predetermined processing by the image processing means is output. When a progressive television signal having a number of 1280 dots and a vertical number of lines of 720 lines is output, the drive pulse generating means causes the progressive number of 1920 dots in the horizontal direction and 1080 lines in the vertical direction. Drive the image sensor to output the image signal of the The preparative converting means for outputting a television signal converted to the video format.

Thus, in the video camera according to the present invention, when a 1080 / 60i system television signal is desired, the image sensor is driven by the 1080 / 60i system, and only when a 720 / 60p television signal is desired. By operating the conversion means, both 1080 / 60i system and 720 / 60p system television signals can be obtained while suppressing power consumption when the image sensor is driven by either 1080 / 60p system or 1080 / 60i. Output with high image quality .

  A camera system to which the present invention is applied will be described below with reference to the drawings.

  As shown in FIG. 1, the camera system 1 to which the present invention is applied captures an image of a subject and outputs a 1080 / 60i system or 720 / 60p system television signal based on the image signal obtained by the imaging. It comprises a camera head unit (CHU) 2 and a camera control unit (CCU) 3 that performs remote control of the CHU 2 and recording and editing of television signals output from the CHU 2. The television signal output from the CHU 2 is transmitted to the CCU 3 by a transmission cable or wireless transmission.

  Note that the 1080 / 60i system television signal is an interlace system in which the number of pixels in the horizontal direction is 1920 dots and the number of lines in the vertical direction is 1080 lines. Signal.

  The 720 / 60p system television signal is a television signal stipulated in SMPTE with a progressive system with 720 dots in the horizontal direction and 1080 lines in the vertical direction and a transmission rate of 60 frames per second. is there.

  FIG. 2 is a block diagram of the camera head unit 2.

  As shown in FIG. 2, the camera head unit 2 includes a lens unit 11, an image sensor 12, an analog processing and AD conversion unit 13, a camera signal processing unit 14, a format conversion unit 15, an output unit 16, An image conversion unit 17, a finder 18, and a drive pulse generation unit 19 are provided.

  The lens unit 11 is provided with a focus lens, a zoom lens, a diaphragm blade, and the like, and a drive unit that drives these lenses. The lens unit 11 receives subject image light to be imaged and forms an image on the light receiving surface of the image sensor 12.

  The image sensor 12 is a solid-state image sensor such as a CCD image sensor. The imaging element 12 has unit pixels arranged in a matrix on the light receiving surface, and photoelectrically converts light irradiated on each unit pixel. The image sensor 12 outputs an image signal by scanning unit pixels arranged in a matrix and reading out an electric signal. The image signal read by the image sensor 12 is supplied to the analog processing and AD conversion unit 13.

  The analog processing and AD conversion unit 13 performs analog processing such as clamping and amplification processing on the signal output from the image sensor 12, performs A / D conversion, and digitizes the signal. The image signal digitized by the analog processing and AD conversion unit 13 is supplied to the camera signal processing unit 14.

  The camera signal processing unit 14 performs processing such as white balance processing, aberration correction processing, and shading processing. The image signal subjected to these processes is supplied to the format conversion unit 15.

  The format conversion unit 15 converts the format of the image signal input from the camera signal processing unit 14 into a 1080 / 60i format or 720 / 60p format television signal. The 1080 / 60i system television signal or the 720 / 60p system television signal is supplied to the output unit 16.

  The output unit 16 modulates a 1080 / 60i television signal or a 720 / 60p television signal into a predetermined carrier wave signal or optical signal and transmits the modulated signal to a camera control unit (CCU).

  The image conversion unit 17 receives the 1080 / 60i television signal or the 720 / 60p television signal output from the format conversion unit 15. The image conversion unit 17 reduces the image size so that the input television signal is displayed by the finder 18 and converts the television signal into a predetermined television signal system in which the finder 18 operates.

  The finder 18 is a display device for shooting confirmation. The finder 18 displays the television signal output from the image conversion unit 17 and displays the image being shot to the operator.

  The drive pulse generator 19 generates a vertical synchronization pulse and a horizontal synchronization pulse, and performs drive control of the image sensor 12.

  Here, the drive pulse generator 19 drives the image sensor 12 by the 1080 / 60p method. That is, the image sensor 12 outputs an image signal corresponding to the 1080 / 60p system.

  The 1080 / 60p format image signal is a progressive format with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction, and an image signal read from the image sensor 12 at a transmission rate of 60 fields / second. It is. That is, the image sensor 12 outputs an image signal having a progressive method with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction and a transmission rate of 60 fields / second.

  The format converter 15 receives a 1080 / 60p image signal. The format conversion unit 15 selects a television system to be output by the user. That is, either the 1080 / 60i method or the 720 / 60p method is selected by the user.

  When the 1080 / 60i format is selected, the format conversion unit 15 generates a 1080 / 60i format television signal based on the 1080 / 60p format image signal. When the 720 / 60p format is selected, the format conversion unit generates a 720 / 60p format television signal based on the 1080 / 60p format image signal.

  For this reason, the video head unit 2 generates, as an original image, a 1080 / 60p format image signal having a large number of pixels both horizontally and vertically for both 1080 / 60i format and 720 / 60p format television signals. Can do. Therefore, when outputting 1080 / 60i system and 720 / 60p system television signals, there are fewer pixels in both the horizontal and vertical directions than the original image. An image quality signal can be obtained.

  In addition, the video head unit 2 transmits data to the camera control unit 3 by the 1080 / 60i method and the 720 / 60p method, although the image pickup device 12 is operated by the 1080 / 60p method. For this reason, the transmission rate from the video head unit 2 to the camera control unit 3 can be reduced, and the necessary bandwidth can be reduced.

  The image pickup device 12 is driven by the 1080 / 60p method, but may be driven by the 1080 / 60i method by making a predetermined change to an internal circuit or the like or a read processing part. With this change, when you want to obtain 1080 / 60i system television signals, drive the image sensor 12 with 1080 / 60i system and convert the format only when you want to obtain 720 / 60p television signals. The unit 15 may be operated.

  In general, the CCD is differentially driven by a vertical synchronizing pulse. In the video head unit 2, the output terminal of the positive differential signal of the vertical synchronizing pulse and the negative differential signal of the vertical synchronizing pulse are used. An LC filter is provided between the output terminals of the output amplifier. When this LC filter is driven by both the 1080 / 60p system and the 1080 / 60i system, the LC filter has two resonance points of a frequency corresponding to the 1080 / 60p system and a frequency corresponding to the 1080 / 60i system. The frequency characteristics are set. This makes it possible to reduce power consumption when driven by either the 1080 / 60p system or 1080 / 60i.

1 is a schematic external view of a video camera system to which the present invention is applied. It is a block block diagram of a camera head unit.

Explanation of symbols

1 camera system, 2 camera head unit, 3 camera control unit, 15 format converter

Claims (1)

The subject is imaged and is a progressive image with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction, or an interlaced image with 1920 dots in the horizontal direction and 1080 lines in the vertical direction. An image sensor that outputs a signal;
Drive pulse generating means for generating a vertical sync pulse and a horizontal sync pulse to control the drive of the image sensor;
Image processing means for performing predetermined processing on the image signal output from the image sensor;
Format conversion means for converting the image signal output from the image processing means into a television signal of a predetermined moving image format,
The drive pulse generating means includes an output amplifier having an output terminal that outputs a positive differential signal of the vertical synchronization pulse and an output terminal that outputs a negative differential signal of the vertical synchronization pulse, and the output An LC filter is connected between the output terminal that outputs the positive differential signal and the output terminal that outputs the negative differential signal of the amplifier ,
The LC filter has a transmission characteristic of a differential transmission path between the output amplifier and the imaging device, a frequency corresponding to a progressive method in which the number of pixels in the horizontal direction is 1920 dots and the number of lines in the vertical direction is 1080 lines, The frequency characteristics are set so that there are two resonance points of the frequency corresponding to the interlace method with the number of pixels in the horizontal direction of 1920 dots and the number of lines in the vertical direction of 1080 lines,
The format conversion means receives a progressive image signal with 1920 pixels in the horizontal direction and 1080 lines in the vertical direction, and the input image signal has 1920 pixels in the horizontal direction and the vertical number. Convert to either an interlace television signal with 1080 lines in the direction, or a progressive television signal with 1280 dots in the horizontal direction and 720 lines in the vertical direction. ,
When an interlaced television signal having a horizontal pixel count of 1920 dots and a vertical line count of 1080 lines is output, the drive pulse generating means causes the horizontal pixel count to be 1920 dots and the vertical line count to be The image pickup device is driven and controlled to output a 1080-line interlaced image signal, and an image signal subjected to predetermined processing by the image processing means is output.
When a progressive-type television signal having a horizontal pixel count of 1280 dots and a vertical line count of 720 lines is output, the drive pulse generator means the horizontal pixel count of 1920 dots and the vertical line count. A video camera that drives and controls the image sensor so as to output a 1080 format progressive image signal, and outputs a television signal converted into a moving image format by the format conversion means.

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