KR100567576B1 - Digital Video Camera Wireless Video Signal Transmitter - Google Patents

Abstract

In a digital CCD camera, an analog signal of a subject photographed by a CCD is converted into a digital signal by an A / D converter, and then digitally modulated and output by a DDS. The digitally modulated signal is converted into an analog signal by the D / A converter and then low-pass filtered by the LPF. The low-pass filtered signal is frequency mixed with the local oscillation frequency and then transmitted as a frequency signal of the corresponding band through the BPF and the antenna. Since this transmitted signal is a frequency-modulated signal, it is strong against noise that may occur during propagation, and is reproduced as a clear image by digitally processing the transmitted signal on the receiving side.

Description

Digital Video Camera Wireless Video Signal Transmitter

The present invention relates to a wireless video signal transmission apparatus, and more particularly, to a digital CCD camera wireless video signal transmission apparatus for wirelessly transmitting a photographed video signal to another device in a digital still camera. It is about.

In general, a digital CCD camera records two-dimensional information of a subject. The digital CCD camera converts an optical image of the subject into an electrical image and stores the image in a memory, and if necessary, reads and prints the image stored in the memory or another device, The camera can transmit and process the video to a device that can display or process the image.

Fig. 2 shows a configuration of a video signal transmission apparatus which conventionally transmits an image photographed by a digital CCD camera to another device.

As shown in FIG. 2, in a conventional digital CCD camera, an analog signal processor 110, an A / D converter 120, and a DCP (digital camera) are output at an output terminal of a charge coupled device (CCD) 100. processor 13 is sequentially connected, and the frame memory 140, the signal mixing unit 150, the compression memory 160, and the image transmitter 180 are sequentially connected to an output terminal of the DCP 130. It is.

The image transmitter 180 may generate a reference frequency generator 181 for generating a reference frequency, a pulse detector PD for detecting a signal according to the reference frequency, and a signal from the pulse detector 182. A low pass filter (LPF) 183 for low-pass filtering and outputting, an adder 184 for adding and outputting the filtered signal and the video signal from the DCP 130, and an adder 184 A voltage controlled oscillator (VCO) 185 for oscillating and outputting a signal, a local osillator 186 for generating a local oscillation frequency, and a signal and a local output from the voltage controlled oscillator 185 An adder 187 for mixing an oscillation frequency to output an intermediate frequency signal, a band pass filter (BPF) 188 for passing only a signal of a corresponding band among the intermediate frequency signals from the adder 187, and a band From pass filter 188 An antenna 189 for transmitting the signal.

The operation of the wireless video signal transmission device of the conventional digital CCD camera having such a structure will be described.

The imaging signal output from the CCD 100, that is, the electrical signal on the subject formed by a photographing lens (not shown) is removed by the analog signal processing unit 110, and then digitally processed by the A / D converter 120. The signal is converted into a signal and input to the DCP 130. The DCP 130 generates a video signal by processing a signal output from the A / D converter 120 according to a conventional video processing technique, and then converts the video signal into an analog signal and outputs the converted video signal.

The analog video signal output from the DCP 130 is displayed or digitally processed through the signal mixing unit 150 and the display unit 17 and stored in the compression memory 160 and transmitted to another video device capable of displaying and storing the image. In order to be input to the image transmitter 180.

The analog image signal input to the image transmitter 180 is frequency-mixed with the signal output from the adder 184 and input to the voltage controlled oscillator 185. The voltage controlled oscillator 185 outputs the oscillation frequency by varying the oscillation frequency according to the signal output from the adder 184, which is mixed with the local oscillation frequency applied from the local oscillator 186 by the adder 187 to an intermediate frequency. It is output as a signal. This intermediate frequency signal is filtered through the BPF 188 only the frequencies of the corresponding band and then transmitted to the other imaging device via the antenna 189.

In this signal transmission operation, the pulse detector 182 detects and feeds back an oscillation frequency output from the voltage controlled oscillator 185 to generate a signal having a constant oscillation frequency.

However, the conventional video signal transmission apparatus has a disadvantage in that noise is frequently generated by analog signal processing.

In addition, since the signal picked up by the CCD is transmitted after being completely processed by the DCP as an image signal, there is a disadvantage that noise may be generated during the image processing operation.

Therefore, the present invention has been made in an effort to provide a wireless video signal transmission apparatus for digitally modulating an image signal in a digital CCD camera and transmitting the same to another image processing apparatus without noise.

In order to achieve this technical problem, in this invention, the analog signal on the subject image | photographed by the imaging means is converted into a digital signal by a 1st conversion means, and this digital signal is digitally modulated by a digital modulation means. The digitally modulated signal is converted into an analog signal by the second conversion means, and then low-pass filtered by the low pass filter means, which is frequency-converted by the tuning means and transmitted as a frequency signal of the corresponding band through the antenna. .

The digital modulating means comprises a DDS (Direct Digital Synthesizer) for converting and outputting a frequency corresponding to the digital signal input from the first signal converting means into digital data.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows the structure of a wireless video signal transmitting apparatus of a digital CCD camera according to an embodiment of the present invention.

As shown in FIG. 1, in the wireless video signal transmitting apparatus of the digital CCD camera according to the embodiment of the present invention, an analog signal processor 2 and an A / D converter 3 are provided at the output terminal of the CCD 1. The DCP 4 and the image transmitter 8 are connected to the output terminal of the A / D converter 3 in sequence.

The signal mixing unit 5, the frame memory 6, the compression memory 7, and the image transmitting unit 8 are sequentially connected to the output terminal of the DCP 4, and the display unit 9 is connected to the output terminal of the signal mixing unit 5. ) Is connected.

The image transmitter 8 is a direct digital synthesizer (DDS) 81 for digitally modulating the signal applied from the A / D converter 3, and a digital signal modulated by being connected to an output terminal of the DDS 81 as an analog signal. A D / A converter 82 for converting and outputting, an LPF 83 for low-pass filtering a signal applied to the output terminal of the D / A converter 82, and a local oscillator 84 for generating a local oscillation frequency. And an adder 85 for mixing the signal of the LPF 83 with the local oscillation frequency to generate an intermediate frequency signal, and a BPF 86 for passing only a signal of a corresponding band among the intermediate frequency signals from the adder 85, An antenna 87 for transmitting signals from the BPF 86.

An image processing apparatus for receiving a signal applied from a wireless image signal transmitting apparatus of such a digital CCD camera includes an antenna 91 for receiving a transmitted signal and a local oscillation unit for generating a local oscillation frequency, as shown in FIG. 92, an adder 93 for mixing a signal received by the antenna 91 and a local oscillation frequency, a demodulator 95 for demodulating a signal applied from the adder 93, and a demodulator 95 A signal delay unit 96 for delaying a demodulated signal of a predetermined time, an A / D converter 97 for converting the delayed signal into a digital signal, and a DCP 98 for processing a digital signal to generate a corresponding video signal. And a video encoder 99 for encoding the video signal and outputting the corresponding video.

The operation of the wireless video signal transmitting apparatus of the digital CCD camera according to the embodiment of the present invention having such a structure will be described.

In the present invention, the captured signal is converted into a digital signal before being processed into an image signal, and then modulated to be transmitted to another image processing apparatus.

First, when power is supplied to the digital CCD camera and the photographing button is pressed by the user, the subject image is imaged on the CCD 1 through a photographing optical system (not shown). The CCD 1 outputs an electric signal corresponding to the image-shaped subject, which is input to the analog signal processor 2.

The analog signal processor 2 includes a known correlated double sampling (CDS) circuit and an automatic gain control (AGC) circuit. The input signal is correlated double sampling and noise is removed and the gain is adjusted and output. The analog signal whose noise is removed and whose gain value is adjusted is converted into a digital signal by the A / D converter 3.

The digitally converted signal is processed by the DCP 4 according to a conventional image processing technique to be output as an image signal, and then displayed or digitally processed through the signal mixing unit 150 and the display unit 17 to be compressed. Are stored in.

In addition, the digitally converted signal is input to the image transmitter 8 as shown in FIG. 1 and transmitted to another image apparatus capable of displaying and storing the image.

The DDS 81 of the video transmitter 8 converts the frequency corresponding to the digital signal output from the A / D converter 3 into digital data and outputs it. At this time, this digital data is digital frequency modulated data. This digital data is converted into an analog signal by the D / A converter 82 and transmitted.

That is, the signal converted into the analog signal by the D / A converter 82 is passed through the LPF 83 only the signal of the low frequency band is output to the adder 85. The adder 85 raises the frequency output from the LPF 83 to the licensed wireless communication frequency band so that the signal is transmitted through the antenna 87. That is, the local oscillator 84 generates a local oscillation frequency, the adder 85 mixes the filtered signal output from the LPF 83 and the local oscillation frequency to generate an intermediate frequency signal, and the intermediate frequency signal is a BPF. Is entered (86). The BPF 86 passes only the frequency signals of the corresponding bands among the intermediate frequency signals output from the adder 85 and outputs them to the antenna 87, whereby image signals are transmitted through the antenna 87.

In this way, the image signal photographed by the digital CCD camera is digitally modulated and transmitted, and the signal transmitted from the digital CCD camera is received by the receiver having the structure as shown in FIG. 1, that is, the image processing apparatus 9. As the image processing apparatus 9, any apparatus capable of processing, storing and displaying image signals such as a computer can be used.

The transmitted signal from the digital CCD camera is received by the antenna 91 and input to the adder 93, and the adder 93 detects the received signal according to the local oscillation frequency applied from the local oscillator 92, that is, Frequency is converted and output.

The signal damped by the adder 93 is input to the demodulator 95 by passing only the signal of the corresponding band by the BPF 99, and the demodulator 95 demodulates and outputs the input signal. Since the signal delay unit 96 may generate a phase delay at the time of modulation and demodulation of the signal, the signal delay unit 96 delays the signal applied from the demodulation unit 95 and adjusts it to match the signal phase at the time of modulation.

The signal output from the signal delay unit 96 is converted into a digital signal by the A / D converter 97 and then input to the DCP 98 to be processed into a video signal reproducible as an original image. In the present invention, the signal captured by the CCD 1 in the digital CCD camera is digitally converted and transmitted before being processed by the DCP 4, so that the receiver, i.e., the image processing device 9 which receives / processes the transmitted signal, DCP (98) for processing the received signal as a video signal should be included.

The video signal output from the DCP 98 is output by the video encoder 99 as an original video.

As described above, according to the embodiment of the present invention, in the digital CCD camera, the picked-up subject signal is converted into a digital signal and then modulated and transmitted, thereby providing the effect of transmitting the signal without noise.

Since this transmitted signal is a frequency-modulated signal, it is strong against noise that may occur during propagation, and is reproduced as a clear image by digitally processing the transmitted signal on the receiving side.

In addition, the signal captured by the digital CCD camera is digitally modulated and transmitted before being processed to provide an effect of simplifying the tuning process.

The wireless video signal transmitting apparatus according to the present invention can be used for digital still cameras, surveillance CCD cameras, and the like, but is not limited thereto, and can be used for all apparatuses using an image pickup device.

1 is a block diagram of a wireless video signal transmitting apparatus of a digital CCD camera according to an embodiment of the present invention;

Fig. 2 is a block diagram of a wireless video signal transmitting apparatus of a conventional digital CCD camera.

Claims (2)

Imaging means for outputting an electrical signal corresponding to an optically imaged subject; First signal conversion means for converting the analog signal output from the image pickup means into a digital signal; Digital modulation means for modulating the digital signal and outputting the digital signal as digital frequency modulated digital data; Second conversion means for converting the digital data output from the digital modulation means into a corresponding analog signal; Low-pass filter means for filtering and outputting the analog signal; And Tuning means for frequency-converting the filtered signal and transmitting it as a frequency signal of a corresponding band Including, The digital modulation means is a wireless video signal wireless transmission device of a digital CCD camera consisting of a direct digital synthesizer (DDS). The method of claim 1, wherein the tuning means, A local oscillator for generating a local oscillation frequency; An adder for mixing the signal output from the low pass filter means with the local oscillation frequency to generate an intermediate frequency signal; A band pass filter for passing only a signal of a corresponding band among the intermediate frequency signals; And an antenna for transmitting a signal output from the band pass filter.