KR0165380B1 - PAL color charge coupled device camera - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a charge coupled device (CCD) camera for monitoring a PAL system. In contrast, the present invention relates to a PAL type CCD camera in which the frequency of the color synchronizing signal has a frequency other than 1/2 of the frequency of the main clock.

That is, the PAL type color CCD camera according to the present invention does not use 1/2 of the frequency of the main driving clock as the frequency of the color synchronizing signal, unlike the NTSC type CCD color camera. In order to match the phase of each horizontal period, it is characterized by using a VCO for providing a color synchronization signal clock, a phase comparing means, and a low pass filter for converting a digital pulse signal, which is a phase difference signal, into an analog signal.

Description

PAL color charge coupled device camera

1 is a block diagram of an image portion of an NTSC type color CCD camera,

2 is a block diagram of an image part of a PAL type color CCD camera according to the present invention.

3 is an internal configuration diagram of a synchronization generator of an image unit of a PAL color CCD camera according to the present invention;

4 is a timing diagram of various signals of the PAL type color CCD camera timing controller according to the present invention.

* Explanation of symbols on the main parts of the drawings

10 CCD imaging unit 11 CCD element

12: vertical driver 20: timing control unit

21: timing generator (IC) 22: synchronization signal generator

23: crystal oscillator 24: low pass filter

25: VCO 30: White Balance IC

40: sample / holder and AGC IC 50: image processor

60: encoder 70: 6 dB amplifier

80: image signal processing unit

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a charge coupled device (hereinafter referred to as CCD) camera for monitoring a PAL system. The frequency of the signal is related to a PAL type CCD camera that is not 1/2 of the main clock frequency.

1 is a block diagram of an image part of an NTSC type color CCD camera. Looking at the configuration with reference to this drawing as follows.

The CCD imager 10 which accumulates an electric pixel signal from the reflected light of the subject, the image signal processor 80 which receives an image signal from the CCD imager and processes the image signal, and three colors of R, G, and B. At the same time, it is necessary for the operation of the white balance unit 30, the CCD imaging unit 10, the white balance unit 30, and the image signal processing unit 80, which balances to realize a perfect white color when overlapped. The timing controller 20 provides a driving clock, a synchronization signal, and the like.

The CCD imager 10 includes a CCD element 11 and a vertical driver 12, and the timing controller 20 includes a timing generator 21, a synchronization signal generator 22, a crystal oscillator 23, and 1. / 2 divider 24.

In addition, the white balance unit 30 is composed of a white balance IC, the image signal processing unit 80 is a sample / holder and AGC IC 40, the image processor 50, encoder 60, 6dB amplifier 70 and 3 It consists of two delays.

The operation of the color CCD camera imager configured as described above is as follows.

The timing controller 20 provides various driving timing clocks required by the CCD imaging unit 10, and the CCD imaging unit 10 outputs pixel (video) signals in accordance with the timing clock supplied by the timing circuit. Done.

The image signal output from the CCD imager 10 is input to the sample / holder function and the AGC (automatic gain control) circuit 40, and the input image signal is controlled after the gain is controlled by the AGC circuit. It is applied to the image processor 50 for generating and processing color signals and luminance signals.

The video signal processed by the image processor 50 modulates the color signal and the luminance signal according to the NTSC broadcasting rule in the encoder 60, adjusts the level thereof, and then again adjusts the level of the 6dB amplifier 70. By amplifying twice through, you get the final composite video signal.

As described above, the conventional method adjusts the aperture of the manual lens to match the location of the CCD camera, that is, the illuminance of the subject, thereby controlling the amount of light incident on the CCD so that the subject can be seen accurately.

When the auto iris lens is not used, the shutter speed control terminal of the three inputs of the timing generators IC and 21 of the timing control circuit 20, as shown in FIG. 1, is appropriately selected to determine the amount of light incident on the CCD. When the amount of light incident on the CCD element of the CCD imaging unit 10 cannot be properly distinguished from the subject on the monitor, the shutter speed control terminal is appropriately selected so that the luminance signal (composite image signal) can be controlled. Can be kept constant at an appropriate value (8 step).

In the NTSC CCD camera, the main clock frequency is 28.63636 MHz, and the color synchronizing signal is 14.318 MHz, which is 1/2 of the main clock frequency. Therefore, NTSC CCD cameras needed only one crystal oscillator for 28.63636MHz.

However, in the PAL CCD camera, the main clock is 28.375 MHz and the color synchronization frequency is 17.734 MHz instead of 1/2 of the main clock. Therefore, the two clocks must be in phase with each horizontal period. The PLL (phase locked loop) function, which was unnecessary in CCD cameras, is needed.

The present invention has been made to meet the above necessity, and an object thereof is to provide a PAL type CCD camera that satisfies the PAL type broadcasting standard.

In order to achieve the above object, a PAL color CCD camera according to the present invention includes a CCD image pickup means for accumulating an electric pixel signal from reflected light of a subject incident through an aperture, and a pixel signal from the CCD image pickup unit. An image signal processing means for generating a color signal and a luminance signal by applying the same, and modulating the color signal and the luminance signal according to a predetermined image standard into a composite image signal, and when producing the composite image signal in the image signal processing means. White balance means for achieving a perfect white color when three colors of red, green, and blue overlap, and a driving clock and synchronization required for the CCD imaging means, the image signal processing means and the white balance means. It provides the signal and the color synchronizing frequency and synchronizes the main clock and the color synchronizing frequency every horizontal period. That the timing control signal generating means having a PLL that includes the features.

In the present invention, the image signal processing means comprises: a sample / holder for receiving the image signal output from the CCD image pickup means for sampling / holding and gain control, AGC; Image processing means for generating and processing a color signal and a luminance signal from the sample / holder and AGC output image signal; Encoding means for modulating a color signal and a luminance signal so as to conform to a PAL broadcast standard of the image signal processed by the image processing means and adjusting a level thereof; And amplifying means for amplifying the video signal output from the encoding means twice to obtain a final composite video signal, wherein the timing control signal generating means provides the main clock. Crystal oscillator; Synchronizing signal generating means for receiving a 1/2 division clock of the main clock and providing horizontal and vertical signals to the timing generating means and the encoding means; A voltage controlled oscillator (VCO) for providing said color synchronizing signal to said synchronizing signal generating means; A low pass filter which compares the OHD signal obtained by the 1/2 division clock with the color synchronizing signal and the fH signal to obtain and integrate a phase difference signal between the two signals; And a timing clock for horizontal and vertical driving required for pixel signal formation in the CCD imaging means, providing the 1/2 divided clock to the synchronization signal generating means, and supplying the integrated signal to the crystal generator. And a timing generating means for applying to the timing generating means so that the phase of the oscillation frequency of the crystal oscillator coincides with the phase of the color synchronizing signal every horizontal period.

In addition, the frequency of the main drive clock is preferably 28.375MHz, the frequency of the color synchronizing signal is preferably 17.734MHz.

Hereinafter, a PAL color CCD camera according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an image part of a PAL type color CCD camera according to the present invention. The configuration is as follows.

A CCD image pickup unit 10 that accumulates an electric pixel signal from reflected light of a subject incident through the aperture, and a video signal processor 80 that receives an image signal from the CCD imager and processes the image signal; Timing control unit 20 which provides a main driving clock, a synchronization signal, and a color synchronizing signal required for the operation of the white balance unit 30, which balances a perfect white color when three colors of G and B overlap at the same time. It consists of

The CCD imaging unit 10 is composed of a CCD element 11 and a vertical driver 12. Here, the CCD element 11 generates a pixel signal from reflected light of an object incident from the outside according to the vertical and horizontal driving clocks, and the vertical driver 12 allows the CCD element 11 to form the pixel signal. To provide.

The timing controller 20 is composed of a timing generator 21, a synchronization signal generator 22, a VCO 25, a horizontal oscillator 23, and a low pass filter 24.

The timing generator 21 provides a timing clock for horizontal and vertical driving required for pixel signal formation, provides a 1/2 division clock of the main driving clock to the synchronization signal generator 22, and provides the integrated signal. By applying the crystal oscillator 23 to the timing generator 21, the phase of the oscillation frequency of the crystal oscillator 23 coincides with the phase of the color synchronizing signal having a frequency of 17.734 MHz every horizontal period.

The synchronization signal generator 22 receives a 1/2 division clock of the main driving clock from the timing generator 21 to provide horizontal and vertical synchronization signals to the timing generator 21 and the encoder 60. The crystal oscillator 23 generates a clock having a frequency of 28.375 MHz, which is the main driving clock. A voltage controlled oscillator (VCO) 25 provides the sync signal generator 22 with a 17.734 MHz color synchronizer signal. The low pass filter 24 compares the OHD signal obtained by the 1/2 division clock and the color synchronizing signal with the fH signal, obtains and integrates a phase difference signal between the two signals, and provides the result to the timing generator 21 through the crystal oscillator 23. do.

As described above, since 1/2 of the main driving clock of 28.375 MHz does not become the color synchronization frequency of 17.734 MHz, the PAL method requires that the two clocks have to be in phase every horizontal period. locked loop) function is required. The phase comparison between the main driving clock and the color synchronizing signal will be described together with the following operation.

In addition, the white balance unit 30 is composed of a white balance IC, the image signal processing unit 80 is a sample / holder and AGC IC 40, the image processor 50, encoder 60, 6dB amplifier 70 and 3 It consists of two delays.

The operation of the PAL type color CCD camera imager configured as described above is as follows.

The timing controller 20 provides various driving timing clocks required by the CCD imaging unit 10, and the CCD imaging unit 10 adjusts pixels (images) in accordance with the timing clock supplied by the timing control unit 20. Will output a signal. In particular, in the PAL color camera, the phase of the main driving clock and the color synchronizing signal must coincide every horizontal period to obtain a complete image signal. This phase synchronization method will be described with reference to FIGS.

First, when the main driving clock of 28.375 MHz oscillated by the horizontal oscillator 23 is inputted to the timing generator 21, the frequency of 14.18 which is 1/2 frequency of the main driving clock by the 1/2 division function built in the timing generator 21 is input. A phase comparison function built in the sync generator 22 by obtaining a clock CL of MHz and inputting it to the sync generator 22, and also applying a 17.734 MHz color sync signal provided from the VCO 25 to the sync generator 22. Outputs the phase difference signals of the two clocks, and integrates the pulse type phase difference signals through a low pass filter (LPF) 24 to convert them into analog amounts so that the oscillation frequency of the crystal oscillator 23 is linearly controlled. This allows the crystal oscillator 23 to perform stable oscillation.

This operation will be described with reference to the internal configuration diagram of the actual synchronization generator shown in FIG.

Input 17.734 MHz, the output of the VCO 25, to 4fsc IN terminal 10 of the sync generator as shown in Figure 3 with the PLL function and a frequency of 1/2 of the main drive clock 28.375 MHz to the CLIN terminal 26. The OHD 8 pulse generated by input and the fH signal applied to 4fsc IN 10 are compared in phase to output to HCOMOUT 24.

The phase relationship of the phase comparison signal OHD, fH and the compared phase difference output HCOMOUT of these two signals is shown in FIG. 4, and as shown here, the signal of the comparison phase difference output HCOMOUT is the OHD terminal signal and the fH signal. The signal is output in the form of a pulse having a width equal to the phase difference of.

Since the pulse signal (Fig. 4c) of the phase comparison output HCOMOUT cannot be directly input to the crystal oscillator 23, the crystal oscillator 23 is integrated by integrating with the LPF 24 so as to become an analog signal like the waveform of D in Fig. 4. Enter Therefore, by varying the oscillation frequency of the crystal oscillator with such an analog signal amount, smooth oscillation frequency control is achieved.

On the other hand, the image signal output from the CCD imager 10 is input to the sample / holder function and the AGC (automatic gain control) circuit 40, and the input image signal is controlled after the gain is controlled by the AGC circuit, and then the image signal. Is applied to the image processor 50 for generating and processing the color signal and the luminance signal.

The video signal processed by the image processor 50 modulates the color signal and the luminance signal in accordance with the PAL broadcast standard at the encoder 60, adjusts the level thereof, and then again operates the 6dB amplifier 70. The result is a doubled amplification to obtain the final composite video signal.

As described above, the PAL color CCD camera according to the present invention does not use 1/2 of the frequency of the main driving clock as the frequency of the color synchronization signal, unlike the NTSC type CCD color camera. And a low pass filter for converting the digital pulse signal, the phase comparison means, and the phase difference signal, to provide a colorimetric signal clock to match the phase of the color sync signal every horizontal period. have.

Claims (1)

CCD imaging means for accumulating an electric pixel signal from reflected light of a subject incident through an aperture and a pixel signal from the CCD imaging unit to generate a color signal and a luminance signal, and to produce a color signal and a luminance signal in accordance with a predetermined image standard. And a video signal processing means for modulating a luminance signal to make a composite video signal, and a perfect white color when three colors of red, green, and blue overlap at the same time when the composite video signal is generated by the image signal processing means. It provides a white balance means for balancing, a driving clock, a synchronization signal, and a color synchronization frequency necessary for the CCD imaging means, the image signal processing means, and the white balance means, and phases the main clock and the color synchronization frequency at every horizontal period. A timing control signal generating means having a PLL for matching, wherein said video signal processing number A stage may include: a sample / holder for receiving a video signal output from the CCD imager and sampling / holding and gain control; Image processing means for generating and processing a color signal and a luminance signal from the sample / holder and AGC output image signal; Encoding means for modulating a color signal and a luminance signal so as to conform to a PAL broadcast standard of the image signal processed by the image processing means and adjusting a level thereof; And amplifying means for amplifying the video signal output from the encoding means twice to obtain a final composite video signal, the timing control signal generating means comprising: a crystal oscillator for providing the main clock; Synchronizing signal generating means for receiving a 1/2 division clock of said main clock and providing horizontal and vertical signals to said timing generating means and said encoding means; A voltage controlled oscillator (VCO) for providing said color synchronizing signal to said synchronizing signal generating means; A low pass filter which compares the OHD signal obtained by the 1/2 division clock with the color synchronizing signal and the fH signal to obtain and integrate a phase difference signal between the two signals; And horizontal and vertical drive timing clocks required for pixel signal formation in the CCD imaging means, providing the 1/2 division clock to the synchronization signal generating means, and supplying the integrated signal to the crystal oscillator. And a timing generating means for applying the phase to the timing generating means so that the phase of the oscillation frequency of the crystal oscillator coincides with the phase of the color synchronizing signal every horizontal period. The frequency of the main driving clock is 28.375 MHz. The frequency of the color synchronization signal is a color CCD camera of the PAL method, characterized in that 17.734MHz.