RU2317652C2 - Method for television surveillance under conditions of complicated lighting and/or complicated brightness of objects and device for realization of the method - Google Patents

Abstract

FIELD: transmitting television equipment, which realizes television observation under conditions of complicated lighting and/or complicated brightness of objects, when strongly and weakly lighted objects and/or objects with sharp difference in brightness may be in the field of view of the camera simultaneously.

SUBSTANCE: in accordance to the invention, components of combined image are generated in charge form on targets of first ands second television sensors with different exposition times, optimal for each one of transmitted scene fragments.

EFFECT: expanded dynamic range of brightness levels for control objects, transmitted in combined image outside the "window" by increasing signal/noise ratio for dark and/or low light details of objects.

2 cl, 7 dwg, 1 tbl

Description

The present invention relates to a transmitting television technique that performs television surveillance in complex lighting and / or complex brightness of objects, when in the field of view can be simultaneously strongly and dimly lit objects and / or objects with a sharp difference in brightness.

The closest in technical essence to the claimed invention should be considered the method of television surveillance [1], which consists in the fact that the input optical image is projected onto the photo targets of the first and second television signal sensors made on the basis of charge-coupled devices (CCD), the sensors are synchronized in frequency and phase, in each of the sensors the formation of the video signal is performed using automatic sensitivity control (ARC), within the frame, a full television is switched sequentially This signal from the first and second sensors reproduce the combined image signal on the screen of the video monitor.

The prototype device [1] consists of sequentially located and optically coupled lens and a beam splitter, as well as a sync pulse selector, a frame and a window driver and a mixer switch, the output of which is connected to the input of the video monitor, the first beam splitter output being optically connected to the photo target the first sensor of the television signal, and the second output of the beam splitter with the photo target of the second sensor of the television signal, the geometric dimensions of the photo targets of the first and second sensors are the same, input "sync the "second sensor" is connected to the "sync" output of the first sensor, the "video" output of which is connected to the first information input of the mixer-mixer, the second information input of which is connected to the "video" output of the second sensor, and the third information input of the mixer-mixer to the output of the shaper signals "frame" and "window".

In the prototype device, a combined image is observed, the formation of which is the result of the synthesis of images produced by the first and second sensors of the television signal. In the centrally located “window” of the combined image, the central fragment of the enlarged image from the second sensor is transmitted, and around the “window”, i.e. outside it is an image from the first sensor with an unchanged scale.

When operating the television surveillance device of the prototype, conditions of complex lighting and / or complex brightness of the observed plots and objects are possible. Examples of complex lighting conditions include:

- observation of the launch of a rocket with a bright torch from running engines;

- observation through a window or against the background of open doors, when you need to simultaneously distinguish between objects on the street and in the room;

- observation against diffused sunlight;

- observation against the background of glare, lighting lamps and more.

A typical example of complex brightness conditions for industrial television is the welding process, including for controlling welding processes of refractory materials in automatic or semi-automatic mode.

When the prototype works in conditions of complex lighting and / or complex brightness of objects in the "window", an image is formed from a strongly lit or bright (light) object, and outside the "window" is an image from a low-light and / or dark plot. At the same time, the accumulation time per frame set for the first and second sensors of the television signal in automatic mode using the electronic shutter of their photodetectors in one (common) plot is clearly underestimated for the second sensor. A similar situation for this sensor takes place in another adjustable parameter - gain. As a result, the video signal from dark and / or low-light parts for the image transmitted outside the “window” can either significantly decrease, or be completely lost.

The disadvantage of the prototype is the limited dynamic range of gradations of brightness for control objects transmitted in a combined image outside the "window".

The objective of the invention is the expansion of the dynamic range of gradations of brightness for control objects transmitted in the combined image outside the "window" by increasing the signal-to-noise ratio for dark and / or low-illuminated objects.

The problem is solved in that in the claimed method, the optical image from highly illuminated and / or bright objects occupies the central part of the angle of the field of view, the formation of the control signal of the AF in each of the sensors is performed by the charge relief of a single target area, and the second sensor implements this function by the central region of his photographic target, and the first sensor - throughout the entire region of his photographic target, except for the central one.

The problem in the inventive device intended for the implementation of the claimed method is solved by the fact that in the television surveillance device of the prototype, consisting of sequentially located and optically coupled lens and a beam splitter, the first output of which is optically connected with the photo target of the first sensor of the television signal, and the second output of the beam splitter with the photo target of the second sensor of the television signal, moreover, the geometric dimensions of the photo targets of the first and second sensors are the same, the sync input is second of the second sensor is connected to the sync output of the first sensor, the video output of which is connected to the first information input of the mixer switch, the second information input of which is connected to the video output of the second sensor, and the output of the mixer switch is connected to the video monitor input, the following signs, namely: the projection of the optical frame of the lens on the photographic targets of the first and second sensors coincide, the "window" of AFM photometry of the second sensor is installed on the central region of its target, the "window" of AFM photometry a new sensor — for the entire area of its target, except for the central one, and the third information input of the switch-mixer is connected to the signal output of the “window” of the first sensor of the television signal.

Comparative analysis with the prototype shows that the inventive method is characterized by the presence of new features, namely the presence of the following actions:

- the spatial orientation of the optical image from a highly illuminated and / or bright object to the central part of the angle of the field of view of television observation;

- the formation of the control signal ARF in the first sensor of the television signal in the Central region of the target;

- the formation of the control signal of the ARF in the second television signal sensor over the entire area of the photo target, except for the central one.

The combination of known and new features is not known from the prior art, therefore, the claimed method meets the requirement of novelty.

Comparative analysis with the prototype shows that the claimed device differs in the form of the elements, namely: the form of execution of each of the sensors in terms of pre-setting the "window" photometry, the parameters of the elements, namely: the coincidence of the projection of the optical frame of the lens on the target of the first and second sensors and the new the connection between the elements, namely: the connection of the first sensor of the television signal with the switch-mixer.

The combination of known and new features of the claimed device is not known from the prior art, therefore, the proposed technical solution meets the criterion of novelty.

In the proposed solution, the primary formation of the components of the video signal of the combined image is performed in charge form on the targets of the first and second sensors at different exposure times and the gain of the video path, optimal or close to the optimal values for each of the transmitted fragments of the scene.

In the output image of the proposed solution, bright and bright details are transmitted by the video signal of the second sensor, as in the prototype, without limitation in white, but only within the "window".

Within the remaining area of the frame of the combined image (outside the "window"), dark and / or low-lit scene details are transmitted by the video signal of the first sensor. But, unlike the prototype, the accumulation time of the photodetector and the gain of the video amplifier of the first sensor are established by evaluating the charge relief of only this region.

Therefore, the signal-to-noise ratio (ψ) for the dark and / or low-illuminated parts of the scene transmitted outside the “window” increases in proportion to the increase in the accumulation time of the photodetector and the gain of the video amplifier for them.

According to the technical result and methods for its achievement, the claimed solution meets the requirement of inventive step.

Figure 1 shows the structural diagram of the inventive device that implements the inventive method; figure 2 shows the device of the beam splitter; figure 3 shows the photometric area for the first and second sensors; figure 4 is an example of a circuit design that explains the preset areas of photometrics; figure 5 is an example of an image that is displayed on the screen of a video monitor.

The inventive television surveillance device (see figure 1) contains sequentially located and optically coupled lens 1 and a beam splitter 2, the first output of which is optically connected to the photo target of the first sensor 3 of the television signal, and the second output of the beam splitter 2 to the photo target of the second sensor 4 of the television signal, moreover, the geometrical sizes of the photographic targets of the first and second sensors are the same, and the projections of the optical frame of the lens on the photographic targets coincide, the preset of the photometer window of the sensor 4 is made for the central region of its photo target, and the preset of the “window” of metering of sensor 3 is for the entire region of its photo target, except for the central one, the input of the “sync” of sensor 4 is connected to the output of the “sync” of sensor 3, the video output of which is connected to the first information input of the mixer 5, the second information input of which is connected to the output of the "video" of the sensor 4, the third information input is to the output of the signal "window" of the sensor 3, and the output is to the input of the video monitor 6.

The beam splitter 2, with the mutually perpendicular arrangement of the photo targets of the sensors 3 and 4, contains (see Fig. 2a) a translucent mirror 2-1, the input of which is the input of the beam splitter, and the first and second outputs of the translucent mirror are the first and second outputs of the beam splitter, respectively.

The beam splitter 2 with mutually parallel arrangement of the photo targets of the sensors 3 and 4 contains (see fig.2b) sequentially located and optically connected translucent mirror 2-1 and a reflecting mirror 2-2, the input of the translucent mirror is the input of the beam splitter, and the output of the reflecting mirror is the second the output of the translucent mirror is, respectively, the first and second outputs of the beam splitter.

In the claimed solution, the sensors of the television signal 3 and 4, as in the prototype, are synchronized in the Genlock mode with frequency and phase matching by the receiver synchronization signal (MTP) from the sensor 3. Another organization of external synchronization, not shown in Fig. 1, is also possible: by a signal from the SSP from the output of the "sync" of the sensor 4 to the input of the "sync" of the sensor 3.

As the sensor 3, the open-frame camera VSI-746 offered by the Russian company "EVS" (St. Petersburg) can be used, and as the sensor 4, the open-frame camera VNI-702 [2], which are based on a CCD with the number of elements, can be used 582 × 752 and the size of the target on a diagonal ^of _1/2 inch. With the same geometric sizes of the photo targets of sensors 3 and 4, the components of the combined image (in the "window" and outside the "window") will have an unchanged scale.

If it is necessary to have an enlarged image within the "window", the geometric dimensions of the photographic target of the first sensor should exceed the corresponding dimensions of the second sensor. Let the target size of the diagonal for the first sensor is _^1/2 inches, and the second - _^1/4 inches. Then multiplicity scaling the composite image will be _{^{1/2 1/4}} = 2 times.

In the prototype device for each of the sensors, the control signal of the ARF is generated over the entire target area, i.e. The “window” of photometry (the “window” of detecting the charge relief) forms the entire target. In the claimed solution, the photometric area for the sensor 4 is the central area of the target (see figa), and for the sensor 3 is the entire area of the target, except for the central one (see fig.3b).

In the VSI-746 and VNI-702 cameras, the SONY CXD2463R chip is used as a sync generator [3]. The capabilities of this chip allow you to organize four modes of photometric targeting of the CCD target, as shown in table 1.

To implement them, it is necessary to supply logic signal levels to terminals 17 and 18 of the CXD2463R chip. In this case, at the output 15 of the CXD2463R microcircuit, a logical signal is formed, designated "BLC", which is fed to the control inputs of the analog switches [3, p. 8]. One of them switches the “window” of automatic adjustment of accumulation time (ARVN), the other - the “window” of automatic gain control (AGC) of the video path.

Table 1 Mode number in order Photometric area (window type) The logic level supplied to pin 17 The logic level applied to pin 18 one Whole photo target 0 0 2 Lower area of the target one 0 3 Central area of the target 0 one four Lower and central areas of the photo target one one

At pin 13 of the CXD2463R chip, the peak voltage of the ARVN peak detector is switched on the capacitor. As follows from the timing diagrams of the switching signal given in [3, pp. 9-12], a high logical level is the active level, and its temporary appearance within the frame corresponds to the temporary position of the selected photometric area.

It follows that in both sensors of the prototype, logic “0” signals should be applied to the terminals 17 and 18 of each of the CXD2463R microcircuits (see the first row of the table - mode 1).

In the claimed solution for the sensor 4, a logic “0” signal should be sent to pin 17, and a logical “1” signal to pin 18 (see the third row of the table — mode 3).

To perform the presetting of sensor 3 in the present invention, it is similarly necessary to apply signals “logical 0” and logic “1” to terminals 17 and 18 of the CXD2463R chip, but the inverted signal “BLC” to the control input of the analog switches. In the example circuit diagram shown in FIG. 4, to simplify the outline, only one switch is shown (a switch for ARVN).

The lens 1, the switch-mixer 5 and the video monitor 6 for the purpose and circuit design do not differ from the corresponding blocks of the prototype.

The method of television surveillance in complex lighting and / or complex brightness of objects is as follows.

We use the structural diagram of the inventive device for television surveillance (see figure 1) that implements the inventive method. Previously, the device is oriented so that highly illuminated and / or bright objects are perceived in the central part of its angle of view (see the example in FIG. 5).

As in the prototype, the input optical image along the optical path: the lens 1, the input of the beam splitter 2, the first output of the beam splitter 2 is projected onto the photo target of the first sensor 3 of the television signal. At the same time, this image is taken along a different optical path: the lens 1, the input of the beam splitter 2, and the second output of the beam splitter 2 is projected onto the photo target of the second television signal sensor 4. We assume that the geometric dimensions fotomisheney sensors 3 and 4 are identical, for example _^1/2 inches diagonally.

Photoelectric conversion of the optical image of each of the sensors into the corresponding video signals is carried out using automatic sensitivity control (ARC). The main adjustable parameter of the ARF is the accumulation time of the photodetector on the CCD, and an additional parameter is the gain of the video amplifier.

Note that both sensors operate in the synchronization mode in frequency and phase of the vertical and horizontal scanning from the receiver synchronization signal (MSS) of sensor 3.

In contrast to the prototype for the ARC of each of the sensors, a preset of different and mutually exclusive photometric areas is provided.

For the sensor 4, the photometric area is the central region of its photo target (see Fig. 3a), and for sensor 3, the entire region of its photo target minus the central one (see Fig. 3b).

Therefore, for the plot of the ARF observed by the claimed device, both the sensor 4 and the sensor 3 will establish various and optimal values of the current exposure and gain.

For the plot observed in our example (see Fig. 5), these parameters satisfy the relations:

T _n1 > T _n2 ; K _y1 > K _y2 ,

where T _n1 , K _y1 and T _n2 , K _y2 - accumulation duration, video _path gain for sensor 3 and sensor 4, respectively.

Further, as in the prototype, within the frame, the television signal from the sensor 3 and the sensor 4 is sequentially switched, providing the formation of the video signal of the combined image and its reproduction on the screen of the video monitor 6.

In the claimed solution for dark and / or low-illuminated objects, the useful signal energy increases by (T _n1 / T _n2 ) ² times, and the energy noise threshold, provided that the noise variances of the charge-voltage converters of the photodetectors decreases, decreases (K _y1 / K _y2 ) ² times Therefore, we have a gain in the signal-to-noise ratio.

If the geometrical dimensions of the photo target of the sensor 3 exceed the dimensions of the photo target of the sensor 4, then in the "window" of the combined image of the claimed solution, ceteris paribus, an enlarged image with a zoom ratio equal to the ratio of these sizes will be played.

The operation of the claimed technical solution occurs in exactly the same way if the external synchronization mode is carried out by applying pulses of the MSS from the output of the "sync" of the sensor 4 to the input of the "sync" of the sensor 3.

Currently, all the elements of the structural diagram of a device for television surveillance in conditions of complex lighting and / or complex brightness of objects that implement all the actions according to the claimed method and determine the claimed device, mastered by domestic industry. Therefore, the present invention should be considered as meeting the requirement for industrial applicability.

INFORMATION SOURCES

1. Patent No. 2171014 of the Russian Federation, MKI ⁷ H04N 5/225, 5/228. Selective Zoom Television Camera / V.M. Smelkov, Yu.A. Smolyakov, N.N. Egorova, V.M. Petrova // B.I. - 2001. - No. 20.

2. Television cameras of the company "EVS", catalog, 2005

3. CXD2463R chip company SONY. Timing Controller for CCD Camera. User manual in English, p.1-12.

Claims (6)

1. The method of television surveillance in conditions of complex lighting and / or complex brightness of objects, which consists in the fact that the input optical image is projected onto the photo targets of the first and second television signal sensors made on the basis of arrays of charge-coupled devices (CCD), the sensors are synchronized in frequency and phase, in each of the sensors, the video signal is formed using automatic sensitivity control (ARC), the entire television signal from of the first and second sensors, they reproduce the signal of the combined image on the screen of the video monitor, characterized in that the optical image from highly illuminated and / or bright objects occupies the central part of the angle of the field of view, the formation of the control signal of the ARF in each of the sensors is performed according to the charge relief of a particular target area moreover, the second sensor implements this function in the central area of the photo target, and the first sensor in the entire area of the photo target, except for the central one. 2. A television surveillance device under complex lighting and / or complex brightness of objects, consisting of sequentially located and optically coupled lens and a beam splitter, the first output of which is optically connected to the photo target of the first television signal sensor, and the second output of the beam splitter - to the photo target of the second television signal sensor moreover, the geometrical sizes of the photographic targets of the first and second sensors are the same, the sync input of the second sensor is connected to the sync output of the first sensor, the video output which is connected to the first information input of the mixer-mixer, the second information input of which is connected to the video output of the second sensor, and the output of the mixer-mixer is connected to the video monitor input, characterized in that the projections of the optical frame of the lens on the photo targets of the first and second sensors coincide, " the window "photometric ARC of the second sensor is installed on the central region of its target, the" window "photometric ARC of the first sensor is on the entire region of its target, except the central, and the third information the input of the switch-mixer is connected to the output of the signal "window" of the first sensor of the television signal. 3. The television surveillance device according to claim 2, characterized in that the beam splitter contains a translucent mirror, the input of which is the input of the beam splitter, and the first and second outputs of the translucent mirror, respectively, the first and second outputs of the beam splitter. 4. The television surveillance device according to claim 2, characterized in that the beam splitter contains sequentially located and optically coupled translucent mirror and a reflecting mirror, the input of the translucent mirror being the input of the beam splitter, and the output of the reflecting mirror and the second output of the translucent mirror, respectively, the first and second outputs beam splitter. 5. The television monitoring device according to claim 2, characterized in that the geometric dimensions of the photographic target of the first television signal sensor exceed the corresponding dimensions of the second television signal sensor, and their ratio determines the zoom ratio of the combined image. 6. The television surveillance device according to claim 2, characterized in that the first and second sensors are synchronized by the synchronization signal of the receiver from the second sensor, the sync output of which is connected to the sync input of the first sensor.

Images