RU2641287C1 - Television camera of colour image for panoramic computer scanning - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to the panoramic television scanning, which runs a computer system using a television camera of the colour image based on a "ring" photodetector manufactured by the technology of the charge-coupled devices (CCD). A block of forming an aperture (BFA) is introduced, the information input of which is connected to the output of the reset pulse unit of the "ring" scan synchronizing the BFA input - to the corresponding block output of the "ring" scan, and the BFA output - to the second control input of the block of the "ring" scan. The area of the light-sensitive elements on the target of the photodetector, coincident with the area of the corresponding "windows" of the mosaic colour filter, and the square of the corresponding shielded elements on the target of the photodetector from row to row are different, increasing in the direction along the "ring" row moving towards the outer periphery to a maximum value not exceeding the pixel area of its "ring" register.

EFFECT: alignment of the television camera image resolution abilities.

5 cl, 8 dwg

Description

The present invention relates to panoramic television scanning, which is performed by a computer system using a color image television camera based on a "ring" photodetector made by the technology of charge-coupled devices (CCD).

The closest in technical essence to the claimed invention should be considered a color television camera for panoramic computer scanning [1], containing sequentially located and optically coupled panoramic lens, infrared cut-off filter (IR-filter) and photodetector (sensor), which is made by CCD technology , has the shape of a ring and contains on the chip sequentially connected by a charge coupling a “ring” four-line photodetector region, a “ring” register, and charge-voltage (LPS), moreover, on the photodetector area, the lines of photosensitive elements alternate with lines of light-shielded elements, and the photodetector area itself is covered with a mosaic filter that separates the light into cyan, yellow, magenta and green components, while in the television The camera also includes a mechanical scanning unit for the sensor, a four-line “ring” scanning unit for the video signal, and a signal processor and an analog-to-digital converter (ADC) connected in series the output of which is the output of a television camera, and the mechanical scanning unit of the sensor is kinematically connected to the photodetector and carries out its mechanical scanning in the perpendicular direction relative to the fixed image plane of the panoramic lens, while the first output of the “circular” scan unit is connected respectively to the control inputs of the photodetector area of the sensor, the second output of the “ring” sweep block - to the control inputs of the “ring” sensor register, the third output of the “ring” block “sweep” scan — to the synchronization input of the signal processor, the fourth output of the “ring” scan block - to the ADC clock input, the output of the signal processor's exposure control is connected to the control input of the “ring” scan block, the fifth output of which is connected to the synchronization input of the sensor mechanical scan unit.

For the prototype, the following features are expected:

- the area of the photosensitive elements and, accordingly, the area of the shielded elements on the "ring" target of the photodetector from row to row is the same;

- The SPS of the photodetector is organized as a "floating diffusion region" [2], and therefore has a control input that provides an elementwise voltage drop of the generated video signal.

The disadvantage of the prototype is a variable value (along the lines) of the resolution of the image formed by the four-line "ring" photodetector within the frame, which changes in the direction of decreasing towards the outer periphery of the sensor due to the increasing gap between its photosensitive elements (pixels) having the same geometric area indicator,

The objective of the invention is to equalize the resolution of the image of the television camera.

The problem in the inventive television camera is solved by the fact that in the prototype television camera device [1], containing sequentially located and optically coupled panoramic lens, an IR filter and a photodetector (sensor), which is made by CCD technology, has the shape of a ring and contains on a crystal successively connected by a charge-coupled “ring” four-line photodetector region (target), a “ring” register, and an SPS, moreover, on the photodetector region, the line of photosensitive elements alternate with the line kami elements shielded from light, and the target itself is covered with a mosaic filter that separates the light into blue, yellow, magenta and green components, while the television camera also includes a mechanical scanning unit for the sensor, a four-line “ring” scan unit of the video signal and connected in series with each other a signal processor and ADC, the output of which is the output of a television camera, and the mechanical scanning unit of the sensor is kinematically connected to the photodetector and implements it mechanically scanning in the perpendicular direction relative to the fixed image plane of the panoramic lens, with the first output of the “circular” scan unit connected respectively to the control inputs of the sensor target, the second output of the “circular” scan unit to the control inputs of the “circular” register of the sensor, the third output of the block ring "sweep - to the input of the synchronization of the signal processor, the fourth output of the block" ring "sweep - to the clock input of the ADC, the output of the exposure control of the signal processor connected to the first control input of the “circular” scan unit, the fifth output of which is connected to the synchronization input of the mechanical scanning unit of the sensor, an aperture forming unit (BFA) is introduced, the information input of which is connected to the output of the reset pulses of the “circular” scan unit, the synchronizing input of the BFA is connected to the corresponding output of the “circular” scan unit, and the BFA output to the second control input of the “circular” scan unit, while the period of the control pulses T _r generated at the BFA output is determined by ratio:

where T _p - the reading period of the element in the photodetector;

n _m is a coefficient, an integer whose value for the current read line in the photodetector is equal to the ratio:

where Δ _l is the area of the photosensitive element for the first read line in the photodetector;

Δ _m is the area of the photosensitive element for the current read line in the photodetector,

the area of the photosensitive elements on the target of the photodetector, which coincides with the area of the corresponding “windows” of the mosaic color filter, and the area of the corresponding shielded elements on the target of the photodetector from row to row is different, increasing in the direction along the “annular” row as it moves to the outer periphery to the maximum a value not exceeding the pixel area of its “circular” register.

In relation to the prototype [1], the claimed television camera is distinguished by the introduction of a new unit - BFA, as well as the implementation on the target of the photodetector of photosensitive elements and "windows" of the mosaic filter, which may vary in their geometric area.

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

The inventive television camera, as in the prototype [1], generates a color digital television signal of the "ring" image at the output.

The fulfillment of the task, namely, alignment of the resolution of the color image, is carried out by organizing charge reading control in the "ring" raster of the photodetector with the same aperture area for photosensitive sensor elements of different sizes.

Therefore, the proposed solution meets the criterion of the presence of an inventive step.

In FIG. 1 shows a structural diagram of the claimed invention - a television camera as part of a computer system for panoramic television scanning of color images; in FIG. 2 shows the circuit organization of the photodetector of a television camera; in FIG. 3 shows a fragment of this photodetector, illustrating the details of its design; in FIG. 4, according to [3], a photograph of an image obtained using a domestic panoramic mirror-lens lens is presented; in FIG. 5 shows the design of the “annular” register of the photodetector, in which the transfer electrodes are made as part of a circular ring; in FIG. 6 - a panoramic image of the current “ring” frame proposed to the operator in the form of a sequence of 6 “rectangular” frames; in FIG. 7, according to [2, p. 19], a structural diagram of the BPS with the organization "floating diffusion region" is presented; in FIG. Figure 8 shows a plot of the output signal of BFA, which performs the control of the aperture of the "ring" photodetector.

The inventive color image television camera for panoramic computer scanning, see FIG. 1 comprises consecutively located and optically coupled panoramic lens 1-1, an IR filter 1-2, and a photodetector 1-3, which has the shape of a circular ring, see FIG. 2, and it contains a “ring” four-line photodetector region 1-3-1, a “ring” register 1-3-2, and an SPS 1-3-3, sequentially connected by charge communication on a crystal, with a 1-3-line of photosensitive and the lines of light-shielded elements are located along radial directions from the imaginary center of the circular ring to its outer periphery, and the number of elements in each “ring” line of the photodetector is equal to the number of elements in the “ring” register, and the target itself is covered with a mosaic color filter, which is “ring” “in shape”, see FIG. 3, which separates the luminous flux incident on the photosensitive elements, respectively, on its cyan, yellow, magenta and green components; the television camera also includes the following blocks: block 1-4 of the mechanical scanning of the sensor, block 1-5 of the "ring" four-line scan of the video signal, the signal processor 1-6, ADC 1-7 and BFA 1-8; the output of BPZN 1-3-3 of the photodetector is connected to the information input of the signal processor 1-6, connected in series with the ADC 1-7, the output of which is the output of the television camera, and block 1-4 is kinematically connected to the photodetector 1-3 and carries out its mechanical scanning (with a step equal to the width of four lines) in the perpendicular direction relative to the fixed image plane of the panoramic lens 1-1; the first output of block 1-5 is connected respectively to the control inputs of the target 1-3-1 of the sensor, the second output of block 1-5 is connected to the control inputs of the "ring" register 1-3-2 of the sensor, the third output of block 1-5 is connected to the synchronization input signal processor 1-6, the fourth output of block 1-5 is to the ADC 1-7 clock input, the exposure control output of signal processor 1-6 is connected to the first control input of block 1-5, the fifth output of which is connected to the synchronization input of block 1-4 ; the information input of BFA 1-8 is connected to the output of the reset pulses of block 1-5, the synchronizing input of BFA 1-8 is connected to the corresponding output of block 1-5, and the output of BFA 1-8 is connected to the second control input of block 1-5.

The panoramic lens 1-1 of the television camera, as in the prototype [1], is intended to form an optical image of a circular view (ring image). As a technical solution for a panoramic lens 1-1, which coincides with a similar solution for the prototype, a panoramic mirror-lens lens can be proposed, the design of which is patented in Russia by Russian specialists from Moscow State University of Geodesy and Cartography [3].

A photograph of the annular image formed by the panoramic lens is shown in FIG. 4. The angular field in the space of objects for this lens is 360 degrees in azimuth and can reach (75-80) degrees in elevation.

The presence of a passive (non-informative) region in the center of the optical frame of the panoramic lens confirms the advisability of choosing the shape of the photodetectors in favor of a circular ring.

The IR filter 1-2, as in the prototype [1], changes the spectral characteristic of the "ring" photodetector 1-3, providing the necessary agreement with the spectral sensitivity of the human eye.

The IR filter 1-2 can be made as part of a panoramic lens 1-1 or integrated directly into the "ring" photodetector 1-3.

Photodetector 1-3 made according to CCD technology, see FIG. 2-3, implements a "circular" scan of four lines of the charge image on the photodetector region 1-3-1, followed by element-by-element reading of charges in the "ring" register 1-3-2 and the formation of the voltage of the color video signal at the output of the CPS 1-3-3 analog form. Moreover, during one interval, the process of accumulation of charge packets occurs in proportion to the illumination of the panoramic plot in the photosensitive pixels of the photodetector region 1-3-1. During a short period of the subsequent interval, a photo shutter opens and the charges of all the “ring” lines involved in the accumulation are transferred (in one rotation step) to the screened from light pixels located in the same region 1-3-1.

Then the shutter closes and in a new cycle, another charge “picture” is accumulated on the target, and the charge packets accumulated in the previous cycle are transferred in radial directions to the periphery of the photodetector crystal, loading the “1-3” register in new intervals with new charges.

The photodetector is the only color image video sensor in which, thanks to the use of a color “ring” filter, CCD pixels become sensitive to cyan (Su), yellow (Ye), magenta (Mg) and green (G) color components. The design of this photodetector is shown in FIG. 3.

It uses the well-known principle of color television, which states that for successful color recovery, in addition to the brightness signal (Y), just two additional signals are enough. This refers to the red color difference signal (R-Y) and the blue color difference signal (B-Y).

As in the prototype [1], in the inventive television camera implements the field accumulation mode. This means that before reading in the “ring” register 1-3-2, the charge packets of neighboring (in the radial direction) photo-target pixels are combined in pairs. Moreover, this procedure is performed separately for the odd "ring" lines (first and third) and, accordingly, even "ring" lines (second and fourth) of the generated image of the "ring" frame.

Therefore, as in the prototype [1], the first line contains pairwise samples: (M _g + C _y ), (G + Y _e ), (M _g + C _y ), (G + Y _e ). The third line will contain similar readings.

And the second line contains pairwise samples: (C _y + G), (Y _e + M _g ), (C _y + G), (Y _e + M _g ). The fourth row will contain similar readings.

To obtain a brightness signal for an odd line, an operation is performed according to the algorithm, which consists in the fact that a delay is performed on the decomposition element, which coincides in time with the gap of the “ring” rotation of charges, and the summation of pairwise readings:

Coefficient Ѕ in the formula (3) returns the “debt” acquired by summing the charges in pairwise readings.

Obviously, expression (3) can be represented as follows:

Applying a similar algorithm for an even line, we obtain the following expression for the luminance signal:

Similarly, we represent the expression (5) in primary colors:

Expressions (4) and (6) show that the luminance signal for the odd and even line is the same.

To obtain the color difference signal blue (B-Y), an operation is performed according to another algorithm, which consists in the fact that for an odd line, a time delay is performed on the decomposition element and subtraction of pairwise samples:

To obtain the color difference signal red (R-Y), the operation is performed according to an algorithm similar to the receipt of the color difference signal blue, but as applied to an even line:

These two color difference signals, together with the luminance signal, are mixed into the CVBS signal in the PAL system. Let us explain that CVBS is an abbreviation of English words: “composite video bar signal”, i.e. full video signal.

It should be noted that for the “ring” photodetector of a television camera, the transfer electrodes on the targets 1-3-1 and in the “ring” register 1-3-2, as well as light “windows” for the “ring” mosaic filter can be made with a geometric shape not as a rectangle, but as part of a circular ring.

As an example in FIG. 5 shows the design of the “annular” register 1-3-2 of the photodetector with such transfer electrodes.

In FIG. Figure 7 shows a possible block diagram of the CCD “ring” photodetector 1-3 with the organization “floating diffusion region”, which completely coincides with the scheme currently used in CCD arrays for realization of rectangular scanning of a video signal, see, for example, [2]. In this drawing, the following notation: U _f1 , U _f2 , U _f3 - voltage on the tires for three-phase control of the "ring" shift register 1-2-3; U _o3 - voltage at the output gate; D _o , D _sbr - output and reset diodes, respectively.

Before reading the next information charge element (pixel) in the process of converting into voltage charge video information of the previous element must be cleared in an erasing diode D _RRF.

This procedure is carried out using control pulses T _r , often referred to in the literature as reset pulses, which are supplied to the corresponding control bus BPS 1-3-3.

The aperture forming unit (BFA) 1-7 is designed to control the reading aperture of the photodetector 1-3 when the element-by-element video signal voltage is removed in the BPZN 1-3-3. As a result, for all the lines of the photodetector, the area of the reading aperture is the same across the field, with the area of the electrodes of the photosensitive elements of the sensor varying from line to line.

The plot of the output signal T _r generated at the output of BFA 1-7 is shown in FIG. 8. Photodetector 1-3 contains four “ring” lines on the target. In this diagram, the first line is indicated as T _c1 , and the last line is indicated as T _c4 .

The control pulses have a positive polarity, short (short) duration and a different repetition period within each of the "ring" lines.

The period of control pulses for the first “ring” line is indicated by T _r1 , and the period of control pulses for the last (fourth) “ring” line is _{indicated by} T _r4 . The period T _r1 is the smallest and is equal to the reading period of the element T _p , and the reading period T _r4 is the largest, which is equal to nT _t .

The coefficient n in the last expression is determined by an integer from the ratio:

where Δ ₁ is the area of the photosensitive element for the first reading line in the "ring"photodetector;

Δ ₄ is the area of the photosensitive element for the fourth reading line in the "ring" photodetector.

In physical terms, the aperture area is controlled by summing the charge packets in the neighboring elements of each current “ring” line of the sensor before performing the charge-voltage conversion procedure.

Therefore, this charge addition cannot be an additional source of noise for the video signal at the output of the television camera.

BFA 1-7 in practice can be implemented using the classic set of technical means (logical elements) of digital electronics. Obviously, BFA 1-7 can be performed as part of the block 1-5 "ring" scan.

Block 1-5 of the "ring" four-line scan of the video signal, the signal processor 1-6 and the ADC 1-7, it is advisable to perform using a set of specialized microcircuits with a high level of integration, including and a programmable kit designed to service CCD color matrices.

Block 1-4 of the mechanical scanning of the sensor is designed to perform step-by-step movement of the photodetector 1-2 with an interval of distance equal to the width of its four "ring" lines. In physics of work, such a movement is electromechanical.

It is important to note that to exclude the occurrence of a vertical smear of the color image being formed, the time interval of the step-by-step movement of the photodetector should be sufficiently small relative to the interval of charge accumulation on the target.

It is obvious that when designing a television camera, the photodetector 1-3 can be made as a part of block 1-4.

BFA 1-7 in practice can be implemented using the classic set of technical means (logical elements) of digital electronics. Obviously, BFA 1-7 can be performed as part of the block 1-5 "ring" scan.

Consider the operation of the inventive television camera color image as part of a panoramic panoramic computer system, as proposed in the prototype [1], see Fig. 1. The system comprises a television camera in position 1 and a server 2 in position, which is a local area network node to which two or more personal computers are connected in position 3.

Panoramic lens 1-1 forms an “annular” optical image of the controlled scene, projecting it through an IR filter 1-2 onto the target 1-3-1 of the photodetector of a television camera. Photodetector 1-3 (see Fig. 2) in a stationary state implements charge accumulation of an optical image on a target 1-3-1, and then performs a “ring” four-line scan of the accumulated charge “picture” with element-wise reading of charge packets in the “ring” register 1-3-2 and the formation of the output voltage BPS 1-3-3-3 voltage of the video signal in analog form.

As a result of the subsequent analog-to-digital conversion of the video signal at the output of the television camera 1, a digital television signal of a color image is generated for one “ring” line of the reconstructed raster. Using the interface (for example, USB 2.0), the digital video signal of this “ring” line of photodetector 1-3 will be transmitted to the RAM of server 2, and then the video signal of other “ring” lines when the photodetector itself is moved stepwise four lines wide of its target.

As a result, video information about the “circular” frame obtained using the “scanner” recording of the “circular” lines constituting it will be recorded in the RAM of server 2.

Suppose that, as in the prototype, the horizontal angle of the field of view (γ _g ) of the presented panoramic image is 60 degrees.

Then it should be provided that one sixth of each “ring” line from the “ring” frame is recorded in server 2, respectively, in one of the six arrays of RAM per frame.

Suppose that the total number of “ring” lines in a “ring” frame is m. The need for time diversity of the process of accumulation of charges in the photodetector and the process of stepwise movement of the sensor determines the mode of formation of the "ring" frame as slow, i.e. small frame.

Further, as in the prototype, in the server 2, the video signal is read, and as a result, the “ring” frame is converted into the usual “rectangular” frames of broadcast television and the ability to provide this information at the network output of the server 2.

Therefore, the digital video recording signal for each "ring" image frame is converted into 6 "rectangular" frames, which can be offered in the form of a selected sequence (see Fig. 6) to computer operators 3.

This means that real-time control of six images can be implemented with the same field and increased clarity of the observed "picture".

Currently, all the elements of the structural diagram of a color television television camera for panoramic computer scanning are mastered or can be mastered by domestic industry.

Therefore, the present invention should be considered as meeting the requirement for industrial applicability.

INFORMATION SOURCES

1. RF patent No. 2579003, IPC H04N 7/00, H04N 5/225. A computer system device for panoramic scanning of a color image. / V.M. Smelkov // B.I. - 2016. - No. 9.

2. Khromov L.I., Lebedev N.V., Tsytsulin A.K., Kulikov A.N. Solid state television. - "Radio and Communications", 1986.

3. RF patent No. 2185645. IPC G02B 13/06, G02B 17/08. Panoramic mirror lens. / A.V. Kurtov, V.A. Solomatin // B.I. - 2002. - No. 20.

Claims (12)

1. Television camera color image for panoramic computer scanning, containing sequentially located and optically coupled panoramic lens, infrared cut-off filter (IR-filter) and a photodetector (sensor), which is made by CCD technology, has the shape of a ring and contains a series of connected charge the “ring” four-line photodetector region, the “ring” register and the charge-voltage conversion unit (CPS), and the photodetector region of the photosensitive line The cell elements alternate with the lines of light-shielded elements, and the photodetector area itself is covered with a mosaic filter that separates the light into blue, yellow, magenta and green components, while the television camera also includes a mechanical scanning unit for the sensor, a four-line “ring” video scanning unit and a signal processor and an analog-to-digital converter (ADC) connected in series, the output of which is the output of a television camera, and the mechanical sensor sensor is kinematically connected to the photodetector and carries out its mechanical scanning in the perpendicular direction relative to the fixed image plane of the panoramic lens, while the first output of the “annular” scan unit is connected respectively to the control inputs of the photodetector region of the sensor, the second output of the “annular” scan unit is to the control inputs “Ring” register of the sensor, the third output of the “ring” scan block - to the synchronization input of the signal processor, the fourth output and the “ring” scan is connected to the ADC clock input, the signal processor exposure control output is connected to the first control input of the “ring” scan block, the fifth output of which is connected to the synchronization input of the sensor mechanical caning unit, characterized in that the aperture forming unit (BFA) is introduced the information input of which is connected to the output of the reset pulses of the “ring” scan block, the synchronizing input of the BFA to the corresponding output of the block of the circular scan, and the output of the BFA to the second control at the input of the block "circular" scan, the period of the control pulses T _r generated at the output of the BFA is determined by the ratio:

where T _p is the reading period of the element in the photodetector;

- coefficient, integer, the value of which for the current reading line in the photodetector is equal to the ratio:

where Δ ₁ is the area of the photosensitive element for the first read line in the photodetector;

- the area of the photosensitive element for the current read line in the photodetector, the area of the photosensitive elements on the target of the photodetector, which coincides with the area of the corresponding “windows” of the mosaic color filter, and the area of the corresponding shielded elements on the target of the photodetector from row to row is different, increasing in the direction along the “annular” row as it moves to the outer periphery to the maximum a value not exceeding the pixel area of its “circular” register. 2. The television camera color image according to claim 1, characterized in that the transfer electrodes of the photodetector region and the “ring” register, as well as light “windows” of the “ring” mosaic filter for the photodetector, are made with a geometric shape in the form of a part of a circular ring. 3. The television camera color image according to claim 1, characterized in that the IR filter is made as part of a panoramic lens or as part of a photodetector. 4. The television camera color image according to claim 1, characterized in that the BFA is made as part of the block "ring" scan. 5. The television camera color image according to claim 1, characterized in that the photodetector is made as part of a mechanical scanning unit of the sensor.

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