JPS63302686A - Picture converting circuit device - Google Patents

Abstract

PURPOSE:To properly adjust a hue by disposing a circuit for switching the quantity of the phase adjustment of a chrominance sub-carrier to plural steps synchronously with the switching of a negative/positive inversion circuit. CONSTITUTION:In the case of a color positive film, at the time of switching a negative/positive change over switch 70 to a positive, it is switched to a circuit passing no inversion circuit 16 by an analog switch 17 and the phase adjusting voltage of the chrominance sub-carrier of the hue adjusting circuit of an encoder is switched to the positive by an analog switch 71. In the case of a color negative film, the negative/positive change over switch 70 is switched to the negative, and then, the inversion circuit 16 is operated by the analog switch 17, the phase adjusting voltage is switched to the negative by the analog switch 71 to carry out the proper hue adjustments respectively and increase the utility of a color video camera.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used in an image pickup/image transmission circuit of a television camera that images general subjects and color films, and in particular, it can be used to capture negative images of color negative films with a simple circuit configuration. The present invention relates to an image conversion circuit device that faithfully inverts and transmits a positive image, and obtains an image signal with no difference in color reproduction between color negative film, color positive film, and real photography.

[Prior Art] Film programs for television broadcasting have various advantages such as omitting the printing process and improving color reproducibility. Therefore, instead of the conventional color positive film, a color negative film is directly exposed to a television camera and the negative image is converted into a positive image. The image is transmitted while being inverted. However, due to the nature of the business in television broadcasting, it is necessary to handle many types of film with different characteristics, and it is not enough to simply reproduce the film, but to reproduce the subject itself as a natural-looking color image on the television screen. Therefore, the entire circuit including the color inverting circuit has a very complicated structure.

On the other hand, with the widespread use of compact color TV cameras for household and industrial use, the demand for compact TV cameras with color reversal functionality is increasing, and research into incorporating color reversal circuits with simple configurations is actively being conducted. It is progressing.

FIG. 14 shows an example of the circuit configuration of a small television camera having the above-mentioned color inversion circuit. High voltage block c1 Amplifier d1 for amplifying the video signal Synchronous signal generator e1 A Y signal processing circuit that separates the three color components sent from the amplifier d and combines them to create a luminance signal. Chroma signal processing circuit h1 that combines components to create a color difference signal Y/C mixing circuit 1 that superimposes a color difference signal on the luminance signal
, output a two-way digital video signal, and
It consists of a video output circuit j that produces VF output, etc.
An inversion circuit 1 for color inverting the luminance signal is incorporated in the Y signal processing circuit f, and an inversion circuit 2 is incorporated in the chroma signal processing circuit f for inverting the color difference signal.

[Problems to be Solved by the Invention] However, when the colors of a color negative film are inverted using the circuit described above and reproduced on a television screen, the projected image lacks luster and the overall tone is dull and sleepy. There was a problem that satisfactory image quality could not be obtained.

Although thorough studies have been carried out to elucidate the cause of this poor image quality, no clear conclusion has been reached. It is speculated that color mixing may have occurred somewhere due to the operation.

In both color negative and color positive films, subject information is stored as the amount of cyan, magenta, and yellow pigments, but since cyan, magenta, and yellow pigments have significant side absorption, color negative film In some cases, masking methods have been used in which dyes are made from couplers that are themselves moderately colored.

For example, in the case of a color negative film, as shown in FIG. 15, the blue-sensitive layer 0 contains a colorless yellow coupler p, the green-sensitive layer q contains a yellow magenta coupler S, and the red-sensitive layer t contains a yellow magenta coupler S. Contains red cyan coupler U.

In the figure, 7 is a protective layer, ν is a yellow filter layer, x, y
2 indicates the intermediate layer, 2 indicates the antihalation layer, and rb indicates the film base.

When such a color negative film is developed, the first
As shown in Figure 6, a yellow negative image is formed in the blue-sensitive layer 0, a magenta negative image is formed in the green-sensitive layer q, and the colored coupler remains, and a cyan negative image is formed in the red-sensitive layer t, and the colored coupler remains. remains. The first yellow filter layer V′ and the second halation layer 2° become colorless and transparent.

The spectral density of the color negative developed in this way is shown in FIG. 17, and the colored coupler p+s,
Also by masking by u (shaded area in Figure 17), 2
There are regions where the secondary absorption cannot be sufficiently corrected; for example, in the cyan dye, secondary absorption remains in the region below 450 na.

In the case of a color positive film, as shown in FIG. 18, the blue sensitive layer 0 contains yellow coupler p, and the green sensitive layer 9
The red-sensitive layer t contains magenta coupler S, and the red-sensitive layer t contains cyan coupler U. In the figure, V indicates a protective layer, V indicates a yellow filter layer, X indicates an intermediate layer, 2 indicates an antihalation layer, and "b" indicates a film base.

When such a color positive film is developed, the first
As shown in FIG. 9, a yellow positive image is formed in the blue-sensitive layer 0, a magenta positive image is formed in the green-sensitive layer q, and a cyan positive image is formed in the red-sensitive layer t. The yellow filter layer V'' and the antihalation layer 2° are colorless and transparent.

As shown in Figure 20, the spectral density of the dye in the color positive film developed in this way has greater secondary absorption than that in the color negative film, and therefore the color reproduction is different between the color negative film and the color positive film. There will be a difference.

For example, when an ITE color par chart published by the Television Society is captured using a three-tube video camera and the saturation and hue of the carrier color signal are displayed in polar coordinates on a vectorscope, the result will be as shown in Figure 21. Magenta M, 57@, red R 102", yellow Y L 170"
”, green G is 238@, cyan CY is 276@, blue B is 335', and these are the values MG131@, R10, which are the theoretically calculated values of the ITE color per chart expressed in polar coordinates.
3., YL 1117@, G 241@, CY 2
g3°, the difference is slight compared to B 347@.

However, when the ITE color par chart is photographed on a color positive film and a color negative film, the images are taken by the three-tube video camera and displayed on a vectorscope, as shown in FIGS. 22 and 23, respectively. In other words, in the case of color positive film, M(, 72@, R1G
G@, YL150', G 223°, CY 271
”, 8337°, and in the case of color negative film, Me55°, R91”, YL 148°, G 2
21@, Cv 2B4°, 8318@.

Therefore, in both positive and negative cases, the phase shift is larger than when the ITE Color Per Chart is directly imaged or when using the theoretically calculated value of the ITE Color Per Chart, and in the case of the negative, the overall clockwise rotation In contrast, in the case of positive, the direction of deviation is not constant.

[Means for Solving the Problems] In view of the above-mentioned problems, the present invention has been made in order to provide an image conversion circuit device that can reproduce a color inverted image with good hue with a relatively simple configuration. The configuration is such that an image conversion circuit device for a color video camera having a negative/positive inversion circuit is provided with a color subcarrier phase adjustment circuit, and the amount of phase adjustment of the color subcarrier by the color subcarrier phase adjustment circuit is set in at least two stages. The present invention is characterized in that switching can be performed in synchronization with switching of the inverting circuit.

[Function] In the case of color positive film, the video signal captured by a color video camera and extracted from a photoelectric conversion device is converted as is.
In the case of color negative film, appropriate hue adjustment is achieved by reversing the polarity of each electrical signal for each electrical signal flow and adjusting the phase of the color subcarrier in the color subcarrier phase adjustment circuit according to the type of positive or negative. This eliminates the risk of unpredictable color mixing and allows for positive,
In either case, it is possible to reproduce a color image with excellent hue, good color reproduction, and good image quality.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. 1st
Figures 1 to 13 show an embodiment of the present invention. )
, 3 is a synchronizing signal generator, 4 is a timing generating circuit for supplying a synchronizing signal, 5 is a storage device that cooperates with this circuit 4 to cover a partial defect in the CCD 1, B and 7.
8 is a V driver and an H driver for horizontal scanning and vertical scanning (in this embodiment, interlaced scanning for each horizontal scanning line) of the photoelectric conversion surface of the CCDI, and 8 is a red, green, and red pixel signal sent from the CCDI. A signal processing circuit that separates the blue component and creates three types of color signals R (red), G (green), and B (blue), and also cooperates with the white balance control circuit 9 and the auto iris/auto white BL circuit IO; 1
2 is a matrix circuit that combines the signals G, R, and B sent from the signal processing circuit 8 to create a luminance signal and a color difference signal; 13 is a matrix circuit that converts the color difference signal sent from this matrix circuit 12 into a carrier color signal; NT superimposed on the luminance signal
14 is a fader circuit for fading in and out the reproduced image; 15 is for synchronizing 3H (3 horizontal scans), and combining signals that are not in ■H. This is an IH delay line circuit for inverting red, green, and blue color signals between the signal processing circuit 8 and the matrix circuit 12.
An analog switch 17 for switching between negative and positive is arranged to selectively use the inverting circuit B and the inverting circuit 16. As shown in FIG. 3, the CCD color filter 2 has windows 9 in the form of a strip for passing green light, and a window r for passing red light or a window r for passing blue light between each window 9. , are arranged alternately every two lines arranged in the vertical direction. Note that the window arrangement of the color filter 2 may be arranged in a different arrangement than the above arrangement.

The signal processing circuit 8 includes a sample-and-hold circuit (not shown), an RGB gain control, a γ compensation circuit (can be set separately for negative and positive), a white balance circuit, and others. Color signals Gγ, Rγ, and Bγ (the subscript γ indicates a signal subjected to γ correction) shown as a model in the figure are output. in this case,
Gγ is an output line 18 provided individually for each horizontal scan.
(a part of which is shown at the left end of FIG. 2), and Rγ and Bγ are output alternately for each horizontal scan, and this output is passed through a common output line 19. Sent to the downstream circuit. In addition, 20.20 in Fig. 4 shows the black level of the signal, and 22 shows the waveform of the color signal (the actual waveform is C
According to the arrangement of colors distributed on the horizontal scanning line of the photoelectric conversion surface of the OD, a complex shape is shown, for example, as shown by virtual lines).

As shown in FIG. 2, the inverting circuit 16 inverts the flow of color signals Gγ sent one after another through the aforementioned line 18 into color signals having approximately complementary colors, and amplifies them to a predetermined voltage level. , the obtained inverted color signal Gγ is sent to a separate line 23
Gγ inverting circuit lea outputs the color signals Rγ and B which are sent one after another and alternately through the common line 19.
The flow of γ is led to two circuits 24.25 branched from the middle, and within each circuit 24.25, Rγ and Bγ are each inverted into color signals having a substantially complementary color relationship, and amplified to a predetermined voltage level. It consists of an Rγ/Bγ inversion circuit 18b which merges the obtained inverted color signals Rγ and Bγ into a common line 27 via an analog switch 2B and outputs them alternately. Note that the components of each of the circuits lea and 16b described above are as follows: the amplifiers 17b and 17c of the inverting circuit 16b are the inverting circuit lea
Gγ inverting circuit 1
The circuit configuration of only 6a will be explained. Furthermore, regarding the reference numerals and symbols of the constituent elements of each inverting circuit 16a, 16b, the same reference numerals and symbols are attached to the constituent elements that perform the same functions.

The Gγ inverting circuit 1f3a includes a buffer amplifier 28 provided at the circuit entrance, a clamp circuit 29 that fixes the black level of the manually input signal to a predetermined DC voltage level, a buffer amplifier 30 provided after this clamp circuit 29, and a Gγ inverting circuit 1f3a. an inverter 32 that inverts the polarity of the signal 33, and a signal 33 whose polarity is inverted
While shifting the black level of (see Figure 5) downward,
A blanking level shift circuit 34 performs H blanking of the signal flow in the time axis direction in synchronization with the start and end points of each horizontal scan, and a color signal 35 obtained by the above operation (see FIGS. 6 and 6). A white clipping circuit 38 and a black clipping circuit 39 respectively clip the white level vicinity 3B and the black level vicinity 37 (see Figure 7), and the signal 40 (see Figure 7) obtained by this operation.
7) to a predetermined voltage level, and a buffer amplifier 42 provided at the circuit outlet. In addition, Cp in the figure is a clamp pulse, Bp is a blanking pulse, 43 is a gain adjustment, 4
4 is offset adjustment, ID is Rγ.

This is an ID pulse for identifying Bγ.

The encoder 13 is equipped with a hue adjustment circuit. The hue adjustment circuit changes the hue by modulating the phase of the color subcarrier. Not only NTSC but also PAL.

The three SECAM systems have in common that two color components are transmitted using subcarriers placed within the video band. For example, in the case of the NTSC system, in order to achieve compatibility between color broadcasting and black and white broadcasting, the luminance signal (Y signal)
is transmitted in the same way as a black-and-white television, and a color signal is placed on a 3.58 MHz subcarrier and inserted into the luminance signal for transmission. Therefore, in order to transmit two color signals by subcarrier,
By choosing the color subcarrier fS to be an odd multiple of half the horizontal operating frequency fH and modulating this subcarrier with two color signals, a color signal sideband is inserted between the sidebands of the luminance signal.

The color signals are transmitted at the same frequency and in phase with each other by 9
The two subcarriers differing by 0° are a wideband chromaticity signal Et (orange and cyan axes) and a narrowband chromaticity signal Eo (orthogonal to the I axis).
The two signals are amplitude-modulated separately, and the combination of these two signals transmits the color signal. In this case, a balanced modulator is used to suppress the carrier wave. The amplitude and phase of the synthesized wave change depending on the amplitude of both Er and EQ signals,
The composite wave has a form in which it has undergone phase modulation, which changes the hue, and amplitude modulation, which changes the saturation, at the same time.

The hue adjustment circuit is configured as shown in FIG. 9, for example. In FIG. 9, 75.7L77 is a transistor, 78 is a volume, 79 to 87 are resistors, and 88, 89.90 is a capacitor.

In the above hue adjustment circuit, the phase can be changed by voltage adjustment (HUE control characteristic) as shown in FIG. 68 is set for color negative film, and the other volume 69 is set for color positive film, so that it can be switched by analog switch 71 so that it can be switched in conjunction with analog switch 17 by negative/positive changeover switch 70. . The setting amount for each volume 68.69 is
Set so that color negative film, color positive film, etc. are properly reproduced.

In other words, for example, in the display on the vectorscope mentioned above,
Settings are made according to FIG. 1O so that the hues of MG, RSYL% G, and CY% B are rotated clockwise or counterclockwise so that they fall within appropriate ranges. Specifically, in the case of a color negative film, the volume 68 sets the hue voltage to 2.55V, and in the case of a color positive film, the volume 69 sets the hue voltage to 2.45V. The encoder 13 used here is, for example, LSI CX 20055,6 manufactured by Sony Corporation.

In the figure, 72 is a resistor, and 73 and 74 are diodes.

Next, an example of an image conversion circuit device incorporating the above circuit device will be explained based on FIGS. 1 and 11. CCDI
The color filter 2 is housed in a television camera head 52 together with a lens device 51, and most of the circuit devices described above are made of a hollow column that supports the television camera head 52 swingably around a horizontal axis 58. A film carrier 56, a light source device 57, and various knobs for operation and adjustment are arranged on a base 55 disposed within the support column 54 and supporting the support column 54. Note that the RGB volume adjustment knobs eo and ei forming part of the knobs mentioned above
, ea are for manually adjusting each RGB gain control (not shown) provided in the signal processing circuit 8, and a fader operation knob 59 is for manually adjusting the fader circuit 14, respectively. Further, the negative/positive changeover switch 70 can be operated in synchronization with the analog switch 17 for the inverting circuit 16 and the analog switch 71 for hue adjustment. Note that when imaging a general subject using this image conversion circuit device, the television camera head 52 is swung around the horizontal axis 53 to align the optical axis 64 of the lens device 51.
Point the camera directly at the subject (see imaginary line).

Next, the operation of this circuit device will be explained.

First, when photographing a color positive film or a real image, the negative/positive changeover switch 7o is switched to positive. As a result, the analog switch air switches to a signal that does not pass through the inverting circuit 1B, and the analog switch 71 switches the phase adjustment voltage of the color subcarrier to positive. The adjustment voltage for the positive is controlled by the volume 69, so that the phase of the color subcarrier in the encoder 13 is displayed on the vectorscope, and the color is reproduced with the same hue voltage for the color positive film and the color negative film on which the ITE color par chart was taken. The phase of the positive image is set and adjusted according to FIG. 1O so that the positive image moves, for example, by 5@ clockwise.

Therefore, the light that enters the color positive film from the light source device 57 without passing through the cyan filter passes through the lens device 51 and the color filter 2, and enters the photoelectric conversion surface of the CCD 1 with R, G and G.
, B are formed as positive images, and charges are accumulated on the photoelectric conversion surface. This electric charge is interlaced scanned every other horizontal scanning line by the driver 6.7 as in the case of color negative film, and the pixel signals are successively transferred to the signal processing circuit 8.
sent to. Each color signal separated from the signal processing circuit 8 is subjected to white balance control, further subjected to γ correction, and directly outputted to the matrix circuit 12.

The matrix circuit 12 receives the input color signal Gγ.

A luminance signal and a color difference signal are created by combining Rγ and Bγ,
The encoder 13 adjusts color reproduction of the luminance signal and color difference signal and converts them into signals of the NTSC system or the like. That is, since the positive phase adjustment voltage is manually applied to the encoder 13 from the volume 69 selected by the analog switch 71, the voltage at the encoder I3 is adjusted according to the characteristics of the color positive film as shown in FIG. The phase of the color subcarrier is adjusted, and the positive image when color reproduction is performed using a common hue voltage that takes into account the color reproduction of both color positive film and color negative film taken with the ITE color per chart is shown on the display on the vectorscope. The phase is moved 5 degrees clockwise, and the optimum hue is adjusted and reproduced.

In this way, the color television signal (arrows, etc.) output from the encoder 13 becomes a color-balanced color reproduction signal, and the television receiver that receives these signals reproduces the color with the same contrast as that of a negative. Images with high resolution and excellent color reproduction can be displayed on the TV screen.

Next, when photographing the color negative film BB, the negative/positive changeover switch 7o is switched to negative. As a result, the analog switch I7 operates the inverting circuit 1B, and the analog switch 71 switches the color reproduction adjustment voltage to the negative voltage.

Light that enters the color negative film 66 from the light source device 57 through the cyan filter 65 passes through the lens device 51 and the color filter 2, and forms a negative image color-coded into red, green, and blue on the photoelectric conversion surface of the CCDI. It forms an image and accumulates charge on the photoelectric conversion surface.

This charge is interlaced scanned every other horizontal scanning line by the driver 8.7, and pixel signals are sent out to the signal processing circuit 8 one after another.

Here, the sample-and-hold circuit (not shown) is
Using the arrangement of windows r and b of the color filter 2 and the timing of arrival of each pixel signal as clues, each pixel signal is separated into red, green, and blue color signals.

The amplification degree of each separated color signal is then controlled.

Further, the signal is γ-corrected and output to inversion circuits 16a and 16b.

The clamp circuit 29 of the inverting circuit 16a fixes the black level 20 (see FIG. 4) of the input Gγ to a predetermined reference voltage level, and then the inverter 32 inverts the polarity of the signal (a signal whose polarity is inverted). 33 is shown in Figure 5). next,
This signal 33 uses a blanking pulse to level shift the black level 20 of the signal 33, and a signal 35 rising upward from the black level 20 is obtained (see FIG. 6). Next, this signal 35 passes through a white clip circuit 38 and a black clip circuit 39, and is clipped near the white level 3B and near the black level 37 as shown in FIG. When the voltage is amplified to a required voltage (voltage necessary to improve the contrast of the image) by 17a, Gγ is obtained (see FIG. 8). The signals Rγ and Bγ are similarly processed in the inversion circuit 16b, and the obtained color inversion signals Rγ and Bγ are sent to the common line 27.
Offset adjustments 44 and 44 provided in the amplifiers 17b and 17c match the black levels of the signals Rγ and Bγ.

Note that if the γ compensation circuit in the signal processing circuit 8 is not configured so that the characteristics of R2O and B can be set individually, it is not necessary to individually install a γ compensation circuit after each inverter 32 of the inverting circuits lea and 18b. It is also possible to improve the tonal characteristics.

is sent to a matrix circuit 12, which generates a luminance signal and a color difference signal by rotating the matrix. These signal operations are exactly the same as in the case of imaging a positive film or a general subject. The encoder 13 converts the aforementioned luminance signal and color difference signal into signals of the NTSC system or other systems. At the same time, since the negative phase adjustment voltage is manually applied to the encoder 13 from the volume 68 selected by the analog switch 71, the encoder 13
If the phase of the color subcarrier at is displayed on a vectorscope, it will be negative if the color positive film and color negative film on which the above-mentioned ITE color perchart was taken are reproduced at the common hue voltage that takes into account the color reproduction of both. Since the phase of the inverted image is modulated to move, for example, 5@ counterclockwise, the hue adjustment as shown in FIG. 13 is performed. Therefore, MG1R% YL% G% C
Both V and B are within the appropriate range, color reproduction with better color balance is performed, and the output is output as a color TV signal or video signal.The TV receiver that receives these signals has a lower contrast. To project an image of excellent image quality with high saturation and good color reproduction on a television screen.

Note that the present invention is not limited to the above-described embodiments; for example, the color filter may be a combination of different colors, and the photoelectric conversion device may be used instead of the solid-state image sensor described in this embodiment. A solid-state image sensor with a different structure or a structure other than a solid-state image sensor may be used, and the circuit configuration may be incorporated into a telecine or other television camera without departing from the gist of the invention. Of course, various changes can be made within the scope.

[Effect of the invention] As described above, the present invention exhibits the following excellent effects.

(1) Since the hue reproduction adjustment is set to be switchable in two stages, positive and negative, and synchronized with the switching of the color inversion circuit, it is possible to adjust the hue reproduction to the appropriate level for both color negative and color positive films. As a result of hue adjustment, image quality with high contrast, high saturation, and excellent hue can be obtained for color negative film, color positive film, and live-action noise film, greatly expanding the use of small TV cameras. can.

(g) Widely applicable to various video cameras with inverting circuits.

[Brief explanation of drawings]

1 to 13 show embodiments of the present invention, FIG. 1 is a block diagram showing the entire circuit device, FIG. 2 is a block diagram of the inverting circuit, and FIG. 3 is the arrangement of color filter windows. 4 is an explanatory diagram of the modeled color signal output from the signal processing circuit, FIG. 5 is an explanatory diagram of the signal obtained by polarity inversion, and FIG. 6 is the H blanking and level shift operation. FIG. 7 is an explanatory diagram of the color signal after applying the white clip and black clip. FIG. 8 is an explanatory diagram of the color signal after color inversion.
The figure shows an example of a phase adjustment circuit. Figure 1O is a diagram showing the control characteristics of the encoder in Figure 1 using the phase adjustment voltage. Figure 11 is a perspective view of a television camera incorporating this circuit device. 13 is a diagram showing the hue adjustment effect on a vectorscope when a color positive film is imaged with this circuit device, and FIG. 13 is a diagram showing the hue adjustment effect on a vectorscope when a color negative film is imaged with this circuit device. FIG. 14 is a block diagram showing an example of a circuit device of a conventional television camera, FIG. 15 is a diagram showing an example of a color negative film before development, FIG. 16 is a diagram showing a color negative film after development, and FIG. 17 is a diagram showing an example of a color negative film before development. Figure 18 is a diagram showing the spectral density of a color negative film after development, Figure 18 is a diagram showing an example of a color positive film before development, Figure 19 is a diagram showing a color positive film after development, and Figure 20 is a diagram showing a color positive film after development. Diagram showing spectral density, No. 21
The figure is a vectorscope display diagram of a color par chart, Figure 22 is a vector scope display diagram using a three-tube camera with color positive film that photographed a color per chart, and Figure 23 is a three-tube display diagram of a color negative film that photographed a color per chart. It is a vector scope display diagram by a camera. In the figure, l is a solid-state image sensor, FIG. 8 is a signal processing circuit, and 12
13 is a matrix circuit, 13 is an encoder, IB is an inverting circuit, 17.71 is an analog switch, and 68° and 69 are volumes.

Claims (1)

[Claims] 1) In an image conversion circuit device for a color video camera having a negative/positive inversion circuit, a color subcarrier phase adjustment circuit is provided, and the amount of phase adjustment of the color subcarrier by the color subcarrier phase adjustment circuit is set to at least two stages; An image conversion circuit device characterized in that it is configured to be able to switch in synchronization with switching of an inverting circuit.