JPS60123187A - Profile correcting system for television camera system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to color television camera systems, and more particularly to improvements in contour augmentation techniques for the purpose of improving image sharpness.

It is known in the art that the sharpness of an image can be enhanced by some form of mask aperture correction or contour correction. Such corrections tend to compensate for the apparent loss of resolution due to imperfections in image signal generation and transmission. In the present technique, after extracting high frequency horizontal and vertical spatial information from one of the three color signals, red, green and blue are added to each of the three color signals or to the luminance signal again. It is known in the art regarding cameras that use camera pink-up devices. - In the crotch, many of the enhancement effects needed in most average scenes are often obtained from the contours from the green video signal, so the mask opening [] is used in the acquisition of the contour correction signal. is a green light.

This obtained green contour correction signal is then added to each of the three color signals or the luminance signal. Thus, the color signal after the open [21 correction] thus obtained provides a sharp transition state.

An aperture-corrected color signal obtained from only a green video signal suffers from the problem that the green information in the scene is mostly weak or completely absent in sharpness.

Thus, for example, a large area red scene will be noticeably weakened, due to the absence of contour information from the red video signal.

In such systems where the red and green video signals are separated from each other, the combination of the contour signal obtained from the augmented green and the unenhanced red signal results in an unbalanced representation;
This often leads the viewer to believe that the image is coming from a camera that appears to be out of focus. Historically, when red and green video signals are adjacent to each other, the green-enhanced contour signal can erode the red video signal area and reduce the brightness at the edges of the red signal. .

If the red image is small, this low brightness condition will occupy a relatively large portion of the overall image size, causing the red image to become dark.

The imbalance in the enhancement measures between the individual red and green images can also be recovered by taking the contour signal from the red video signal and adding the green contour signal to this signal.

However, the positioning of the two images may cause the transition states of the red and green contour signals to cancel each other at adjacent points, resulting in a loss of enhancement or imbalance at the edge of the color. There is a risk that other problems may occur if the Furthermore, if there is some misalignment overlap in the image, this solution will reduce the contour signal, instead of being weakened as would be the case if it were obtained only from a single color video signal, such as the green video signal. May emphasize inconsistency errors.

The problem of using contour signals derived from only one of the three color signals, as well as the tendency to emphasize mismatch errors, has been addressed in the prior art. R-A,
U.S. Pat. No. 4,209.801 to Dischert et al.
The problem is that the mask aperture correction signal is always obtained from the green video signal, but also from the red video signal when the red video signal is approximately twice the amplitude level of the green video signal. We are presenting a system that can be used. H,5chn
Eider U.S. Patent No. 3.681.520 describes green,
A system is presented in which an aperture correction signal is obtained by examining the amplitudes of blue and red video signals and using the signal with the largest amplitude to obtain a contour correction or aperture correction signal. Still other examples of related prior art (1, U.S. Re-Patent No. 29°570 of Brucimer et al.
No. 1, the patent presents a system for preventing overcompensation of open [] corrections, especially in overlap errors. @Kuo correction signal is obtained from only one of the color signals,
This signal is then applied individually to each of the red, green and blue color signals by the input matrix circuit.

From the prior art US patents cited above, it is known to sharpen images produced by color cameras by adding an aperture correction signal or a contour signal to the video signal to enhance its edges. I understand. , but if the color signal is always generated from only one of the three colors, such as the green color video signal, most of the information from the red video signal is absent. Scenes that are another color, such as red, will result in blurring at the edges.However, if the contour signal is fMed from more than one color signal, such as the green and red video signals, the images will not overlap with each other. Adjacent time rings Wl (total cancellation of the signal, distortion, or alternatively an emphasis on matching errors in one image in a mismatched state) may occur.

It is an object of the present invention to improve the sharpness of an image by providing a signal in such a way that the enhancement of color registration errors is suppressed to a minimum of II. According to one feature of the present invention, this is accomplished by providing a contour signal derived from a green video signal and a red video signal, where the addition of the two signals results in an enhancement of color registration errors. When (l
Only when the two contour signals are selectively added together.

Thus, a primary object of the present invention is to provide an aperture correction signal or contour signal to be added to a video signal to enhance the edges of the video signal such that enhancement of color registration errors is minimized. It's about doing.

Yet another object of the present invention is that such a % Gii signal ((( 33. The present invention resides in providing a contour signal derived from a red video signal. Contour correction/Sdeno is provided for the first and second @
→(ζ signals are obtained from the first and second video signals, respectively.

Typically, this first color signal is added to all video signals to improve image sharpness, and a second color signal (d) is added to all video signals to improve image clarity. selectively added to the first color signal to provide a composite color signal for alignment to the video signal only when the first color signal is aligned to the video signal;

These and other objects of the invention will be apparent from the following description of the preferred embodiments, taken in conjunction with the drawings forming a part thereof.
will be readily apparent.

First, referring to FIG. 1, this figure shows a prior art contour correction system for a telephotography system using a blue image pickup tube 10, a green image pickup tube 12, and a red image pickup tube 14. As is well known, the green video signal is applied to a contour generator 16 which extracts high frequency information therefrom and applies the resulting contour signal to a summing circuit 18.20.22. These two-way circuits are
For the purpose of contour augmentation, which has the effect of increasing the sharpness of the image, the blue video signal, the green video signal and the red video signal are combined respectively. ? 11 signal. The blue, green and red video signals are each routed to delay line 2.
4.26.28 for the adder circuit.

The delay in each of these delay lines is
Generator] 6; Approximate to -1ffl, +1. Alternatively, the blue, green and red video signals can first be summed together to obtain the luminance signal to which the contour supplemented iE signal is added.1 The prior art system as shown in FIG. A contour or aperture correction signal is typically obtained from the green video signal. This is because in practice it has been discovered that the contour signal and the correction signal should be derived from the color signal forming the luminance component of the signal.

Generally, in a telephoto camera system, the luminance signal is 030R plus 0.11. B plus 059G
, where R, G, and Bil''I represent red, green, and blue color signals, respectively.

For this reason, the number commonly selected for use in obtaining the contour correction signal is the green color signal. However, if the scene has little or no green information,
These scenes appear blurred or lack sharpness. For example, a red scene with a large area becomes noticeably blurred because the red video signal does not provide enough information.

Figures 2 and 3 illustrate two situations in which disturbances occur when the contour signal is obtained only from the green video signal.

As shown in FIG. 2A, the green (G) and red (R) video signals are separated from each other.

The waveform of FIG. 2B shows the contour signal obtained from the green video signal only, and FIG. 2C shows the resulting delayed luminance waveform when the green contour signal is added. From this waveform, a ring! 11≦The composite of the augmented green value signal and the unenhanced red video signal ε" is found to be unbalanced. This makes it seem like the image is coming from a camera that does not appear to be coming from the camera.

The waveforms of FIGS. 3A-3C illustrate another condition that occurs when the red and green video signals are adjacent to each other. Rings obtained from green video signals only! ; IIζ correction signal is shown in FIG. 3B; 5J when the green contour correction signal is calculated with respect to the delayed luminance signal as shown in the waveform of FIG. 3C, the transition of the green contour correction signal to become negative; The condition invades the red video signal region and reduces the brightness at the edges of the red signal. As a result, if the red image is small, this low luminance signal becomes a relatively large portion of the overall image size, darkening the entire red image.

The enhancement imbalance between the red and green images, as shown in the waveforms of FIGS. 2A, 2B, and 2C, can be achieved by simply obtaining the contour signal from the red video signal and adding the green contour signal to the red contour signal. signal and then add the resulting contour signal to each color video signal or luminance signal. However, this simple solution may very well result in other problems, as the addition of red and green contour signals creates other problems, especially when the images are close to each other. This is illustrated in the waveforms of FIGS. 4A-4D. FIG. 4A is a waveform illustrating a red and green image of roughly similar levels in an adjacent relationship. The green contour signal is shown in the waveform of FIG. 4B and is derived from the red video signal. The resulting red contour signal is shown in Figure 4C. When the red and green contour signals are added together and superimposed on the delayed luminance signal, the result is shown by the waveform in Figure 4D. It can be seen that the red and green contour signals cancel each other out at adjacent points in the red and green images of equal levels.This results in a loss of enhancement effect at the edge of the color but still causes an imbalance, and then Figures 5A to 5D
Let's match the waveforms in the figure. The waveform in Figure 5A shows a slightly misaligned image. - In the example, the green and red images are separated, and in the second example, the green and red images overlap. 1. Green and red rings obtained from green and red video signals! When the i11ζ signal is added to the luminance signal delayed by the 13 contour signal shown in the waveforms of FIGS. 513 and 5C, respectively, the result is as shown by the waveform of FIG. 5D. It will now be seen that the misalignment error can be accentuated instead of being attenuated as in the case of one contour signal.

Let us now examine Figure 6, which shows a circuit according to the invention. As can be seen, the embodiment of the present invention as shown in FIG. 6 uses a contour generator to obtain the contour signal from the green video signal, as in the prior art of FIG. Historically, this circuit was used to convert the red video signal to
The circle! a second contour signal derived from the red signal is selectively added to the green contour signal to produce a composite contour signal;
This composite signal is then added to the luminance signal in a manner known in the art.

The circuit in FIG. 6 is similar to the circuit in FIG.
The present invention relates to a television system that uses a blue image tube 50, a green image tube 52, and a red image tube 54 to produce blue, green, and red signals, respectively. These signals are, respectively,
They are each delayed by delay lines 56, 58, and 60 before being added together by summing circuit 62 to produce the luminance signal. The luminance signal obtained from the summing circuit 62 is fed singly to another summing circuit 64 in which the luminance signal is summed together with the contour signal obtained according to the invention.

A green contour generator 70 obtains a contour signal from the green video signal and provides this signal to a summing circuit 72 to which a gated red contour signal is selectively added.

The circuit that produces the gated red contour signal is shown at the bottom of FIG. The red contour signal is sent to the red video signal by the buffer 74.・1+M! C1 is obtained from the red video signal by inputting the red video signal to the generator 76. This circuit is constructed similarly to the loop 11t generator 16.70 and operates to produce a red contour signal having a waveform as shown in Figures 4C and 5C previously described. .

The output from the contour generator is provided as a power source to a cage 80, which preferably includes, for example, a field effect transoster. The gate signal is the contour generator 7
The gate 80 is selectively opened and closed to block or pass the red contour signal provided by 6. This gate signal is derived from the red video signal. Thus, the green video signal is presented to a delay line 82 that provides a delay T, which is half the delay 2T caused by the contour generator 763, and the delayed green video signal is Then, if the level of the green video signal is greater than 10% of the normal level, it is passed through the buffer 84 +/(thus IJl'l to the level detector 86) to the amplifier. Increased by 1] due to 88 etc.

This video signal is applied to gate drive circuit 90 which also provides a gating signal to gate 80 to selectively pass or block the red contour signal.

Each contour generator disclosed herein may take the form of contour generator 76 in FIG. here,
The output of buffer 74 is applied directly to the base of NPN transnoster 100 via resistor 92, and is applied to second NPN run/meta 102 by delay line 101. The emitters of the transistors 100.1'02 are connected to a common junction by resistors 104 and 106 and then to the B voltage supply 100 (through a resistor 108). The collector of transistor 02 is directly connected to the power source of B102 voltage.This resistor and transistor 102
The junction between the collector and the collector serves as the output to gate 80.

For example, as shown in FIGS. 7A and 7C, when the red video signal has a positive rising edge, the output from the contour generator will be negative for a time lapse T, and then the pressure for a time lapse T. . Therefore, the total time elapsed amount of the contour generator is 2T. The gating signal applied to the gate 80 is obtained from the green video signal, and in the waveform of FIG. It is delayed by a time T.

The operation of the circuit of FIG. 6 is best understood in light of the following description of the waveforms of FIGS. 7 and 8. As will be clear ((, the waveforms in Figures 7A and 8A illustrate the same conditions as previously discussed with respect to the waveforms in Figures 4A and 5A, respectively. The conditions shown represent a video signal when the green and red images are adjacent to each other.As in the prior art, the green contours are shown in the waveforms of FIG. 7B. Furthermore, a red contour signal of Da shown in the waveform of FIG. 7c is provided by a red contour generator 76.

The red outlined gating signal is derived from the green video signal and takes the form shown in the waveform of FIG. 7D. When a red outline gate signal is given to game l-80,
This prevents the red contour signal from going negative and leaves it with only positive transitions as shown in the waveform of FIG. 7E. That journey! I, the transition of the green contour signal line is not canceled by this addition process, and this positive transition is shown in Figures 7F and 7.
As shown in the waveform of Figure 8, it provides a balanced fC enhancement condition of the red and green edges without producing dark red dispersion. This is in contrast to the resulting waveform of FIG. 4D, where the green contour signal and the uncompensated red contour signal are combined and added to the luminance signal. Therefore, the circuit according to the invention When the red and green video signals are adjacent to each other, it provides balanced enhancement for the red and green edges.

A comparison of FIGS. 3 and 7 shows that the negative transition in the small red region is removed by the addition of the red contour. This eliminates the appearance of "ugly red" in the scene, which is often seen with only green outlines.

Next, similar to the waveforms in Figure 5A, we will create a condition in which the red and green video signals are slightly misaligned in the sense that they are separated in some cases and overlap in other cases, similar to the waveforms in Figure 5A. Please refer to the waveform shown in FIG. 8A.

The circuit of FIG. 6 operates to provide green and red contour signals as shown by the waveforms of FIGS. 8B and 8C, and a red contour gating signal as shown by the waveform of FIG. 8C. As shown in the waveform of FIG. 8E, this gating signal causes gate 80 to block the red contour signal 1 in conditions where the red and green video signals overlap, but to block the adjacent but distant green video signal. The red contour signal obtained from the rising edge of the red video signal is passed when leaving the trailing edge. When this gated red contour signal is added to the green contour signal, the result is the 8th F
As shown by the waveforms in the figure. When this gated red and green contour signal is added to the luminance signal, this results in a waveform as shown in Figure 8G.

Comparing the waveform of FIG. 8G with the waveform in FIG. 5B shows that the circuit of FIG. 6 eliminates the multiple transition states shown in the waveform of FIG. 5D for conditions of mismatch crossing. I understand. As a result, it can be seen that the red contour signal is added to the red contour signal only when the result is to emphasize color matching errors.

Although the invention has been described in terms of preferred embodiments, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention as defined by the following claims.

[Brief explanation of the drawing]

1 is a schematic block diagram illustrating a prior art method of enhancing image sharpness; FIGS. 2A-2C are waveform diagrams illustrating one mode of operation of the prior art system shown in FIG. 1; 3A-3C are waveform diagrams illustrating alternative modes of operation of the prior art system shown in FIG. 1, and FIGS. 4A-4D are waveforms useful in explaining the problems addressed by the present invention. A diagram showing this, Figure 5A! S% Fig. 50 is a diagram similar to Figs. 4A to 41) useful for explaining various problems to which the present invention is directed, and Fig. 6 is a schematic block diagram showing a preferred implementation of the present invention. , FIGS. 7A to 7G show the first embodiment of the present invention.
Waveform diagrams showing two modes of action, and Figures 8A to 8
Figure G is a waveform diagram showing another mode of operation of the present invention. 10.50... Blue image pickup tube, 12.52 Green image pickup tube, 14.54... Red image pickup tube, 16. Contour generator,
18.20.22 ・Addition circuit, 24.26.28.5
6.58.60 Delay line, 62.64.72 Addition circuit, 70.76 Contour generator, 74 Buffer, 80 Case 1, 82 Delay line, 84 Buffer, 86 Level detection device, 88・amplifier, 90・・gate drive circuit, 92・resistance, 100・NPN l・runnostar, 101・delay line, 102−NPN transformer
,; Star, 1.04.106.108.110...
resistance. Foreign book of drawings (no change in content) FIG, 2 FIG, 3 FIG, 7 FIG, 8 7N Hita” Higosu HtoHda Procedures Amended Book July 1939/1933 Published by the Japan Patent Office Gakudon Shiga ゛Display of Open Mouth 1 Incident Showa / Year 1 Permit Application No. 22! 〆No. 9S cis-rlA Relationship with the case of the person making the amendment Address of the patent applicant

Claims (1)

Claims: (1) A contour correction system for a television system, comprising: an apparatus for providing at least first and second color video signals; each first
and a device for constantly synthesizing the first contour signal with the color signal for emphasizing the sharpness of the image in the color transition region of the image, and , independently of the first color signal, applying the second contour signal to the color signal so as not to augment the color transition states of the color signals when the color signals are in a mismatched state; A contour correction system, comprising a device for selectively compositing. (2) The selective synthesis device includes a gating device controlled independently of the first color signal to pass the second contour signal as a gated contour signal. 3. The contour correction system of claim 1, further comprising: a summing device for receiving and adding the first color signal and the gated color signal to produce a composite contour signal. 2. The contour correction system of claim 2. (4) The synthesis device is also responsive to the composite contour signal and synthesizes the signal with the color signal. (5) A device for obtaining a gate signal from the first color signal in order to control the gate device is provided. The contour correction system according to item 2. (6) The gate signal acquisition device delays the first color signal so that the gate signal lags the first color signal by a time delay amount T. Claim 5, characterized in that it includes a device for delaying fiT.
Contour correction system as described in section. (7) The contour correction system according to claim 6, wherein each contour signal acquisition device includes a time delay device such that each contour signal has a duration of 2T. (8) The gating device σ normally passes the second contour signal and blocks the second contour signal for a period corresponding to the gating signal, and transmits the gating signal to block the second contour signal. 8. The contour correction system according to claim 7, further comprising a device for feeding the gate device. (9) The device for adding the signal includes a level detection device for adding the gate signal only when the first color signal exceeds a predetermined value. 9. The contour correction system according to item 8.