JP4488620B2 - TV camera equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a television camera device, and more particularly to a television camera device that facilitates focusing by a cameraman.
[0002]
[Prior art]
In a commercial television camera such as a broadcast, a conventional standard television camera (SDTV) has a higher viewfinder resolution than a video band, and is relatively easy to focus. However, in the case of a high-definition television camera (HDTV), the performance has not improved so far that the resolution of the viewfinder exceeds the video bandwidth (the HDTV resolution is considered when viewed on a monitor exceeding 30 inches, (The finder is only 2 inches or 7 inches, and the resolution cannot be taken). Therefore, in particular, in HDTV, it has become necessary to make it easier to focus on the viewfinder than at present.
[0003]
On the other hand, in shooting with a television camera, a cameraman focuses a subject image by adjusting a focal length of a lens while monitoring a viewfinder image. Further, in order to make this focusing easier, a method of performing contour enhancement dedicated to the viewfinder image is employed.
[0004]
A conventional outline enhancement of a viewfinder image will be described. FIG. 1 conceptually shows shooting by a television camera. In FIG. 1, it is assumed that the subject is composed only of the object A and the object B, and the distance between the object A and the object B from the television camera C is different. In the following, it is assumed that the object A and the object B are particularly in focus by the object A.
[0005]
2A and 2B show the camera output signal and the contour-enhanced camera output signal, respectively. As described above, since the object A and the object B are particularly focused by the object A, the rising and falling of the object A in the camera output signal are sharper than those of the object B (FIG. 2 ( a)). Therefore, when contour enhancement is performed, the object A has a large edge and the object B does not have a large edge (see FIG. 2B).
[0006]
As described above, since a significant difference occurs in the size of the edge between the case where the focus is achieved and the case where the focus is not, the cameraman can easily focus by monitoring the edge.
[0007]
[Problems to be solved by the invention]
However, in the above-described contour emphasis of the viewfinder image, when there is not much difference in the distance from the TV camera to the plurality of objects, the most focused object and the next focused object are the edges. Does not make much difference. For this reason, in such a case, it is difficult for the photographer to precisely focus on the desired object.
[0008]
An object of the present invention is to provide a television camera device that facilitates focusing on a desired object even when there is not much difference in distance from the television camera to a plurality of objects.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention a television camera device, the television camera output signal, by supplying to the viewfinder by adding the edge enhancement signal extracted from the television camera output signal, the video viewfinder contour In a TV camera device that emphasizes
A distribution circuit for distributing the contour enhancement signal to two systems;
A first clipping circuit for clipping a signal having a level lower than a first predetermined level for identifying the level of the edge enhancement signal with respect to the one of the distributed signals;
A second clip that clips a signal having a level lower than the first predetermined level and higher than a second predetermined level that identifies the level of the edge enhancement signal with respect to the signal of the other distributed system. Circuit,
And a combining circuit for combining the outputs of said second clip circuit and the first clip circuit,
A signal obtained by adding the output of the synthesis circuit to the camera signal is supplied to the viewfinder.
[0010]
Further, the present invention a television camera device, the television camera output signal, by supplying to the viewfinder by adding the edge enhancement signal extracted from the television camera output signal, and to emphasize the contour of the image of the viewfinder In a TV camera device,
A multiplication circuit for multiplying the contour enhancement signal by a constant value;
A subtraction circuit for subtracting a predetermined value from the contour enhancement signal ;
A level detection circuit for detecting whether or not the contour enhancement signal has reached a predetermined level;
When the input of the level detection circuit is less than the predetermined level, the output of the multiplication circuit is switched by the output of the level detection circuit. When the input of the level detection circuit is equal to or higher than the predetermined level, the output of the subtraction circuit is A switching circuit that switches according to the output of the level detection circuit;
A signal obtained by adding the output of the switching circuit to the camera signal is supplied to the viewfinder.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on an embodiment of the invention with reference to the accompanying drawings. As described above, according to the present invention, when the level of the edge enhancement signal does not exceed a predetermined level, the edge enhancement signal is not added to the video signal for viewfinder. FIGS. 7A and 7B respectively show a camera output signal and a contour-enhanced camera output signal (video signal supplied to the viewfinder) in the television camera apparatus of the present invention.
[0012]
As can be seen from FIG. 3B, no edge is attached to the object B. Therefore, according to the present invention, the photographer does not focus on the object B by mistake.
[0013]
Hereinafter, signal processing for preventing the edge enhancement signal from being added to the video signal for the viewfinder when the level of the edge enhancement signal does not exceed a predetermined level will be described. This signal processing is basically achieved by providing a dead zone in the contour enhancement signal added to the video signal for viewfinder.
[0014]
4A to 4D show the signal processing, FIG. 4A is a camera output signal, FIG. 4B is an edge emphasis signal, and FIG. 4C is an edge emphasis signal considering the dead zone. FIG. 4D shows a camera output signal (video signal for viewfinder) with edge enhancement.
[0015]
Here, the contour enhancement signal considering the dead zone shown in FIG. 4C is provided with a dead zone sandwiched between two upper and lower broken lines in the contour enhancement signal as shown in FIG. The contour emphasizing signal is obtained by not treating it as the contour emphasizing signal.
[0016]
In the following, two circuit examples will be described as examples of a circuit that provides a dead zone in the contour enhancement signal and obtains a contour enhancement signal in consideration of the dead zone shown in FIG. 4C from the output side of the circuit. FIG. 5 shows a first circuit example. In FIG. 5, 1 is a signal dividing unit, 2 is a clipping unit above a certain level, 3 is a clipping unit below a certain level, and 4 is a signal synthesis unit. 6A to 6F show the waveforms of the respective parts in FIG.
[0017]
The operation of the circuit shown in FIG. 5 will be described. In FIG. 5, first, an edge emphasis signal (shown as an input signal in the figure) shown in FIG. Since a method for extracting the contour emphasis signal (a) from a camera output signal (generally a video signal) using an integration circuit, a phase delay circuit, or the like is well known, the extraction method will not be described here. The contour emphasis signals (b) and (c) divided into two by the signal dividing unit 1 are input to the clip unit 2 above a certain level and the clip unit 3 below a certain level, respectively.
[0018]
The edge emphasis signals (b) and (c) are not different from the signals shown in FIG. 6 (a) by only dividing the signal shown in FIG. 6 (a) into two parts. In c), the boundary line indicating the level of the dead zone is indicated by a broken line. The broken line shown in FIG. 6B corresponds to the lower broken line in FIG. 4B, and the broken line shown in FIG. 6C corresponds to the upper broken line in FIG.
[0019]
Signals shown in FIGS. 6 (d) and 6 (e) are taken out from the clip unit 2 above the certain level and the clip unit 3 below the certain level, and inputted to the signal synthesis circuit 4. Then, an edge enhancement signal (shown as an output signal in the figure) corresponding to FIG. 4C and taking into account the dead zone shown in FIG. 6F is extracted from the output side of the signal synthesis unit 4.
[0020]
FIG. 7 shows a second circuit example in which a dead zone is provided in the contour emphasizing signal and an edge emphasizing signal taking into account the dead zone shown in FIG. 4C is obtained from the output side of the circuit. In FIG. 7, 5 is a subtracter for subtracting a constant value, 6 is a multiplier for multiplying the constant value, 7 is a multiplexer, and 8 is a level detector. 8 and 9 show how the signal level at each part in FIG. 7 changes due to the level change of the input signal (a).
[0021]
The operation of the circuit shown in FIG. 7 will be described. In FIG. 7, the input signal is an edge emphasis signal as in FIG. 5, but this is shown by (a) in FIG. 8 as a reference of the signal level in each part in FIG. When the constant value is subtracted from the input signal (a) in the subtracter 5 for subtracting the constant value in FIG. 7, the signal is shown as (b) in FIG. Similarly, when the input signal (a) is multiplied by a constant value in the multiplier 6 that multiplies the constant value in FIG. 7, a signal indicated by (c) in FIG. 8 is obtained. These obtained signals (b) and (c) are supplied to each switching contact of the multiplexer 7.
[0022]
On the other hand, the input signal (a) is also supplied to the level detection unit 8 to detect whether or not the level of the input signal (a) has reached a predetermined constant level. Now, it is assumed that the predetermined constant level is p level (see FIG. 8) where the straight line (b) and the straight line (c) intersect, and the detection output of the level detection unit 8 is supplied to the control input terminal of the multiplexer 7. Then, when the switching contact of the multiplexer 7 is controlled (connection control), the input signal (a) does not exceed the level p, the straight line (c), and the input signal (a) exceeds the level p. Sometimes the straight line (b) is selected and output.
[0023]
The output signal (d) of the multiplexer 7 is a signal represented by the input / output characteristics of FIG. 9 with respect to the input signal (a). This is because the contour emphasis signal (input signal) input to the circuit shown in FIG. 7 does not appear in the output of the circuit when the level is equal to or lower than the level p. It means that it is output. That is, it should be noted that the contour emphasis signal below the level p is in the dead zone. The level p corresponds to the level of the broken line shown in FIGS. 4B, 6B, and 6C.
[0024]
【The invention's effect】
According to the present invention, it is possible to realize a television camera device that facilitates focusing on a desired object even when there is not much difference in distance from the television camera to a plurality of objects.
[0025]
In addition, the present invention that can accurately focus on an object is particularly useful even when the performance of the viewfinder does not increase so as to exceed the video bandwidth, as in a high-definition television camera.
[Brief description of the drawings]
FIG. 1 conceptually shows shooting by a television camera.
FIG. 2 shows a camera output signal and a contour-enhanced camera output signal.
FIG. 3 shows a camera output signal and a contour-enhanced camera output signal in the television camera apparatus of the present invention.
FIG. 4 shows signal processing for providing a dead zone in an edge emphasis signal added to a video signal for viewfinder.
FIG. 5 shows a first circuit example for obtaining a contour enhancement signal in consideration of a dead zone.
6 shows the waveform of each part in FIG.
FIG. 7 shows a second circuit example for obtaining an edge enhancement signal in consideration of a dead zone.
FIG. 8 shows how the signal level at each part in FIG. 7 changes due to a change in the level of the input signal.
FIG. 9 shows how the signal level at each part in FIG. 7 changes due to a change in the level of the input signal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Signal division part 2 Clip part more than fixed level 3 Clip part below fixed level 4 Signal composition part 5 Subtractor which subtracts fixed value 6 Multiplier which multiplies fixed value 7 Multiplexer 8 Level detection part

Claims (2)

In the television camera apparatus that enhances the contour of the video of the viewfinder by adding the contour enhancement signal extracted from the television camera output signal to the television camera output signal and supplying it to the viewfinder,
A distribution circuit for distributing the contour enhancement signal to two systems;
A first clipping circuit for clipping a signal having a level lower than a first predetermined level for identifying the level of the edge enhancement signal with respect to the one of the distributed signals;
A second clip that clips a signal having a level lower than the first predetermined level and higher than a second predetermined level that identifies the level of the edge enhancement signal with respect to the signal of the other distributed system. Circuit,
And a combining circuit for combining the outputs of said second clip circuit and the first clip circuit,
A television camera apparatus , wherein a signal obtained by adding the output of the synthesis circuit to the camera signal is supplied to the viewfinder. In the television camera apparatus that enhances the contour of the video of the viewfinder by adding the contour enhancement signal extracted from the television camera output signal to the television camera output signal and supplying it to the viewfinder,
A multiplication circuit for multiplying the contour enhancement signal by a constant value;
A subtraction circuit for subtracting a predetermined value from the contour enhancement signal ;
A level detection circuit for detecting whether or not the contour enhancement signal has reached a predetermined level;
When the input of the level detection circuit is less than the predetermined level, the output of the multiplication circuit is switched by the output of the level detection circuit. When the input of the level detection circuit is equal to or higher than the predetermined level, the output of the subtraction circuit is A switching circuit that switches according to the output of the level detection circuit;
A television camera apparatus , wherein a signal obtained by adding the output of the switching circuit to the camera signal is supplied to the viewfinder.

Images