JPH09247525A - Video special effect device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate the picture of a realistic shadow through simple configuration. SOLUTION: A gain control circuit 5 to control the gain of a shadow key signal, low pass filters 6 and 7 to filter the picture of the shadow, a controller 8 which controls the gain in the gain control circuit 5 in accordance with a gain characteristic based on distance (x) between the shadow and an object and the distance (y) between a light source and the object, and also controls a filter characteristic in the low pass filters 6 and 7 in accordance with the filter characteristic corresponding to a ratio x/y, and an over/under circuit 13 to subtract a part to be hidden with a key signal K from the shadow key signal SK are provided, and a background signal, the signal of an object picture and an object video signal Vi are mixed based on the key signal K.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video special effect device suitable for application to, for example, a video special effect device.

[0002]

2. Description of the Related Art As a video special effect device, for example, FIG.
There is something like that shown in FIG. 4A is an explanatory diagram showing one of the effects of the image special effect device, and FIG. 4B is a configuration diagram of the image special effect device capable of realizing such an effect.

As shown in FIG. 4A, the image special effect device shown in FIG.
Is generated and the object O and the pseudo shadow IS are combined.

The video special effect apparatus shown in FIG. 4B subtracts the key signal K supplied via the input terminal 101 from the background signal BG supplied via the input terminal 103, and inputs the subtraction result to the key signal K. The mixing circuit 102 for adding the video signal Vi supplied through the terminal 100, the memory 104 for storing the key signal K supplied through the input terminal 101, and the key signal stored in the memory 104 are An operation unit 105 that generates a pseudo shadow signal IS by changing its position by an address operation in the X and Y directions.
And the pseudo shadow signal IS from the memory 104, and the pseudo shadow signal IS and the key signal K supplied via the input terminal 101.
Over / under circuit 106 for reducing the overlapping portion with
And the over / under processed output K / IS from the over / under circuit 106 is subtracted from the mixed signal MIX from the mixing circuit 102, and the input terminal 10 is added to the subtraction result.
A mixing circuit 1 which adds a color matte signal supplied via 8 and outputs it as an output signal OUT from an output terminal 109.
07.

Next, the operation of the video special effect device shown in FIG. 4B will be described with reference to FIG. 4A.

The object video signal Vi is supplied via the input terminal 100. This corresponds to the object O shown in FIG. 4A. A key signal K supplied via the input terminal 101 is a key signal K corresponding to the object video signal Vi, and has a box-shaped image signal with an aspect ratio of 4: 3, an image signal in the form of title characters, chroma key, etc. Is. The mixing circuit 102 subtracts the signal corresponding to the key signal K from the background signal BG, adds the object video signal Vi to the position, and generates the mixed signal MIX.

On the other hand, the key signal K supplied via the input terminal 101 is supplied to the memory 104. Operation unit 10
When the addresses in the X and Y directions are changed by 5, the operation unit 105 changes the position of the key signal K in the memory 104. The key signal K is read from the memory 104 and used as a pseudo shadow signal IS for the over / under circuit 1.
06. Here, the image of the pseudo shadow signal IS is
The pseudo shadow I shown in FIG. 4A is an image that is not hidden by the object O. Over / under circuit 10
The key signal K and the pseudo shadow signal IS are supplied to 6.
The over / under circuit 106 subtracts only the overlapping portion of the key signal K and the pseudo shadow signal IS from the pseudo shadow signal IS. The over / under processing output K / IS from the over / under circuit 106 corresponds to the pseudo shadow IS shown in FIG. 4A.

The over / under processing output K / IS and the mixed signal MIX are respectively supplied to the mixing circuit 107.
In the mixing circuit 107, the over / under processing output K / IS from the over / under circuit 106 is subtracted from the mixed signal MIX from the mixing circuit 102, and the color matte supplied to the subtraction result via the input terminal 108. A signal is added, and the addition result is the output signal OUT.
Is output from the output terminal 109. This output signal is the entire image shown in FIG. 4A.

[0009]

By the way, the pseudo shadow I shown in FIG. 4A is merely a shift of the key signal generated from the object O. That is, the pseudo shaded image shown in FIG. 4A is a two-dimensional image.
Therefore, in order to bring it closer to the actual shadow, it is necessary to form a three-dimensional image. In this case, it is necessary to generate a shadow that is rotated with respect to the object and combine the shadow with the object. For this purpose, it is necessary to prepare one image special effect device for the object and one image special effect device for the shadow, and change the respective rotation axes of the object and the shadow before combining them. In this case, the operation technique required is a combination of images generated by different video special effect devices, and thus is extremely advanced.

Further, in the actual shadow, as the distance from the object increases, the outline of the shadow becomes blurred and the color of the shadow becomes lighter. Therefore, in order to satisfy the desire to add a shadow similar to the actual shadow by a special effect, it is necessary to perform processing according to the distance from the object. However, at the present time, it is very difficult to easily perform such processing by the video special effect device. Of course, it is possible to generate a shadow image that is very close to a real shadow by using computer graphics technology. However, in computer graphics, it takes a huge amount of time to generate one image. Therefore, it is almost impossible to use computer graphics to process images that are input without interruption, such as broadcasting and authoring.

The present invention has been made in consideration of the above points, and a shadow closer to a real shadow can be added to a target object image at high speed with a simple configuration and simple processing. It is intended to propose a video special effect device.

[0012]

SUMMARY OF THE INVENTION The present invention includes a shadow generating means for generating a shadow image, a combining means for combining an object image to be a shadow object, the shadow image, and a background image, and Gain characteristic data according to the ratio x / y, storage means for storing the filtering characteristic data, gain control means for controlling the gain of the shadow image, filtering means for filtering the shadow image, and the shadow The ratio x / y between the distance x between the image of the object and the image of the object and the distance y between the virtual light source and the image of the object is calculated. The gain control means controls the gain and the control means controls the filtering characteristic of the filtering means according to the filtering characteristic corresponding to the ratio x / y.

The gain in the gain control means is controlled according to the gain characteristic according to the ratio x / y, and the ratio x / y
The filtering characteristic in the filtering means is controlled according to the filtering characteristic according to the above, an image of a shadow closer to the actual shadow is generated, and the image of the shadow, the object image, and the background image are combined.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a block diagram of a video special effect device. The key signal K corresponding to the object video signal Vi supplied via the input terminal 2 is supplied to the input terminal 1. The conversion memory 3 receives the key signal K from the input terminal 2.
And the object video signal Vi supplied via the input terminal 1.

The gain control circuit 5 is a circuit for controlling the gain given to the key signal K supplied through the input terminal 2. The horizontal low-pass filter 6 is a low-pass filter for the horizontal frequency components of the key signal K from the gain control circuit 5. The vertical low pass filter 7 is a low pass filter for the frequency component in the vertical direction of the key signal K from the horizontal low pass filter 6. Controller 8
Is based on the value indicating the distance between the light source and the object from the operation unit 10 and the predetermined gain characteristic and the filtering characteristic of the low-pass filter stored in the ROM 9, based on the gain control circuit 5 and the horizontal low-pass filter. The filter 6 and the vertical low pass filter 7 are controlled respectively. The predetermined gain characteristic is the table data that results in the intended gain characteristic, and the filtering characteristic is the table data that results in the intended filtering characteristic. Here, the control content of the controller 8 will be described.

In the present embodiment, for example, the image shown in FIG. 2A is the image to be finally obtained. The light source L shown in FIG. 2A is virtual and does not actually appear as an image. In the image shown in FIG. 2A, the light from the light source L is applied to the object O, whereby the shadow S is cast from below the object O.
It is an image showing a state of being formed. Note that, as shown in FIG. 2A, the shadow S becomes fainter as it moves away from the object O. In this shadow, the gradation does not change smoothly for the convenience of drawing,
In reality, it changes very smoothly.

FIG. 2B shows the state shown in FIG. 2A.
It is shown more clearly. As shown in FIG. 2B, the greater the distance Y between the light source L and the object O, the more Y Y '. Therefore, the light source L
The distance between the object and the object O can be assumed to be constant (= Y). In that case, the shade S of the shadow S, that is,
The gain characteristic is as shown in FIG. 2C. This FIG. 2C
As the ratio x / y increases, the gain for the shadow key signal SK decreases as shown in FIG.
As becomes smaller, the gain for the shadow key signal SK is increased. That is, the farther the shadow S is from the object O, the lower the brightness. The table data composed of the ratio x / y and the gain data having the characteristic shown in FIG. 2C is stored in the ROM 9 shown in FIG.

The conversion memory 11 is for storing the key signal K supplied from the vertical low pass filter 7. The memory controller 12 uses the conversion memory 3 and the conversion memory 11 based on operation information of the operation unit 10, for example, information such as position (x, y), size (z), and rotation angle.
The conversion memory 3 and the conversion memory 1 are controlled to change the position of the data stored in the storage space in the storage space.
This is a circuit for each of 1. The operation unit 10 includes, for example, a stick for performing operations in the X direction and the Y direction, a ten-key pad for inputting numerical values, and the like.

The over / under circuit 13 subtracts the overlapping portion of the shadow key signal SK and the key signal K from the shadow key signal SK read from the conversion memory 11, and outputs the subtraction result to the over / under processing output US.
It is a circuit that outputs as K. The over / under processing output USK from the over / under circuit 13 is supplied to the mixing circuit 14.

The background signal generation circuit 15 is a circuit for generating a background signal BG such as a background. The shadow matte generation circuit 16 generates a shadow matte signal SM, which is a color signal, based on the information indicating the size, shape, and position from the operation unit 10. Therefore, the mixing circuit 14 includes the background signal generating circuit 15
Background signal BG from the shadow mat generation circuit 16, shadow mat signal SM from the shadow mat generation circuit 16, and over / under processing output US from the over / under circuit 13.
The following operation is performed using K to obtain the mixed signal MIX.

MIX = BG × (1-USK) + SM × U
SK (0≤USK≤1)

The mixing circuit 17 is a circuit for obtaining a final output OUT by using the mixing signal MIX, the key signal K and the object video signal Vi. That is, in the mixing circuit 17, an operation of MIX × (1−K) is performed from the mixed signal MIX, and a multiplication of Vi × K is performed on the object video signal Vi, and the above two results are obtained. By the addition, the combining process is performed. That is, output O
The UT can be expressed as:

OUT = MIX × (1−K) + Vi × K

Further, the blurring amount (softness) of the shadow S, that is, the characteristic of the low-pass filter is as shown in FIG. 2D. As shown in FIG. 2D, as the ratio x / y increases, the horizontal and vertical low pass filters 6
And 7 become narrower and the ratio x / y becomes smaller, the lower pass bands of the horizontal and vertical low-pass filters 6 and 7 become flat, that is, wider. That is, the further away the shadow S is from the object O,
The outline of the shadow S becomes unclear. The table data consisting of the ratio x / y and the filter coefficient data for varying the pass band, which has the characteristics shown in FIG. 2D, is shown in FIG.
It is stored in the ROM 9 shown in FIG. It should be noted that the horizontal and vertical low-pass filters 6 and 7 shown in FIG.
One type of characteristic data shown in is used. The use of the horizontal low-pass filter 6 means that high frequency components cannot pass in the horizontal direction.
The fewer the high frequency components are, the less clear the contours are. The same applies in the vertical direction.

Next, the operation of the video special effect apparatus shown in FIG. 1 will be described with reference to FIG.

In the operation unit 10, for example, the movement amount in the X and Y directions of the designated point of the object video signal Vi shown in FIG. 3A is input. Here, the designated point is shown in FIG. 3A.
The four corners of the image of the object video signal Vi shown in FIG. The memory controller 4 controls the address, the read, and the write of the conversion memory 3 based on the movement amounts in the X and Y directions input via the operation unit 10. Therefore, when the movement amounts in the X and Y directions are other than "0", the object video signal Vi shown in FIG. 3A is transformed.

That is, the memory controller 4 determines which corner of the image of the object video signal Vi moves in which direction and how much based on the movement amount information in the X and Y directions input via the operation unit 10. recognize. Then, the memory controller 4, based on this recognition,
A new address of each dot of the object video signal Vi shown in A is sequentially calculated, and the address is supplied to the conversion memory 3 as the address of the sequentially read data of 1 dot. Note that FIG. 3A shows a case where neither the object video signal Vi nor the key signal K is deformed.

The key signal K read from the conversion memory 3
And the object video signal Vi are supplied to the mixing circuit 17, respectively. On the other hand, the key signal K is also supplied to the gain control circuit 5. From the operation unit 10, the object video signal V
The coordinate data (x, y) of i and the key signal K is supplied to the controller 8. Here, this coordinate data (x,
2B is the coordinates of the upper part of the object O and the coordinates of the tip of the shadow S in FIG. 2B. Further, data indicating the distance y between the light source L and the object O is input via the operation unit 10.

The controller 8 is based on the coordinate data (x, y) of the object video signal Vi and the key signal K.
The coordinate data (x, y) of each dot of the key signal K sequentially input is obtained, and the obtained coordinate data (x, y) of the key signal K and the coordinate data (x, y) of the object video signal Vi are obtained. Then, the corresponding value of x is obtained, and then the value of x / y is obtained.

Then, the controller 8 obtains the calculated x / y.
Based on the value of, the corresponding gain data is read from the table of the ratio x / y and the gain data stored in the ROM 9, and the gain data is supplied to the gain control circuit 5. Therefore, the gain control circuit 5 gives the key signal K a gain according to the gain data supplied from the controller 8. The controller 8 repeats the above processing.

Therefore, as shown in FIG. 3C, the data of the shadow S at the position farthest from the object O is far from the object O and the gain to be given is the lowest, so that the BG signal of almost 100% level is obtained. Becomes And
As shown in FIG. 3C, as the gain is gradually increased toward the object O, the level of the shadow S gradually becomes dark black. This will be described. As already explained, the output OUT
Is OUT = MIX × (1−K) + Vi × K. Further, the mixed signal MIX is MIX = BG × (1-USK)
+ SM x USK. Therefore, when the expression of MIX is substituted into the expression of output OUT, the result is as follows. OUT = Vi * K + BG * (1-K) (1-USK) + SM * (1-K) * USK ... (Formula 1)

Here, assuming that the gain of the shadow key signal USK is approximately 0%, it becomes USK0. In this case, the portion other than Vi × K in (Equation 1) is BG × (1
-K). Further, if the gain of the shadow key signal USK is 100%, it becomes USK1. In this case, the portion other than Vi × K in (Equation 1) is SM × (1
-K). That is, when the gain of the shadow key signal USK is low, almost 100% of the background signal BG is output, and when the gain of the shadow key signal USK is high, almost 100% of the shadow mat signal SM is output. Usually, the shadow matte signal SM is black on the screen of the television monitor, and in this case, it is displayed as dark black.

Next, the controller 8 obtains the filter coefficient data having the corresponding characteristic from the table of the ratio x / y and the filter coefficient data stored in the ROM 9 based on the obtained value of x / y. Read out and supply the filter coefficient data to the horizontal low-pass filter 6. Therefore, the horizontal low-pass filter 6 multiplies the key signal K from the gain control circuit 5 by the filter coefficient data supplied from the controller 8. The controller 8 repeats the above processing. Therefore, as shown in FIG. 2A, the data of the shadow S near the object O is close to the object O, and the value of the filter coefficient data to be multiplied is large, so that the contour is clear. Then, as the value of the filter coefficient data to be multiplied decreases as the distance from the object O increases, the data of the shadow S gradually becomes unclear (blurring) (see FIG. 3B). For the convenience of drawing, it is not possible to show the outline gradually blurring, but please understand this.

Next, the controller 8 uses the table of the ratio x / y and the filter coefficient data stored in the ROM 9 based on the obtained value of x / y to obtain the filter coefficient data having the corresponding characteristic. Is read out and the filter coefficient data is supplied to the vertical low-pass filter 7. Therefore, the vertical low pass filter 7 multiplies the key signal K from the horizontal low pass filter 6 by the filter coefficient data supplied from the controller 8. The controller 8 repeats the above processing. Therefore, as shown in FIG. 2A, the data of the shadow S near the object O is
Since the value of the filter coefficient data to be multiplied is large near the object O, the contour is clear. Then, as the distance from the object O increases, the value of the filter coefficient data to be multiplied decreases, so that the shadow S
The data of (1) gradually becomes less clear (out of focus) (see FIG. 3B). For the convenience of drawing, it is not possible to show the outline gradually blurring,
Please acknowledge this.

The key signal K is supplied to the conversion memory 11. The operation unit 10 inputs, for example, the amount of movement of the designated point of the key signal K in the X and Y directions. Here, the designated points are the four corners of the image of the key signal K. The memory controller 12 inputs X and Y through the operation unit 10.
Based on the amount of movement in the direction, address control, read / write control are performed on the conversion memory 11. By this control, the key signal K stored in the conversion memory 11
By performing the read process and the write process, the modified shadow key signal SK shown in FIG. 3C is displayed.
Becomes

That is, the memory controller 12 recognizes which corner of the image of the key signal K moves in which direction and how much based on the movement amount information in the X and Y directions input through the operation unit 10. To do. Then, based on this recognition, the memory controller 12 sequentially calculates a new address of each dot of the key signal K, and supplies the address to the conversion memory 11 as the address of the sequentially read 1-dot data. Therefore, the shadow key signal S
K will be transformed as shown in FIG. 3C.

Shadow key signal S from conversion memory 11
K is supplied to the over / under circuit 13. The over / under circuit 13 subtracts the overlapping portion of the key signal K and the shadow key signal SK from the shadow key signal SK. As a result, the over / under processed output USK becomes as shown in FIG. 3D. Over / under processing output US from this over / under circuit 13
K is supplied to the mixing circuit 14.

On the other hand, the background signal generating circuit 15
Generates a background signal BG based on the control signal from the operation unit 10, and outputs the background signal BG.
Are supplied to the mixing circuit 14. Here, the control signal from the operation unit 10 is a control signal based on an operation for designating luminance (luminance), saturation (, hue (hue), etc. Therefore, the background signal generating circuit 15
Generates a uniform color signal on the front surface based on the control signal.

Further, the shadow mat generation circuit 16 generates a shadow mat signal SM based on the control signal from the operation section 10 and supplies the shadow mat signal SM to the mixing circuit 14. Here, the control signal from the operation unit 10 is a control signal based on an operation of designating luminance (luminance), saturation (, hue (hue), etc. Therefore, the shadow matte generation circuit 16 is controlled by the control signal. A uniform color signal on the front side is generated based on the above, except that the color of the shadow matte is specified by the user and is usually black.

The mixing circuit 14 is based on the background signal BG from the background signal generating circuit 15, the shadow mat signal SM from the shadow mat generating circuit 16, and the over / under processing output USK from the over / under circuit 13. The mixed signal MIX shown in FIG. 3E is obtained, and the mixed signal MIX is supplied to the mixing circuit 17.
The processing at this time is as follows. MIX = BG × (1
-USK) + SM x USK

Mixing circuit 17 mixes mixed signal MIX from mixing circuit 14 (see FIG. 3E) and object video signal V.
An output signal OUT is obtained based on i and the key signal K. Then, the mixing circuit 17 outputs the output signal OUT to the output terminal 18
Output from This output signal OUT is shown in FIG. 3F.
Here, the output signal OUT can be expressed by the following equation. OUT = MIX × (1-K) + Vi × K = BG × (1-USK) × (1-K) + SM × USK ×
(1-K) + Vi × K

As described above, in the present embodiment, the gain is given to the key signal K by referring to the table of the ratio x / y and the gain data having the characteristic shown in FIG. The filter coefficient data is multiplied by referring to the table of the ratio x / y and the filter coefficient data, which has the characteristic shown in 2D, and the shadow key signal SK is obtained by transforming the filter coefficient data. Since this is combined with, there is a great merit that a three-dimensional and realistic shadow image can be generated with a simple configuration.

[0044]

According to the present invention described above, the gain in the gain control means is controlled according to the gain characteristic according to the ratio x / y, and the filtering is performed according to the filtering characteristic according to the ratio x / y. Since the filtering characteristic in the means is controlled, a shadow image closer to the real shadow is generated, and the shadow image, the object image, and the background image are combined,
With a simple configuration and simple processing, you can create shadows that are more realistic.
There is an effect that it can be added to a target object image at high speed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a video special effect apparatus showing an embodiment.

FIG. 2 is an explanatory diagram for explaining the video special effect apparatus shown in FIG. FIG. 2A is an explanatory diagram showing an example of an image finally created. FIG. 2B is an explanatory diagram for explaining a positional relationship between an object and a shadow. [FIG. 2C] FIG. 2C is an explanatory diagram showing an example of gain characteristics based on table data stored in a ROM 14 shown in FIG. 1. [FIG. 2D] FIG. 2D is an explanatory diagram showing an example of characteristics of a low-pass filter based on table data stored in a ROM 14 shown in FIG. 1.

FIG. 3 is an explanatory diagram for explaining the operation of the video special effect apparatus shown in FIG. FIG. 3A is an explanatory diagram showing a display state of an object video signal Vi and a key signal K. FIG. 3B is an explanatory diagram showing a gain of the key signal K and a display state after filtering control. FIG. 3C is an explanatory diagram showing a display state of the shadow key signal SK. [FIG. 3D] FIG. 3D is an explanatory diagram showing a display state of over / under processing output. FIG. 3E is an explanatory diagram showing a display state of the mixed signal MIX. FIG. 3F is an explanatory diagram showing a display state of the output signal OUT.

FIG. 4 is a configuration diagram showing a conventional video special effect device. [FIG. 4A] FIG. 4A is an explanatory diagram showing processing performed in a conventional image special effect device. FIG. 4B is a configuration diagram of a conventional image special effect device.

[Explanation of symbols]

3, 11 conversion memory, 4, 12 memory controller, 5 gain control circuit, 6 horizontal low-pass filter, 7
Vertical low-pass filter, 8 controller, 9RO
M, 10 operation part, 13 over / under circuit, 1
4, 17 mixing circuit, 15 background signal generation circuit, 16 shadow mat generation circuit

Claims (2)

[Claims] 1. A gain control means for controlling a gain of a shadow image of an object, a filtering means for filtering the shadow image, a distance x between the shadow image and the object image, and a virtual light source. And the ratio y of the distance y between the image of the object and
Control means for controlling the gain in the gain control means according to the gain characteristic according to the ratio x / y and controlling the filtering characteristic in the filtering means according to the filtering characteristic according to the ratio x / y. And a video special effect device having a synthesizing means for synthesizing the image of the object, the image of the shadow, and the image of the background of the object. 2. The video special effect apparatus according to claim 1, wherein the control means has a storage means in which gain characteristic data according to the ratio x / y and filtering characteristic data are stored.