JPH0622311A - Automatic camera switching device - Google Patents

Abstract

PURPOSE:To avoid the trouble of a switching operation on the progress of a conference by preventing mistake in the switching operation between a moving picture and a document picture. CONSTITUTION:A subtractor 6 takes a difference between digital document picture data (c) from an A/D converter 3 and frame picture data (e) from a storage device 5 and outputs its difference (f) to a decision device 7. The decision device 7 calculates the mean value of levels of the difference (f) inputted from the subtractor 6 for a prescribed time and compares the mean value with a predetermined threshold level. The decision device 7 outputs a switching signal (g) at a high level when the calculated mean value is larger than the threshold level and at a low level when the means value is smaller than the threshold level to the switching device 8. The switching device 8 selects moving picture data (a) outputted from a moving picture camera 1 or document picture data (b) outputted from a document picture camera 2 in response to the switching signal (g) from the decision device 7 and outputs selected picture data (h) to an output terminal 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic camera switching device, and more particularly to a method for switching the output selection of a camera in a system such as a video conference in which a video camera and a document camera are used for image transmission.

[0002]

2. Description of the Related Art Conventionally, in a system such as a video conference, one of a moving image output from a moving image camera and a document image output from a document camera is manually selected.

In such a conventional system such as a video conference, a moving image output from a moving image camera and a writing image output from a writing camera are manually selected, so that the moving image and the writing image are selected. There is a problem in that switching to an image is mistaken and a manual switching operation performed during a conference is troublesome.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned problems of the conventional ones, and can prevent a mistaken operation of switching between a moving image and a calligraphic image. It is an object of the present invention to provide an automatic camera switching device that can eliminate the troublesomeness of.

[0005]

A camera automatic switching device according to the present invention is a camera automatic switching device for switching between a moving image from a moving image camera and a writing image from a writing camera, and A document table to be placed, a detecting means for detecting whether or not the document is placed on the document table, a moving image from the moving image camera and the document camera according to the detection result of the detecting means. And a switching means for switching and outputting the written image from.

[0006]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, the moving image data a output from the moving image camera 1 is input to the switching device 8, and the writing image data b output from the writing camera 2 attached to a writing stand (not shown) is A / D (analog). / Digital) converter 3
Is input to the switch 8.

The digital written image data c, which is digitally converted by the A / D converter 3 and output, is input to the memory 5 and the subtractor 6. Only one frame of digital written image data c is written in the memory 5 by the write signal d from the input terminal 4.

Here, one frame of data to be written in the storage device 5 can be arbitrarily written as an initial setting, but in the initial stage, one frame of the image on the black-colored writing stand is in the absence of any drawing. It is written in the memory device 5. The data written in the memory 5 is continuously read every frame and is output to the subtractor 6 as frame image data e.

The subtracter 6 takes the difference between the digital written image data c from the A / D converter 3 and the frame image data e from the storage device 5, and outputs the difference value f to the decision unit 7. The determiner 7 calculates the average of the levels of the difference value f input from the subtractor 6 for a preset fixed time, and compares the average value with a predetermined threshold value.

The judging device 7 outputs to the switching device 8 a switching signal g which becomes a high (H) level when the calculated average value is larger than the threshold value and a low (L) level when the calculated average value is smaller than the threshold value. .

That is, when a calligraph is placed on a calligraphy table, since the calligraphy has many white levels, the difference value between the digital calligraphic image data c from the A / D converter 3 and the frame image data e output from the memory 5 is obtained. f becomes larger than the threshold value, and the decision unit 7 outputs the high-level switching signal g.

On the other hand, when there is no writing on the writing table, the difference value f between the image on the writing table having many black levels and the frame image data e output from the storage device 5 becomes a value close to 0 and smaller than the threshold value. Then, the decision unit 7 outputs a low-level switching signal g.

The switching device 8 selects one of the moving image data a output from the moving image camera 1 and the writing image data b output from the writing camera 2 according to the switching signal g from the determination device 7. Then, the selected image data h is output to the output terminal 9.

FIG. 2 is a block diagram showing the configuration of the decision unit 7 of FIG. In the figure, the average value calculator 10 is a subtractor 6
From the input terminal 11 and the clock i that is phase-synchronized with the difference value f are input, the level average value j of the difference value f for a certain period of time is calculated, and the level average value j is calculated by the comparator 13 Output to.

The comparator 13 compares the level average value j output from the average value calculator 10 with the fixed level q output from the fixed level generator 12. The comparator 13 outputs to the holding circuit 14 a comparison value p which becomes a high level when the level average value j is larger than the fixed level q and becomes a low level when the level average value j is smaller than the fixed level q.

The holding circuit 14 holds the comparison value p input from the comparator 13 for a preset period of time and outputs a switching signal g to the switching device 8. Here, if the document is updated while being transmitted using the document during the video conference, the state where the document disappears from the stage for a moment occurs, and the camera 2
In some cases, the written image data b output from the above may be switched to the moving image data a output from the moving image camera 1. Therefore, the switching operation is prevented by holding the comparison value p in the holding circuit 14 for a certain period of time.

FIG. 3 is a diagram showing the operation timing in the decision unit 7 of FIG. In the figure, when the difference value f is compared with the threshold value when there is a drawing, if the difference value f is smaller than the threshold value like the u point, the switching signal g is low level only at the u point part. turn into.

At this time, the document image data b output from the document camera 2 is switched to the moving image data a output from the moving image camera 1 by the switch 8.
However, the switching signal g can be made constant by averaging the difference value f by the average value calculator 10 for a certain period of time and comparing the level average value j with the threshold value.
Therefore, even if there is a portion where the difference value f is smaller than the threshold value such as the point u, the writing image data b output from the writing camera 2 is changed to the moving image data a output from the moving image camera 1 by the switch 8. Never be switched to.

FIG. 4 is a diagram showing the operation of one embodiment of the present invention. The operation of the embodiment of the present invention will be described with reference to FIGS.

Initially, in the state where no writing image is placed on the writing table, the value w2 of the digital writing image data c of the second frame is written in the memory 5 by the pulse of the writing signal d to perform the initial setting. As a result, the value of the initial data e in the memory 5 becomes w2 from the third frame. At this time, the threshold value determined by the determiner 7 is k, the digital document image data c and the initial data e are
Let mn be the level average value j of the difference with.

During the first frame to the nth frame,
From the video camera 1, "Motion 1, Motion 2, Motion 3, Motion 4, Motion 5"
, Motion 6, ..., motion n-3, motion n-2, motion n-1, motion n "is output, and the document camera 2 outputs" book 1, book 2, book ". 3, Book 4, Book 5, Book 6,…, Book n
-3, book n-2, book n-1, book n "is output.

In frames such as the third frame and the fourth frame in which no calligraphy is placed, m3, m4 <k, and
Since the switching signal g is output at a low level, the switching device 8 selects the moving image data a output from the moving image camera 1.

Similarly, k <m6, ..., Mn-3 from the sixth frame to the n-3th frame, and the switching signal g is output at a high level.
The print image data b output from is selected.

When the writing image is removed from the writing table at the (n-2) th frame, mn-2 <k, and the switching signal g is output at a low level, so that the switching device 8 outputs it from the moving image camera 1. The moving image data a is selected.

By operating as described above, the moving image data a output from the moving image camera 1 when there is no writing image on the writing table, and the writing image output from the writing image camera 2 when there is a writing image on the writing table. The data b can be automatically switched and output respectively.

In this way, the switching device 8 causes the switch 8 to display the moving image data a from the moving picture camera 1 and the drawing camera 2 in accordance with the result of the judgment made by the judging device 7 as to whether or not a drawing is placed on the writing table.
It is possible to automatically switch and output the moving image data a and the book image data b, respectively, by switching and outputting the book image data b. Therefore, it is possible to prevent a mistake in the switching operation between the moving image data a and the writing image data b, and it is possible to eliminate the inconvenience of the switching operation during the conference.

[0028]

As described above, according to the present invention, it is detected whether or not a document image is placed on the document table, and the moving image from the moving image camera and the document image camera are detected according to the detection result. By switching and outputting the book image of No. 3, it is possible to prevent a mistake in the switching operation of the moving image and the book image, and it is possible to eliminate the troublesomeness of the switching operation when the conference is in progress.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a determiner shown in FIG.

FIG. 3 is a diagram showing an operation timing in the decision unit of FIG.

FIG. 4 is a diagram showing an operation of one embodiment of the present invention.

[Explanation of symbols]

 1 Video Camera 2 Document Camera 3 A / D Converter 5 Memory 6 Subtractor 7 Judgmenter 8 Switcher 10 Average Value Calculator 12 Fixed Level Generator 13 Comparator 14 Holding Circuit

Claims (3)

[Claims] 1. An automatic camera switching device for switching between a moving image from a moving image camera and a document image from a document camera, and a document stand on which a document image captured by the document camera is placed, and the document image. Detecting means for detecting whether or not the document is placed on the table, and switching between the moving image from the moving image camera and the document image from the document camera according to the detection result of the detecting means and outputting. An automatic camera switching device, characterized in that it is provided with a switching means. 2. The detecting means stores the difference between the storage means for storing the frame image of the frame image from the document camera by one frame, and the difference between the frame image from the camera for the frame image and the frame image stored in the storing means. 2. The automatic camera switching device according to claim 1, further comprising: subtraction means for taking and a determination means for determining whether or not the writing image is placed on the writing table based on a subtraction result of the subtracting means. 3. The calculating means, wherein the judging means calculates an average value of the subtraction results of the subtracting means at predetermined time intervals, and a comparing means for comparing the calculation result of the calculating means with a preset predetermined value. The automatic camera switching device according to claim 2, wherein the automatic camera switching device comprises: