JPH04249990A - Picture signal processing unit - Google Patents

Abstract

PURPOSE:To locate a portrait picture to a prescribed position immediately accordingly even when a person being an object is moving. CONSTITUTION:A head position detection circuit 23 detects a head position of a portrait picture from an input picture signal Vin, and a read address setting circuit 25 decides a read address so that a pattern containing the portrait picture at a prescribed position (e.g. at a center position) is formed, and the picture data read from a memory circuit 22 is controlled based on the read address and the position of the portrait picture is controlled by a picture signal level based on the head position of the portrait picture thereby allowing the portrait picture to immediately cope with the movement of the person being an object.

Description

[Detailed description of the invention]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal processing apparatus for effectively displaying persons such as a speaker or a called party in a videophone or video conference.

0002

2. Description of the Related Art In videophone calls and video conferences, an image of a speaker or a person on the other end of the call is imaged and the image signal is transmitted to the other party. At this time, it is desirable to place the person's face in the center of the screen so that the face of the speaker or the other party can be reliably seen on the screen.

[0003] By the way, in general, people move vertically and horizontally, and the body shapes of the target people are different, so conventionally, the camera direction has to be adjusted, panning, tilting, etc. to capture the face of the person. I tried to bring it to the center of the screen, but this method has the problem of lacking immediacy.

0004

[Problem to be Solved by the Invention] Conventionally, it is necessary to adjust the direction of the camera, panning, tilting, etc. in order to place a person's face in the center of the screen, which is difficult to do in real time. There was a problem with missing parts. The present invention has been made in view of the problems of the above-mentioned prior art, and its purpose is to
It is an object of the present invention to provide an image signal processing device that can instantly respond to this and cause a person image to exist at a predetermined position on the screen.

[Configuration of the invention]

[Means for Solving the Problems] The image signal processing device of the present invention includes a storage means for storing an input image signal, a screen forming means for forming a screen using the image signal read from the storage means, and an input image signal processing device. head position detection means for detecting the head position of the person image from the image and outputting the position information; and readout address setting means for providing the storage means with a readout address for extracting a part of the input image signal.

[0006]

[Operation] According to the present invention, the position of the human image on the screen is determined based on the head position of the human image, and the screen is controlled based on the image signal level. Also, in response to this, the person image can be made to exist at a predetermined position on the screen.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a signal processing circuit that is a main part of an image signal processing device according to an embodiment of the present invention, and FIG.
3 is a schematic block diagram of the entire image signal processing apparatus having the signal processing circuit, and FIG. 3 is an explanatory diagram conceptually showing the image processing of the apparatus shown in FIGS. 1 and 2 on an image signal screen.

First, in FIG. 2, 1 is a television camera;
2 is a processing circuit, 3 is a signal transmission/display output circuit, and 4 is a television monitor. An image signal from the television camera 1 is subjected to image processing according to the present invention in a processing circuit 2, and then transmitted from the processing circuit 2 to a television monitor 4 through a signal transmission/display output circuit 3. The processing circuit 2 is configured as shown in FIG.

In FIG. 1, numeral 21 is an input signal processing circuit, and this input signal processing circuit 21 decomposes an input image signal from the television camera 1 into 640 horizontal pixels and 480 vertical pixels. The number of pixels in the vertical direction is defined by the number of scanning lines of the television, and the number of pixels in the horizontal direction is determined so that the aspect ratio is 1:1. Therefore, the ratio may be changed depending on the display method. Reference numeral 22 denotes a memory circuit, and the output signal of the input signal processing circuit 21 is written into this memory circuit 22 every frame time, and read out and output every frame or field.

Reference numeral 23 denotes a head detection circuit, to which the same pixelated image signal from the input signal processing circuit 21 as written into the memory circuit 22 is input. In this method, a head is identified from the background based on the difference in signals between adjacent scanning lines from the top of the input image signal in the order of scanning lines, and the position of the center vertex of the head in the screen is determined. Differences in signals refer to differences in brightness and color.

Reference numeral 24 denotes a movement amount determination circuit, and this movement amount determination circuit 24 has a position information storage section, and stores the head position information indicated by the output signal of the head detection circuit 23 and the position information storage section. If the difference is less than a predetermined threshold, the currently adopted head position information will be continued. When the difference exceeds the threshold value, the head detection circuit 23 decides to adopt the newly obtained head position information and stores it in the position information memory. It is stored in the section and output to the subsequent circuit.

25 is a read address setting circuit. This read address setting circuit 25 is connected to the movement amount determination circuit 24.
The range of the image to be sent from the memory circuit 22 is determined based on the head position information from the memory circuit 22 so that a screen with the human image in the center of the screen is formed.
Set the read address. In other words, the position of the top of the head is set in a range such that the horizontal center and the top in the vertical direction include a background of several scan lines to several tens of scan lines, and the image information in that range is read out. The address will be given to the memory circuit 22.

Here, in FIG. 3, 31 is a screen consisting of the entire input image signal written in the memory circuit 22, 32 is the person's image, 33 is the top position of the head, and 34
is a screen consisting of an image signal output from the memory circuit 22 according to address designation from the read address setting circuit 25.

As can be seen from this figure, the human image 32
The position of the person's image on the screen is determined based on the head apex position 33 of the person, and the angle of view of the camera 1 remains fixed, and the screen is controlled based on the image signal level. Even if the person moves, the image of the person can be placed at the center of the screen in response to the movement.

Note that the number of pixels read out from the memory circuit 22 is a value that can be used by a standard transmission encoding device, such as horizontal 176 x vertical 144 (or 120), or horizontal 352 x vertical 288 (or 240), or a horizontal You can select a value that matches the normal television format, such as 360 (or 180) x vertical 240 (or 120).

[0016] Here, in a video conference, horizontal 35
A sufficient image can be obtained with 2×vertical 288 (or 240) pixels, and in the case of a videophone, horizontal 176×vertical 144 (or 120) pixels.

[0017]

[Effects of the Invention] As explained above, according to the present invention, the position of a person's image in the screen is determined based on the head position of the person's image, and the screen is controlled based on the image signal level. Therefore, even if the subject person moves, it is possible to immediately respond to the movement and make the person image appear at a predetermined position on the screen.

Furthermore, since a part of the input image signal is extracted and transmitted, there is an advantage that not only effective image display can be performed, but also the amount of transmitted information can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a signal processing circuit that is a main part of an image signal processing device according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of the entire image signal processing device including the signal processing circuit.

FIG. 3 is an explanatory diagram conceptually showing the image processing of the apparatus shown in FIGS. 1 and 2 on an image signal screen.

[Explanation of symbols]

1 TV camera 2 Processing circuit 3 Signal transmission/display output device 4 TV monitor 21 Input signal processing circuit 22 Memory circuit 23 Head detection circuit 24 Movement amount determination circuit 25 Read address setting circuit

Claims (1)

[Claims] 1. A storage means for storing an input image signal, a screen forming means for forming a screen using the image signal read from the storage means, a head position of a human image detected from the input image signal, and position information thereof. and a readout address for extracting a part of the input image signal so that the screen forming means forms a screen in which the person image is placed in a fixed position based on the head position information. an image signal processing device, comprising: read address setting means for providing a read address to the storage means.