JPH0955876A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit video and sound information by a bit rate and a compression method which are adapted to a connected personal computer or application software. SOLUTION: A compression/expansion processing circuit 7 and interfaces 9 and 10 for communication are provided in an image pickup device 24. When this device is connected to an external device 21 and is used, a system control microcomputer 14 controls the compression/expansion processing circuit in accordance with information related to the compression method and the compression ratio transmitted from the external device 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device.

[0002]

2. Description of the Related Art As a known example of an image pickup apparatus for outputting image information to a personal computer, there is a CCD camera for a personal computer described in "Nikkei Electronics April 24, 1995 No. 634 pp. 160-162". As is known in the prior art, analog NTSC / PAL signals and digital RGB signals have been conventionally used as an interface between a personal computer and a camera.

Further, as described in pp.15 of the same magazine, the IEEE1394 extended specification allows the image quality of video to be selected from several types in terms of resolution, number of colors and frame rate in communication between a camera and a personal computer. In addition, any image quality could be specified from application software.

[0004]

In the above-mentioned publicly known example, the application software selects the resolution and the frame rate so that the image quality of the video output by the camera can be designated. The main purpose of the application software is the transmission capacity of the communication path. It is to match the output bit rate on the camera side with the limitation that comes from and the bit rate that can be accepted by application software and PC. The problem here is that when the resolution and the frame rate are reduced in order to reduce the bit rate, the definition of the image and the smoothness of movement are reduced. Even if the number of colors is reduced, the number of gradations of colors is reduced, which makes it difficult to view an image.

An object of the present invention is to provide an image pickup apparatus which is less deteriorated and which can output more natural video or audio information at a bit rate designated by the information receiving side such as a personal computer. .

[0006]

In order to achieve the above object, the present invention uses the following means.

(1) A means for changing the information about the compression ratio used in the compression processing by communicating with an external device.

(2) A means for changing the information about the compression method and compression ratio used in the compression processing by communicating with an external device.

[0009]

According to the present invention, by the first means, the information relating to the compression ratio used in the compression processing is changed to a desired value, and the personal computer or the application software requests the information including the video or audio with little deterioration. It can be sent at the bit rate.

The second means is used to obtain the compression method used in the compression process and the information about the compression ratio.
By changing the value, information including video or audio with little deterioration can be transmitted at the bit rate required by the personal computer or application software. Also, since the bit rate can be specified externally on the receiving side, a personal computer that performs compressed data decompression processing with software can make detailed adjustments such as changing the bit rate according to the load of other processing. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS.

First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram of an image pickup apparatus according to each of the following embodiments. 1 is a lens, 2 is a diaphragm, 3 is an image sensor, 4 is a CDS / AGC circuit, 5 is an A / D converter, and 6 is signal processing. A circuit 7 is a compression / expansion processing circuit for compressing / expanding video and audio. The compression / decompression processing circuit 7 includes a function of compressing and expanding video and audio, a function of demultiplexing compressed data of video and audio, a function of controlling an external memory, and the like. Reference numeral 8 is a semiconductor memory used by the compression / expansion circuit 7 for compression / expansion processing, 9 is a digital input / output interface for communicating with an external device using a predetermined protocol, and 10 is a digital input / output interface for communicating with an external device using a predetermined protocol. is there. 11 is a lens drive circuit, 12
Is a diaphragm drive circuit, 13 is an image pickup element drive circuit, and 14 is a microcomputer (hereinafter abbreviated as a microcomputer) that controls the entire system. The microcomputer 14 has an input / output interface, RAM, and ROM required for various control processes.
A microphone 15 is abbreviated as a microphone hereinafter. 16 is an A / D converter, 17 is a D / A converter, 18 is a speaker,
19 is the input / output terminal of the interface 9, 20 is the input / output terminal of the interface B, and 21 is the interface B
An external storage device connected to 20, 22 a D / A converter,
Reference numeral 23 is a television signal output terminal, and 24 is an imaging device. In FIG. 1, light that has entered the image sensor 3 through the lens 1 and the diaphragm 2 is converted into an electric signal and input to the CDS / AGC circuit 4. The CDS / AGC circuit 4 carries out noise reduction processing and processing for making the signal level constant, and the result is input to the A / D converter 5. The input signal is converted into a digital signal by the A / D converter 5 and input to the signal processing circuit 6. The signal processing circuit 6 generates a luminance signal and a color difference signal from the input electric signal and converts the luminance signal and the color difference signal into a video signal of a broadcasting standard such as NTSC. The video signal is converted into an analog signal by the D / A converter 22 and then output from the signal output terminal 23. The luminance signal and the color difference signal generated by the signal processing circuit 6 are compressed by the compression / expansion processing circuit 7. Here, the voice is converted into an electric signal by the microphone 15 and then becomes a digital signal by the A / D converter. The converted digital signal is compressed by the compression / expansion processing circuit 7 and time-division-multiplexed with video compression data.
The compressed data in which video and audio are multiplexed is recorded in the external storage device 21 via the interface 10, and
It is output from the input / output terminal 19 via the interface 9. When reproducing the video and audio information recorded in the external storage device 21, the compressed data is read from the external storage device 21 via the interface 10 to separate the video and audio compressed data. The video and audio are individually expanded by the compression / expansion processing circuit 7, and the expanded luminance / color difference signals are input to the signal processing circuit 6. The signal processing circuit 6 converts the input luminance / color difference signal into a video signal of a broadcasting standard such as NTSC, and inputs it into the D / A converter 22. The input signal is converted into an analog signal by the D / A converter 22 and output from the television signal output terminal 23. The sound is expanded by the compression processing circuit 7, converted into an analog signal by the D / A converter 17, and output from the speaker 18. This also applies to each of the following embodiments.

Next, the structure of the compression / expansion processing circuit 7 will be described with reference to FIG. Reference numeral 71 denotes a communication unit for communicating with the microcomputer 14, 7
Reference numeral 2 is a control unit for controlling each compression / expansion circuit, 73 is a video compression / expansion unit for compressing / expanding a video signal, 74 is an audio compression / expansion unit for compressing / expanding an audio signal, and 75 is demultiplexing video and audio compression data. The demultiplexing unit 76 is a memory control unit that controls memory exchange with each compression / expansion circuit and the like.

In the present embodiment, the video compression / expansion unit 73, the audio compression / expansion unit 74, and the demultiplexing unit 75 are all composed of circuits conforming to the MPEG standard. In the compression / expansion circuit 7, the luminance / color difference signal input from the signal processing circuit 6 and the audio signal A / D converted by the A / D converter 16 are MPEG-compressed by the video compression / expansion unit 73 and the audio compression / expansion unit 74, respectively. The compressed data is input to the demultiplexing unit 75. Demultiplexer 75
Then, according to the MPEG system standard, the video and audio compressed data are encoded into an MPEG system stream and output to the interfaces 9 and 10. The microcomputer 14 is an MPEG input to the interface 9.
The interface 9 is controlled so as to convert the system stream into a predetermined communication protocol.

Here, when the image pickup device 24 is connected to a personal computer and video and audio are transmitted by communication, first, a communication path is secured between the personal computer and the microcomputer 14 via the interface 9, and then the personal computer. Sends the information about the bit rate value or the data compression ratio requested by the personal computer side to the microcomputer 14 via the interface 9. The bit rate that a personal computer can request is, of course, that video and audio can be specified independently. The microcomputer 14 transmits control parameters to the communication unit 71 of the compression / expansion processing circuit 7 in accordance with the request, and the control unit 72 follows the control parameters received from the communication unit 71, and the video compression / expansion unit 73, the audio compression / expansion unit 74, and the demultiplexing unit. 75, and controls the memory control unit 76 to change the bit rates of video and audio. It is also possible to request non-compressed data among the options that can be designated as information regarding the data compression ratio.
If the personal computer issues a request to change the bit rate even after the data transmission has started, the microcomputer 14 sends a control parameter to the compression / expansion processing circuit 7 in accordance with the request to transmit the bit rate of the video and audio. Can be changed.

According to the present embodiment, since the output bit rate of the image pickup device 24 can be operated from the outside by communication, the image pickup device capable of transmitting the video and audio information with little deterioration in accordance with the request of the personal computer or application software. Can be provided.

Next, a second embodiment of the present invention will be described with reference to FIGS. The basic configuration of the compression / expansion processing circuit 7 of FIG. 1 is as shown in FIG. 2, and its operation is similar to that of the first embodiment. However, regarding the video compression / expansion unit 73, by transmitting the parameter for selecting the video compression method to the communication unit 71, the control unit 72 switches the compression method in the video compression / expansion unit 73 and selects MPEG or JPEG. It will be possible. When JPEG is selected as the video compression method, the video compression data is multiplexed with the audio stream as a private stream in the MPEG system standard. In this way, when the image pickup device 24 is connected to a personal computer and video and audio are transmitted by communication,
Similar to the first embodiment, the interface 9 is MPEG
System stream is input. The microcomputer 14 controls the interface 9 to convert this into a predetermined communication protocol. This is also the first for communication
In the same manner as in the embodiment described above, a communication path is secured between the personal computer and the microcomputer 14 through the interface 9, and thereafter, information relating to the video compression method and the video and audio compression ratio required by the personal computer is transferred through the interface 9 to the microcomputer. Send to 14. The microcomputer 14 transmits the control parameter to the communication unit 71 of the compression / expansion processing circuit 7 according to the request, and the control unit 72
Controls the video compression / expansion unit 73, the audio compression / expansion unit 74, the demultiplexing unit 75, and the memory control unit 76 according to the control parameters received from the communication unit 71 to change the video / audio bit rate and the video compression method. . When MPEG is selected as the video compression method, the procedure is exactly the same as in the first embodiment. However, when JPEG is selected, there is JPEG data in the private stream as described above. If the personal computer side records the MPEG system stream on a hard disk or the like when it receives it, it is possible to retrieve only the desired JPEG data later. In this embodiment, the compression method can be changed only for the video, but the options can be increased by configuring the compression / expansion processing circuit 7 so that a plurality of compression methods can be used for the audio. Further, with respect to the compression / expansion processing circuit 7, some or all of the processing can be performed by the microcomputer 14 when the processing capability of the microcomputer is high.

According to this embodiment, the compression method and the output bit rate to be performed in the image pickup device 24 can be operated from the outside by communication, so that the video and audio information with little deterioration is transmitted in accordance with the request of the personal computer or application software. A possible imaging device can be provided.

[0019]

According to the present invention, video and audio can be transmitted at a bit rate and a compression method according to the capability of the receiving device side. Further, since the information is compressed and transmitted, it is possible to realize an imaging device that transmits more natural video and audio.

[Brief description of drawings]

FIG. 1 is a block diagram of an image pickup apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an image pickup apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 1 ... Lens, 2 ... Aperture, 3 ... Image sensor, 4 ... CDS / AGC circuit, 5 ... A / D converter, 6 ... Signal processing circuit, 7 ... Compression / expansion processing circuit, 8 ... Semiconductor memory, 9 ... Digital input Output interface, 10 ... Digital input / output interface, 11 ... Lens drive circuit, 12 ... Aperture drive circuit, 13 ... Imaging device drive circuit, 14 ... Microcomputer, 15 ... Microphone, 16 ... A / D converter, 17 ... D / A converter, 18 ... Speaker, 19 ... Input / output terminal, 20 ... Input / output terminal, 21 ... External storage device, 22 ... D / A converter, 23 ... Television signal output terminal, 24 ... Imaging device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihito Nishizawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Ltd. Multimedia system development headquarters, Hitachi, Ltd. (72) Inventor Tomoyuki Kurashige Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa 292 In stock Hitachi Image Information Systems Co., Ltd. (72) Inventor Masato Ito 1410 Inada, Hitachinaka City, Ibaraki Prefecture Inside Hitachi, Ltd. Personal Media Equipment Division

Claims (2)

[Claims] 1. A compression processing means for compressing information including video or audio, a recording means for recording the compressed data compressed by the compression processing means, and a communication means for communicating with an external device. In the imaging device capable of outputting the compressed data by the communication unit while performing the compression process, the information about the compression ratio used by the compression processing unit is changed according to the communication content of the communication unit. Imaging device. 2. A compression processing means for compressing information including video or audio, a recording means for recording the compressed data compressed by the compression processing means, and a compression method changing means for changing the compression method of the compression processing means. And a communication unit that communicates with an external device, and in the image pickup apparatus capable of outputting the compressed data by the communication unit while performing compression processing, the compression unit according to the communication content of the communication unit. An image pickup apparatus, characterized by changing information regarding a compression method and a compression ratio used in the processing means.