JP2004260425A - Image input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image input device capable of removing factors causing delay or data loss on a network while improving or keeping the quality of an image to be sent. <P>SOLUTION: A data encoding means comprises: a setting means for compressing data at a fixed frame rate; a judging means for judging whether a set value is to be changed by a change of a value obtained by a speed detection means; a set value changing means for changing the set value of the setting means on the basis of the judged result of the judging means; and a detection means for detecting the set value of the fixed frame rate which is previously determined from the value obtained by the speed detection means. The value of the detection means is detected by the value detected by the speed detection means and the set value is changed by the set value changing means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a video input device having means for detecting the moving speed of the video input device using a position detection device, an acceleration sensor, or the like of the video input device mounted on a movable object, The present invention relates to an apparatus having means for varying an encoding rate of an input video signal depending on a change state.
[0002]
[Prior art]
recent years. As a moving image compression unit, a large number of image input devices using a predictive coding compression unit such as MPEG2 or MPEG4 are used. In these compressions, there are two main types of frame rate control, which are roughly classified into a variable bit rate (VBR) and a fixed bit rate (CBR). VBR is a control that averages the generation amount of encoded data to be constant, and generally has an effect of suppressing a change in image quality.
[0003]
CBR is a means for controlling the amount of encoded data to be always constant, and the change in image quality is larger than that of VBR. FIG. 6 shows a general flow of an image encoding frame.
[0004]
Among them, the I-frame is a frame called an intra-frame and is a base frame. The B frame is a frame that can be predicted from both directions of the preceding and succeeding frames, and the P frame is a frame that can be predicted from the previous frame. Data composed of such a group of frames is transmitted as compression-encoded data of an image. . In addition, the image is reproduced by performing the data reverse conversion. The data of each frame described in the frame flow is data generated upon image input / reproduction.
[0005]
In addition, in view of the use of image input devices, recently, when such image compression and encoding technology is used to fix the image input device indoors and outdoors, or when using portable terminals such as portable terminals. As an image input device, it is often used as a video input device by being freely carried outdoors or mounted on a moving means such as a car.
[0006]
[Problems to be solved by the invention]
In such use, there is a demand for transmitting a compression-encoded video frame in real time via a network from a signal input to an image input device.
[0007]
In such a case, at a bit rate such as the VBR described above, the amount of change in the image to be captured is increased due to an increase in the amount of change in the image to be captured, which leads to an increase in the compression-encoded data. May occur, or data loss may occur due to congestion in the network.
[0008]
On the other hand, in the case of CBR, since the amount of data generation is controlled to be constant when the amount of change in the image to be captured increases, there is a disadvantage that the image quality in that state deteriorates.
[0009]
When sending such video data from a remote location to a central collection center, frame control using CBR is used, ignoring the occurrence of image degradation, in order to suppress data delay and data volume on the network. Often done. However, in this case, in the video input information of the fixed point, the change in the amount of video data to be captured is relatively small, and the problem is often small.
[0010]
However, recently, the use of a video input device mounted on a mobile object has been increasing, and in the case where the image data is transmitted via a network in this state, the amount of image data to be transmitted is suppressed as much as possible. Means for maintaining or improving image quality are required.
[0011]
The present invention has been made in view of the above circumstances, and a purpose thereof is to improve or maintain the image quality of a transmitted image and eliminate a factor that causes a delay or data loss on a network. It is to provide a device.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a position detecting means using a satellite such as a GPS every predetermined time, a storing means for storing a value of the position detecting means, a previous value and a next value of the storing means. Video input having speed detecting means for detecting a speed based on a change in the image, having image capturing means for capturing an external scene, data encoding means for encoding a signal of the image capturing means, and transmitting means for outputting the encoded data In the apparatus, the data encoding unit includes a setting unit that performs compression at a fixed frame rate, a determination unit that determines whether to change a set value based on a change in a value obtained by the speed detection unit, Setting value changing means for changing a setting value of the setting means; detecting means for detecting a predetermined set value of the fixed frame rate from a value obtained from the speed detecting means; The stage of the value, and performs the setting change by detecting the set value changing means the value of the detection means.
[0013]
Further, the present invention has an acceleration detecting means for detecting an acceleration at regular time intervals, an imaging means for imaging an external scenery, a data encoding means for encoding a signal of the imaging means, and outputting the encoded data. In the video input apparatus having a transmitting unit for performing the setting, the data encoding unit determines whether to change the set value based on a change in the value obtained from the acceleration detecting unit, the setting unit performing compression at a fixed frame rate. Means, setting value changing means for changing the setting value of the setting means by the determining means, detecting means for detecting a predetermined set value of the fixed frame rate from a value obtained from the acceleration detecting means, The value of the detecting means is detected by the value of the acceleration detecting means, and the set value is changed by the set value changing means.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0015]
FIG. 1 is a conceptual diagram of a “video input system” according to an embodiment of the present invention.
[0016]
A video input device 103 equipped with a GPS navigation device using radio waves from a GPS satellite 101, and a receiving antenna 102 are installed in the image input device.
[0017]
The image of the image input device is sent to the information collection center 105 via the network 104. In the information collection center 105, images of a plurality of image input devices 103 connected via the network 104 can be viewed. Although not described therein, it is assumed that the image input terminal 103 is mounted on a moving object such as a car and is connected to the network 104 by wireless or the like. Similarly, there is a case where the connection is made via a wireless connection with respect to 105 as well.
[0018]
FIG. 2 shows a functional block configuration for explaining specific functions in the video input device 103.
[0019]
First, a GPS receiving unit 201 to which a signal input from the GPS receiving antenna 102 described with reference to FIG. 1 is input, a position detecting unit 202 for detecting position data from the GPS receiving unit 201, and a signal receiving unit 202 at a certain time interval. The position storage unit 203 that stores the value of the position detection unit, and the position storage unit 203 stores data of position detection up to the previous time, which is a certain fixed amount.
[0020]
Next, the speed detection unit 204 has a function of detecting the moving speed of the image input device 103 by comparing the previously measured position detection data from the position storage unit 203 with the currently measured position detection data.
[0021]
The speed detection unit 204 has a function of storing speed data relating to the movement of the 103 detected this time.
[0022]
Next, the system processing unit 205 is a processing unit that performs general control of the image input device 103, and includes a processor, a memory, a register, and the like.
[0023]
In addition, the description of the other image input unit will be given with respect to the description from the position information input unit such as GPS.
[0024]
A video data signal 207 obtained by imaging an external scenery or the like is first input to a video signal processing unit 208 and subjected to analog signal processing. Next, the video signal encoding unit 209 generates fixed-bit-rate compressed and encoded data such as MPEG2, which is a predictive encoding and compression means for the video, from the input analog video signal. After the generation of this data, the video signal output section 210 outputs the multiplexed data such as a transport stream (TS) to the network 104 described with reference to FIG.
[0025]
Next, the video compression rate control unit 206 will be described. The encoding sampling rate table preset in the video compression rate control unit 206 will be described first with reference to FIGS.
[0026]
The encoding sampling table has a certain moving speed range (range) with respect to the moving speed of the image input device 103 as shown in the encoding sampling rate table example 1 in FIG. An encoding sampling table for setting a fixed bit rate for video encoding is set. More specifically, as shown in FIG. 4, there is a preset value of an encoding sampling rate corresponding to a range which is a range of a moving speed at which the image input device 103 moves. There is a table including corresponding setting values in order to perform setting of an encoder in the video signal coding unit 209 in order to perform compression coding. For example, when the distance exceeds 100 km, the value of “m” is obtained as the setting value of the encoder to set the sampling rate to the value of “M”.
[0027]
Next, details of the video compression rate control unit 206 will be described.
[0028]
The video compression rate control unit 206 has a function of setting the value obtained from the table shown in FIG. 4 in the video compression rate control unit 206 to the encoder in the video data 209 with respect to the data from the speed detection unit 204.
[0029]
In performing the above-described setting function in the video compression rate control unit 206, since the width (range) of the moving speed described with reference to FIGS. 3 and 4 exists, it is determined whether the setting value needs to be changed. Have the means to do. Therefore, the current moving speed information of the video input device 103 stored in the above-mentioned 204 is called, and it is determined whether the moving speed is within the predetermined width of the moving speed range in FIG. Has the function of detecting
[0030]
The above is the description of the functional configuration of the video input device.
[0031]
FIG. 5 is a flowchart illustrating an operation flow of controlling the compression / encoding rate of a video, centering on the system processing unit 205 to perform a series of these controls. Next, FIG. 5 will be described.
[0032]
First, in the system processing unit 205 described above, a predetermined time of 501 is measured, and a predetermined elapsed time set in 502 is determined in 502. If the time has not been reached, the process returns to the determination of 502 again. If the predetermined time has been reached, the process proceeds to the next step 503.
[0033]
In step 503, the image input terminal 103 detects the value of the position detection unit 202 in order to detect the position at that time. Then, storage processing is performed in the position storage unit 203. This value is the N-th value. Next, in step 504, the difference from the previous (N-1) -th position information is obtained as the processing of the speed detection unit 204 described above. Because of the difference per fixed time, the moving speed of 103 is obtained. This is stored at 505 as the Nth moving speed detection data. This is specifically performed by the speed detection unit in 204 described above.
[0034]
Next, in step 506, the speed data at the time when the speed was the previous (N-1) is compared with the difference value to make a determination. That is, it is determined whether or not the moving speed is within the moving speed range shown in FIG.
[0035]
If it is within the predetermined value that falls within the range width, the process returns to step 502, and the process again enters the speed detection process flow.
[0036]
If the moving speed range is changed beyond the predetermined value, the process proceeds to step 507.
[0037]
In step 507, as described above, the setting of the encoder is obtained in order to obtain the encoding sampling rate corresponding to the moving speed range using the table of FIG. This operation is specifically performed by the video compression rate control unit 206.
[0038]
Next, in step 508, the setting value is obtained, and in step 509, the process proceeds to a process of changing the video coding rate of the encoder. These processes are also specifically performed by the video compression rate control unit 206 described above and the video signal encoding unit 209 described above.
[0039]
By the operation described in the operation flow of the present embodiment, the video compression encoding rate of the video input device 103 changes following the change in the moving speed.
[0040]
Normally, in MPEG2, control is performed within a range of 3 Mbps to 15 Mbps.
[0041]
In the decoding of the video data in the information collection center 105 connected on the network corresponding to the video input device 103 described with reference to FIG. By recognizing the bit rate information in the compressed and encoded data, the decoding operation is continuously performed according to the rate.
[0042]
In the present embodiment, an example of the means for detecting the moving speed of the image input device by the position detecting means using the GPS satellite has been described, but the part up to the detection of the moving speed is described in the claims. This can be performed using a means such as an acceleration sensor. Also in this case, control is performed by managing the value of the acceleration sensor monitored over a certain period of time. In addition, the table shown in FIG. 4 has a range of the acceleration sensor corresponding to the acceleration sensor according to the table, and the table has a set value corresponding to this value. Then, this is realized by performing a setting value changing operation of this value.
[0043]
【The invention's effect】
As is apparent from the above description, according to the present invention, there is provided a means for detecting the position of an image input device mounted on a movable object or detecting the moving speed of the image input device using an acceleration sensor or the like. The video input device has means for changing the coding rate of the video signal in video compression coding at a fixed bit rate (CBR) according to the moving speed of the video input device, and a network is connected to a remote information collection center. By dynamically changing the amount of data to be transmitted according to the moving speed of the image input device, it is possible to improve or maintain the image quality of the image to be transmitted and to eliminate factors causing a delay or data loss on the network.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a video input system.
FIG. 2 is a diagram showing a functional configuration of a video input device.
FIG. 3 is an explanatory diagram for creating a sampling control table for video encoding.
FIG. 4 is a diagram illustrating a specific example of a sampling control table for video encoding.
FIG. 5 is a flowchart showing the operation of the embodiment of the present invention.
FIG. 6 is a diagram illustrating an example of a flow of a general frame of image compression encoding.
[Explanation of symbols]
101 GPS satellite 102 Receiving antenna 103 Video input device 104 Network 105 Information collection center 201 GPS receiving unit 202 Position detecting unit 203 Position storing unit 204 Speed detecting unit 205 System processing unit 206 Video compression rate control unit 207 Video data signal 208 Video signal processing Unit 209 video signal encoding unit 210 video signal output unit

Claims (2)

Position detecting means using a satellite such as a GPS every predetermined time; storing means for storing the value of the position detecting means; speed detecting means for detecting a speed based on a change between a previous value and a next value of the storing means. An image input device having an imaging unit that captures an external landscape, a data encoding unit that encodes a signal of the imaging unit, and a transmission unit that outputs the encoded data.
The data encoding unit includes a setting unit that performs compression at a fixed frame rate, a determination unit that determines whether to change a set value based on a change in a value obtained from the speed detection unit, and a determination unit that determines whether the setting value is changed. Setting value changing means for changing a setting value; detecting means for detecting a predetermined set value of the fixed frame rate from a value obtained from the speed detecting means; A video input device for detecting the value of the set value and changing the set value by the set value changing means. An image having an acceleration detecting means for detecting an acceleration at regular time intervals, an imaging means for imaging an external scene, a data encoding means for encoding a signal of the imaging means, and a transmitting means for outputting the encoded data In the input device,
The data encoding unit includes a setting unit that performs compression at a fixed frame rate, a determination unit that determines whether to change a set value based on a change in a value obtained by the acceleration detection unit, and a determination unit that determines whether the setting value is changed. Setting value changing means for changing a setting value; detecting means for detecting a predetermined set value of the fixed frame rate from a value obtained from the acceleration detecting means; A video input device for detecting the value of the set value and changing the set value by the set value changing means.

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