JP2003244709A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera that can be downsized and prevent deterioration in image quality to a degree. <P>SOLUTION: When a shutter button is depressed and a GPS sensor can acquire a current position, the digital camera implements imaging processing and acquires the current position by external communication and acquires a current date and time (steps 100 to 108). Then the digital camera accesses a weather information server connected to a network to transmit the acquired current position and current date and time to the server, receives weather information corresponding to them from the weather information server and applies white balance correction to the photographed image on the basis of the received weather information (steps 110 to 116). When the digital camera cannot acquire the current position, the digital camera activates a strobe to implement imaging processing (steps 118, 120). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera, and more particularly to a digital camera capable of correcting a photographed image according to the environment at the time of photographing.

[0002]

2. Description of the Related Art In recent years, digital cameras have been downsized due to downsizing of image pickup devices including an image pickup element and its peripheral circuits, and digital cameras have been incorporated in various electronic devices. For example, mobile phones and PDAs (Personal Digit
Al assistants) have been commercialized products that have digital cameras built into personal information terminals.

Since portable devices such as mobile phones and PDAs and inexpensive digital cameras are desired to be small and lightweight, they are equipped with a plurality of lenses and an aperture adjustment mechanism like ordinary digital cameras. A digital camera cannot be installed, and the image quality is relatively low.

Further, the image quality can be improved to some extent by correcting the photographed image in accordance with the environmental conditions such as weather to obtain an image suitable for the environmental conditions. For example, in Japanese Unexamined Patent Publication No. 5-199491, a weather sensor detects a change in outdoor weather such as brightness, temperature, and rainfall at the time of shooting, and based on this, an image is converted to obtain an image suitable for environmental conditions. Techniques for obtaining are disclosed.

[0005]

However, in the above-mentioned prior art, since a weather sensor for detecting environmental conditions is required, it is not possible to reduce the size and weight of the device, such as a mobile phone or PDA. Difficult to apply to,
There was a problem.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a digital camera capable of reducing the size of an apparatus and preventing deterioration of image quality to some extent.

[0007]

In order to achieve the above object, the invention according to claim 1 is a photographing location information obtaining means for obtaining photographing location information on a photographing location for photographing a subject, and the photographing location information acquisition. Based on the weather information acquisition unit that acquires the weather information near the shooting location acquired by the means by external communication, and the tendency of at least the color information of the captured image of the subject has a predetermined tendency based on the acquired weather information. And a correction unit that corrects the captured image.

The photographing location information acquisition means acquires photographing location information relating to the photographing location for photographing the subject, such as latitude / longitude information of the photographing location. The shooting location information acquisition means is
For example, a GPS sensor or the like that can obtain the current position by receiving and analyzing GPS signals from GPS satellites can be used.

The weather information acquisition means acquires, by external communication, weather information near the shooting location acquired by the shooting location information acquisition means, for example, information such as fine weather or cloudy weather. That is, the weather is not detected by itself, but is acquired by external communication from a device or the like that provides weather information. The weather information acquisition means is, for example, in accordance with the transmission means for transmitting the shooting location information to a weather information server that provides the weather information via a wireless communication line, and the shooting location information transmitted from the weather information server. A receiving unit that receives the weather information may be included. As described above, since the weather information is acquired by external communication, a weather sensor or the like is not required, and the device can be downsized and the cost can be reduced.

The correcting means corrects the photographed image based on the weather information acquired by the weather information acquiring means so that at least the tendency of the color information of the photographed image of the subject has a predetermined tendency. That is, when the photographed image photographed when the weather is fine and the photographed image photographed when the weather is cloudy are processed under the same processing conditions, the color shade may be different. For this reason, the correction means corrects the white balance and brightness of the captured image according to the weather information, for example, so as to have a predetermined tendency regardless of the weather.
This makes it possible to obtain images of substantially the same quality regardless of the weather.

As described in claim 2, the correction means includes a correction value storage means for storing a white balance correction value determined corresponding to each of a plurality of predetermined weather information, and the correction value storage means is acquired. The captured image may be white-balance corrected by a white-balance correction value corresponding to the weather information. The white balance correction value is determined so that the light source color related to the weather at the time of shooting is white, for example. As a result, the white balance of the captured image is corrected and an appropriate image can be obtained.

Further, as described in claim 3, it is possible to further comprise a strobe for strobe emission when the photographing location information cannot be obtained. That is,
When the shooting location cannot be acquired by indoor shooting, as in the case where the shooting location information acquisition means is configured by a GPS sensor, the flash light is emitted for shooting. As a result, since the image is taken with sufficient exposure, an appropriate taken image can be obtained.

Further, the image forming apparatus further comprises photographing date / time obtaining means for obtaining photographing date / time information relating to the photographing date / time of the subject, and the weather information obtaining means is adapted to obtain the weather information of the photographing place and the photographing date / time by external communication. May be. As described above, more accurate weather information can be obtained by specifying not only the shooting location but also the shooting date and time to acquire the weather information. Moreover, since it is not necessary to immediately obtain the weather information, it is possible to later obtain the weather information and correct the captured image.

Further, the weather information storage means for storing the acquired weather information in association with the photographed image may be further provided. As a result, it is possible to search for the photographed image using the weather information as the search condition, and it is possible to improve the convenience of the search. In addition, you may make it memorize | store in correspondence with a photography place and photography date and time.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this Embodiment demonstrates the case where this invention is applied to portable terminals, such as a mobile telephone and PDA.

FIG. 1 schematically shows the configuration of the network system according to this embodiment. In the present embodiment, the network system 80 serves as a communication medium.
LAN as the Internet and other networks
Network 8 represented by (Local Area Network)
2. It includes a communication network 84 represented by a public telephone network constructed and provided by a telephone company in each country or region.

The communication network 84 includes, for example, PSTN (Public
Switched Telephone Network) and ISDN (Integrate
d Service Digital Network). Further, as the communication network 84, a PDC (Personal Digital Cel
lural) and PHS (Personal Handyphone System). The network 82 and the communication network 84 are interconnected by a gateway system 88.

In a network 82 typified by the Internet, a server computer 90 for providing weather information of various places and a computer (not shown) are respectively a modem, a router, and a TA (terminal adapter: Terminal A).
It is connected via a connection device such as dapter). These computers have a configuration capable of exchanging information by mutual communication via the network 82.

In the network 82, mutual connection is possible via a connection device such as a modem or a router, and computers on such a network can communicate with each other by, for example, TCP.
/ IP (Transmission Control Protocol / Internet Pro
Mutual access is possible according to a predetermined communication protocol such as tocol). Therefore, the network system 80
An innumerable server computer (host terminal) and a user computer (user terminal) are connected above. At this time, the access position (data composed of the position of the computer to be accessed and the position of information in the computer) is specified by a URL (Uniform Resource Locator).

In these computer systems, some computers operate as "servers" that provide various resource services for a fee or free of charge, and some operate as "clients" that request resource services from the server. It functions as a so-called server / client system.

On the other hand, the communication network 84 includes a base station 86 having a data transmission / reception function with respect to a transmission / reception device such as a portable terminal 92 with a digital camera according to this embodiment. This allows the transmission / reception device such as the mobile terminal 92 to participate in the network 82 via the communication network 84. It is preferable that the communication network 84 can provide not only a data transmission / reception function for a transmission / reception device such as the mobile terminal 92, but also an addition function such as an authentication function and a position detection function.

FIG. 2 shows a schematic structure of the portable terminal 92, mainly the digital camera portion. Note that the configuration relating to the function of the mobile terminal 92 as the original mobile terminal is a general configuration, and thus the description thereof is omitted.

In FIG. 2, the taking lens 10 and the diaphragm 1 are shown.
The subject image formed on the light receiving surface of the solid-state image sensor (CCD) 14 via 2 is converted into a signal charge of an amount corresponding to the incident light amount of light by each sensor. The signal charge thus accumulated is read out to the shift register by the read gate pulse applied from the CCD drive circuit 16, and sequentially read out as a voltage signal corresponding to the signal charge by the register transfer pulse. The CCD 14 has a so-called electronic shutter function that can sweep out the accumulated signal charge by a shutter gate pulse and control the charge accumulation time (shutter speed).

Since the portable terminal 92 is required to be small and lightweight, the solid-state image pickup device having a relatively small size and low resolution (for example, about 300,000 pixels) is used, and the taking lens 10 is used. The monofocal lens and diaphragm are fixed, and the structure is such that there are restrictions on exposure conditions and the like.

The voltage signals sequentially read from the CCD 14 are applied to a correlated double sampling circuit (CDS circuit) 18, where the R, G, B signals for each pixel are sampled and held, and the A / D converter is used. 20 added. A
The / D converter 20 converts the R, G, B signals sequentially added from the CDS circuit 18 into, for example, 10-bit (0 to 1023) digital R, G, B signals and outputs them. Incidentally, C
CD drive circuit 16, CDS circuit 18, and A / D converter 2
0 is driven in synchronization with a timing signal applied from the timing generation circuit (TG) 22.

R, G output from the A / D converter 20
The B signal is temporarily stored in the memory 24, and then the R, G, B signals stored in the memory 24 are input to the digital signal processing circuit 26.

The R, G, B signals output from the A / D converter 20 are also output to the integrating circuit 48. The integrating circuit 48 calculates the integrated value of the R, G, B signals and outputs it to the multipliers 50R, 50G, 50B. Multipliers 50R, 5
0G, 50B multiplies the R, G, B signals by the adjustment gain value for adjusting the variation of the device, and outputs them to the CPU 38 which is the central processing unit.

The CPU 38 obtains the subject brightness (photographing EV value) based on the input integrated value and stores it in the memory 39. Exposure control is performed based on the subject brightness. Further, as will be described later in detail, the CPU 38 acquires weather information at the time of shooting, and based on this, correction values (gain values) R for white balance correction of the R, G, B signals.
g, Gg, Bg are calculated, and are calculated by the digital signal processing circuit 2
6 to the white balance adjustment circuit 30.

The digital signal processing circuit 26 comprises a synchronization circuit 28, a white balance adjusting circuit 30, a gamma correction circuit 32, a YC signal generating circuit 34, and a memory 36.

The synchronizing circuit 28 converts the dot-sequential R, G, B signals read from the memory 24 into a simultaneous signal, and outputs R,
The G and B signals are simultaneously output to the white balance adjustment circuit 30. The white balance adjustment circuit 30 has R, G, B
Multiplier 30 for increasing / decreasing the digital value of each signal
It is composed of R, 30G and 30B, and the R, G and B signals are added to the multipliers 30R, 30G and 30B, respectively.

Gain values Rg, Gg, Bg for white balance control are added from the CPU 38 to the other inputs of the multipliers 30R, 30G, 30B.
0R, 30G, and 30B multiply the two inputs of the input from the synchronization circuit 28 and the input from the CPU 38, respectively, and white balance-adjusted R ′, G ′,
The B ′ signal is output to the gamma correction circuit 32. In addition, CPU
Details of the white balance correction values Rg, Gg, and Bg added from 38 to the white balance adjustment circuit 30 will be described later.

The gamma correction circuit 32 changes the input / output characteristics so that the white balance-adjusted R ', G', and B'signals have desired gamma characteristics, and the 10-bit signal is an 8-bit signal. And output to the YC signal creation circuit 34. The YC signal creation circuit 34 creates a luminance signal Y and chroma signals Cr and Cb from the gamma-corrected R, G, and B signals. The luminance signal Y and the chroma signals Cr and Cb (YC signals) are stored in the memory 36 in the same memory space as the memory 24.

Here, by reading the YC signal in the memory 36 and outputting it to the liquid crystal monitor 52, a moving picture or a still picture can be displayed on the liquid crystal monitor 52. Also,
The YC signal after shooting is compressed into a predetermined format by the compression / expansion circuit 54, and then recorded in the recording unit 56 in a recording medium such as a memory card. Further, in the reproduction mode, the image data recorded on the memory card or the like is expanded by the compression / expansion circuit 54 and then output to the liquid crystal monitor 52 so that the reproduced image is displayed on the liquid crystal monitor 52. .

The CPU 38 has an operation unit 40 including a shutter button, a numeric keypad, and the like (not shown), a memory 39 for storing various data such as an EV value, a strobe 46 for emitting strobe light, and a current date and time. Timer 60, GPS sensor 62 for acquiring the current position,
Also, a communication unit 64 for communicating with the base station 86 is connected, and each circuit is integrally controlled based on an input from the operation unit 40, auto focus, automatic exposure control, auto white balance, and other portable terminals. Controls various functions as.

The GPS sensor 62 corresponds to the photographing location information obtaining means of the present invention, the CPU 38 and the white balance adjusting circuit 30 correspond to the correcting means of the present invention, and the memory 39 stores the correction value storage of the present invention. CPU equivalent to means
38 and the communication unit 64 correspond to the weather information acquisition unit of the present invention, the communication unit 64 corresponds to the transmission unit and the reception unit of the present invention, and the timer 60 corresponds to the shooting date and time acquisition unit of the present invention.

The GPS sensor 62 is a GPS (Global Pos)
itioning system) GPS signals from satellites are received, the received GPS signals are analyzed to obtain the current position (for example, latitude and longitude), and the result is output to the CPU 38.

The CPU 38 communicates with the base station 86 via the communication unit 64 to provide another portable terminal connected to the communication network 84, a server computer 90 providing weather information connected to the network 82, or the like. It is possible to exchange information with these computers by connecting to other servers.

In the present embodiment, the CPU 38 sends the current date and time information about the current date and time (shooting date and time) acquired from the timer 60 and the current position information about the current position (shooting position) acquired from the GPS sensor 62 via the communication section 64. To the server computer 90.

The server computer 90 stores past and latest weather information (for example, fine weather, fine weather, cloudy weather, rain, etc.) in various places.
Is stored, and the weather information corresponding to the current date / time information and the current position information transmitted from the mobile terminal 92 is transmitted to the mobile terminal 92.

The CPU 38, based on the weather information transmitted from the server computer 90, gain values Rg, G
g and Bg are obtained and output to the white balance adjustment circuit 30. As a result, white balance control suitable for the weather at the time of shooting is performed, and deterioration of image quality can be suppressed even when there are restrictions on the exposure conditions such as a fixed aperture.

Next, as an operation of this embodiment, a control routine executed by the CPU 38 shown in the flowchart of FIG. 3 will be described.

The control routine shown in FIG.
It is executed when the power of is turned on. First, step 10
At 0, it is determined whether or not a shutter button (not shown) or a button having a function as a shutter button included in the operation unit 40 is pressed.

If the shutter button has not been pressed, the determination at step 100 is negative, and the process waits until the shutter button is pressed. On the other hand, if the shutter button is pressed, the determination in step 100 is positive,
In the next step 102, it is determined whether or not the current position can be acquired. That is, it is determined whether or not the GPS sensor 62 receives a GPS signal from a GPS satellite and calculates the current position (for example, latitude and longitude) from the received GPS signal.

When the current position can be acquired, that is, when the current position is calculated by the GPS sensor 62, the determination at step 102 is affirmative, and at the next step 104, the current position is detected from the GPS sensor. Information is acquired, and in the next step 106, the current date and time is acquired from the timer 60.

At the next step 108, connection is made to the server computer 90 which is a weather information server. That is,
URL indicating the address position of the server computer 90
Is transmitted to the base station 86 via the communication unit 64. The base station 86 provides the gateway system 88 with the URL and information (address position, etc.) for specifying the mobile terminal 92.
To the server computer 90 connected to the network 82 via. As a result, the connection between the mobile terminal 92 and the server computer 90 is established, and information can be exchanged between them.

Then, in the next step 110, the acquired current position information and current date and time information are transmitted to the server computer 90. In the server computer 90, weather information corresponding to the received current position information and current date and time information, for example, whether the weather at the received current position and current date and time is sunny, sunny, or cloudy,
Information such as whether it is raining or the like is transmitted to the mobile terminal 92.

At step 112, the portable terminal 92 determines whether or not the weather information is received from the server computer 90. If the weather information has not been received from the server computer 90, the determination at step 112 is denied and the process waits until the weather information is received. On the other hand, when the weather information is received from the server computer 90,
The determination in step 112 is affirmed, and the next step 114
In, the gain values Rg, G according to the received weather information
g and Bg are calculated. Specifically, as shown in FIG. 4, for example, the gain value Rg and the gain value B are determined from the corresponding relationship between the gain value Rg and the gain value Bg that is predetermined according to the weather.
Find g. The gain value Gg is set to 1.0 regardless of the weather. The correspondence between the gain value Rg and the gain value Gg and the gain value Gg are stored in the memory 39 in advance, for example.

That is, in fine weather, the gain values Rg, B
Since both g are 1.0, there is no correction, and the gain values Rg and Bg are determined so that the gain value Rg increases and the gain value Bg decreases as the degree of fineness decreases.

The obtained gain values Rg, Gg, Bg are output to the white balance adjusting circuit 30.

Then, in the next step 116, image pickup processing is performed. That is, the timing generation circuit 22 is instructed to start imaging and the CCD drive circuit 16 is driven.

CC through the taking lens 10 and diaphragm 12.
The subject image formed on the light receiving surface of D14 is converted by each sensor into a signal charge of an amount corresponding to the incident light amount of light. The signal charge thus accumulated is read out to the shift register by the read gate pulse applied from the CCD drive circuit 16, and sequentially read out as a voltage signal corresponding to the signal charge by the register transfer pulse.

The voltage signals sequentially read from the CCD 14 are applied to a correlated double sampling circuit (CDS circuit) 18, where the R, G, B signals for each pixel are sampled and held, and the A / D converter is used. 20 added. A
The / D converter 20 converts the R, G, B signals sequentially added from the CDS circuit 18 into, for example, 10-bit (0 to 1023) digital R, G, B signals and outputs them.

R, G output from the A / D converter 20
The B signal is temporarily stored in the memory 24, and then the R, G, B signals stored in the memory 24 are output to the synchronization circuit 28 of the digital signal processing circuit 26.

The synchronizing circuit 28 converts the dot-sequential R, G, B signals read out from the memory 24 into a simultaneous signal and outputs R,
The G and B signals are simultaneously output to the white balance adjustment circuit 30.

The white balance adjusting circuit 30 multiplies the R, G, B signals output from the synchronization circuit 28 by the gain values Rg, Gg, Bg output from the CPU 38, respectively.
White balance adjusted R'by this multiplication,
The G ′ and B ′ signals are output to the gamma correction circuit 32.

The gamma correction circuit 32 changes the input / output characteristics so that the white balance-adjusted R ', G', and B'signals have desired gamma characteristics, and the 10-bit signal is an 8-bit signal. And output to the YC signal creation circuit 34. The YC signal creation circuit 34 creates a luminance signal Y and chroma signals Cr and Cb from the gamma-corrected R, G, and B signals. The luminance signal Y and the chroma signals Cr and Cb (YC signals) are stored in the memory 36 in the same memory space as the memory 24.

Here, by reading the YC signal in the memory 36 and outputting it to the liquid crystal monitor 52, a moving picture or a still picture can be displayed on the liquid crystal monitor 52. Also,
The YC signal after photographing is compressed as image data of a predetermined format (for example, JPEG or the like) by the compression / expansion circuit 54, and then recorded in the storage unit such as a memory card by the recording unit 56.

The current position information, the current date and time information, and the weather information received from the server computer 90 may be recorded in the storage medium together with the image data. As a result, when searching the recorded image data, it is possible to search using the shooting location, shooting date, weather information, etc. as a search key, and the convenience of the search can be improved.

As described above, since the weather information according to the shooting location and the shooting date and time is acquired by the external communication and the white balance control is performed according to the acquired weather information, the shutter button is half-pressed as in the conventional camera. There is no need for a complicated sequence such as pre-shooting the subject while the button is pressed, and determining the weather value at the shooting location, that is, the light source color based on this to determine the gain value for white balance control.
Therefore, hardware such as a weather sensor and a shutter button half-press mechanism is not required, and a simple and inexpensive configuration can be achieved, and even if there are restrictions on the exposure conditions, deterioration of image quality can be prevented to some extent. it can.

On the other hand, the GPS sensor 62 cannot capture the GPS satellites, such as when photographing indoors, and the GPS sensor 62
If the signal cannot be received due to, the current position may not be acquired. When the current position cannot be acquired in this way, the determination in step 102 is denied, and in the next step 118, the strobe 46 is controlled to force the strobe to emit light. Then, the image capturing process is performed as in step 116. Thus, if you can't get the current position,
Since the strobe light is forcibly emitted, the subject becomes sufficiently bright and a good image can be obtained to some extent without performing white balance control.

In this embodiment, the case where the current date and time information is acquired from the timer 60 has been described.
The current date and time information included in the GPS signal received by the S sensor 62 may be used. Further, the weather information may not be acquired at the time of shooting, and the weather information may be acquired after shooting to correct the shot image.

[0062]

As described above, according to the present invention, the photographed image is corrected based on the weather information acquired by the external communication so that at least the tendency of the color information of the photographed image of the subject has a predetermined tendency. With this configuration, it is possible to reduce the size of the device and prevent deterioration of image quality.
Has the effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a network system according to an embodiment.

FIG. 2 is a block diagram showing an internal configuration of a digital camera.

FIG. 3 is a flowchart of a control routine executed by a CPU.

FIG. 4 is a diagram showing a relationship between a gain value Rg and a gain value Bg.

[Explanation of symbols]

10 Shooting lens 16 Drive circuit 18 CDS circuit 20 A / D converter 24 memory 26 Digital Signal Processing Circuit 28 Synchronization circuit 30 White balance adjustment circuit 38 CPU

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C022 AA13 AB15 AC32 AC42 AC52                       AC69                 5C064 BA04 BC23 BC25 BD02 BD08                       BD13                 5C065 AA03 BB02 BB41 CC01 DD01                       EE18 GG26                 5K067 AA42 BB41 FF02 FF03 JJ56

Claims (3)

[Claims] 1. A shooting location information acquisition unit that acquires shooting location information relating to a shooting location for shooting a subject, and weather information acquisition that acquires weather information near the shooting location acquired by the shooting location information acquisition unit by external communication. Means for correcting the photographed image so that at least the tendency of the color information of the photographed image of the subject has a predetermined tendency based on the acquired weather information. 2. The correction means includes a correction value storage means for storing a white balance correction value determined corresponding to each of a plurality of predetermined weather information, and a white balance correction corresponding to the acquired weather information. The digital camera according to claim 1, wherein the captured image is subjected to white balance correction according to a value. 3. The digital camera according to claim 1, further comprising a strobe that emits a strobe light when the shooting location information cannot be acquired.