JP4094834B2 - Mobile information terminal with camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a portable information terminal device with a camera including a CMOS image sensor, and particularly to a technique for suppressing the occurrence of flicker itself. The present invention is suitable for application to a terminal of a mobile communication system such as a car phone, a mobile phone, or a PHS (Personal Handyphone System).
[0002]
[Prior art]
FIG. 7 is a block diagram showing a conventional configuration of a camera-equipped personal digital assistant device represented by a mobile phone, for example. In FIG. 7, 1 is a camera having a CMOS image sensor or CMOS sensor, 2 is a display control unit, 3 is a liquid crystal display device (hereinafter referred to as LCD) as a display panel device, 4 is an antenna, 5 is a radio unit, 6 Is an input key, 7 is a CPU control unit, and 8 is a voice control unit.
[0003]
An image captured by the camera 1 controlled by the CPU control unit 7 is displayed on the LCD 3 through the display control unit 2. At this time, regarding the setting of the accumulation time in the CMOS sensor of the camera 1, as shown in FIG. 8, there is a difference in the time for starting accumulation for each line direction of the CMOS sensor.
[0004]
Here, when the image repeats its light and dark at a constant cycle, for example, when the light and dark of the image is repeated at a cycle of 50 Hz or 60 Hz as in a fluorescent lamp environment, the accumulation time becomes an integral multiple of the cycle. If this is the case, the accumulated brightness is constant for each line, but if not, the brightness differs for each line and a light and shade stripe pattern is generated (see FIG. 9). This is defined as flicker.
[0005]
In a portable information terminal device with a camera such as a mobile phone, if this flicker occurs, it becomes difficult to see the original captured image. Therefore, it is important to suppress the flicker. In the prior art, a method of visually reducing the appearance of fringes has been adopted by performing conversion called a γ curve between input and output with a lookup table or the like to brighten the captured image as a whole.
[0006]
[Problems to be solved by the invention]
In the method of correcting the brightness of a captured image by correction using a γ curve, flicker is only reduced, and flicker generation itself cannot be suppressed.
[0007]
The present invention has been made in view of such problems, and an object of the present invention is to provide a portable information terminal device with a camera capable of automatically suppressing the occurrence of flicker itself.
[0008]
[Means for Solving the Problems]
The invention of claim 1 is a portable information terminal device with a camera comprising a CMOS image sensor and a means for displaying an image imaged by the CMOS image sensor, and acquires information on a current position of the portable information terminal device with a camera Means for storing a table composed of latitude and longitude data of an arbitrary number of points on the boundary line obtained by modeling the actual boundary line of the commercial power supply frequency with an approximate line, and based on the current position information By referring to and comparing the table, the commercial power supply frequency in the region where the camera-equipped portable information terminal device is used is determined, and a time corresponding to an integral multiple of the determined period of the commercial power supply frequency is determined by the CMOS image sensor. And flicker generation suppressing means for setting the storage time of the image.
[0009]
Further, in the invention of claim 1, the flicker occurrence suppressing means includes the position data that is one of the latitude data and the longitude data of the current position information, and the latitude and longitude data in the table. By referring to and comparing one position data corresponding to one position data, which point on the modeled boundary line the current position of the portable information terminal with camera is between The portable information terminal device with a camera is used based on the other position data of the latitude data and longitude data of the current position information and the other position data of the determined two points. It is characterized by determining the commercial power supply frequency in the area.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The feature point of the first camera-equipped portable information terminal device according to the present invention is that data of a device capable of acquiring current position information such as GPS (Global Positioning System) is used for the region where the terminal device is used. It is to enable determination of commercial power supply frequency. As a result, the apparatus can automatically suppress the occurrence of flicker itself.
[0015]
The feature of the second portable information terminal with camera according to the present invention is that the commercial power supply frequency in the area where the terminal device is used is determined from the flicker behavior, and the accumulation time is set according to the frequency. There is. As a result, the present apparatus can automatically control the occurrence of flicker itself. Furthermore, this apparatus has a feature that it receives a handover signal in a mobile communication system such as a mobile phone or a PHS, and acquires position change information.
[0016]
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0017]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a portable information terminal device with a camera or a mobile communication terminal device according to the first embodiment, as represented by a mobile phone with a camera. In FIG. 1, 1 is a camera having a CMOS image sensor or a CMOS sensor, 2 is a display control unit that converts image signals output from the camera 1 into optimum data, and 3 is a display control unit 2. Is a liquid crystal display device (hereinafter referred to as LCD) as a display panel device controlled by. Here, the display control unit 2 and the LCD 3 constitute “display means for displaying an image picked up by the CMOS image pickup device”. Reference numeral 4 denotes an antenna that transmits and receives signals to and from a radio base station (not shown), 5 denotes a radio unit, and 6 denotes an input key. Further, reference numeral 7 denotes a CPU control unit that executes functions of table reference, data comparison, and frequency determination, which will be described later, and is a core part that constitutes flicker generation suppression means. In addition to the above functions, the unit 7 controls the camera 1 and the display control unit 2, and “an arbitrary number of points on the boundary line obtained by modeling the actual boundary line of the commercial power supply frequency with an approximate line” A memory (for example, RAM or ROM) 7M is provided in the inside thereof as “means for storing a table composed of set data of latitude and longitude”. Reference numeral 8 denotes a voice control unit. Further, 10 is a GPS antenna used in the GPS system, 9 is a GPS control unit, and both units 9 and 10 constitute “means for acquiring current position information of the camera-equipped mobile information terminal device”. .
[0018]
Next, the operation of the terminal device in FIG. 1 will be described. First, a signal input from the GPS antenna 10 is once processed by the GPS control unit 9, and as a result, current position information composed of latitude data and longitude data of the current position of the terminal device is transmitted to the CPU control unit 7. The The CPU control unit 7 executes an operation of referring to the table in the memory 7M based on the input longitude / latitude data.
[0019]
Here, the contents of the table stored in the memory 7M will be described. That is, as shown in FIG. 2, the actual boundary line is preliminarily set as an approximate line so that the intersection of the actual boundary line of the commercial power supply frequency and the latitude line at a certain interval does not have a plurality of longitudes. The modeled one is defined as a boundary line. Then, the latitude 1 data and the longitude 1 data of the intersection of the latitude line and the modeled boundary line are set in the set information of the points on the modeled boundary line. Then, by preparing only a plurality (for example, m) of set information of points on the boundary line thus modeled, a table as shown in FIG. 3 is created, and this table is stored in the memory 7M. Remember it. In the above-mentioned table formation, the more accurate the position determination becomes possible as the number of points on the modeled boundary line increases.
[0020]
As a specific determination process, the CPU control unit 7 first uses latitude data (one position data) in the current position information input from the GPS control unit 9, and uses the latitude i data in the table of FIG. By referring / comparing (1 ≦ i ≦ m) (one corresponding position data), it is determined which point on the boundary line the current position of the terminal device is between judge.
[0021]
Next, based on the previously obtained two-point longitude information (corresponding other position data), the CPU control section 7 includes the longitude information and the current position information input from the GPS control section 9. By comparing with the longitude data (the other position data), the commercial power supply frequency in the area where the terminal device is used is determined. That is, as shown in (1) of FIG. 4, when the two points of longitude information are the same, the CPU control unit 7 compares the input longitude data with the two points of longitude information. When the longitude data is located on the west side with respect to the 2-point longitude line, the commercial power supply frequency in the area where the terminal device is used is determined to be 60 Hz, and conversely, if the east side is indicated, the determination result is 50 Hz. . On the other hand, when the two points of longitude information are different from each other, the CPU control unit 7 sets a straight line passing through the two points as a boundary line, and then (2) or (3) in FIG. ), The power supply frequency of the region where the terminal device is used depends on whether the slope of the straight line forming the boundary line is positive or negative, and on which side the input latitude / longitude data exists. As a result, 50/60 Hz is determined.
[0022]
Actually, in order to prevent frequent switching between 50 Hz and 60 Hz due to the influence of a measurement error in the vicinity of the boundary line, the CPU control unit 7 performs the above-described processing any number of times within a unit time, The final frequency is determined by the majority decision of the result.
[0023]
Further, based on the frequency determined by the above processing, the CPU control unit 7 determines a value obtained by multiplying the period by an integer n corresponding to the brightness of the subject to be imaged as an accumulation time, and this accumulation time is determined by the camera. Set to 1. As a result, the accumulation time of the camera 1 is always equal to a time corresponding to an integral multiple of the period of the commercial power frequency in the region where the terminal device is used. Therefore, even if the terminal device crosses the boundary of the commercial power frequency. In addition, the occurrence of flicker in a fluorescent lamp environment is automatically suppressed.
[0024]
Specifically, under a 50 Hz fluorescent lamp environment,
1000 ms / 50 Hz / 2 = 10.00 ms
Storage time to be set = n × 10.00 ms (n is an integer proportional to brightness).
[0025]
If it is under 60Hz fluorescent lamp environment,
1000 ms / 60 Hz / 2 = 8.33 ms,
Storage time to be set = n × 8.33 ms (n is an integer proportional to brightness).
[0026]
In the present embodiment, latitudes are specified at regular intervals, and the pair information with longitudes is tabulated. Conversely, the same is true when the longitudes are specified at regular intervals and the pair information with latitudes is tabulated. An effect is obtained.
[0027]
In this embodiment, the commercial power supply frequency in the region where the portable information terminal with camera is currently used is determined based on the GPS data. Instead, it is currently implemented in the mobile communication service. It is also possible to determine the commercial power supply frequency with accuracy in units of radio base stations based on the location information providing service data.
[0028]
(Embodiment 2)
FIG. 5 is a block diagram showing a configuration of a camera-equipped portable information terminal device (for example, a camera-equipped cellular phone) according to the present embodiment. In FIG. 5, the same reference numerals as those in FIG. 1 denote the same components, but here, the antenna 4 and the radio unit 5 also serve as radio means for receiving a handover signal.
[0029]
Also in the present embodiment, the core part is in the CPU control unit 7, which determines the commercial power supply frequency in the region where the camera-equipped personal digital assistant device is used from the flicker behavior. The flicker generation suppressing means for setting the time corresponding to the integral multiple of the cycle of the commercial power supply frequency as the accumulation time of the CMOS image sensor of the camera 1 is formed. More specifically, the same unit 7 described, “Once the accumulation time is set to a time corresponding to an integral multiple of a 60 Hz period, whether or not a stripe flows on a continuous image captured by a CMOS image sensor”. When the fringe flows, it is determined that the commercial power supply frequency in the area where the portable information terminal with a camera is used is 50 Hz, and the time corresponding to an integral multiple of the 50 Hz cycle is set as the accumulation time, “When the stripes do not flow, the accumulation time is set as a time corresponding to an integral multiple of the 60 Hz period”.
[0030]
Next, the operation of the terminal device in FIG. 5 will be described. Here, a case where the imaging frame rate is 15 Hz will be described as an example.
[0031]
First, when the accumulation time is set to a time corresponding to an integral multiple of a 50 Hz cycle, flicker does not occur in a 50 Hz fluorescent lamp environment, but in a 60 Hz fluorescent lamp environment,
1000 ms / 15 Hz = 66.66 ms,
66.66 ms / 8.33 ms = 8.00 stripes are displayed in one screen, and since the number of stripes is an integral multiple, even in a continuous image, the stripes are always at a fixed position in one screen. Will occur.
[0032]
Next, when the accumulation time is set to a time corresponding to an integral multiple of a 60 Hz cycle, flicker does not occur in a 60 Hz fluorescent lamp environment, but in a 50 Hz fluorescent lamp environment,
1000 ms / 15 Hz = 66.66 ms,
Since 66.66 ms / 10.00 ms = 6.66, and the number of stripes is not an integral multiple, in continuous images, the stripes appear to flow.
[0033]
Therefore, the CPU control unit 7 according to the present embodiment once sets the accumulation time to a time corresponding to an integral multiple of a 60 Hz cycle for each determination, and detects whether or not such a stripe flows, and 50 Hz Alternatively, by determining which frequency is within 60 Hz, the corresponding accumulation time is automatically switched.
[0034]
Specifically, the CPU control unit 7 calculates the difference between the integrated data of the continuous frames for each line using the data obtained by integrating the in-screen data of the continuous two frame periods in the line direction. Then, the CPU control unit 7 determines that the fluorescent light is illuminated by 50 Hz when detecting the case where the obtained difference value is regularly increased and decreased in a predetermined cycle.
[0035]
However, this determination means has the following problems. That is, in this method, since the frequency of 50 Hz cannot be determined unless the accumulation time is set to an integral multiple of the 60 Hz period, there is no problem in a 60 Hz fluorescent lamp environment, but in a 50 Hz fluorescent lamp environment, Since the accumulation time must be set to an integral multiple of the 60 Hz period, stripes that flow during the determination period are generated. Therefore, when the above determination is performed too frequently, the effect of flicker removal, which is the original purpose, is impaired, and flicker may be generated by its own processing.
[0036]
Therefore, when determining using this means, handover with a radio base station in the mobile communication system is used. Here, as shown in FIG. 6, handover can be continued by automatically switching from one radio base station cell to another radio base station cell during communication of this terminal apparatus. It is a function for doing so. The information that the radio base station has changed (handover signal) can be sufficiently recognized by the terminal device such as a mobile phone.
[0037]
By applying this feature, the above-mentioned flicker determination interval is set to a relatively long time interval during normal times when a handover signal is not input, so that the number of determinations is reduced, and the wireless unit 5 transmits the handover signal. When the signal is received, the handover signal is input to the CPU control unit 7 so that the CPU control unit 7 recognizes the information that the radio base station has changed. In such a case, since this terminal device is moving and may cross the boundary of the commercial power supply frequency, the CPU control unit 7 immediately performs the above determination process in response to the reception of the handover signal. Execute. As a result, when there is a possibility that the terminal device has crossed the boundary of the commercial power supply frequency, it is possible to effectively determine the frequency and set the accumulation time in real time. In addition, since the determination is executed at a relatively long time interval in normal times, the number of times of displaying the stripes flowing at the time of determination can be kept to the minimum necessary level.
[0038]
【The invention's effect】
Each invention of Claims 1 and 2 has an effect that generation of flicker itself can be automatically suppressed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a camera-equipped portable information terminal device according to Embodiment 1 of the present invention.
FIG. 2 is a diagram showing an example in which a boundary line of a commercial power supply frequency is modeled in Embodiment 1 of the present invention.
FIG. 3 is a diagram showing a table configuration of a boundary line of a commercial power frequency in Embodiment 1 of the present invention.
FIG. 4 is a diagram showing a method of boundary recognition means in Embodiment 1 of the present invention.
FIG. 5 is a block diagram showing a configuration of a camera-equipped portable information terminal device according to Embodiment 2 of the present invention.
FIG. 6 is a diagram for explaining a mechanism of a handover signal.
FIG. 7 is a block diagram showing a configuration of a conventional camera-equipped personal digital assistant device.
FIG. 8 is a diagram for explaining an example when flicker does not occur.
FIG. 9 is a diagram illustrating an example when flicker occurs.
[Explanation of symbols]
1 camera, 2 display control unit, 3 LCD, 4 antenna, 5 radio unit, 7 CPU control unit, 7M memory, 9 GPS control unit, 10 GPS antenna.

Claims (2)

A portable information terminal device with a camera comprising a CMOS image sensor and a means for displaying an image imaged by the CMOS image sensor,
Means for acquiring information of a current position of the camera-equipped personal digital assistant device;
Means for storing a table comprising latitude and longitude data of an arbitrary number of points on the boundary line obtained by modeling the actual boundary line of the commercial power supply frequency with an approximate line;
Refer to and compare the table based on the current position information to determine the commercial power frequency in the region where the camera-equipped portable information terminal device is used, and correspond to an integer multiple of the determined commercial power frequency period Flicker occurrence suppression means for setting the time to be set to the accumulation time of the CMOS image sensor,
The flicker occurrence suppressing means is
Refer to the position data that is one of the latitude data and longitude data of the current position information, and one position data corresponding to the one position data among the latitude and longitude data in the table and By comparing, it is determined which point on the modeled boundary line the current position of the camera-equipped personal digital assistant device is between, and the latitude data and longitude data of the current position information A commercial power frequency in a region where the mobile information terminal device with a camera is used is determined based on the other position data of the two and the other position data of the determined two points.
A personal digital assistant with camera. It is a portable information terminal device with a camera according to claim 1,
The flicker occurrence suppressing means is
When the other position data of the two points are both equal, it is determined by determining which side the other position data of the current position information is located with respect to the other position data of the two points. While determining the commercial power frequency in the region where the camera-equipped personal digital assistant is used,
When the other position data of the two points are different from each other, the straight line passing through the two points is defined as a boundary line, and the positive / negative information of the inclination of the straight line and the current position information are any of the straight lines. Based on the information on whether or not the mobile information terminal device with a camera is used, the commercial power supply frequency in the region where the camera is used is determined.
Portable information terminal equipment with a camera.

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