JP2009089086A - Imaging device and portable terminal device - Google Patents

Abstract

An imaging device and a portable terminal device capable of displaying a histogram in real time with a low load are provided.
When performing real-time histogram analysis of an image captured by a camera, a frame division unit 91 divides each frame into M regions, and a histogram analysis unit 92 differs for each of M consecutive frames. The histogram analysis of the area is performed, and the totaling unit 93 adds the analysis results and outputs the result as a histogram analysis result of one frame.
[Selection] Figure 3

Description

  The present invention relates to an imaging device and a portable terminal device that can capture a digital image.

A camera mounted on a portable terminal device such as a cellular phone has a strong demand for higher image quality, and the image quality has been improved by a technique such as increasing the number of pixels.
As one end of such high image quality, it is conceivable to display a histogram (frequency distribution diagram) of the imaging screen on the screen.
In the field of digital images, the histogram refers to a graph showing the brightness distribution of an image. Based on this distribution balance, it is possible to determine whether the exposure of the image is appropriate, under or over.

As a technique for displaying a histogram of an image taken by a camera, for example, there is a technique disclosed in Patent Document 1.
In Patent Document 1, the brightness of each pixel constituting a reference image serving as a reference imaged by a CCD (Charge Coupled Device) at the time of pre-imaging is divided into a plurality of brightness areas, and the brightness of each pixel is evaluated. An imaging device that acquires a histogram indicating a distribution is disclosed.
JP 2000-92379 A

However, when the technique disclosed in Patent Document 1 is applied to a mobile terminal device such as a mobile phone, the following disadvantages occur.
Many portable terminal devices such as cellular phones are designed so that all processing of the portable terminal device is performed by a one-chip CPU for miniaturization and power saving. That is, it is necessary to perform communication such as a telephone call and e-mail, and processing such as imaging and image processing on a single chip. Even if not all processing is performed by one chip, it is not preferable to mount a high-level CPU in terms of cost and size. For this reason, there is a disadvantage that a complicated process like the technique disclosed in Patent Document 1 is difficult to execute in the mobile terminal device.

Many portable terminal devices have a display device such as a liquid crystal or an organic EL (Electro Luminescence). These display devices have a plurality of types of resolutions depending on the mobile terminal device. That is, there are mobile terminals with different display resolutions such as QQVGA (Quarter Quarter Video Graphics Array: 160 × 120 pixels) and QVGA (Quarter Video Graphics Array: 320 × 240 pixels). For this reason, in portable terminal devices designed on the assumption that a captured image is sent by e-mail, the mainstream is a camera that can acquire images in different sizes, such as QQVGA and QVGA, as the capability of the mounted camera. It has become.
In such a case, since the analysis method for generating the histogram differs between when the QVGA image is acquired at the time of image capture and when the QQVGA image is acquired, the processing becomes complicated. There was a profit.
In addition, if a histogram is displayed in order to capture a high-quality image with a camera, it is meaningless unless the histogram is displayed in real time. As described above, since the mobile terminal device has a strong tendency to perform all the processing in one chip, there is a disadvantage that the real-time histogram analysis and display processing may not be performed well due to insufficient processing capability.

  An object of the present invention is to provide an imaging device and a portable terminal device capable of displaying a histogram in real time with a low load.

  An imaging apparatus according to a first aspect of the present invention includes a camera that captures images at a predetermined interval, a display unit that updates and displays an image acquired by the camera at each predetermined interval, a control unit, And the control unit similarly divides each of consecutive M (M is a positive integer) images acquired by the camera into M regions, and the dividing unit divides the image. A histogram analysis unit that analyzes histograms of different regions of the M images, and histograms of different regions of the M images analyzed by the histogram analysis unit are aggregated to obtain a histogram as one image. And the display unit displays a histogram generated by the totaling unit together with an image acquired by the camera.

  Preferably, the control unit includes a thinning unit that performs a thinning process on the number of pixels analyzed by the histogram analysis unit among all the pixels in the region in accordance with the resolution of the display unit.

  Preferably, the resolution of the display unit is any one of QQVGA, QVGA, and WQVGA, and M is 5 or a multiple of 5, and when the resolution is QQVGA, When the resolution is QVGA, 1 pixel per 4 pixels is analyzed by the histogram analysis unit, and when the resolution is WQVGA, 1 pixel per 5 pixels is analyzed by the histogram analysis unit.

  A mobile terminal device according to a second aspect of the present invention is a mobile terminal device that performs wireless communication with a base station connected to a communication network, and is acquired by a camera that captures images at predetermined intervals. A display unit that updates and displays an image at each predetermined interval; a communication unit that can transmit an image acquired by the camera by wireless communication; and a control unit, wherein the control unit includes the camera Similarly, a dividing unit that similarly divides each of M consecutive images (M is a positive integer) acquired into M regions, and histograms of different regions of the M images divided by the dividing unit. A histogram analyzing unit that analyzes the histogram, and a totaling unit that totalizes histograms of different areas of the M images analyzed by the histogram analyzing unit and generates a histogram as one image Has, the display unit displays the histogram the aggregate portion is produced together with the image acquired by the camera.

  Preferably, the image processing apparatus further includes an operation unit that receives an operation input instructing a change in the size of the acquired image thereafter in a state where images are continuously acquired by the camera.

  According to the present invention, an imaging device and a mobile terminal device capable of displaying a histogram in real time with a low load are provided.

Hereinafter, the mobile terminal 100 will be described as an example of the mobile terminal device of the present invention.
FIG. 1 is a block diagram for explaining each configuration of the mobile terminal 100.
As shown in FIG. 1, the mobile terminal 100 includes a communication unit 1, an operation unit 2, an audio processing unit 3, a speaker 4, a microphone 5, a display unit 6, a camera 7, a storage unit 8, And a control unit 9.

FIG. 2 is a diagram illustrating an example of the appearance of the mobile terminal 100.
As shown in FIG. 2, in the mobile terminal 100, an upper housing 101 and a lower housing 102 are connected by a hinge portion 103 so as to be opened and closed.
2A shows a state where the casing of the portable terminal 100 is opened, and FIG. 2B shows a state where the casing of the portable terminal 100 is closed.
The upper housing 101 includes a speaker 4 and a display unit 6.
The lower housing 102 includes the operation unit 2 and the microphone 5.

The communication unit 1 captures a wireless communication system, performs wireless communication with a base station (not shown) connected to the communication network, and transmits and receives various data. The various data includes voice data at the time of voice call, mail data at the time of mail transmission / reception, web page data at the time of browsing the web, and the like.
The operation unit 2 has keys to which various functions are assigned, such as a power key, a call key, a numeric key, a character key, a direction key, a determination key, and a call key. These keys are operated by the user. If so, a signal corresponding to the operation content is generated and output to the control unit 9 as a user instruction.

  The audio processing unit 3 processes an audio signal output from the speaker 4 and an audio signal input from the microphone 5. That is, the sound input from the microphone 5 is amplified, subjected to analog / digital conversion, further subjected to signal processing such as encoding, converted into digital sound data, and output to the control unit 9. Further, the audio data supplied from the control unit 9 is subjected to signal processing such as decoding, digital / analog conversion, amplification, etc., converted into an analog audio signal and output to the speaker 4.

The display unit 6 is configured using, for example, a liquid crystal display (LCD) or an organic EL (OLED) display, which is configured by arranging a large number of pixels (a combination of light emitting elements of a plurality of colors) vertically and horizontally. 9 displays an image corresponding to the video signal supplied from 9. The display unit 6 displays, for example, a destination telephone number at the time of outgoing call, a telephone number of the outgoing call source at the time of incoming call, contents of received mail and outgoing mail, date, time, remaining battery level, success / failure of outgoing call, standby screen, etc. .
The display unit 6 has different resolutions depending on the terminal. Examples of the resolution include QQVGA (160 × 120 pixels), QVGA (320 × 240 pixels), and WQVGA (Wide QVGA: 400 × 240 pixels).
The display unit 6 can acquire an image currently captured by a camera 7 (to be described later) at a predetermined rate (for example, 15 frames / second) and display the image in real time while updating the display image at the rate. At the same time, the result of the histogram analysis processing performed on the image captured by the camera 7 by the control unit 9 described later is displayed in the form of a graph, for example.
As for the histogram display method of the display unit 6, it is desirable that the display is performed in an area of a predetermined size or less displayed on the display unit 6. This is to make it easier to see the image taken by the camera 7 and to make the histogram itself easier to see (the histogram is a distribution diagram, and a smaller one looks smoother).

  The camera 7 is an imaging device configured by, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The camera 7 is activated in accordance with the control of the control unit 9, takes an image of a predetermined size among QQVGA, QVGA, WQVGA, and the like and sends the image to the control unit 9.

  The storage unit 8 stores various data used for various processes of the mobile terminal 100. For example, a computer program executed by the control unit 9, an address book for managing personal information such as a telephone number or an e-mail address of a communication partner, a sound file for reproducing a ring tone or an alarm sound, an image file for a standby screen The image file captured by the camera 7, various setting data, temporary data used in the process of the program, and the like are stored. The above-described storage unit 8 is configured by, for example, a nonvolatile storage device (nonvolatile semiconductor memory, hard disk device, optical disk device, etc.), a randomly accessible storage device (eg, SRAM, DRAM), or the like.

The control unit 9 comprehensively controls the overall operation of the mobile terminal 100. That is, various processes of the mobile phone (voice calls performed via a circuit switching network, creation and transmission / reception of e-mails, browsing of Internet websites, etc.) are executed in an appropriate procedure according to the operation of the operation unit 2. In this manner, the operation of each block described above (transmission / reception of signals in the communication unit 1, input / output of audio in the audio processing unit 3, display of images on the display unit 6, imaging by the camera 7, etc.) is controlled.
The control unit 9 includes a computer (microprocessor) that executes processing based on a program (operating system, application program, etc.) stored in the storage unit 8, and performs the above-described processing according to a procedure instructed in this program. Execute. That is, instruction codes are sequentially read from programs such as an operating system and application programs stored in the storage unit 8 to execute processing.

The control unit 9 activates the camera 7 in response to an operation input via the operation unit 2, acquires an image captured by the camera 7 as a preview image, and displays the image on the display unit 6 in real time. In addition, when a shutter operation is performed via the operation unit 2 or the like in this state, the preview image displayed on the display unit 6 at the time when the shutter operation is performed is stored in the storage unit 8 or the like as a captured image, and at the same time. A captured image is displayed on the display unit 6.
The control unit 9 performs a histogram display process for displaying a histogram (brightness frequency distribution diagram) of an image displayed on the display unit 6 in real time while the camera 7 is activated. That is, the histogram display processing of the control unit 9 includes both a state where an image captured by the camera 7 is displayed in real time on the display unit 6 and a state where a shutter operation is performed and a captured image is displayed on the display unit 6. Done in
Hereinafter, the histogram display process of the control unit 9 will be described.
First, a process when a display (160 × 120 pixels) in QQVGA is performed will be described.
FIG. 3 is a diagram showing a preview image acquired by the control unit 9 from the camera 7.
It is assumed that, for example, 15 images / second are sent from the camera 7 as a preview image. That is, the control unit 9 acquires one image per 0.066. In the following, each image acquired every 0.066... Seconds is referred to as a frame.
For example, it is assumed that the control unit 9 starts analysis for histogram display from the Nth frame (N is a positive integer).
FIG. 3A shows the Nth frame (hereinafter referred to as frame N). As shown in FIG. 3A, the frame N is a 160 × 120 pixel image.

The control unit 9 includes a frame dividing unit 91, a histogram analyzing unit 92, a totaling unit 93, and a thinning unit 94 for histogram display processing.
The frame dividing unit 91 divides a frame to be subjected to histogram analysis into a predetermined number (hereinafter referred to as M: M is a positive integer). In the present embodiment, for example, it is assumed that the image is divided into five areas.
An example of the frame divided by the frame dividing unit 91 is shown in FIG.
FIG. 3B shows an example in which the frame N is divided into five regions.
As shown in FIG. 3B, the frame dividing unit 91 divides the frame N into five areas of 32 × 120 pixels. As shown in FIG. 3B, hereinafter, each area is referred to as Index_0 to 4 in order from the top of the frame.
The frame dividing unit 91 divides not only the frame N but also all the frames acquired from the camera 7 into five (M) regions.
Here, the frame dividing unit 91 divides in the vertical direction of each frame assuming that the scanning direction of the image acquired by the camera 7 is a horizontal base. However, the present invention is not limited to this, for example, scanning If the direction is based on the vertical direction, each frame may be divided in the horizontal direction, that is, divided into five areas of 160 × 24 pixels.

The histogram analysis unit 92 performs a histogram analysis of the region divided by the frame division unit 91. The histogram analysis method of the histogram analysis unit 92 is not limited in the present invention. Existing technologies can be used.
The histogram analysis unit 92 performs histogram analysis of different regions of each frame.
FIG. 3C is a diagram illustrating an example of a region to be subjected to histogram analysis by the histogram analysis unit 92.
The histogram analysis unit 92 performs histogram analysis of the shaded area of each frame shown in FIG.

That is, the histogram analysis unit 92 performs histogram analysis of Index_0 of frame N, Index_1 of frame N + 1, Index_2 of frame N + 2, Index_2 of frame N + 3, and Index_4 of frame N + 4, and again performs histogram analysis of Index_0 in frame N + 5.
As described above, the histogram analysis unit 92 continuously performs histogram analysis of a partial region of each frame acquired from the camera 7 every 0.66... Seconds.
The histogram analysis unit 92 has a memory 921, and the memory 921 stores the histogram analysis result acquired by the histogram analysis unit 92. In this case, only the latest result of each region is stored instead of storing the histogram analysis results of all frames.

FIG. 4 is a diagram for explaining the retention of the histogram analysis result in the memory 921.
As shown in FIG. 4 (a), the memory 921 at the time when the histogram analysis unit 92 performs the histogram analysis from frame N to N + 4, as shown in FIG. The analysis results of Index_3 of Index_3 and Index_4 of Frame N + 4 are stored.
Next, when the frame N + 5 is acquired, the histogram analysis unit 92 performs the histogram analysis of Index_0 of the frame N + 5. The memory 921 stores the contents of Index_0 of the frame N as shown in FIG. To the frame N + 5.
Similarly, when the frame N + 6 is acquired, the histogram analysis unit 92 performs the histogram analysis of the Index_1 of the frame N + 6. As illustrated in FIG. 4C, the memory 921 stores the storage content of the Index_1 of the frame N + 1. Overwrite the frame N + 6.
During the histogram analysis process of the control unit 9, the memory 921 always keeps the latest histogram analysis result of each region in this way.

Next, the totaling unit 93 totals the histogram analysis results analyzed by the histogram analyzing unit 92. That is, the totaling unit 93 adds the histogram analysis results of each region stored in the memory 921 and outputs the result as a histogram analysis result of one frame.
In this way, the control unit 9 performs a histogram analysis process.

Heretofore, the case where the histogram analysis of the QQVGA image is performed has been described.
Hereinafter, a case where histogram analysis of an image having a size equal to or larger than QVGA (320 × 240 pixels) is performed will be described.
When each frame to be acquired is equal to or higher than QVGA, the thinning unit 94 thins the number of target pixels for which the histogram analysis unit 92 performs the histogram analysis.
FIG. 5 is a conceptual diagram showing how the thinning unit 94 is thinned.
FIG. 5A is a diagram for explaining a case where a QQVGA frame histogram analysis is performed, that is, a case where thinning is not performed. For simplicity, only 11 pixels in the horizontal direction are shown.
FIG. 5B is a diagram illustrating a case where the histogram analysis of the QVGA frame is performed.
In the case of a QVGA frame, the thinning unit 94 extracts only one pixel from four pixels, and excludes other pixels from the analysis target of the histogram analysis unit 92, as shown in FIG. In this way, the number of pixels to be analyzed by the histogram analysis unit 92 can be the same as the number of QQVGA frames.
The QQVGA frame has 160 × 120 = 19200 pixels. Here, by extracting only one pixel in four pixels of the QVGA frame, 320 × 240 ÷ 4 = 19200 pixels is obtained, and the number of pixels to be analyzed by the histogram analysis unit 92 can be the same as that of the QQVGA frame. .

FIG. 5C is a diagram showing a case where a histogram analysis of a WQVGA (400 × 240 pixel) frame is performed.
In the case of a WQVGA frame, the thinning unit 94 extracts only one pixel from five pixels as shown in FIG. 5C, and excludes other pixels from the analysis target of the histogram analysis unit 92. In this way, the number of pixels to be analyzed by the histogram analysis unit 92 can be the same as the number of QQVGA frames.
By extracting only one pixel in 5 pixels of the WQVGA frame, 400 × 240 ÷ 5 = 19200 pixels is obtained, and the number of pixels to be analyzed by the histogram analysis unit 92 is reduced to the QQVGA frame (and the QVGA frame is thinned). And can be the same number.
Note that the thinning process in the thinning unit 94 is preferably performed at a certain rate depending on the image size acquired by the camera 7. That is, QQVGA does not perform thinning, QVGA extracts only one pixel from 4 pixels, and WQVGA extracts only one pixel from 5 pixels, so the thinning rate is 1/5. Further, when the capability of the camera 7 is compatible up to the VGA (640 × 480 pixel) size, only one pixel is extracted from 16 pixels to the VGA image (thinning rate is 1/16). As described above, in this embodiment, the QQVGA size (160 × 120 pixels) is the greatest common divisor of all the obtainable image sizes. Therefore, thinning is not performed in the QQVGA size, and the greatest common divisor is used in other sizes. Thinning processing is performed according to how many times. That is, by performing a thinning process for each division value of the greatest common divisor of a plurality of image sizes that can be acquired by the camera 7, the histogram analysis unit 92 that is a subsequent processing unit is made the same regardless of the image size to be processed. And the size of the processing program can be reduced as much as possible.

  In addition, the number of regions to be divided (that is, the value of M) is preferably 5 in the above case (when an image having a size such as QQVGA, QVGA, or WQVGA is handled). In the present embodiment, since it is divided into 5 in the vertical direction, in the case of the QQVGA size, 160 ÷ 5 × 120 = 3840 pixels exist in one divided area. On the other hand, in the case of the QVGA size, 320 ÷ 5 × 240 = 15360 pixels exist, and since one pixel is extracted from four pixels, the number of pixels to be analyzed for the histogram is 3840 pixels. Similarly, in the case of WQVGA size, it is 400/5 × 240 = 1/5 in 1920 pixels, and in the case of handling VGA size, it is 640 ÷ 5 × 480 = 1/16 in 6440 pixels. In any case, the number of pixels to be analyzed is 3840 pixels. That is, by setting the number of regions to be divided (that is, the value of M) to 5, the number of pixels that can be just divided by the above-described thinning process can be secured for any image size. No special processing is required, and processing can be performed in the same processing process, so that processing blocks can be shared. It goes without saying that the value of M may be a multiple of 5 as long as it is within the range in which the above divisible value can be provided.

In addition, by doing so, the load applied to the control unit 9 at the time of histogram analysis can be almost the same at any resolution, so that high-speed and real-time histogram analysis can be performed.
The control unit 9 displays the histogram analysis result output from the counting unit 93 on the display unit 6. The display format of the histogram analysis result on the display unit 6 is preferably a display format in which the histogram analysis result is displayed, for example, superimposed on an image captured by the camera 7.

Hereinafter, an operation example of the control unit 9 during the histogram analysis process will be described.
FIG. 6 is a flowchart showing an example of the operation of the control unit 9 during the histogram analysis process.
Step ST1:
The control unit 9 acquires an image from the camera 7 every 0.066..., For example. Hereinafter, this image, that is, the image of the xth frame is referred to as a frame x (x is a positive integer).
Step ST2:
The frame dividing unit 91 divides the frame x acquired in step ST1 into M areas Index_0 to (M−1) (M is a positive integer).

Step ST3:
If the resolution of the frame x is QQVGA, the process proceeds to step ST4. If the resolution is QVGA, the process proceeds to step ST5. If the resolution is WQVGA, the process proceeds to step ST6.
Step ST4:
The thinning unit 94 sets the pixels to be analyzed in the histogram of the frame x without thinning.

Step ST5:
The thinning unit 94 sets the pixel to be subjected to the histogram analysis of the frame x so that one pixel per four pixels.
Step ST6:
The thinning unit 94 sets the pixel to be analyzed in the histogram of the frame x so as to be one pixel per five pixels.

Step ST7:
The histogram analysis unit 92 analyzes the region Index_y of the frame x according to the setting of the thinning unit 94 in steps ST4 to ST6. y is the remainder of dividing x by M, and is a number from 0 to (M−1).
Step ST8:
The memory 921 stores the analysis result analyzed by the histogram analysis unit 92 in step ST7. At this time, the memory 921 overwrites the analysis result of Index_y.

Step ST9:
The totaling unit 93 adds the histogram analysis results of Index_0 to (M−1) stored in the memory 921 and outputs the result as a histogram analysis result of one frame.
Step ST10:
The control unit 9 causes the display unit 6 to display the analysis result output by the counting unit 93 in step ST9.
Step ST11:
Add 1 to x and return to step ST1 to repeat each step.

  In the flowchart described with reference to FIG. 6, when each frame is divided into M regions, the histogram analysis unit 92 uses the region Index_y (y is a remainder obtained by dividing x by M, and 0 to ( Although the analysis of M-1)) is performed, the present invention is not limited to this. That is, each of M frames may be divided into M areas, and a different area (one area including an area other than Index_y) may be analyzed for each frame.

As described above, according to the mobile terminal 100 of the present embodiment, when performing real-time histogram analysis of an image acquired by the camera 7, the frame dividing unit 91 divides each frame into M regions, Since the histogram analysis unit 92 performs histogram analysis of different regions of M consecutive frames, and the totalization unit 93 adds the analysis results and outputs the result as a histogram analysis result for one screen, the histogram analysis according to the control unit 9 Time load is reduced, and real-time and light processing is possible.
In addition, when the image size is QQVGA, the histogram analysis of all pixels is performed. In the case of QVGA, the thinning unit 94 thins out the target of the histogram analysis to one in four pixels, and in the case of WQVGA, the thinning unit 94 Since the target of histogram analysis is thinned out to one for every five pixels, the processing load at the time of histogram analysis can be further reduced, and the time until histogram display does not differ due to the difference in size.

As described above, when the acquisition rate of the image being previewed is 15 frames / second, one frame is 0.066... Every second. When M is 5, the histogram is updated once every 5 frames. In this case, the histogram is updated at a cycle of 0.33.
Further, in the above-described embodiment, the region for calculating the histogram is not sampled only for the specific region, but the region for distribution calculation for each frame is changed as needed, and is added to several frames and displayed as a histogram. As a result, the average value of the analysis results every several frames is displayed. Even if an instantaneous camera shake or a change in the surrounding environment occurs during image acquisition by the camera 7, a smooth display is possible when displaying the histogram. It can continue to be displayed as a transition image. For this reason, the histogram is merely a reference value during acquisition of the preview screen by the camera 7, so that a histogram showing smooth fluctuations can be easily referred to by the user.

  In addition, when shooting for the purpose of attaching a shot image to an e-mail and sending it to another mobile terminal device by the communication unit 1, the user can match the image display capability of the partner terminal during preview with a histogram display. In some cases, the size of the output image of the camera is changed by operating the operation unit 2 in order to obtain a captured size. Even in such a situation, according to the present invention, there is no large difference in the processing amount for each shooting size, and since the basic analysis processing routine is common, the histogram can be displayed immediately even after the size change instruction. I can do it. Thereby, the user can perform imaging with reference to the histogram without stress.

The present invention is not limited to the embodiment described above.
That is, when implementing the present invention, various modifications, combinations, sub-combinations, and alternatives may be made to the components of the above-described embodiments within the technical scope of the present invention or an equivalent scope thereof.

In the embodiment described above, the mobile terminal 100 is a foldable mobile phone as shown in FIG. 2, but the present invention is not limited to this, and a straight type, a slide type, a biaxial hinge type, etc. The portable terminal device of another form may be sufficient. Further, the present invention can be applied not only to a mobile phone having a communication unit but also to an imaging apparatus having no communication unit.
In the above-described embodiment, each frame is acquired at 15 frames / second. However, the present invention is applicable to other cases. That is, for example, it may be acquired at 30 sheets / second or the like.
In the above-described embodiment, the case of QQVGA, QVGA, and WQVGA (VGA) is described as an example of the image size. However, the present invention is not limited to this. That is, for example, when performing a histogram analysis of an image of SVGA (800 × 600 pixels) or larger, the thinning unit 94 performs thinning to such an extent that the processing at the time of histogram analysis does not become heavy (extracting pixels to be subjected to histogram analysis) Do it). Further, the thinning unit 94 is not thinned out in the case of a QQVGA frame, but thinned out in the case of an image size equal to or larger than QVGA. However, the present invention is not limited to this, and is an image of the size of QQVGA. However, it should be thinned out to such an extent that the processing at the time of histogram analysis does not become heavy. In this case, for an image having a size equal to or larger than QVGA, the histogram analysis may be performed by thinning out the QQVGA image so that the number of pixels is the same as the number of pixels targeted for histogram analysis.

FIG. 1 is a block diagram for explaining each configuration of the mobile terminal. FIG. 2 is a diagram illustrating an example of the appearance of the mobile terminal. FIG. 3 is a diagram illustrating an image acquired from the camera by the control unit. FIG. 4 is a diagram for explaining holding of the histogram analysis result of the memory. FIG. 5 is a conceptual diagram showing a thinning state of the thinning portion. FIG. 6 is a flowchart illustrating an operation example of the control unit during the histogram analysis process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Portable terminal 101 ... Upper housing | casing 102 ... Lower housing | casing 103 ... Hinge part 1 ... Communication part 2 ... Operation part 3 ... Audio | voice processing part 4 ... Speaker 5 ... Microphone 6 ... Display part , 7 ... Camera, 8 ... Storage unit, 9 ... Control unit, 91 ... Frame division unit, 92 ... Histogram analysis unit, 921 ... Memory, 93 ... Counting unit, 94 ... Thinning-out unit

Claims (5)

A camera for taking images at predetermined intervals;
A display unit that updates and displays images acquired by the camera at predetermined intervals;
A control unit;
Have
The controller is
A dividing unit that similarly divides each of consecutive M (M is a positive integer) images acquired by the camera into M regions;
A histogram analysis unit that analyzes histograms of different areas of the M images divided by the division unit;
A totaling unit for totalizing histograms of different areas of the M images analyzed by the histogram analysis unit to generate a histogram for one image;
Have
The display unit displays a histogram generated by the counting unit together with an image acquired by the camera. The said control part has a thinning | decimation part which performs the thinning-out process of the pixel number which the said histogram analysis part analyzes among all the pixels of the said area | region according to the resolution of the said display part. Imaging device. The display unit has a resolution of QQVGA, QVGA, or WQVGA,
M is 5 or a multiple of 5,
The thinning unit causes the histogram analysis unit to analyze all pixels when the resolution is QQVGA, and causes the histogram analysis unit to analyze one pixel per four pixels when the resolution is QVGA, and 5 when the resolution is WQVGA. The imaging apparatus according to claim 2, wherein the histogram analysis unit analyzes one pixel per pixel. A mobile terminal device that performs wireless communication with a base station connected to a communication network,
A camera for taking images at predetermined intervals;
A display unit that updates and displays images acquired by the camera at predetermined intervals;
A communication unit capable of transmitting an image acquired by the camera by wireless communication;
A control unit;
Have
The controller is
A dividing unit that similarly divides each of consecutive M (M is a positive integer) images acquired by the camera into M regions;
A histogram analysis unit that analyzes histograms of different areas of the M images divided by the division unit;
A totaling unit for totalizing histograms of different areas of the M images analyzed by the histogram analysis unit to generate a histogram for one image;
Have
The said display part displays the histogram which the said total part produced | generated with the image acquired by the said camera. The portable terminal device characterized by the above-mentioned. The mobile terminal device according to claim 4, further comprising an operation unit that receives an operation input instructing a change in a size of a subsequent acquired image in a state where images are continuously acquired by the camera.

Images