JPH10276356A - Electronic still camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the electronic still camera where power consumption is reduced while providing a prescribed level of visibility or over to an LCD section at all times. SOLUTION: The camera is provided with an image pickup section 2 that converts an optical signal into image data, a capture memory 3 (storage section) that temporarily stores the image data outputted from the image pickup section 2, a display section 4 that displays the image data stored in the capture memory 3, an LCD luminance control means 12 display luminance control section) that controls a display luminance of the display section 4, and an exposure control means 11 (exposure control section) that sets exposure of the image pickup section 2 based on the image data stored in the capture memory 3. The LCD luminance control means 12 controls the display luminance of the display section 4 in response to the lightness of the surrounding discriminated from the lightness of the image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic still camera, and more particularly to an electronic still camera that changes the brightness of an image display LCD to reduce power consumption.

[0002]

2. Description of the Related Art For example, in Japanese Patent Application Laid-Open No. 4-184484, a backlight of an LCD is turned on only for a predetermined period in which a specific operation is performed, and is turned off or dimmed in other periods. The power consumption of the LCD unit has been reduced.

The electronic still camera includes an image pickup device, a viewfinder having a liquid crystal image display device for displaying a video signal from the image pickup device and a backlight illuminator, an illumination controller for controlling the backlight illuminator,
The switch includes a switch for changing a photographing mode and a switch for setting an image pickup driving circuit in two stages of a standby state and an operation state.

When the switch is operated to set the imaging drive circuit to a standby state, the illumination control means turns on the backlight illumination means at a normal light amount for a predetermined period of time. The light illumination means is turned off or dimmed.

[0005]

However, in the above-mentioned conventional example, when the surroundings are bright, if the backlight illumination is turned off or dimmed, the visibility of the LCD unit is reduced. There is an inconvenience that it is difficult to select a subject using the LCD.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electronic still camera in which the disadvantages of the prior art are improved, and in particular, the power consumption is reduced while the LCD section always has a certain level of visibility. With that purpose.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, an image pickup unit for converting an optical signal into image data, and image data output from the image pickup unit are temporarily stored. A storage unit, a display unit that displays an image stored in the storage unit, a display brightness control unit that controls the display brightness of the display unit, and an imaging unit based on the image data stored in the storage unit. An exposure control unit for setting the exposure. The electronic still camera stores images stored in a storage unit when a shutter signal is input as still images in a nonvolatile memory. In particular, a configuration is adopted in which the display luminance control unit controls the display luminance of the display unit according to the surrounding brightness determined from the brightness of the image data.

In the present invention, when it is determined from the image data that the surroundings have become brighter, the display brightness control unit increases the display brightness of the display unit such as an LCD to the minimum brightness at which the display is easy to see. On the other hand, when it is determined from the image data that the surroundings have become dark, the display luminance control unit reduces the display luminance of the display unit to the minimum light amount within a range in which the display is easy to see.

The display brightness control unit calculates the display brightness of the display unit from the shutter speed of the imaging unit set by the exposure control unit based on the image data.

According to the present invention, when it is determined that the surroundings have become brighter based on the shutter speed set by the exposure controller in accordance with the brightness of the image data, the display brightness controller controls the display of the display unit based on the shutter speed. The brightness is calculated, and the display is improved to the minimum brightness for easy viewing. On the other hand, when it is determined from the shutter speed that the surroundings have become dark, the display brightness control unit calculates the display brightness of the display unit from the shutter speed, and reduces the display brightness to the minimum light amount in a range where the display is easy to see.

According to a third aspect of the present invention, the display luminance control unit determines the control direction of the display luminance from the temporal change of the shutter speed set by the exposure control unit.

In the present invention, for example, when the shutter speed sequentially calculated by the exposure controller is gradually reduced,
Control is performed in a direction to reduce the display luminance of the display unit.

The electronic still camera according to claim 1, wherein the display brightness control section calculates the display brightness of the display section from the image data stored in the storage section.

According to the present invention, when it is determined from the image data in the storage section that the surroundings have become brighter, the display luminance control section calculates the display luminance of the display section from the image data and sets the display luminance to the minimum luminance at which the display is easy to see. improves. On the other hand, when it is determined from the image data in the storage unit that the surroundings are dark, the display brightness control unit calculates the display brightness of the display unit from the image data,
The amount of light is reduced to the minimum in a range where the display is easy to see.

[0015] With the above, the above-mentioned object is achieved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

The electronic still camera shown in FIG. 1 has an imaging unit 2 for converting an optical signal into image data, a capture memory 3 (storage unit) for temporarily storing image data output from the imaging unit 2, A display unit 4 for displaying an image stored in the capture memory 3, an LCD brightness control unit 12 (display brightness control unit) for controlling the display brightness of the display unit 4, and image data stored in the capture memory 3 Exposure control means 1 for setting the exposure of the imaging unit 2 based on the
1 (exposure control unit). Then, similarly to a conventional general electronic still camera, when a shutter signal is input, an image stored in the capture memory 3 is stored as a still image in a nonvolatile memory (not shown). . Among them, LCD brightness control means 1
Numeral 2 controls the display brightness of the display unit 4 according to the surrounding brightness determined from the brightness of the image data.

In this embodiment, the LCD brightness control means 12 calculates the display brightness of the display section 4 from the shutter speed of the imaging section 2 set by the exposure control means 11 based on the image data. The LCD brightness control means 12 has a function of determining the control direction of the display brightness from the temporal change of the shutter speed set by the exposure control means 11.

More specifically, the electronic still camera shown in FIG. 1 has a control unit 1 operated by software processing.
And the above-described imaging unit 2, capture memory 3, and display unit 4
And

The image pickup section 2 has a CCD 21 and a CCD controller 22. The CCD controller 22 receives a shutter speed, an instruction to start imaging, etc., drives the CCD 21 to perform imaging, and stores the data in the capture memory 3.

The display unit 4 comprises an LCD 41 and an LCD.
And a controller 42. Among them, the LCD controller 42 receives LCD display data, a luminance change command, etc., and drives the LCD 41 to display predetermined data including an image.

On the other hand, the software processing unit 1 includes an L control unit in addition to the exposure control unit 11 and the LCD brightness control unit 12 described above.
CD display control means 13 is provided. Among them, the exposure control means 11 processes the image data stored (captured) in the capture memory 3, calculates an optimum shutter speed to be set at the time of the next photographing, and sends it to the CCD controller 22. Set the value. The LCD brightness control unit 12 calculates the approximate brightness of the surroundings based on the information processed by the exposure control unit 11, and then sets the value to be set for the LCD backlight illumination to the LCD controller 42.
Set to. Further, the LCD display control means 13 processes the image data captured in the capture memory 3, creates LCD display data, transfers the data to the LCD controller 42, and causes the LCD 41 to display the data.

Next, the operation of the present embodiment will be described with reference to FIGS.

The image data obtained by the imaging unit 2 is temporarily stored in the capture memory 3 (step A1). The exposure control means 11 determines the brightness of the image by using a part of the image data, calculates the exposure, and when it is determined that the shutter speed should be changed,
A new shutter speed is set for the CD controller 22 (steps A2 and A3). According to the shutter speed, the LCD brightness control means 12 determines that if the speed is fast, the brightness is high, and if the speed is slow, the brightness is dark, and sets the brightness of the backlight considered appropriate from the past multiple shutter speeds to the LCD controller 42 (step A4). ). The LCD display control means 13 creates display data using the captured image, transfers the data to the LCD controller 42,
It is displayed on the LCD 41.

According to this, the ambient brightness is determined from the image data captured during the preview operation,
D Because the brightness is changed dynamically, when the surroundings are dark, the LCD
The brightness can be reduced, and the power consumption of the device can be reduced while maintaining a certain level of visibility.

[0026]

Next, an example based on the above embodiment will be described.

Referring to FIG. 3, in step A4, LC
The D luminance control unit 12 determines that the surroundings are dark from the past five transitions of the shutter speed, and sets a new backlight luminance value in the LCD controller 42. Here, the calculation is performed from the past five data, but the number is arbitrarily changed according to the preview speed or the backlight luminance control method. More specifically, in the preview before photographing, the exposure control unit 11 determines that the n-th exposure of the preview is under (less than or equal to a specified value), and sends a new value to the CCD controller to lower the shutter speed. Set. Also, the (n + 1) -th and (n +
2) In the same manner, underexposure is also determined, and the shutter speed is reduced. Here, the exposure is proper, and the preview is continued without changing the shutter speed at the (n + 3) th and (n + 4) th times. The LCD brightness control means 12 determines that the surroundings are dark based on the temporal transition of the five shutter speeds, and sets a new backlight brightness value in the LCD controller 42.

Next, another embodiment of the present invention will be described with reference to FIG.

In this embodiment, the LCD brightness control means 11
2 calculates the display luminance of the display unit 4 from the image data stored in the capture memory 3. Referring to FIG. 4, in the present embodiment, the LCD brightness control means 112 directly processes the image data captured in the capture memory 3 to determine the surrounding brightness. This is different from the embodiment of FIG. 1 in which the approximate brightness of the surroundings is determined based on the information processed by the exposure control means 11. Other configurations are the same as those of the embodiment of FIG.

Here, since the exposure control means 11 generally processes surface image data on the basis of a subject, information on underexposure is transmitted to the LCD luminance control means 12 despite the surroundings are bright under conditions such as backlight. Be feared.
However, independent of the exposure control means 11, the LCD brightness control means 12 directly processes the image data,
Since image data can be processed based on the background, that is, around the subject, there is an effect that the LCD brightness can be more appropriately controlled.

Here, the technical idea of the present invention can be applied not only to the above-described embodiments but also to a display unit other than the LCD. The control unit 1 may be realized by hardware logic.

[0032]

Since the present invention is constructed and functions as described above, according to this, the display brightness control unit controls the display brightness of the display unit according to the ambient brightness determined from the brightness of the image data. , The display brightness is reduced when the surroundings are dark, and the power consumption of the device can be reduced while maintaining a certain level of visibility. Also, when the surroundings are bright, the display brightness is improved, and L
A CD or the like can be driven.

According to the second aspect of the present invention, the display brightness control section calculates the optimum display brightness from the shutter speed set by the exposure control section based on the image data, so that the display brightness control section overlaps with the exposure control section. Where it is not necessary to process a large amount of image data, display brightness can be controlled at a relatively high speed, and a reduction in the processing speed of the entire system can be suppressed.

According to the third aspect of the present invention, the display brightness control section determines the control direction of the display brightness from the temporal change of the shutter speed. Control of the displayed brightness can be performed.

According to the fourth aspect of the present invention, the display brightness control section calculates the optimum display brightness directly from the image data in the storage section. Since image data can be processed as a reference, it is possible to provide an unprecedented excellent electronic still camera capable of appropriately controlling display luminance under such circumstances.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the embodiment of FIG. 1;

FIG. 3 is a diagram illustrating an example of an LCD brightness control unit in the embodiment of FIG. 1;

FIG. 4 is a block diagram showing a configuration of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Software processing part (control part) 2 Image pick-up part 3 Capture memory (storage part) 4 LCD part (display part) 11 Exposure control means (exposure control part) 12,112 LCD luminance control means (display luminance control part)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/781 H04N 5/91 J 5/91

Claims (4)

[Claims] An imaging unit for converting an optical signal into image data; a storage unit for temporarily storing image data output from the imaging unit; and a display unit for displaying an image stored in the storage unit. A display brightness control unit that controls the display brightness of the display unit, and an exposure control unit that sets the exposure of the imaging unit based on the image data stored in the storage unit, and a shutter signal is input. In an electronic still camera in which an image stored in the storage unit is sometimes stored as a still image in a non-volatile memory, the display brightness control unit may be configured to control the display brightness control unit according to ambient brightness determined from the brightness of the image data. An electronic still camera, wherein the display brightness of the display section is controlled by the electronic still camera. 2. The display brightness control unit according to claim 1, wherein the display brightness control unit calculates display brightness of the display unit from a shutter speed of an imaging unit set based on the image data by the exposure control unit. Electronic still camera. 3. The electronic still camera according to claim 2, wherein the display luminance control unit determines the control direction of the display luminance from a temporal change of a shutter speed set by the exposure control unit. 4. The electronic still camera according to claim 1, wherein the display luminance control unit calculates display luminance of the display unit from image data stored in the storage unit.