Imaging device equipped with automatic exposure control function

• US 7,436,446 B2
• Filed: 08/23/2004
• Issued: 10/14/2008
• Est. Priority Date: 08/29/2003
• Status: Expired due to Fees

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Shibutani, Atsushi
• Primary Examiner(s): Tran; Nhan T
• Application Number:
  US10/924,601
• Publication Number:
  US 20050057546A1
• Time in Patent Office: 1,513 Days
• Field of Search: 348/333.13, 348/363, 348/364, 348/372, 348/229.1, 348/221.1, 345/77, 313/310
• US Class Current: 348/333.13
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/651 for reducing power consumption by affecting camera operations, e.g. sleep mode, hibernation mode or power off of selective parts of the camera
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene

Abstract

An imaging device comprises an organic EL monitor for displaying an image from an image pick-up device. A controller sets such initial values of at least one of a diaphragm amount, an exposure time, and a gain to values for causing control that the luminance level is increased toward a proper level when a power is turned on. Displaying of a through-image of only white is prevented.

Claims

1. An imaging device comprising:

an imaging element which outputs an image signal obtained by an imaging operation;

a self-luminous element which displays an image based on the image signal output from the imaging element;

a limiting unit which limits brightness of the image displayed by the self-luminous element;

an exposure control unit which controls a luminance level of the image signal output from the imaging element such that the luminance level becomes a proper value, wherein the self-luminous element displays the image based on the image signal whose luminance level is controlled by the exposure control unit, and wherein the limiting unit limits the luminance level of the image signal controlled by the exposure control unit to a lower level when a power is turned on;

a setting unit to which an exposure control value is set, wherein the exposure control unit comprises a controller which controls the luminance level of the image signal output from the imaging element based on the set exposure control value, and wherein the exposure control value is set to cause the luminance level of the image signal to become the proper value; and

a mode selection unit which selects a first control mode or a second control mode, and wherein the limiting unit comprises a setter which sets a first initial exposure control value to the setting unit when the first control mode is selected at a time of power on, and a second initial exposure control value which is lower than the first initial exposure control value to the setting unit when the second control mode is selected at the time of power on.

2. The imaging device according to claim 1, wherein the second initial exposure control value is set such that the exposure control unit causes the luminance level of the image signal output from the imaging element to always increase toward the proper value when the power is turned on.

3. The imaging device according to claim 1, wherein the second initial exposure control value is lower than a medium value in a range values when the power is turned on.

4. The imaging device according to claim 1, wherein the first exposure control value is a medium value in a range of values which can be set in the setting unit.

5. The imaging device according to claim 1, wherein:

the imaging element continuously outputs a plurality of image signals obtained by a plurality of continuous imaging operations; and

the exposure control unit determines the exposure control value based on a luminance level of a current image signal output from the imaging element and controls a luminance level of a next image signal based on the determined exposure control value.

6. The imaging device according to claim 5, wherein:

the exposure control unit changes a current exposure control value by a predetermined value based on the luminance level of the current image signal output from the imaging element, and controls the luminance level of the next image signal based on the changed exposure control value.

7. The imaging device according to claim 1, wherein the exposure control unit controls the luminance level of the image signal by controlling at least one of a diaphragm amount of the imaging element, an exposure time of the imaging element, and an amplification factor of the image signal so that the luminance level becomes the proper value.

8. The imaging device according to claim 1, wherein:

the exposure control unit controls the luminance level of the image signal by controlling at least one of a diaphragm amount of the imaging element, an exposure time of the imaging element, and an amplification factor of the image signal so that the luminance level may be a proper value; and

the limiting unit controls the luminance level of the image signal to be low by controlling at least one of the diaphragm amount of the imaging element, the exposure time of the imaging element, and the amplification factor of the image signal.

9. An imaging device comprising:

means for outputting an image signal obtained by an imaging operation;

a self-luminous element which displays an image based on the output image signal;

limiting means for limiting brightness of the image displayed by the self-luminous element;

exposure control means for controlling a luminance level of the output image signal such that the luminance level becomes a proper value, wherein the self-luminous element displays the image based on the image signal whose luminance level is controlled, and wherein the limiting unit limits the luminance level of the image signal controlled by the exposure control means to a lower level when a power is turned on;

setting means for setting an exposure control value, wherein the exposure control means controls the luminance level of the output image signal based on the set exposure control value, and wherein the exposure control value is set to cause the luminance level of the image signal to become the proper value; and

mode selection means for selecting a first control mode or a second control mode, and wherein the limiting means sets a first initial exposure control value to the setting means when the first control mode is selected at a time of power on, and a second initial exposure control value which is lower than the first initial exposure control value to the setting means when the second control mode is selected at the time of power on.

10. An imaging method comprising:

outputting an image signal obtained by an imaging operation;

controlling a self-luminous element to display an image based on the image signal;

limiting brightness of the image displayed by the self-luminous element; and

controlling a luminance level of the output image signal such that the luminance level becomes a proper value, wherein the self-luminous element displays the image based on the image signal whose luminance level is controlled, and wherein the controlled luminance level is limited to a lower level when a power is turned on;

setting an exposure control value, wherein the luminance level of the output image signal is controlled based on the set exposure control value, and wherein the exposure control value is set to cause the luminance level of the image signal to become the proper value; and

selecting a first control mode or a second control mode, wherein a first initial exposure control value is set when the first control mode is selected at a time of power on, and a second initial exposure control value which is lower than the first initial exposure control value is set when the second control mode is selected at the time of power on.

11. A computer readable medium having stored thereon an imaging control program which controls a computer of an imaging device to execute functions of:

outputting an image signal obtained by an imaging operation;

controlling a self-luminous element to display an image based on the image signal;

limiting brightness of the image displayed by the self-luminous element; and

controlling a luminance level of the output image signal such that the luminance level becomes a proper value, wherein the self-luminous element displays the image based on the image signal whose luminance level is controlled, and wherein the controlled luminance level is limited to a lower level when a power is turned on;

setting an exposure control value, wherein the luminance level of the output image signal is controlled based on the set exposure control value, and wherein the exposure control value is set to cause the luminance level of the image signal to become the proper value; and

selecting a first control mode or a second control mode, wherein a first initial exposure control value is set when the first control mode is selected at a time of power on, and a second initial exposure control value which is lower than the first initial exposure control value is set when the second control mode is selected at the time of power on.