JP2008193211A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of effectively solving the illegibility of a dark part in an image. <P>SOLUTION: The imaging apparatus includes an imaging device for performing imaging operation and a display part 50 for displaying a through image based on an image signal obtained by the imaging operation. In displaying the through image, at least one of gamma adjustment processing for correcting a gamma point for an image signal, magnification correction processing for an image luminance value of the image signal and addition correction processing for the image luminance value of the image signal is performed as image brightness adjustment, and processing for increasing the luminance value of a backlight of the display part 50 is performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus that adjusts the brightness of a through image.

  An imaging device that brightens an image displayed on a display device in the imaging device has been proposed.

Patent Document 1 discloses an imaging device that brightens an image by increasing the light emission luminance of a backlight of a display device.
JP 2002-344778 A

  However, even if the brightness of the backlight is increased, the difficulty of seeing the dark part of the image may not be resolved.

  Accordingly, an object of the present invention is to provide an imaging apparatus that effectively eliminates the difficulty in viewing dark portions of an image.

  An imaging apparatus according to the present invention includes an imaging device that performs an imaging operation and a display unit that displays a through image based on an image signal obtained by the imaging operation, and adjusts image brightness when displaying the through image. At least one of gamma adjustment processing for correcting the gamma point for the image signal, magnification correction processing for the image luminance value of the image signal, and addition correction processing for the image luminance value of the image signal is performed, and the display unit Processing to increase the luminance value of the backlight is performed.

  Preferably, an operation unit used for an instruction to perform image brightness adjustment is further provided.

  Preferably, the image processing apparatus further includes a determination unit configured to determine whether the image signal is obtained by imaging in the backlight state, and performs image brightness adjustment when it is determined that the image signal is captured in the backlight state. Is called.

  More preferably, the backlight determination is performed based on photometric data.

  Preferably, the backlight determination is performed when an instruction to perform a process of increasing the luminance value of the backlight is given.

  Preferably, at least one of gamma adjustment processing, magnification correction processing, and addition correction processing is performed when an instruction to perform an imaging operation with strobe light emission is performed.

  As described above, according to the present invention, it is possible to provide an imaging apparatus that effectively eliminates difficulty in viewing dark portions of an image.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The imaging device 1 in the first embodiment includes an imaging block 10, a control unit 30, a memory unit 40, a display unit 50 having a liquid crystal unit and a backlight, and an operation unit 60 (see FIG. 1). In the first embodiment, the imaging device 1 is a digital camera.

  The imaging block 10 includes an imaging optical system, an imaging element such as a CCD or a CMOS, and a signal processing circuit. An optical image obtained by projecting the subject image via the imaging optical system is formed on the imaging surface of the imaging element. The image sensor converts an optical image into an electrical signal by photoelectric conversion. After being accumulated in the image sensor for a certain time (exposure time), an electrical signal based on the read-out charge is output to the signal processing circuit. The signal processing circuit outputs an electrical signal of the subject obtained by imaging to the control unit 30 as an image signal.

  The control unit 30 is a device that performs conversion of image signals into image data to be recorded in the memory unit 40, image processing for display on the display unit 50, and control of each unit. The control unit 30 includes a DSP (Digital Signal Processor) 31, a sample hold A unit 32, a gamma correction unit 33, an amplification unit 34, an offset unit 35, a DAC (Digital Analogue Converter) 36, and a timing generator 37.

  Specifically, the image signal output from the imaging block 10 is subjected to image processing for display on the display unit 50 in the DSP 31, and is converted into data corresponding to the dot arrangement of the display unit 50 in the sample hold unit 32. The sample is held, gamma correction processing is performed by the gamma correction unit 33, gain adjustment is performed by the amplification unit 34, and addition correction processing of the image luminance value of the video signal is performed by the offset unit 35 such as an LCD IC corresponding to the display unit 50. The D / A conversion is performed by the DAC 36 and is output to the display unit 50. Display timing control of the display unit 50 is performed based on timing pulses output from the timing generator 37 under the control of the DSP 31.

  The image luminance value addition correction processing (offset processing) in the offset unit 35 is correction processing that brightens the display image and makes it easy to see a region with a low luminance value, and is imaged at regular time intervals without being recorded in the memory unit 40. This is performed when brightness adjustment processing is performed in image processing for through image display (live view display) for continuously displaying still images.

  The memory unit 40 records image data obtained by imaging in a predetermined file format (JPEG format or the like). The display unit 50 displays information related to images and operations based on image signals obtained by imaging.

  The operation unit 60 has an on / off button (not shown) for performing brightness adjustment processing that makes it easy to see a dark part of a through image.

  When the on / off button for performing the brightness adjustment processing is turned on, the offset processing by the offset unit 35 and the backlight of the display unit 50 are performed during the through image display in the image display on the display unit 50. The operation of increasing the brightness value of the is performed. The process of increasing the luminance value of the backlight is performed by increasing the value of a current flowing through the LEDs constituting the backlight. However, when the still image to be recorded in the memory unit 40 is displayed on the display unit 50, the offset process by the offset unit 35 is not performed.

  As a result, the through image is brightened as compared with the case where the brightness adjustment processing is not performed, and the dark part of the through image is easy to see. Therefore, it is possible to eliminate the situation in which the image pickup apparatus 1 is used under strong external light such as the sun and the image displayed on the display unit 50 is difficult to see due to the reflected light that the external light reflects on the surface of the display unit 50 or the like. Become. When the outside light is bright, the user's pupil is narrowed down, and it is difficult to visually recognize an image in a particularly dark part. However, as in the first embodiment, a process for brightening the through image display is performed. It becomes possible to improve the visibility even in a dark part.

  It is possible to make the image brighter and easier to see simply by increasing the brightness of the backlight of the display unit 50. However, even if the brightness of the backlight is increased to brighten the entire through image, the dark part is backed up. There are cases in which it is not easy to see just by being displayed whitish by light. However, as in the first embodiment, by adding and correcting the image luminance value by offset processing to shift the luminance of the dark part to the intermediate region and increasing the luminance of the backlight, the through image is brightened. It is possible to effectively eliminate the difficulty of seeing dark parts. In addition, it is possible to reduce power consumption and eliminate the difficulty of seeing a dark part of a through image as compared with a mode in which the luminance of the backlight is simply increased.

  Next, a second embodiment will be described. In the second embodiment, the DSP 31 calculates the LV (Light Value) value of the subject and the contrast between the central portion and the peripheral portion of the subject from the photometric data based on the image signal, and obtains the image signal from these in the backlight state. It is different from the first embodiment in that the backlight is determined whether or not the light has been emitted and the offset processing is automatically performed when it is determined that the light is back. The luminance value of the backlight is increased independently of the backlight determination based on the operation of the operation unit 60.

  Specifically, when the LV value obtained from the photometric data is not less than a predetermined value and the contrast ratio is not less than a predetermined value (the central part is dark and the peripheral part is bright), the backlighting state It is determined that the image was taken. When an image is captured in a backlight state, there is a dark part that is a shadow of a bright part in the peripheral part and is difficult to see (not easy to see). In the second embodiment, in such a case, an offset process for automatically brightening the through image is performed, so that it is possible to effectively eliminate the state in which the dark part of the through image is difficult to see.

  Next, the flow of offset processing in the second embodiment will be described using the flowchart of FIG. In step S11, the imaging block 10 outputs an image signal for displaying a through image. In step S12, the control unit 30 performs image processing on the image signal, and the display unit 50 performs through image display.

  In step S13, it is determined whether or not the operation unit 60 has been operated to increase the luminance value of the backlight of the display unit 50. If it has been performed, the luminance value of the backlight of the display unit 50 is increased according to the operation state of the operation unit 60 in step S14. If not, the process proceeds to step S15.

  In step S15, a photometric operation based on a half-press operation of the release button or the like is performed. In step S16, a backlight determination is made as to whether or not the image signal is obtained by imaging in the backlight state from the photometric data based on the image signal. If it is determined that the backlight is in the backlight state, an offset process is performed on the image signal corresponding to the through image displayed on the display unit 50 in step S17. If it is not determined that the backlight is in the backlight state, the process proceeds to step S18.

  In step S18, it is determined whether or not an operation for starting an imaging operation such as a full press operation of a release button has been performed. If it has been performed, an imaging operation is performed (enters a shooting loop) in step S19. In the shooting loop, the offset process performed in step S17 is not reflected. If not, it is determined whether or not an operation for ending the operation of the imaging apparatus 1 (turning off the power) such as pressing an end button has been performed. If not, the process proceeds to step S11. If so, the operation of the imaging device 1 is terminated.

  In addition, although the form which performs discrimination | determination of the backlight state in the second embodiment (determination of whether or not to perform offset processing) based on the photometric data has been described, instead of this, in an imaging operation using the imaging device 1 You may perform based on the judgment whether a flash light emission operation | movement is performed. In the imaging operation in the backlight state, since the imaging operation accompanied by the flash emission is often performed, it is determined that the imaging apparatus 1 is in the backlight state when the imaging apparatus 1 is instructed to emit the flash. Further, both backlight discrimination based on the presence / absence of a strobe emission instruction and backlight discrimination based on photometric data may be performed.

  The backlight determination (determination of whether or not to perform offset processing) may be performed on the condition that the operation of the operation unit 60 for increasing the luminance value of the backlight of the display unit 50 in step S13 has been performed. . In the through image display confirmation in the backlight state, an operation to increase the luminance value of the backlight of the display unit 50 is often performed in order to make it easier to see the shadowed subject. Therefore, when the operation is performed, the backlight state And offset processing as brightness adjustment is performed.

  In the first and second embodiments, the mode in which the offset processing by the offset unit 35 is performed in order to brighten the through image and make it easy to see the dark part has been described. However, the gamma correction by the gamma correction unit 33 is performed on the image signal. Brightness that brightens the through image by adjusting the gamma (halftone) that corrects the gamma point between the highlight and shadow and correcting the magnification of the image luminance value of the image signal in the gain adjustment by the amplifying unit 34 in FIG. The adjustment process may be performed.

It is a block diagram of the imaging device in 1st, 2nd embodiment. It is a block diagram which shows the detail of a control part. It is a flowchart which shows the flow of the offset process in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 10 Imaging block 30 Control part 31 DSP
32 Sample hold unit 33 Gamma correction unit 34 Amplification unit 35 Offset unit 36 DAC
37 Timing generator 40 Memory unit 50 Display unit 60 Operation unit

Claims (6)

An image sensor that performs an imaging operation;
A display unit that displays a through image based on an image signal obtained by the imaging operation,
When displaying the through image, as image brightness adjustment, gamma adjustment processing for correcting a gamma point with respect to the image signal, magnification correction processing for the image luminance value of the image signal, and image luminance value of the image signal An image pickup apparatus, wherein at least one of the addition correction processes is performed, and a process of increasing the luminance value of the backlight of the display unit is performed.   The imaging apparatus according to claim 1, further comprising an operation unit used for an instruction to perform the image brightness adjustment. A determination unit that performs backlight determination as to whether or not the image signal is obtained by imaging in a backlight state;
The imaging apparatus according to claim 1, wherein at least one of the gamma adjustment process, the magnification correction process, and the addition correction process is performed when it is determined that the image is captured in the backlight state.   The imaging apparatus according to claim 3, wherein the backlight determination is performed based on photometric data.   The imaging apparatus according to claim 3, wherein the backlight determination is performed when an instruction to increase the luminance value of the backlight is issued.   2. The imaging according to claim 1, wherein when an instruction to perform an imaging operation with strobe light emission is performed, at least one of the gamma adjustment processing, the magnification correction processing, and the addition correction processing is performed. apparatus.

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