JP2019161335A - Imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus that displays HDR linearly with a dynamic range corresponding to a video being shot.SOLUTION: In a main unit 100, in a case in which an HDR mode determination unit determines that the setting is a wide dynamic range, when the brightness value of a focus area is less than or equal to a first threshold value, a video signal is processed with the setting of the dynamic range mode 1 for performing a setting with a narrow dynamic range is performed, when the brightness value of the focus area is greater than or equal to a second threshold value of the brightness value greater than the first threshold value, a dynamic range mode 2 is set to have a wider dynamic range than the dynamic range mode 1 to process the video signal with settings.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus.

  In recent years, High Dynamic Range (HDR) technology has been advanced that allows a wide dynamic range captured by a camera in a video production or television development field to be directly applied to a video signal. Along with this, the spread of cameras capable of shooting with a high dynamic range is increasing. In order to display an image taken with a high dynamic range, a large monitor with high peak luminance, high contrast, and a wide dynamic range is required. However, since the EVF and small monitor attached to the camera body have a narrow dynamic range, if the entire dynamic range is expressed as it is, the luminance becomes dark due to insufficient brightness.

  In order to maintain the overall brightness, display is performed in a state where high-luminance or low-luminance gradation is crushed. In addition, some cameras have a “HDR mode” as a function that makes it easy to visually recognize a high gradation portion during HDR shooting on a monitor with a narrow dynamic range. In the HDR mode, for example, as shown in FIG. 4, the display brightness of the monitor is linear with respect to the input range of the camera, so that the gradation expression of the high gradation part is enhanced, and the high gradation part is visually recognized during HDR shooting. There are ways to make it easier. The HDR expression method on this monitor is referred to as “HDR linear display”.

  When an image with a wide dynamic range is displayed in HDR linear display, the overall gradation can be confirmed at the time of shooting, but the entire image becomes darker than at the time of normal shooting. Therefore, in addition to the “HDR all gradation mode” in which the HDR linear display as shown in FIG. 4 linearly displays up to the maximum dynamic range, for example, when the camera input has a maximum dynamic range of 1000%, as shown in FIG. There is an “HDR 300% mode” in which the gradation of up to 300% can be confirmed on a monitor with a narrow dynamic range while ensuring the brightness of the entire monitor by displaying the area up to 300%, which is often in a normal subject, with HDR linear display. In the HDR 300% mode, gradations higher than that are all displayed at the maximum brightness, and gradation confirmation cannot be performed.

  However, the dynamic range for HDR linear display is selected by a user from a menu or the like, and may not be optimally set for an actually captured image. It is desirable to switch the dynamic range for HDR linear display to an optimal value in accordance with the user's current image. In Patent Document 1, the entire video is divided into several areas, luminance values are calculated, and gradation correction is performed for each area.

JP 2012-159846 A

  However, in Patent Document 1, it is necessary to change the gradation processing for each region, and the processing becomes complicated. In addition, when the dynamic range for HDR linear display is switched for each area by the same method in the HDR mode, the dynamic range is different for each area, and the entire video becomes difficult to see.

  Therefore, the present invention is to solve the above-mentioned problem of the prior art document, and by switching the dynamic range for HDR linear display in the HDR mode from the luminance value of the focus area most noticed by the user, the present invention is optimal for video. A method of visually recognizing in the HDR mode is presented.

  To achieve the above object, an imaging device, a video signal output unit for converting a video signal captured by the imaging device into a digital signal, a display unit for displaying video, and a focus in the video signal That the setting of the focus area detecting unit for detecting the matching area, the luminance calculating unit for calculating the luminance value of the area detected by the focus area detecting unit, and the setting of the imaging device is a setting with a wide dynamic range. An HDR mode determination unit to detect, a gradation correction unit that corrects a dynamic range and a gradation of an image displayed on the display unit when the HDR mode determination unit determines that the setting is a wide dynamic range; Dynamic range mode 1 in which the tone correction unit performs setting with a narrow dynamic range, and the gradation correction unit is more dynamic than in dynamic range mode 1 A dynamic range mode 2 for setting a wide range, a threshold value α for switching the dynamic range mode 2 to the dynamic range mode 1, and a switch for switching the dynamic range mode 1 to the dynamic range mode 2 , Having a threshold value β of a luminance value larger than the threshold value α, the HDR mode determination unit determines that the setting is a wide dynamic range, and the luminance value of the focus area calculated by the luminance calculation unit is equal to or less than the threshold value α If there is, the gradation correction unit processes the video signal with the setting of the dynamic range mode 1, and if it is equal to or greater than the threshold value β, the gradation correction unit processes the video signal with the setting of the dynamic range mode 2 An imaging apparatus characterized by that.

  According to the present invention, when HDR linear display is performed in the imaging apparatus, the mode that is in the focus position most noticed by the user is switched by switching the range of the dynamic range displayed on the monitor from the luminance value of the focus area of the video. Can be visually recognized.

It is a block diagram which shows the structure of the imaging device in a 1st Example. It is a flowchart of the control by the focus area | region brightness value in a 1st Example. It is an image figure showing the difference of the brightness value by a focus position. It is an image figure showing HDR linear display. It is an image figure showing the difference of the dynamic range width in each mode

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The operation of each embodiment of the present invention will be described below with reference to FIGS.

<First Embodiment>
In the first embodiment, in an imaging apparatus, when an image with a wide dynamic range is displayed on a display unit with a narrow dynamic range and HDR linear display is performed with respect to the input dynamic range of the imaging apparatus, the dynamic range for HDR linear display is displayed. The range is changed according to the luminance value of the focus area.

  The configuration of the image pickup apparatus according to the first embodiment of the present invention will be described below. FIG. 1 is a block diagram showing the configuration of an image pickup apparatus according to an embodiment of the present invention.

  The main body 100 includes an imaging unit 101, a digital signal processing unit 102, a focus position detection unit 103, a focus position luminance calculation unit 104, a dynamic range determination unit 105, a dynamic range conversion unit 106, a display control unit 107, a mode determination unit 108, an operation Unit 109, memory unit 110, system control unit 111, power switch unit 112, and the like, and displays captured images on display unit 113. The dynamic range of the captured video signal is, for example, 1000%. The image pickup unit 101 is an image pickup element including a CCD, a CMOS element, or the like that converts an optical image into an electric signal.

  The digital signal processing unit 102 performs resize processing such as predetermined pixel interpolation and reduction and color conversion processing on the digital data from the imaging unit 101. The digital signal processing unit 102 performs predetermined calculation processing using the captured image data, and the system control unit 105 performs exposure control and distance measurement control based on the obtained calculation result. Thereby, AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-emission) processing of the TTL (through-the-lens) method are performed.

  The focus position detection unit 103 receives information on whether or not the HDR mode is selected from the mode determination unit 108. If the HDR mode is selected, the focus position detection unit 103 detects a focused area in the video signal from the digital signal processing unit 102, and the detection result. Is sent to the focus position luminance calculation unit 104. The focus position luminance calculation unit 104 calculates the luminance value of the focused area from the focus position detection result of the video signal. The calculated result is sent to the dynamic range determination unit 105. For example, the average brightness of the focus area is calculated.

  The dynamic range determination unit 105 acquires the luminance calculation result of the focus position from the focus position luminance calculation unit 104, the maximum dynamic range information of the current video signal, and information on whether or not the HDR mode is selected from the mode determination unit 108. In the HDR mode, for example, if the luminance calculation result is 600% or more, parameters for HDR linear display up to the maximum range of the imaging device in the current setting, and if it is 400% or less, 300% in the input of the imaging device. Parameters from the memory 110 are received when HDR linear display is performed. When not in the HDR mode, information not displayed in HDR linear is sent to the dynamic range conversion unit 106.

  The dynamic range conversion unit 106 receives parameters from the dynamic range determination unit 105 or information not to be displayed in HDR linear, performs gradation control on the video signal, and sends it to the display control unit 107. The display control unit 107 sends the video signal from the dynamic range conversion unit 106 to the liquid crystal panel 114 and performs lighting control of the liquid crystal panel 114 and luminance control of the backlight driver 116.

  The mode determination unit 108 receives the user menu setting and the imaging device setting from the system control unit 111, and sends to the dynamic range determination unit information about the maximum dynamic range that can be captured by the imaging device with the current settings and the HDR mode. . In addition, information indicating whether the HDR mode is set is sent to the focus position detection unit 103.

  The operation members of the operation unit 109 include, for example, menu buttons, up / down / left / right four-way buttons, a SET button, and the like as function buttons. When the menu button is pressed, various setting menu screens are displayed on the display unit 113. The user can make a selection by using the menu screen displayed on the display unit 113 and the four-way button up / down / left / right and using the SET button. The operation unit 109 may be a touch panel. The touch panel may be any of various types of touch panels such as a resistive film method, a capacitance method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, an image recognition method, and an optical sensor method. .

  The memory unit 110 is, for example, a flash memory, and parameters for HDR linear display on the liquid crystal panel 114 up to the maximum dynamic range of the imaging apparatus for each setting, and parameters for HDR linear display on the liquid crystal panel 114 up to 300%. Storing. The system control unit 111 performs menu control based on information from the operation unit 109, and sends setting values of the imaging apparatus and menu setting information to the mode determination unit 108. In addition, the luminance setting value to be set in the backlight driver 116 is sent to the display control unit 107.

  The power switch 112 detects whether the power is turned on and sends it to the system control unit 111. The detection means is, for example, a mechanical switch. The display unit 113 includes a liquid crystal panel 114, a backlight 115, and a backlight driver 116, and displays a video signal from the main body unit 100. The liquid crystal panel 114 is display means capable of displaying a reproduced video and a captured video, and is, for example, an organic EL panel or a liquid crystal panel.

  The backlight 115 is provided on the back surface of the display unit 113, and the luminance can be controlled by the backlight driver 116. The backlight driver 116 controls the luminance of the backlight 115 according to the backlight setting value sent from the display control unit 107.

  Next, in the first embodiment of the present invention, when an image with a wide dynamic range is HDR linearly displayed in the imaging apparatus, a method of switching the dynamic range range for HDR linear display using the luminance value of the focus area is described. explain. FIG. 2 is a flowchart showing a method of switching the dynamic range for HDR linear display according to the brightness value at the focus position in the embodiment of the invention of claim 1.

  In step S <b> 201, the power switch unit 112 determines whether the system is powered on, and sends it to the system control unit 111. If it is ON, the process proceeds to step S202. If it is not ON, the process ends. In step S <b> 202, the display control unit 107 performs lighting control of the liquid crystal panel 114 using a video signal that has not been processed by the dynamic range conversion unit 103. In addition, luminance information is received from the system control unit 111, luminance control of the backlight driver 116 is performed, and the process proceeds to step S203.

  In step S203, the mode determination unit 108 receives the current shooting setting from the system control unit 111, and determines whether the input device has a wide input dynamic range, for example, a setting with a dynamic range of 500% or more. When the dynamic range is smaller than 500%, the process proceeds to step S204, and when it is 500% or more, the process proceeds to step S205. In step S204, the dynamic range determination unit 105 sends information indicating that HDR linear display is not performed to the dynamic range conversion unit 106 because the input dynamic range of the imaging apparatus is not wide from the information received from the mode determination unit 108.

  The dynamic range conversion unit 106 sends the display to the display control unit 107 without performing HDR linear display. In step S205, the mode determination unit 108 receives the menu setting value from the system control unit 111, and determines whether or not the mode is the HDR mode. If the mode is the HDR mode, the process proceeds to step S206. If the mode is not the HDR mode, the process proceeds to step S204. In step S <b> 206, the focus position detection unit 103 receives information indicating the HDR mode from the mode determination unit 108, detects the focus area of the video signal, and sends it to the focus position luminance calculation unit 104.

  Even when there is no in-focus portion, information indicating that the portion does not exist is sent to the focus position luminance calculation unit 104. Thereafter, the process proceeds to step S207. In step S207, the focus position luminance calculation unit 104 receives from the focus position detection unit 103 information on the in-focus area or information indicating that there is no in-focus position. If the image is in focus, the average luminance value in the focus area is calculated and sent to the dynamic range determination unit 105, and the process proceeds to step S208.

  In step S208, the dynamic range determination unit 105 receives information from the mode determination unit 108 that the HDR mode is set, and the focus position luminance calculation unit 104 receives the average luminance value of the focus area or out-of-focus information, and performs dynamic display for HDR linear display. Determine the range. If it is out of focus or the average luminance value is larger than 400% and smaller than 600%, the process proceeds to step S209. If the average luminance value is 600% or more as shown in FIG. 3A, the process proceeds to step S210. If the average luminance value is 400% or less as shown in FIG. 3B, the process proceeds to step S211.

  In step S209, the dynamic range conversion unit 106 sends the video signal to the display control unit 107 with the current setting, and the process proceeds to step S203. In step S <b> 210, the dynamic range determination unit 105 receives from the memory determination unit 110 a parameter for HDR linear display up to the maximum dynamic range in the current shooting setting, for example, 1000%, and sends the parameter to the dynamic range conversion unit 106. The dynamic range conversion unit 106 processes the video signal according to the received parameter and sends it to the display control unit 107, and the process proceeds to step S203.

  In step S <b> 211, the dynamic range determination unit 105 receives parameters for HDR linear display from the memory determination unit 110 to the dynamic range of 300%, and sends them to the dynamic range conversion unit 106. The dynamic range conversion unit 106 processes the video signal according to the received parameter and sends it to the display control unit 107, and the process proceeds to step S203.

  As described above, in the image pickup apparatus according to the first embodiment, when displaying an image with a wide dynamic range on an HDR linear display on a display unit with a narrow dynamic range, the dynamic range range for HDR linear display using the luminance value of the focus area is set. By switching, it is possible to display in accordance with the focus area most noticed by the user.

  In the first embodiment, whether the dynamic range is wide is determined at 500%, but may be determined at another value. In addition, the dynamic range for linear display is selected from 1000% and 300%, but different values may be used and a plurality of options may be provided. Furthermore, although determination of the average value of luminance values is performed at 400% and 600%, another value may be taken or a plurality of threshold values may be provided. Although the determination of the luminance value is performed based on the average value, the determination may be made based on the maximum value of the focus area or the ratio of the luminance values of the focus area.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. A part of the above-described embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 100 ... Main-body part 101 ... Imaging part 102 ... Digital signal processing part 103 ... Focus position detection part 104 ... Focus position brightness | luminance calculation part 105 ... Dynamic range determination part 106 ... Dynamic range conversion part 107 ... Display Control unit 108 ... Mode determination unit 109 ... Operation unit 110 ... Memory unit 111 ... System control unit 112 ... Power switch unit 113 ... Display unit 114 ... Liquid crystal panel 115 ... Backlight 116 ... Backlight driver

Claims (1)

An imaging device;
A video signal output unit that converts the video signal captured by the imaging device into a digital signal and outputs the digital signal;
A display unit for displaying images;
A focus area detector for detecting a focused area in the video signal;
A luminance calculation unit for calculating a luminance value of the area detected by the focus area detection unit;
An HDR mode determination unit for detecting that the setting of the imaging device is a setting with a wide dynamic range;
A gradation correction unit that corrects the dynamic range and gradation of the video displayed on the display unit when the HDR mode determination unit determines that the setting is a wide dynamic range;
Dynamic range mode 1 in which the gradation correction unit performs a narrow dynamic range setting;
A dynamic range mode 2 in which the gradation correction unit performs a wider dynamic range setting than the dynamic range mode 1;
A threshold value α of a luminance value for switching the dynamic range mode 2 to the dynamic range mode 1;
A threshold value β of a luminance value larger than the threshold value α for switching the dynamic range mode 1 to the dynamic range mode 2;
If the HDR mode determination unit determines that the setting of the dynamic range is wide, and the luminance value of the focus area calculated by the luminance calculation unit is less than or equal to the threshold value α, the gradation correction unit is in the dynamic range mode 1 An image pickup apparatus characterized in that a video signal is processed by setting, and if the threshold value β is equal to or greater than the threshold value β, the gradation correction unit performs processing on the video signal by setting the dynamic range mode 2.