JP2019080358A - Imaging apparatus and control method of imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus that can calculate a correction value of exposure control from white image data not including a chromatic color area.SOLUTION: An imaging apparatus 10 includes: an imaging part 2 that acquires image data from a subject image formed by an imaging lens part 1; a high-luminance white determination part 6ac that calculates a high-luminance white area from the image data; a high-luminance white area occupancy calculation part 6ad that calculates high-luminance white area occupancy that is proportion of the high-luminance white area to the image data; an exposure condition correction value calculation part 6ae that calculates a correction value on the basis of the high-luminance white area occupancy; and an exposure control part 6ai that controls exposure of the imaging part on the basis of the correction value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging device and a control method of the imaging device.

  A general imaging device focuses light emitted from a subject on an imaging area of an imaging device to obtain image data. This image data can be used for display and recording. Automatic exposure control (AE) is performed to make the exposure (brightness) of the image data obtained by the imaging element appropriate. In the automatic exposure control, for example, the brightness of image data is measured, and, for example, the shutter speed or the aperture is set based on the result of the light measurement.

  As one method of photometry, multi-division photometry is known. In the multi-division photometry method, image data is divided into a plurality of photometry areas, luminance is calculated for each photometry area, and the luminance for each photometry area is evaluated. For example, weighted exposure is performed to set an exposure condition. In such a multi-division photometry method, when image data containing white on most of the background is obtained, it is determined that the brightness is high, and exposure control is performed so as to make the brightness darker than actually necessary. There is a thing.

  The imaging apparatus disclosed in Patent Document 1 detects a chromatic photometric area and an achromatic photometric area, respectively, and makes the chromatic photometric area weight larger than the achromatic photometric area weight, thereby forming a chromatic color. The exposure control is performed so that the exposure of the area of, that is, the area of the subject becomes appropriate.

Patent No. 4304628

  Here, in the imaging device of Patent Document 1, it is assumed that the subject is a chromatic color. That is, in the imaging device of Patent Document 1, for example, when the subject is white, the subject is achromatically weighted. In this case, the subject is photographed darker than expected.

  The present invention has been made in view of such circumstances. The present invention provides an imaging apparatus and an imaging apparatus control method that perform exposure control such that the exposure of the subject becomes appropriate even if the subject is not a chromatic color.

  An image pickup apparatus according to an aspect of the present invention is an image pickup unit that picks up an object image formed in an image pickup area to generate image data, and the brightness of the entire image based on the image data generated by the image pickup unit. Pre-correction luminance calculation unit for calculating luminance before correction; High-brightness white judgment unit for judging high-brightness and white area in image data generated by the imaging unit; Image data generated by the imaging unit A high brightness white area dominance calculation unit that calculates a high brightness white area dominance ratio, which is a ratio of the high brightness white area that is the high brightness and white area to the entire image; A correction value calculation unit that calculates a correction value for correcting the luminance as an exposure condition so that the exposure amount becomes large, the luminance before the correction, and imaging as a subject image by the imaging unit The effect rate calculation unit for calculating an effect rate for adjusting the correction value according to a comparison between the first luminance and the second luminance corresponding to the reference of switching of the photographed scene; And an exposure control unit that adjusts the value and controls the exposure of the imaging unit based on the luminance corrected by the adjusted correction value.

  In the control method of an imaging apparatus according to an aspect of the present invention, an imaging unit captures an object image formed in an imaging region to generate image data, and based on the generated image data, luminance of the entire image is generated. Calculating the luminance before correction, determining the high luminance and white area in the generated image data, and the high luminance and white area with respect to the entire generated image data image A correction value for correcting the luminance as an exposure condition so that the higher the luminance white area dominance, which is the proportion of the high luminance white area, is calculated, and the exposure amount increases as the high luminance white area dominance increases. According to the comparison between the luminance before correction and the first luminance and the second luminance corresponding to the reference of the switching of the photographed scene imaged as a subject image by the imaging unit. And calculating the effectiveness factor for adjusting the correction value, the correction value is adjusted by the effect index comprises and controlling the exposure based on the corrected luminance by the adjustment correction value.

  According to the present invention, it is possible to provide an imaging apparatus and an imaging apparatus control method that perform exposure control such that the exposure of the subject becomes appropriate even if the subject is not a chromatic color.

FIG. 1 is a block diagram showing a configuration example of an imaging device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the function of the control unit. FIG. 3 shows the definition of white. FIG. 4 is a flowchart showing an example of the main operation of the imaging device according to the embodiment. FIG. 5 is a flowchart showing a determination example related to the determination of the correction value. FIG. 6 is a diagram illustrating the correspondence between the high-intensity white area dominance and the correction value. FIG. 7 is a flowchart showing a determination example related to the determination of the effect rate. FIG. 8 is a diagram showing the correspondence between the pre-correction luminance and the effect rate. FIG. 9 is a diagram for explaining the post-correction luminance according to the shooting scene. FIG. 10 is a schematic view of the embodiment.

  Hereinafter, an embodiment of an imaging device according to the present invention will be described. A configuration example of the imaging device 10 will be described with reference to FIG. The imaging device 10 includes a photographing lens unit 1, an imaging unit 2, a status display unit 3, an operation unit 4, a temporary storage unit 5, and a control unit 6.

  The imaging lens unit 1 causes the light emitted from the subject to be incident on the imaging unit 2. The photographing lens unit 1 includes a single or a plurality of lenses such as a focus lens and a zoom lens, and a stop. The imaging unit 2 generates image data from a subject image based on light incident through the photographing lens unit 1. The imaging unit 2 includes an imaging element, an analog processing circuit, and an A / D conversion circuit. The imaging element has an imaging area on which light incident through the imaging lens unit 1 is imaged. Pixels are two-dimensionally arranged in the imaging region. Each pixel is, for example, a photodiode. Further, for each pixel, for example, a color filter of primary color Bayer array is formed. In such a configuration, the imaging device outputs an electrical signal (image signal) according to the amount of light incident on each pixel. The analog processing circuit performs analog processing such as correlated double sampling processing and automatic gain adjustment processing on the image signal output from the imaging device. The A / D conversion circuit converts the image signal analog-processed by the analog processing circuit into a digital image signal (image data).

  The status display unit 3 is, for example, a liquid crystal display or an organic EL display, and displays an image based on image data.

  The operation unit 4 includes mechanical operation members such as buttons and switches, and operation members such as a touch panel. When one of the operation members is operated by the user, the operation unit 4 outputs a predetermined signal according to the operated operation member to the control unit 6. The operation unit 4 includes, for example, a release button and a power switch. The release button is a button for the user to instruct the control unit 6 to execute shooting. The power switch is a switch for instructing the user to turn on or off the power of the imaging device 10.

  The temporary storage unit 5 is, for example, an SDRAM, and temporarily stores data. This data is, for example, image data obtained by the imaging unit 2 or data calculated by the control unit 6.

  The control unit 6 is, for example, a CPU or an ASIC, and controls the overall operation of the imaging device 10. The control unit 6 includes a correction exposure unit 6 a and a photographing control unit 6 b. The corrected exposure unit 6 a performs exposure control on the imaging unit 2. The correction exposure unit 6 a includes a photometric area luminance calculation unit 6 aa, a pre-correction exposure condition calculation unit 6 ab, a high luminance white determination unit 6 ac, a high luminance white area dominance ratio calculation unit 6 ad, and an exposure condition correction value calculation unit 6ae, an effect rate calculation unit 6af, a final exposure condition correction value calculation unit 6ag, a corrected luminance determination unit 6ah, and an exposure control unit 6ai.

  A functional example of each configuration of the control unit 6 will be described with reference to FIG. FIG. 2 is a diagram for explaining the calculation of the exposure of the image data.

  The photometric area luminance calculator 6aa divides the image data obtained by the imaging unit 2 and stored in the temporary storage 5 into a plurality of photometric areas, and calculates the luminance of each of the divided photometric data. The photometric area is shown in FIG. As shown in FIG. 2, assuming that the vertical direction of the image data is the x direction and the horizontal direction of the image data is the y direction, the image data is divided into a plurality of photometric areas along the x direction and the y direction. In FIG. 2, the image data is divided into 18 × 18 photometric areas. After dividing the image data, the photometric area luminance calculator 6aa calculates the luminance for each of the divided photometric areas. As a calculation method of luminance, various methods such as a method of integrating data of pixels of the same color in the photometric area are known. In the present embodiment, the method of calculating the luminance is not limited to a specific method. In the following description, the luminance is treated as being converted to an APEX value.

  The pre-correction exposure condition calculation unit 6ab calculates the luminance of the entire image as the exposure condition based on the luminance calculated for each photometric area in the photometric area luminance calculation unit 6aa. The brightness of the entire image is calculated, for example, by a weighted average of the brightness calculated for each photometric area. Hereinafter, the brightness of the entire image is referred to as pre-correction brightness BV.

The high luminance white determination unit 6ac determines a high luminance and white (high luminance white) photometric area in the image data. "White" in the present embodiment is defined as a color within the dotted line range shown in the chromaticity diagram of FIG. The colors in the range of white in FIG. 3 have the relationships shown in the following formulas (1) and (2) when expressed in RGB ratios. R, G, and B shown in Equation (1) and Equation (2) are, for example, average values of data of pixels of the same color included in the photometric area. A photometric area which satisfies the expressions (1) and (2) and whose luminance is equal to or greater than a predetermined value is a high luminance white photometric area. For example, in the example of FIG. 2, the high brightness white photometric area is the white photometric area W. Further, the photometric area which is not high brightness white is the photometric area of the oblique line in FIG. 2 and the photometric area of the main subject O.
0.6 <B / R <1.9 (1)
0.6 <G / R <1.9 (2)
However, this RGB ratio is an example. This RGB ratio may vary depending on, for example, the spectral sensitivity of the imaging device (not shown).

  The high brightness white area dominance factor calculation unit 6 ad calculates a high brightness white area dominance factor [%] which is the number of high brightness white photometric areas with respect to the number of photometric areas included in the imaging area.

  The exposure condition correction value calculation unit 6 ae calculates a correction value of the exposure condition based on the high luminance white area dominance. The correction value is a correction value to be subtracted from the pre-correction luminance BV in order to reduce the value of the pre-correction luminance BV. The correction value basically increases as the high brightness white area dominance rate increases, that is, as the degree of influence of the high brightness white photometric area in the entire image increases. However, the basic value of the correction value has an upper limit value and a lower limit value.

  The effect rate calculation unit 6af calculates the effect rate of the correction value based on the pre-correction luminance BV. The effect rate is a value used to adjust the correction value in accordance with the brightness of the shooting scene. The effect rate basically increases as the pre-correction brightness BV increases, that is, as a bright captured scene. However, the effect rate is a value from 0 to 1.

  The final exposure condition correction value calculation unit 6ag calculates a correction value (final exposure condition correction value) to be subtracted from the pre-correction luminance BV to determine the exposure condition based on the correction value and the effect rate. The final exposure condition correction value is obtained by multiplying the basic correction value described later by the effect rate.

  The post-correction luminance determination unit 6ah calculates the post-correction luminance BV as the exposure condition by subtracting the final exposure condition correction value from the pre-correction luminance BV.

  The exposure control unit 6 ai performs exposure control using the corrected brightness BV. The exposure control is processing for setting a photographing condition necessary to set the exposure of the image data obtained by the imaging unit 2 to a predetermined reference exposure. The shooting conditions include either or both of the shutter speed and the aperture value.

  The imaging control unit 6 b controls the operation of the imaging unit 2 and the status display unit 3. For example, the photographing control unit 6b controls the operation of the imaging unit 2 according to the result of the exposure control. Further, the imaging control unit 6 b performs image processing on the image data obtained by the imaging unit 2. Further, the photographing control unit 6 b causes the situation display unit 3 to display an image based on the image data subjected to the image processing.

  The operation of the imaging device 10 described with reference to FIGS. 1 to 3 will be described with reference to the flowchart of FIG. 4. This operation is performed by the control unit 6. The processing in FIG. 4 is performed, for example, when a shooting operation is performed after the user operates the release button, or when a live view is displayed after the power of the imaging apparatus 10 is turned on. First, the photographing control unit 6b of the control unit 6 controls the imaging unit 2 to execute the photographing operation of the subject by the imaging unit 2 (step S101). The image data obtained by the imaging unit 2 by the photographing operation is stored in the temporary storage unit 5. After step S101, the photometric area luminance calculator 6aa of the controller 6 divides the image data stored in the temporary storage 5 into a plurality of photometric areas, and calculates the luminance of each photometric area (step S102). After step S102, the pre-correction exposure condition calculation unit 6ab of the control unit 6 calculates the pre-correction luminance BV based on the luminances of all the photometric areas (step S103). After step S103, the high brightness white determination unit 6ac of the control unit 6 detects a high brightness white area (step S104). The high luminance white determination unit 6ac is a photometric area having an RGB ratio as shown in the equations (1) and (2), and detects a photometric area having a luminance of a predetermined value or more as a high luminance white area. After step S104, the control unit 6 counts the total number of high brightness white areas, and calculates a high brightness white area dominant rate that is a ratio of the high brightness white areas to the total number of photometric areas (step S105).

  After step S105, the exposure condition correction value calculation unit 6ae of the control unit 6 calculates a correction value of the pre-correction brightness BV based on the high-brightness white area dominance rate (step S106). Hereinafter, an example of calculation of the correction value will be described with reference to the flowchart of FIG.

  First, the exposure condition correction value calculation unit 6ae calculates a basic correction value based on the following equation (3) (step S201).

Basic correction value = a * high brightness white area control rate [%] − b (3)
Here, a and b are constants representing luminance. For the constants a and b, for example, values converted to APEX values are used.

  After step S201, the exposure condition correction value calculation unit 6ae determines whether the calculated basic correction value is smaller than the upper limit value A2 (step 202). The upper limit value A2 is a constant representing luminance, as with the constants a and b. The upper limit value A2 is also used as a value converted to the APEX value.

  When it is determined that the basic correction value is not smaller than the upper limit value A2 (when NO in step S202), the exposure condition correction value calculation unit 6ae clips the basic correction value to the upper limit value A2 (step S203). After step S203, the exposure condition correction value calculation unit 6ae ends the process.

  On the other hand, when exposure condition correction value calculation unit 6ae determines that the basic correction value is smaller than upper limit value A2 (when YES in step S202), it determines whether the basic correction value is larger than lower limit value A1 (step S204). The lower limit value A1 is, like the constants a and b, a constant representing luminance, and has a relationship of A1 <A2. The lower limit value A1 is also used as a value converted to the APEX value.

  If the exposure condition correction value calculation unit 6ae determines that the basic correction value is larger than the lower limit value A1 (YES in step S204), the process ends. The exposure condition correction value calculation unit 6ae clips the basic correction value to the lower limit value A1 (step S205) when it determines that the basic correction value is not larger than the lower limit value A1 (when NO in step S204). After step S205, the exposure condition correction value calculation unit 6ae ends the process.

  FIG. 6 shows the relationship between the basic correction value calculated according to the process of FIG. 5 and the high luminance white area dominance. The basic correction value changes linearly with respect to the change of the high luminance white area dominance in the range from the lower limit value A1 to the upper limit value A2.

  Here, it returns to the explanation of FIG. After the correction value is calculated in step S106, the effect rate calculation unit 6af of the control unit 6 calculates an effect rate for adjusting the basic correction value (step S107). Hereinafter, a calculation example of the effect rate will be described with reference to FIG. First, the effect rate calculating unit 6af calculates the effect rate based on the following equation (4) (step S301).

Effect ratio = (pre-correction luminance BV−pre-correction luminance TH1) / (pre-correction luminance TH−pre-correction luminance TH1) (4)
Here, the pre-correction luminance TH1 and the pre-correction luminance TH2 are threshold values of the luminance serving as a reference for switching of the shooting scene, and the pre-correction luminance TH1 <the pre-correction luminance TH2. The pre-correction luminance TH1 and the pre-correction luminance TH2 are also values converted into APEX values. The pre-correction luminance TH1 is, for example, BV5.5. The pre-correction luminance TH2 is, for example, BV7.5. The pre-correction luminance TH1 and the pre-correction luminance TH2 are not limited to the illustrated values as long as they are appropriate values according to the shooting scene. The shooting scene having the pre-correction brightness BV smaller than the pre-correction brightness TH1 corresponds to, for example, a shooting scene where the entire image is dark, such as an outdoor after sunset, a room with normal brightness, a daytime shade and a dark environment. In addition, a shooting scene having a pre-correction brightness BV greater than the pre-correction brightness TH2 may be, for example, a white wall in a daytime sunny environment, or a cloud in a daytime sunny environment, a sky in a daytime cloudy environment, a daytime snowfield The entire image, such as, corresponds to a bright shooting scene. Furthermore, a shooting scene having a pre-correction brightness BV between the pre-correction brightness TH1 and the pre-correction brightness TH2 is, for example, a white wall or a cloud in the early morning or evening, the sky in the early morning or evening cloudy weather, or a daytime shade. It is a shooting scene such as a mixed scene.

  After step S301, the effect rate calculation unit 6af determines whether the magnitude of the effect rate is less than the upper limit (for example, 1) (step S302). When it is determined that the value of the effect rate is not less than 1 (when NO in step S302), the effect rate calculator 6af clips the value of the effect rate to 1 (step S303). After step S303, the effectiveness calculating unit 6af ends the process.

  On the other hand, when the effect rate calculating unit 6af determines that the effect rate is less than 1 (YES in step S302), it determines whether the value of the effect rate is greater than the lower limit (for example, 0) (step S304). When it is determined that the value of the effect rate is not larger than 0 (when NO in step S304), the effect rate calculation unit 6af clips the value of the effect rate to 0 (step S305). When YES in step S304 or after step S305, the effectiveness rate calculation unit 6af ends the process.

  FIG. 8 shows the relationship between the effect rate calculated according to the process of FIG. 7 and the luminance BV before correction. The effect rate becomes the upper limit value 1 when the pre-correction luminance BV is larger than the pre-correction luminance TH2. Further, the effect rate becomes the lower limit value 0 when the pre-correction luminance BV is smaller than the pre-correction luminance TH1. Furthermore, the effect rate changes linearly with the change in the pre-correction luminance BV when the pre-correction luminance BV is a value between the pre-correction luminance TH1 and the pre-correction luminance TH2.

  Here, it returns to the explanation of FIG. After the effect rate is calculated in step S107, the last correction value calculation unit 6ag of the control unit 6 calculates the following equation (5) from the basic correction value calculated in step S106 and the effect rate calculated in step S107. The final exposure condition correction value (final correction value, hereinafter referred to as the last correction value) is calculated based on (step S108).

Last correction value = basic correction value * effect rate (5)
After step S108, the after-correction luminance determination unit 6ah of the control unit 6 subtracts the last correction value from the before-correction luminance BV to calculate the after-correction luminance BV (step S109). FIG. 9 shows the relationship between the pre-correction luminance BV and the post-correction luminance BV. The variation of the post-correction brightness BV with respect to the pre-correction brightness BV changes with the last correction value. And the last correction value changes with an effect rate. As described above, the effect rate changes according to the relationship between the pre-correction luminance BV, the pre-correction luminance TH1, and the pre-correction luminance TH2. Therefore, the change amount of the post-correction luminance BV also changes with the pre-correction luminance TH1 and the pre-correction luminance TH2 as boundaries.

  Area B1 in FIG. 9 is an area in which the pre-correction luminance BV is smaller than the pre-correction luminance TH1. In the area B1, the effectiveness rate becomes the lower limit value. Therefore, in the area B1, the last correction value is the minimum value. FIG. 9 shows an example in which the effect rate of the area B1 is zero. In this case, the pre-correction luminance BV and the post-correction luminance BV become equal.

  Area B2 in FIG. 9 is an area in which the pre-correction luminance BV is larger than the pre-correction luminance TH2. In the area B2, the effectiveness rate is the upper limit value. Therefore, in the area B2, the last correction value is the maximum value. FIG. 9 shows an example in which the effect rate of the area B2 is one. In this case, the post-correction brightness BV is smaller than the pre-correction brightness BV by the basic correction value determined according to the high-brightness white area dominance.

  Area B3 in FIG. 9 is an area in which the pre-correction luminance BV is a value between the pre-correction luminance TH1 and the pre-correction luminance TH2. In the area B3, the effect rate linearly changes in accordance with the size of the pre-correction luminance BV. In this case, the post-correction brightness BV changes in a straight line connecting the area B1 and the area B2 according to the pre-correction brightness BV.

  After step S109, the exposure control unit 6ai of the control unit 6 and the photographing control unit 6b execute exposure control (step S110). At the time of exposure control, the exposure control unit 6ai calculates the corrected exposure EV based on the following formula (6).

Corrected exposure EV = corrected brightness BV + SV (6)
Here, SV is obtained by converting the sensitivity value of the imaging device into an APEX value. After calculating the exposure EV after correction, the exposure control unit 6ai uses the corrected exposure EV to perform imaging by the imaging unit 2 at a predetermined reference exposure (for example, an exposure corresponding to 18% gray). Set the necessary shooting conditions (shutter speed and / or aperture value or both). Then, the photographing control unit 6b of the control unit 6 controls the imaging unit 2 based on the shutter speed and the aperture value set by the exposure control unit 6ai. Subsequently, the imaging control unit 6 b performs image processing on the image data captured by the imaging unit 2 and stored in the temporary storage unit 5. Thereafter, the photographing control unit 6b causes the situation display unit 3 to display an image based on the image data subjected to the image processing (step S111).

  The effects of the embodiment of the imaging device according to the present invention are described above with reference to FIG. In the case of multi-segment photometry, a shooting scene in which a large number of high brightness white areas are included in the background is determined to be a bright scene. In this case, the subject may be photographed darker than originally expected in order to match the background exposure with the reference exposure. On the other hand, the imaging device 10 according to the present embodiment performs the exposure control after correcting the pre-correction luminance BV to be smaller according to the high luminance white area dominant ratio (the degree of influence of the high luminance white area). Therefore, in the present embodiment, it is possible to suppress the degree to which the subject is photographed dark by the exposure control. Also, the basic correction value is determined based on the high luminance white area dominance. Therefore, even if the area of the subject is a high luminance white area, the basic correction value can be calculated. Further, since the upper limit value and the lower limit value are provided in the basic correction value, overcorrection of the luminance is suppressed.

Further, in the imaging device 10, the basic correction value is adjusted by the effect rate. Exposure control is performed with a correction value according to the shooting scene by changing the effect rate according to the pre-correction brightness BV, that is, the brightness of the shooting scene. For example, in the area B1 of FIG. 9, by adjusting the correction value to be small, a dark photographed scene is not photographed brighter than necessary. On the contrary, in the area B2 of FIG. 9, by adjusting the correction value to be large, it is possible to suppress the extent to which the subject is darkened by the influence of the high luminance white area. Furthermore, in the area B3 of FIG. 9, it is possible to suppress a rapid change in the imaging condition when, for example, the pre-correction luminance BV changes during live view display. It is prevented that the dark shooting scene is shot brighter than necessary.
In addition, when calculating the effect rate, the pre-correction luminances TH1 and TH2 may be changed according to the shooting scene. In the above embodiment, although the pre-correction luminance TH1 = 5.5 and the pre-correction luminance TH2 = 7.5, for example, the pre-correction luminance TH1 = 2.5 when it is determined that the shooting scene is indoors. The pre-correction luminance TH2 may be changed to the low luminance side of 4.5. Further, for example, when it is determined that the photographed scene is cloudy in the early morning / evening, the pre-correction luminance TH1 = 4 and the pre-correction luminance TH2 = 6 may be changed to the low luminance side. As described above, by setting the pre-correction luminances TH1 and TH2 appropriately according to the shooting scene, it is possible to perform more appropriate exposure. The determination of the shooting scene may be performed by a known method according to the brightness, the type of the light source, the time, and the like.
In addition, when performing high-intensity white determination, the range determined to be white may be changed according to the shooting scene. That is, the ranges of B / R and G / R may be changed from the ranges of Formula (1) and Formula (2) according to the shooting scene. As a result, appropriate high brightness white determination can be performed regardless of the shooting scene.
Here, each process by the imaging device in the above-described embodiment may be stored as a program that can be executed. This program is used as a storage medium for external storage devices such as memory cards (ROM cards, RAM cards, etc.), magnetic disks (floppy (registered trademark), hard disks, etc.), optical disks (CD-ROM, DVD, etc.), semiconductor memory, etc. The above-described processing can be executed by loading a stored program and controlling the operation by the loaded program.

  DESCRIPTION OF SYMBOLS 1 ... photography lens part, 2 ... imaging part, 3 ... status display part, 4 ... operation part, 5 ... temporary memory part, 6 ... control part, 6a ... correction | amendment exposure part to be corrected, 6aa ... metering area brightness calculation part, 6ab ... Correction pre-exposure condition calculation unit, 6ac: high brightness white judgment unit, 6ad: high brightness white area dominance calculation unit, 6ae: exposure condition correction value calculation unit, 6af: effect ratio calculation unit, 6ag: last exposure condition correction value Calculation unit 6ah: corrected luminance determination unit 6ai: exposure control unit 6b: imaging control unit 10: imaging device, A1: lower limit value of correction value, A2: upper limit value of correction value, BV: luminance, B1, B2, B3 ... area, Ev ... exposure, O ... main subject, Sv ... sensitivity, TH1, TH2 ... predetermined pre-correction luminance threshold, W ... high luminance white photometric area.

Claims (4)

An imaging unit that captures an object image formed in an imaging region to generate image data;
An uncorrected luminance calculation unit that calculates the uncorrected luminance that is the luminance of the entire image based on the image data generated by the imaging unit;
In the image data generated by the imaging unit, a high brightness white determination unit that determines a high brightness and white area;
A high brightness white area dominance ratio calculation unit that calculates a high brightness white area dominance ratio that is a ratio of the high brightness white area that is the high brightness and white area to the entire image of the image data generated by the imaging unit;
A correction value calculation unit that calculates a correction value for correcting the luminance as the exposure condition such that the exposure amount becomes larger as the high-brightness white area dominance rate becomes larger;
An effect of adjusting the correction value according to a comparison between the luminance before the correction and the first luminance and the second luminance corresponding to a reference of switching of a photographed scene imaged as a subject image by the imaging unit An efficiency calculation unit that calculates the ratio;
An exposure control unit which adjusts the correction value by the effect rate and controls the exposure of the imaging unit based on the luminance corrected by the adjusted correction value;
An imaging device equipped with   The imaging device according to claim 1, wherein the correction value has a predetermined upper limit value and a predetermined lower limit value.   The effect ratio calculation unit calculates the effect ratio by dividing the difference between the brightness before the correction and the first brightness by the difference between the first brightness and the second brightness. The imaging device according to 1. The image pickup unit picks up an image of a subject formed in the image pickup area to generate image data;
Calculating the luminance before correction, which is the luminance of the entire image, based on the generated image data;
Determining a high brightness and white area in the generated image data;
Calculating a high brightness white area dominance rate that is a ratio of the high brightness white area that is the high brightness and white area to the entire generated image data image;
Calculating a correction value for correcting the luminance as an exposure condition so that the exposure amount becomes larger as the high-brightness white area dominance rate becomes larger;
The effect rate for adjusting the correction value according to the comparison between the luminance before correction and the first luminance and the second luminance corresponding to the reference of the switching of the photographed scene captured as a subject image by the imaging unit Calculating and
Adjusting the correction value by the effect rate, and controlling the exposure based on the brightness corrected by the adjusted correction value;
Method of controlling an imaging device comprising the