JP5053811B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus capable of providing good image quality with reduced degradation of resolution due to a lens flare phenomenon.

  In an imaging apparatus using a lens having an optical zoom function, the influence of incident light from other than the main subject that is photographed on the wide side with a short focal length and the tele side with a long focal length may be different.

  Using the optical zoom function of the imaging device, as the focal length is zoomed to the tele side, the influence of incident light from other than the main subject is more affected, and the entire screen tends to become brighter. . This is due to the fact that as the focal length increases, the distance between the lenses within the lens also increases and the reflection of light occurs more significantly inside the lens (in other words, the distance between the lenses decreases). The effect of reflection is small.

  Due to this influence, the gradation of the dark part is lost, and a phenomenon in which the black part appears to be whitish, that is, so-called black floating occurs, which causes deterioration in image quality.

  A phenomenon in which black float occurs in the photographing screen in accordance with the focal length of the zoom lens is generally called a flare phenomenon.

  When the flare phenomenon occurs in the shooting screen, the contrast is lowered due to the black float, so that the resolution of the image is lowered, and the quality of the image quality near the tele end is significantly lowered.

  In order to avoid the flare phenomenon, it is possible to reduce the complex reflection by applying an anti-reflection coating to each of the several lenses that make up the lens, but each has a special coating. Therefore, the manufacturing cost increases.

  In addition, the zoom magnification of the image pickup apparatus is rapidly increasing. For example, in a lens having a very large zoom magnification exceeding 30 times optical, for example, the difference in focal length between the wide end and the tele end becomes large. More and more are affected by the flare phenomenon.

  As described above, as the zoom lens increases in magnification, resolution degradation due to a flare phenomenon at the telephoto end has become a problem.

  In order to solve this problem, there has been proposed a technique in which a luminance gamma table, which is a gradation characteristic table that has a flare characteristic specific to a lens in advance and removes the influence of the zoom position, is changed (Patent Document 1). reference).

  By doing so, it is possible to eliminate the influence of flare and provide good image quality even at the telephoto end.

  In addition, in order to suppress the influence of the flare phenomenon, an imaging apparatus including a histogram generation unit indicating a luminance level distribution and a black level correction value calculation unit that calculates a black level correction value prepared in advance from the flare characteristic of the lens is proposed. (See Patent Document 2).

This imaging device observes the histogram of the luminance signal during shooting of the subject and the lens state during shooting, compares it with the correction characteristics at that time, calculates the correction value of the black level, and corrects the black level when capturing a still image Value is applied. By doing so, it is possible to gradually reduce image quality degradation due to the flare phenomenon.
Japanese Patent Laying-Open No. 2005-065054 JP 2006-165937 A

  In the method disclosed in Patent Document 1, since the luminance gamma characteristic is changed according to the zoom position, it is possible to remove the influence of black floating due to the flare phenomenon inherent to the lens for each focal length, and in particular, the tele end having a long focal length. Therefore, it is possible to provide good image quality.

  In this method, gamma correction based on a luminance gamma table prepared in advance is performed according to the focal length.

  For this reason, in luminance gamma correction to be performed in order to suppress black float due to flare phenomenon, the gamma correction value that lowers the gain of the low luminance part is set to be small, or the luminance gamma correction value is shifted overall.

  For this reason, since the luminance gamma correction value is changed or shifted during the focal length, that is, during the zoom operation, a luminance flicker phenomenon may occur at the switching point of the luminance gamma correction value.

  Furthermore, since the luminance gamma correction value varies depending on the focal length under the same illuminance, there is a problem that a change in the S / N ratio appears in the image quality.

  Further, in the technique disclosed in Patent Document 2, black floating due to flare phenomenon is corrected based on recorded still image information.

  Therefore, when black level correction is performed in real time, it is possible to provide a good quality image in which the black level luminance change that occurs according to the focal length is not recorded and the black float due to the flare phenomenon is corrected. It becomes.

  However, in this method, since the black level is corrected from the recorded still image, the black level changes according to the focal length during moving images. In addition, since only the focal length and the flare characteristic of the lens are observed and corrected, there is a problem in that, when the subject to be photographed is in a low illuminance environment, blackout occurs in the low-luminance part and the gradation characteristic deteriorates.

To achieve the above object, an imaging apparatus of the present invention is an imaging apparatus capable of performing optical zooming by driving the lens of the lens unit ing a plurality of lenses, the state of the lens the focal length control means for generating information about the focal length from the luminance detection means for detecting the brightness of the shooting image, based on the information about the focal length generated by the focal length control unit, the signal level of the offset signal Setting means for setting, and determination means for determining whether or not to add an offset signal of the signal level set by the setting means to the luminance signal of the captured image based on the luminance detected by the luminance detecting means; , characterized by having a.
According to another configuration, the imaging device of the present invention is an imaging device capable of performing optical zoom by driving the lens of a lens unit including a plurality of lenses, and the state of the lens A focal length control unit that generates information on the focal length from the image, a gain control unit that performs gain control on the captured image, a luminance detection unit that detects the luminance of the captured image, and a set recording rate at the time of moving image recording Recording rate detection means for detecting the information, information on the focal length generated by the focal length control means, the gain value set in the gain control means, the luminance detected by the luminance detection means, and the recording And an adding means for adding an offset signal to the luminance signal of the photographed image based on the recording rate detected by the rate detecting means. The features.

To achieve the above object, a control method of the image pickup apparatus of the present invention is a method of controlling a plurality of lens units ing from the lens of the imaging device capable of performing the optical zooming by driving the lens there are, the focal length control step of generating information about the focal length from the state of the lens, and the luminance detecting step of detecting the brightness of the shooting image, based on the information about the focal length generated by the focal length control step A setting step for setting the signal level of the offset signal, and whether to add an offset signal of the signal level set by the setting step to the luminance signal of the captured image based on the luminance detected by the luminance detection step And a determining step for determining whether or not .
According to another configuration, the imaging apparatus control method of the present invention is an imaging apparatus control method capable of performing optical zoom by driving the lens of a lens unit including a plurality of lenses. A focal length control step for generating information on the focal length from the state of the lens, a gain control step for performing gain control on the photographed image, and a luminance detection step for detecting the luminance of the photographed image. A recording rate detecting step for detecting a recording rate at the time of moving image recording; information on a focal length generated by the focal length controlling step; a gain value set in the gain controlling step; and a luminance detecting step. The offset signal is added to the luminance signal of the photographed image based on the recorded luminance and the recording rate detected by the recording rate detection step. And having a step.

  According to the present invention, by controlling the luminance offset value, it is possible to prevent the resolution from deteriorating due to black floating due to lens flare and black crushing that occurs at low luminance.

  Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings.

  The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment.

<First Embodiment>
A first embodiment of the present invention will be described. FIG. 1 is a block diagram of an imaging apparatus according to the first embodiment.

  In the figure, reference numeral 1 denotes a lens unit composed of a plurality of lenses, and optical zoom can be performed by driving a plurality of lens groups. Reference numeral 3 denotes an image pickup device having a photoelectric conversion function, and reference numeral 2 denotes an aperture for limiting the amount of incident light and allowing appropriate light to enter the image pickup device 3.

  The optical signal that has passed through the lens unit 1 is input to the image sensor 3 through the diaphragm 2. Reference numeral 10 denotes a CPU that controls the imaging apparatus and the entire imaging apparatus. Reference numeral 9 denotes a timing generator (hereinafter referred to as TG) which is controlled by the CPU 10 and outputs a signal having a constant period in synchronization with a transfer pulse having an amplitude of 3V and the horizontal synchronization signal HD.

  The image sensor 3 is driven by a timing pulse output from the TG 5, photoelectrically converts the input optical signal into an electrical signal, and outputs the electrical signal.

  4 is a CDS circuit that performs correlated double sampling, 5 is an AGC circuit that performs auto gain control, and 6 is an A / D conversion circuit that converts an analog signal into a digital signal.

  The output signal of the image sensor 3 is correlated double sampled by the CDS circuit 4 and then passed through an AGC circuit 5 that performs gain control and an A / D conversion circuit 6 that converts an analog signal into a digital signal. The signal is input to the signal processing circuit 7.

  Reference numeral 7 denotes a camera signal processing circuit that performs Y / C separation, video signal processing, color signal processing, and gamma correction on an input signal to generate an image signal and output the image signal to the video signal processing circuit 12.

  Here, the camera signal processing circuit 7 adds a certain luminance offset value to the image signal generated after the video signal processing.

  On the other hand, the Y signal after Y / C separation by the camera signal processing circuit 7 is output to the luminance detection unit 8 in order to perform exposure correction of the imaging apparatus.

  The luminance detection unit 8 calculates the luminance level and the average luminance value in the image signal from the input Y signal, and outputs them to the CPU 10.

  Note that the average luminance value calculated here may be the average value of the entire image signal, or the average of the luminance of only the area subject to photometry, or the average after weighting But it ’s okay.

A memory 11 temporarily stores various data calculated by the CPU 10.
Reference numeral 12 denotes a video signal processing circuit that performs various processes for converting an image signal output from the camera signal processing circuit 7 into a video signal.
Reference numeral 13 denotes a motor driver that gives the lens unit 1 a driving force for optical zooming, and reference numeral 14 denotes a zoom key that allows the user to perform optical zooming. Reference numeral 15 denotes a recording rate detection unit that detects a recording rate set in the imaging apparatus during moving image recording.

Next, the internal control of the CPU 10 will be described with reference to FIG.
FIG. 2 is a block diagram inside the CPU 10.

  In FIG. 2, reference numeral 109 denotes an evaluation value calculation unit that evaluates the exposure state in the image signal from the luminance level output from the luminance detection unit 8.

  Reference numeral 110 denotes an imaging device state determination unit that determines the control state of various imaging devices (aperture, ND, shutter, ACG) during exposure control based on the exposure evaluation value, which is an output of the evaluation value calculation unit.

  Reference numeral 111 denotes an aperture control table that is a control table that is referred to during aperture control, and 112 is an ND control table that is a control table referred to during ND filter control. Reference numeral 113 denotes a shutter control table that is a control table that is referred to during shutter control, and reference numeral 114 denotes an AGC control table that is a control table referred to during AGC control.

  The control value of the imaging device to be controlled is referred to from the aperture control table 111, the ND control table 112, the shutter control table 113, and the AGC control table 114 in accordance with the determination result in the imaging device state determination unit 110.

  Specifically, in the exposure control performed at that time, if the aperture 2 is in operation, the aperture control is performed by referring to the aperture control value at which the exposure is appropriate from the aperture control table 111, and the exposure control is performed. Take control.

  Further, the average luminance value output from the luminance detection unit 8 is input to the average luminance value comparator 115.

  The average luminance value comparator 115 compares the inputted average luminance value with a reference luminance value 116 provided in advance in the CPU 10, and if it is equal to or higher than the reference value, the “HIGH” signal is smaller than the reference value. Outputs “LOW” signal.

  Then, the output signal of the average luminance value comparator 115 is input to the time comparator 117.

  The time comparator 117 compares the time during which the “HIGH” signal or the “LOW” signal, which is the output signal of the average luminance value comparator 115, with the reference time 118 provided in advance in the CPU 10.

  Specifically, when “HIGH” continues for a reference time or longer, a “HIGH” signal is output to the camera signal processing circuit 7 when a “LOW” signal continues for a reference time or longer. To do.

  When the zoom key 14 provided outside the imaging apparatus is selected, information indicating that is input to the focal length control unit 119 inside the CPU 10.

  The focal length control unit 119 generates information on motor driving and information on focal length for operating the zoom mechanism in the lens included in the imaging device in accordance with the operation of the zoom key 14, and information on motor driving is generated by the motor driver 13. Output to.

Next, control performed in the camera signal processing circuit 7 in FIG. 1 will be described with reference to FIG.
FIG. 3 is a block diagram inside the camera signal processing circuit 7.

  A signal output from the A / D conversion circuit 6 and input to the camera signal processing circuit 7 is input to the Y / C separation circuit 200.

  The Y / C separation circuit 200 separates the input signal into a “Y” signal representing a luminance signal and a “C” signal representing a color signal, and outputs a “Y” signal to the luminance LPF 201.

  Here, the luminance LPF 201 constitutes a low-pass filter for removing noise in the image signal.

  The “Y” signal is also input to the contour correction circuit 203, and the contour correction circuit 203 performs contour enhancement processing on the “Y” signal.

  The signal subjected to the contour emphasis processing in the contour correction circuit 203 is input to the luminance offset addition circuit 204.

  The luminance offset addition circuit 204 adds an offset signal prepared in advance to the input signal (captured image), and outputs a signal to the luminance gamma correction circuit 205. Note that the luminance offset is set so that the offset value differs depending on the shooting mode.

  FIG. 4 shows the relationship between the luminance offset value, the gain value, and the zoom state of the zoom lens in the present invention.

  In FIG. 4, a straight line A represents the relationship between the luminance offset value and the gain value when the zoom lens is at the wide end. In the figure, a straight line B represents the relationship between the luminance offset and the gain value when the zoom lens is at the telephoto end.

  In the figure, the tele end is brighter than the wide end, so that the offset value given to the image signal is negative.

  In B1 and B2, the position of the zoom lens is both at the TELE end, but the gain control value has increased to the maximum value, and no further gain adjustment is possible, so the field luminance is lower than the predetermined value. In some cases, black sun may occur, and the quality of the image may deteriorate. As used herein, black sink means a state in which the quality of image quality is lowered in a state where the black level is lower than a predetermined reference value (a level at which black looks black).

  Therefore, when the gain control value has increased to the maximum value and the field luminance is lower than a predetermined value, the luminance offset is forcibly canceled so that the luminance offset value becomes zero ( Straight line B2).

  Details of the adjustment of the luminance offset value will be described later.

  The luminance gamma correction circuit 205 performs gamma correction processing on the input signal, then outputs the input signal to the first adder 202 and adds it to the output signal of the luminance LPF 201.

  The output signal of the first adder 203 is input to the second adder 206.

  The “C” signal that is the output signal of the Y / C separation circuit 200 is input to the color signal processing circuit 207, subjected to appropriate color signal processing, and then input to the color gamma correction circuit 208.

  The color gamma correction circuit 208 performs gamma correction processing on the input signal, and then outputs the signal to the second adder 206.

  The second adder 206 combines the output signal from the first adder 202 and the output signal from the color gamma correction circuit 208, generates an image, and outputs the signal to the video signal processing circuit 12.

  Next, the control of the luminance offset value will be described in detail using the flowchart of FIG.

  When a power supply (not shown) of the imaging apparatus is turned on, the imaging apparatus enters a shooting standby state, and the imaging apparatus starts processing from step 100.

  In step S100, the CPU 10 calculates a focal length.

  In step S101, the imaging device state determination unit 110 determines an imaging device in operation in the exposure control currently performed.

  When the determination of the imaging device in operation is finished, the CPU 10 advances the process to step S102, and determines whether or not the focal length calculated in step S100 is greater than or equal to a preset reference value.

  If the CPU 10 determines in step S102 that the calculated focal length is smaller than a preset reference value, that is, if the focal length is short, the process proceeds to step S110.

  If the CPU 10 determines in step S102 that the calculated focal length is greater than or equal to a preset reference value, that is, if the focal length is long, the process proceeds to step S103.

  In step S103, the CPU 10 determines whether or not the gain value currently set in the AGC circuit 5 is set to the maximum value.

  If the CPU 10 determines in step S103 that the gain value currently set in the AGC circuit 5 is not the maximum value setting, the process proceeds to step S109.

  In step S103, when the CPU 10 determines that the gain value currently set in the AGC circuit 5 is the maximum value setting, the process proceeds to step S104, and the luminance detection unit 8 causes the currently captured image to be captured. The average luminance value of is calculated.

  In step S105, the CPU 10 determines whether or not the average luminance value calculated in step S104 is less than or equal to a preset reference value. If it is determined that the average brightness value is greater than the reference value, the process proceeds to step S109.

  In step S105, when the CPU 10 determines that the average luminance value calculated in step S104 is equal to or less than a preset reference value, the process proceeds to step S106, and the elapsed time after the signal is detected is determined. taking measurement.

  In step S107, the CPU 10 determines whether or not the elapsed time measured in step S106 is greater than or equal to the reference time compared to the reference time preset in the CPU 10, and determines that it is greater than or equal to the reference time. Advances to step S108.

  In step S107, if the CPU 10 determines that the elapsed time measured in step S106 is shorter than the reference time set in advance in the CPU 10, the process proceeds to step S109.

  In step S108, the brightness offset value for correcting the flare characteristic of the lens currently being performed is set to 0, the process is terminated, and the camera signal processing circuit 7 processes the image signal.

  Note that the brightness offset value is set to 0 in step S108 because the scene is under low brightness, the black level falls below the reference level, black crushing occurs, and the quality of the image is lowered. Set to 0 to perform normal control.

  In this embodiment, the luminance offset value is set to 0 in step S108. However, when the currently set luminance offset value is 0 or more, it is not particularly necessary to set it to 0.

  In step S109, the brightness offset value for correcting the flare characteristic of the lens provided in advance is changed to a negative value, the process is terminated, and the camera signal processing circuit 7 processes the image signal.

  In step S109, the luminance offset value for correcting the lens flare characteristic provided in advance is changed to a negative value for the following reason.

  In scenes where the field brightness is brighter than the specified level, or where there is room for gain control, even if the brightness offset value is adjusted to a negative value to reduce black float, the effect of black sinking will be affected. This is because there is little to receive.

  In step S110, the camera signal processing circuit 7 processes the image signal without changing the luminance offset value added to the image signal from the default setting.

  The reason why the luminance offset value is not changed from the default setting in step S110 is that there is no particular need to correct the black level because the focal length is set so that the influence of the black float caused by the lens flare can be ignored.

  As described above, in the present embodiment, by changing the luminance offset value added to the image signal according to the focal length during shooting of the subject, the black floating phenomenon due to the flare characteristic of the lens can be prevented. Degradation of resolution can be reduced.

  In addition, when it is determined that the focal length during shooting of the subject is at the tele end, the average luminance value of the shooting scene is equal to or less than a predetermined value, and the luminance state of the shooting scene is stable, the luminance applied to the shot image By setting the offset value to 0, black crushing in the low luminance region is suppressed.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. In addition, about the structure of an imaging device, the structure similar to 1st Embodiment is abbreviate | omitted description.

  In the first embodiment, the luminance offset value is changed according to the focal length information, the gain control value applied to the image, and the average luminance value of the image, thereby reducing degradation of resolution due to black float caused by lens flare. I am letting.

  On the other hand, in the second embodiment, in addition to the above-described conditions for changing the luminance offset value, the frame rate at the time of moving image recording is also a condition for changing the luminance offset value. It is a different point.

Thus, the control of the luminance offset value in the second embodiment will be described with reference to FIG.
In FIG. 6, the description of the part that performs the same processing as in the first embodiment is omitted.
In step S201, the recording rate detector 15 detects the recording rate of the currently captured image.

  In step S202, the CPU 10 determines whether or not the recording rate detected in step S201 is, for example, 4 Mbps or less.

  If the CPU 10 determines in step S202 that the recording rate detected in step S201 is, for example, 4 Mbps or less, the process proceeds to step S102 to determine the focal length.

  Here, when the detected recording rate is 4 Mbps or less, the process proceeds to the processing described in the first embodiment because the recording rate is set such that the resolution is deteriorated depending on the shooting conditions. Because. Therefore, in this embodiment, 4 Mbps is set as the reference value set in advance, but the reference value is not limited to this, and it may be determined whether or not the shooting mode has a recording rate higher than a predetermined value.

  If the CPU 10 determines in step S202 that the recording rate detected in step S201 is greater than 4 Mbps, for example, the process proceeds to step S110.

  In step S110, the camera signal processing circuit 7 processes the image signal without changing the luminance offset value added to the image signal from the default setting.

  Here, when the detected recording rate is larger than 4 Mbps, the luminance offset value is not changed from the default setting because the detected recording rate is set to a recording rate that can maintain a good resolution. It is.

  As described above, in the present embodiment, the frame rate at the time of moving image recording is added to the various conditions for changing the luminance offset value of the first embodiment.

  Thereby, exposure control with higher accuracy becomes possible.

It is a block diagram of the imaging device concerning the present invention. It is a block diagram inside CPU of the imaging device of this invention. . It is a block diagram inside the camera signal processing circuit of the imaging device of this invention. It is the figure which showed the relationship between the brightness | luminance offset value and gain value, and the zoom state of a zoom lens in the imaging device of this invention. It is the figure shown about the control flowchart of the brightness | luminance offset value in the 1st Embodiment of this invention. It is the figure shown about the control flowchart of the brightness | luminance offset value in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens unit 2 Aperture 3 Image pick-up element 4 CDS circuit 5 AGC circuit 6 A / D conversion circuit 7 Camera signal processing circuit 8 Luminance detection part 9 TG
10 CPU
DESCRIPTION OF SYMBOLS 11 Memory 12 Video signal processing circuit 13 Motor driver 14 Zoom key 15 Recording rate detection part 109 Evaluation value calculation part 110 Imaging device state determination part 111 Aperture control table 112 ND control table 113 Shutter control table 114 AGC control table 115 Average luminance value comparator 116 Reference luminance value 117 Time comparator 118 Reference time 119 Focal length control unit 200 Y / C separation circuit 201 Luminance LPF
202 first adder 203 contour correction circuit 204 luminance offset addition circuit 205 luminance gamma correction circuit 206 second adder 207 color signal processing circuit 208 color gamma correction circuit

Claims (10)

An imaging apparatus capable of performing optical zooming by driving the lens of the lens unit ing a plurality of lenses,
Focal length control means for generating information on the focal length from the state of the lens;
A luminance detecting means for detecting the brightness of the shadow image shooting,
Setting means for setting the signal level of the offset signal based on information on the focal length generated by the focal length control means ;
Determining means for determining whether or not to add an offset signal of the signal level set by the setting means to the luminance signal of the photographed image based on the brightness detected by the brightness detecting means. An imaging device. When the average brightness value of the photographed image calculated based on the brightness detected by the brightness detection means is larger than a reference value, the determination means is a signal set by the setting means as the brightness signal of the photographed image. The imaging apparatus according to claim 1, wherein it is determined that a level offset signal is added. In the case where the average luminance value is equal to or less than the reference value, the determining unit is configured to set the luminance signal of the captured image when the elapsed time after the average luminance value is equal to or less than the reference value is shorter than a reference time. When it is determined that an offset signal of the signal level set by the means is added, and the elapsed time is equal to or longer than the reference time, the offset signal of the signal level set by the setting means is not added to the luminance signal of the captured image The imaging apparatus according to claim 2, wherein: When the focal length based on the information on the focal length is longer than a reference focal length, the setting means makes the signal level smaller than when the focal length based on the information on the focal length is shorter than the reference focal length. The imaging device according to any one of claims 1 to 3, wherein A gain control unit that performs gain control on the captured image;
The said setting means sets the said signal level based on the information regarding the said focal distance, and the gain value at the time of performing gain control by the said gain control means, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. The imaging device described in 1. The imaging apparatus according to claim 5, wherein the setting unit decreases the signal level as the gain value decreases. An imaging apparatus capable of performing optical zoom by driving the lens of a lens unit composed of a plurality of lenses,
Focal length control means for generating information on the focal length from the state of the lens;
Gain control means for performing gain control on the captured image;
Luminance detection means for detecting the luminance of the captured image;
Recording rate detection means for detecting the recording rate at the time of recording the set video,
Information on the focal length generated by the focal length control means, the gain value set in the gain control means, the luminance detected by the luminance detection means, and the recording rate detected by the recording rate detection means And an adding means for adding an offset signal to the luminance signal of the photographed image based on the image pickup apparatus. The adding means sets the gain value to a maximum value when the recording rate is equal to or less than a preset reference value, and when the focal length based on the focal length information is equal to or greater than a preset reference value. And an offset added to the luminance signal when the average luminance value of the photographed image calculated based on the luminance detected by the luminance detecting means is equal to or smaller than a preset reference value. The image pickup apparatus according to claim 7, wherein the signal is set to zero. An imaging apparatus control method capable of performing optical zoom by driving the lens of a lens unit composed of a plurality of lenses,
A focal length control step of generating information on a focal length from the state of the lens;
A luminance detection step for detecting the luminance of the captured image;
A setting step of setting a signal level of the offset signal based on information on the focal length generated by the focal length control step;
A determination step of determining whether or not to add an offset signal having a signal level set by the setting step to the luminance signal of the captured image based on the luminance detected by the luminance detection step. A method for controlling the imaging apparatus. An imaging apparatus control method capable of performing optical zoom by driving the lens of a lens unit composed of a plurality of lenses,
A focal length control step of generating information on a focal length from the state of the lens;
A gain control step for performing gain control on the captured image;
A luminance detection step of detecting the luminance of the captured image;
A recording rate detection step for detecting a recording rate at the time of recording a set video,
Information on the focal length generated by the focal length control step, the gain value set in the gain control step, the luminance detected by the luminance detection step, and the recording rate detected by the recording rate detection step And an adding step of adding an offset signal to the luminance signal of the photographed image based on the control method.

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