JP5811409B2 - Imaging apparatus, imaging method, and program - Google Patents

Description

  The present invention relates to an imaging apparatus, an imaging method, and a program for controlling the amount of auxiliary photographing light.

  In recent years, an LED (Light Emitting Diode) has been widely used as illumination when photographing a subject in a dark place. For example, in Patent Document 1 below, an LED is used as illumination and dynamic range expansion or illumination power is used. A technique for reducing the above is disclosed.

JP 2001-333420 A

  When an LED is used as illumination, a light distribution lens is generally used in order to make the light of the LED with strong directivity into photographing auxiliary light with a wide irradiation range. In that case, shading inevitable occurs in the photographed image due to a decrease in the amount of peripheral light due to the optical characteristics of the light distribution lens, with the central portion being brighter and the peripheral portion being darker.

  Therefore, when shooting an object whose position changes within the angle of view, for example, if the object moves from the central part to the peripheral part within the angle of view, the image becomes dark, and the image quality of the captured image decreases due to insufficient light quantity. It becomes. There is a problem that such a problem cannot be solved even if the dynamic range is expanded using the above-described prior art.

  The present invention has been made in view of such conventional problems, and obtains an image with high quality image quality even when shooting an object using shooting auxiliary light with uneven irradiation light quantity. It is an object of the present invention to provide an imaging apparatus, an imaging method, and a program capable of performing the above.

To solve the above problems, the imaging apparatus of the present invention includes an imaging means for imaging an object that moves in succession, and irradiating means for irradiating continuously auxiliary photographic light to an object to the move, the irradiation the amount of auxiliary photographic light means is continuously irradiated with the object to the move, that a light amount control means for sequentially determined according to the position of the subject changes have you in the imaging screen of the imaging means Features.

  According to the present invention, it is possible to obtain an image in which high quality image quality is ensured even when photographing an object using photographing auxiliary light having a non-uniform amount of irradiation light.

It is a block diagram which shows the imaging device which concerns on the 1st and 2nd embodiment of this invention. (A) is a figure which shows the light distribution characteristic of imaging assistance light, (b) is a figure which shows the irradiation area | region of imaging assistance light within an angle of view. It is the flowchart which showed the process regarding the light quantity control of imaging | photography auxiliary light in 1st Embodiment. It is explanatory drawing which illustrates the position in the image of a moving object in 1st Embodiment. It is the flowchart which showed the process regarding the light quantity control of the imaging | photography auxiliary light in 2nd Embodiment. It is explanatory drawing which illustrates the position in the image of a moving object in 2nd Embodiment.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus 1 common to the first embodiment and a second embodiment to be described later.

  As shown in FIG. 1, the imaging apparatus 1 includes a main CPU (Central Processing Unit) 2, an imaging sensor 3, an imaging lens 4, an LCD (Liquid Crystal Display) 5, an image memory 6, a key input block 7, and an auxiliary light block. 8 and a power supply block 9.

  A main CPU (hereinafter simply referred to as a CPU) 2 includes an image processing block 11, a working memory 12 such as a RAM (Random Access Memory), and a ROM (Read Only Memory) 13, and controls the operation of the entire apparatus. To do. The ROM 13 stores various programs and data for causing the CPU 2 to perform control of each unit of the imaging apparatus 1, AE (Auto Exposure) control, and control of the amount of photographing auxiliary light described later.

  The image sensor 3 is a CCD (Charge Coupled Device) or CMOS (Complementary Meta 10xide Semiconductor) type image sensor that can be driven at a high frame rate (for example, 200 fps to 1000 fps). The subject is imaged at the rate, and the imaging signal is sent to the image processing block 11 of the CPU 2.

  The image processing block 11 generates image data for recording by performing analog processing, conversion processing to digital signals, and various types of image processing on the imaging signal sent from the imaging sensor 3. Further, the image processing block 11 compresses the generated image data as still image data by a JPEG (Joint Photographic Expert Group) method or the like, or compresses it as moving image data by an MPEG (Motion Picture Experts Group) method or the like.

  The compressed still image data and moving image data are recorded in the image memory 6. Still image data and moving image data recorded in the image memory 6 are decompressed in the image processing block 11 and then reproduced (displayed) as a still image or a moving image on the LCD 5.

  The key input block 7 includes a power key, a shutter key, and a plurality of operation keys used for operation of the imaging device 1. The operation state of the operation key in the key input block 7 is sent to the CPU 2 as needed.

  The power supply block 9 includes a rechargeable battery, a DC / DC converter, and the like, and supplies power necessary for operation to each unit of the imaging apparatus 1.

  The auxiliary light block 8 includes a high-brightness LED 21 that is a light source, an LED control block 22, and a light distribution lens 23, and irradiates the subject with light emitted from the LED 21 as photographing auxiliary light through the light distribution lens 23. .

  The LED control block 22 supplies a predetermined drive current to the LED 21 to cause the LED 21 to emit light, and controls the light emission amount of the LED 21 by controlling the drive current according to a command from the CPU 2. More specifically, the light emission amount of the LED 21 is controlled in a plurality of stages as will be described later. In addition, unlike a flash or the like, the light emission is not repeated every time the image is taken, but the light is emitted continuously during the image taking.

  The light distribution lens 23 enlarges the irradiation angle of the highly directional light emitted from the LED 21 and controls the light distribution characteristic of the photographing auxiliary light.

  FIG. 2A is a diagram illustrating a light distribution characteristic of the photographing auxiliary light by the light distribution lens 23. This figure shows the light distribution characteristics in the left-right direction. The light intensity shown on the vertical axis in FIG. 2A is a ratio when the maximum intensity is 100%. As shown in the drawing, the light distribution characteristic of the photographing auxiliary light is 30 degrees with respect to the optical axis. If it becomes above, it is the characteristic which the intensity | strength of light falls rapidly.

  FIG. 2B is a diagram showing an irradiation area of the photographing auxiliary light within the angle of view of the imaging apparatus 1. The irradiation area has an elliptical shape with a narrow light distribution angle in the vertical direction with respect to the horizontal direction. Further, in the irradiation region, the peripheral light amount decreases with respect to the light amount at the center of the optical axis due to the optical characteristics of the light distribution lens 23. For this reason, when imaging is performed by irradiating with imaging assistance light in a dark environment, shading occurs in the captured image.

  On the other hand, in the present embodiment, the three brightness areas shown in FIG. 2B are set in advance in the irradiation area of the photographing auxiliary light. That is, in the irradiation area of the photographing auxiliary light, there are three areas: a first brightness area A located at the center, a second brightness area B outside the center, and a third brightness area C located further outside. Is set. The outer edges of the first to third brightness areas A, B, and C are ellipses that can represent the coordinate position, size, and flatness in the imaging screen imaged by the imaging sensor 3 by a predetermined function. It is.

  The first to third brightness areas A, B, and C are areas when the brightness of the irradiation area is divided into three stages, and shooting is performed at the time of moving image shooting using shooting auxiliary light as described later. This is a region that serves as a control reference when controlling the amount of auxiliary light according to the position in the imaging screen of a moving object that is the main subject.

  In other words, the first brightness area A in the center of the irradiation area is an area that treats the brightness within the entire area as the maximum (100%) when controlling the light amount of the photographing auxiliary light. The second brightness area B is an area that is handled as a brightness that is 20% lower than the maximum brightness in the entire area. The third brightness area C is an area that is handled as a brightness that is reduced by 50% from the maximum brightness in the entire area.

  In the imaging apparatus 1 having the above-described configuration, the LED 21 is automatically turned on to irradiate the subject with shooting auxiliary light during moving image shooting when proper exposure cannot be obtained. Here, the case where the proper exposure cannot be obtained is a case where the surrounding is dark, for example, at night, or a case where the frame rate used is high and the exposure time that can be secured within one frame period is extremely short. Note that moving image shooting at a high frame rate is performed on an object that moves at high speed (baseball, golf, tennis ball, etc. immediately after impact), for example, and is performed with the imaging device 1 fixed to a tripod or the like. Is expected.

  In addition, during the moving image shooting, the imaging device 1 controls the light emission amount of the LED 21 so that the amount of the photographing auxiliary light at the imaging timing of each frame corresponds to the position of the moving object that is the main subject in the imaging screen. Control the amount of light emitted.

  Specifically, the light emission amount of the LED 21 is controlled to a predetermined light emission amount set in advance corresponding to each of the first to third brightness areas A, B, and C. The preset light emission amount is 50% of the maximum light emission amount in the first brightness region A, 62.5% of the maximum light emission amount in the second brightness region B, and the third brightness. Region C is the maximum light emission amount (100%).

  That is, the light emission amount set in the first brightness region A is the brightness of an arbitrary moving object located at a position where the peripheral light amount does not decrease within the angle of view. % Is the amount of light emitted to make it equal to the brightness of an arbitrary moving object located at a location where the percentage has decreased. Similarly, the light emission amount set in the second brightness region B is the brightness of an arbitrary moving object located at a position where the brightness is reduced by 20% due to the decrease in the peripheral light amount within the angle of view. Is a light emission amount for making the brightness equal to the brightness of an arbitrary moving object located at a location where the brightness is reduced by 50% due to the decrease in the brightness.

  Hereinafter, the above-described light amount control of the auxiliary photographing light in the imaging apparatus 1 will be specifically described. FIG. 3 is a flowchart showing processing related to the light amount control of the photographing auxiliary light, which is executed by the CPU 2 based on the program stored in the ROM 13 at the time of moving image photographing.

  At the time of moving image shooting, the CPU 2 first assumes that an arbitrary moving object is located in the first brightness area A in the imaging screen, and is set in the LED control block 22 to the first brightness area A. The LED 21 is turned on with a light emission amount that is 50% of the maximum light emission amount (step SA1).

  The reason why the light emission amount of the LED 21 is set to 50% of the maximum light emission amount is that it is expected that the moving object is often in the first brightness region A at the beginning of photographing.

  Next, the CPU 2 starts shooting a moving image (step SA2). That is, the CPU 2 starts driving the image sensor 3 at a predetermined frame rate. In the following description, it is assumed that the frame rate is set to 200 fps.

  Further, the CPU 2 starts counting the number of frames as soon as it starts shooting a moving image (step SA3).

  Thereafter, the CPU 2 detects a moving object in the image based on the first frame image and the second frame image at the stage of obtaining the second frame image (step SA4: YES), and both images. The position of the moving object within the frame and the amount of movement of the moving object between the frames are acquired (step SA5).

  Specifically, for example, the CPU 2 divides both frame images into a plurality of detection blocks, detects a motion vector by a known method such as a block matching method using the detection block as a unit, and then detects the magnitude of the detected motion vector. The area is divided into a plurality of stages, and an area composed of a plurality of detection blocks in which the maximum motion vector is detected is specified as an area corresponding to the moving object. Then, for the specified region, that is, the moving object, the position in the first frame image and the position in the second frame image are acquired, and the moving amount of the moving object between frames is acquired. Note that the position of the moving object acquired by the CPU 2 in the process of step SA5 is the coordinate position of the center of the moving object in the image space.

  Thereafter, when the position of the moving object in the image of the second frame, that is, the current position is the first brightness area A (step SA6: YES), the CPU 2 immediately detects by the process of step SA5. The moving speed of the moving object is calculated based on the amount of movement and the imaging interval corresponding to the frame rate (here, 5 msec) (step SA8).

  If the current position of the moving object is not the first brightness region A (step SA6: NO), the CPU 2 causes the LED control block 22 to switch the drive current of the LED 21, and the amount of light emitted from the LED is determined by the moving object. Is controlled to a light emission amount corresponding to the brightness region where the current position is (step SA7).

  That is, the CPU 2 controls the light emission amount of the lit LED 21 to 62.5% of the maximum light emission amount when the current position of the moving object is the second brightness region B, and the current position of the moving object is In the third brightness region C, the maximum light emission amount (100%) is controlled. Thereafter, the CPU 2 calculates the moving speed of the moving object (step SA8).

  Next, the CPU 2 changes the moving direction in which the moving object is determined from the position (center position) of the moving object in the first frame image and the position (center position) of the moving object in the second frame image. Instead, all the coordinate positions of the passing points of the region boundaries in the first to third brightness regions A, B, and C, which are expected to pass when moving in the same direction, are acquired (step SA9). .

  More specifically, the CPU 2 assumes a straight line passing through the center of the moving object in the first frame image specified in the process of step SA5 and the center of the moving object in the second frame image. A point that intersects one of the region boundaries on the moving direction side of the moving object is defined as a passing point, and the coordinate positions of all the passing points are acquired.

  At this time, for example, in the image of the first frame, the center of the moving object X is the center of the image as shown in FIG. When the center of the object X is the position shown in FIG. 4B, there are two passing points.

  That is, the two passing points are the right direction of the moving object X shown in FIG. 4B, and the straight line shown by the broken line in FIG. 4B is the boundary between the first brightness area A and the first brightness area B. The first passing point K1 that intersects the line and the second passing point K2 that intersects the boundary line between the second brightness region B and the third brightness region C.

  Next, after acquiring the coordinate position of the passing point described above, the CPU 2 moves the position of the moving object in the second frame image, the position of each passing point (may be one), and the moving speed of the moving object. Based on the above, the required time is calculated until the moving object reaches each passing point (step SA10).

  Further, the CPU 2 calculates the number of frames according to the time required to reach each passing point, and uses the calculated previous frame number as the number of specific frames whose light emission amount of the LED 21 should be changed. Is stored in association with the brightness area of the movement destination where the moving object is located (step SA11). Here, the brightness area of the movement destination is, for example, the second brightness area when the number of specific frames is the number of frames according to the required time to the first passing point K1 shown in FIG. B.

  Thereafter, every time the CPU 2 acquires an image of a new frame after the third frame (step SA12: YES), the CPU 2 confirms whether or not the number of frames at that time has reached the specific number of frames stored in the process of step SA11. (Step SA13).

  Further, the CPU 2 acquires a new frame image until acquisition of a new frame image (step SA12: NO), and when the number of frames at that time is not the specific frame number (step SA13: NO). Whether or not the end of shooting has been instructed is confirmed. If the end of shooting has not been instructed (step SA15: NO), the process returns to step SA12 as it is.

  If the number of frames when the image of a new frame is acquired is the specific frame number (step SA13: YES), the CPU 2 corresponds the light emission amount of the LED 21 to the specific frame number in the process of step SA11. Then, the light emission amount is controlled according to the stored brightness area (step SA14).

  That is, for example, when the number of specific frames is the number of frames according to the required time to the first passing point K1 shown in FIG. 4B, the CPU 2 sets the light emission amount of the LED 21 to the second brightness region. The light emission amount is controlled to 62.5% of the maximum light emission amount set for B.

  Thereafter, the CPU 2 returns to the process of step SA12 as it is until the end of shooting is instructed (step SA15: NO), and repeats the process described above.

  As a result, the CPU 2 determines that the number of frames when a new frame image is acquired before the end of shooting is instructed corresponds to the required time to the second passing point K2 shown in FIG. When the number of frames (specific frame number) is reached, the light emission amount of the LED 21 is controlled to the maximum light emission amount set in the third brightness region C.

  Then, when the end of shooting is instructed at any time (step SA15: YES), the CPU 2 turns off the LED 21 (step SA16) and ends the process.

  As described above, in the present embodiment, the amount of light of the auxiliary photographing light is controlled to the amount of light emission according to the position of the moving object in the imaging screen during moving image photographing in which the subject is irradiated with the photographing auxiliary light. Thereby, a decrease in the peripheral light amount due to the optical characteristics of the light distribution lens 23 in the imaging screen can be compensated by adjusting the light amount of the photographing auxiliary light. Therefore, even when photographing an object using photographing auxiliary light having a non-uniform amount of irradiation light, an image with a high quality image can be obtained.

  In the present embodiment, the light amount of the photographing auxiliary light is set in advance corresponding to each of the first to third brightness regions A, B, and C obtained by dividing the irradiation region of the photographing auxiliary light according to the light amount distribution. The amount of emitted light is controlled. Therefore, it is possible to efficiently control the amount of photographing auxiliary light.

  In the present embodiment, the moving speed of the moving object in the imaging screen is calculated, the time required for the moving object to reach different brightness areas is calculated based on the moving speed, and the required time has elapsed. Each time the control is performed, the light emission amount set in the brightness area of the movement destination is controlled.

  That is, in the present embodiment, based on the moving speed of the moving object, the position of the moving object at the imaging operation timing when the moving object reaches different brightness regions, that is, the movement destination is predicted, and the light amount of the photographing auxiliary light Is controlled to the light emission amount set in the predicted brightness area of the movement destination. Accordingly, it is possible to simplify the processing related to the light amount control of the auxiliary photographing light after predicting one or a plurality of destinations.

  In this embodiment, the CPU 2 counts the number of frames during moving image shooting, and causes the LED control block 22 to switch the drive current supplied to the LED 21 when the number of frames reaches the specific number of frames described above. The configuration. However, with regard to such a configuration, for example, the LED control block 22 counts the number of frames during moving image shooting, and the LED control block 22 causes the drive current to be supplied to the LED 21 when the number of frames being counted reaches a specific number of frames. Can be automatically switched.

  In that case, for example, the LED control block 22 is separately provided with a timing generator that generates a timing signal synchronized with the driving timing of the imaging sensor 3 during moving image shooting, and a counter for counting the number of frames.

  And the structure which sends the information which shows the drive current corresponding to the 1 or several specific frame number mentioned above and the specific frame number to LED control block 22 collectively from CPU2, and makes LED control block 22 memorize | store in advance. do it.

  Further, in the present embodiment, the number of the specific frames is determined according to the time required for the moving object X to reach the first passing point K1 or the second passing point K2 in the example shown in FIG. The number of frames is one before the number. That is, the light emission amount of the LED 21 is switched immediately before the moving object X reaches the new brightness regions B and C. However, the timing for switching the light emission amount of the LED 21 may be the time when the moving object X reaches the new brightness regions B and C.

  In this embodiment, the moving speed of the moving object is acquired at the stage of acquiring the image of the second frame after the start of the moving image shooting. You may acquire in the acquired stage. For example, the CPU 2 performs the processing from step SA5 onward when the fourth frame image is acquired, and the moving speed of the moving object is determined based on any one of the plurality of images from the first frame image to the fourth frame image. It may be acquired.

  As described above, when the moving speed of the moving object is acquired at the stage where the image of the third and subsequent frames is acquired, a more accurate moving speed can be acquired as the moving speed of the moving object. Can be calculated more accurately.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the present embodiment, in the imaging apparatus 1 having the configuration described in the first embodiment, the CPU 2 executes the following processing that is different from that of the first embodiment based on a program stored in the ROM 13. .

  That is, FIG. 5 is a flowchart showing processing related to the light amount control of the photographing auxiliary light executed by the CPU 2 during moving image photographing in the present embodiment.

  Also in this embodiment, at the time of moving image shooting, the CPU 2 first assumes that an arbitrary moving object is located in the first brightness area A in the imaging screen, and the LED control block 22 receives the first brightness. The LED 21 is turned on with the light emission amount set in the area A, that is, the light emission amount 50% of the maximum light emission amount (step SB1).

  Next, the CPU 2 starts shooting a moving image (step SB2). That is, the CPU 2 starts driving the image sensor 3 at a predetermined frame rate.

  Thereafter, the CPU 2 detects a moving object in the image based on the first frame image and the second frame image at the stage of acquiring the second frame image (step SB3: YES), and both images. The position of the moving object in the frame and the moving amount of the moving object between the frames are acquired (step SB4).

  Thereafter, when the position of the moving object in the image of the second frame, that is, the current position is the first brightness area A (step SB5: YES), the CPU 2 immediately proceeds to the process of step SB9. To do. On the other hand, if the current position of the moving object is not the first brightness region A (step SB5: NO), the CPU 2 controls the light emission amount of the lit LED to the light emission amount corresponding to the current position (step SB5). SB6). Thereafter, the CPU 2 proceeds to the process of step SB9.

  Note that the processing from step SB4 to step SB6 is the same as the processing from step SA5 to step SA7 shown in FIG. 3 in the first embodiment.

  On the other hand, in the subsequent process of step SB9, the CPU 2 moves the moving object in the next frame, which is predicted when the moving object moves the movement amount acquired in the process of step SB4 without changing the moving direction. To get. In the process of step SB9 immediately after the second frame image is acquired, the moving direction of the moving object is the position (center position) of the moving object in the first frame image acquired in the process of step SB4, and two frames. The moving direction is determined from the position (center position) of the moving object in the eye image.

  For example, the center of the moving object X in the first frame image is the center within the angle of view as shown in FIG. 6A, and the position of the moving object X in the second frame image is shown in FIG. If the movement amount is the movement amount L shown in FIG. 6B, the movement destination position is the position indicated by P in the drawing.

  Next, the CPU 2 confirms whether or not the moving destination of the moving object X is a brightness area different from the current brightness area, and in the case where it is not a different brightness area, that is, illustrated in FIG. 6B. As described above, when both the current area and the movement destination are the first brightness area A (step SB10: NO), it is confirmed whether or not the end of shooting has been instructed and the end of shooting must be instructed. If (step SB12: NO), the process proceeds to step SB7.

  Each time the CPU 2 acquires an image of a new frame after the third frame (step SB7: YES), the CPU 2 tracks the moving object detected in the immediately previous frame and acquires the position of the moving object in the image of the new frame. Then, the movement amount between the immediately preceding frame is acquired (step SB8).

  Thereafter, the CPU 2 acquires the position of the moving object predicted when the moving object moves the movement amount acquired in step SB8 without changing the moving direction (step SB9). Note that the moving direction of the moving object used in such processing is, for example, immediately after acquiring the third frame image, the position of the moving object in the second frame image acquired in step SB4, and the step SB8. This is the moving direction that can be determined from the position of the moving object in the third frame image acquired by the processing. Further, the moving direction used immediately after the acquisition of the fourth and subsequent images is a moving direction that can be determined from the position of the moving object in each successive frame acquired in the process of step SB8.

  If the brightness area of the movement destination is not an area different from the current brightness area (step SB10: NO), the CPU 2 performs the processing from step 7 onward until the end of shooting is instructed (step SA12: NO). repeat.

  After that, when an image of any frame is acquired, when the movement destination of the moving object in the predicted next frame is a brightness area different from the current brightness area (step SB10: YES), The CPU 2 controls the light emission amount of the LED 21 to the light emission amount according to the brightness area of the movement destination (step SB11).

  That is, as illustrated in FIG. 6C, when the current area is the first brightness area A and the movement destination area is the second brightness area B, the CPU 2 determines that the moving object X is At the timing just before moving to the second brightness region B, the light emission amount of the LED 21 is controlled to 62.5% of the maximum light emission amount set in the second brightness region B.

  Thereafter, until the end of shooting is instructed (step SB12: NO), the CPU 2 returns to the process of step SB7 and repeats the above-described process.

  As a result, when the CPU 2 acquires the image of a new frame before the end of shooting is instructed, the movement destination of the moving object in the predicted next frame becomes the third brightness region C. At that time, the light emission amount of the LED 21 is controlled to the maximum light emission amount set in the third brightness region C.

  Then, when the CPU 2 is instructed to end photographing at any time (step SB12: YES), the LED 21 is turned off at that time (step SB13), and the processing is ended.

  As described above, also in the imaging apparatus 1 according to the present embodiment, the amount of the shooting assistance light is controlled to the light emission amount according to the position of the moving object in the imaging screen during shooting of the moving image in which the shooting auxiliary light is irradiated to the subject. . Thereby, a decrease in the peripheral light amount due to the optical characteristics of the light distribution lens 23 in the imaging screen can be compensated by adjusting the light amount of the photographing auxiliary light. Therefore, even when photographing an object using photographing auxiliary light having a non-uniform amount of irradiation light, an image with a high quality image can be obtained.

  Further, the light amount of the photographing auxiliary light is set to a light emission amount set in advance corresponding to each of the first to third brightness regions A, B, and C obtained by dividing the irradiation region of the photographing auxiliary light according to the light amount distribution. By controlling, it is possible to efficiently control the light amount of the photographing auxiliary light.

  Also, in the present embodiment, unlike the first embodiment, each time a new frame image is acquired, the movement destination of the moving object in the next frame is determined based on the movement amount of the moving object between frames. Predicting and controlling the amount of photographing auxiliary light according to the predicted destination area. Therefore, in the present embodiment, even when the moving direction of the moving object changes in an arbitrary direction at an arbitrary time during moving image shooting, it is possible to cope with it.

  In the present embodiment, every time the second and subsequent frames are acquired, if the predicted movement destination is a brightness area different from the current brightness area, the amount of photographing auxiliary light is predicted and moved. It is assumed that the control is performed according to the previous area, and as in the first embodiment, the light emission amount of the LED 21 is switched immediately before the moving object X reaches the new brightness areas B and C. However, as described in the first embodiment, the timing for switching the light emission amount of the LED 21 may be the time when the moving object X reaches the new brightness regions B and C.

  When the timing at which the light emission amount of the LED 21 is switched is the time when the moving object X reaches new brightness regions B and C, for example, the position of the moving object in the image every time a new frame image is acquired. Then, the light amount of the auxiliary photographing light may be controlled to the light amount set in the brightness area including the confirmed position. Even in this case, as in the present embodiment, if the moving direction of the moving object changes to an arbitrary direction at an arbitrary time during moving image shooting, it can be dealt with.

  Here, in the first and second embodiments described above, the configuration in which the light emission amount of the LED 21 is controlled by the drive current has been described. However, the present invention is not limited to this, and the light emission amount of the LED 21 is, for example, the LED 21 for one frame period. Control may be performed by causing the pulse light to be emitted and switching the duty ratio.

  In the first and second embodiments, the configuration in which the imaging assist light is generated by the LED 21 and the light distribution lens 23 has been described. However, in the present invention, the configuration of the irradiation means for irradiating the subject with the photographing auxiliary light is arbitrary, the light source may be other than the LED 21, and the light distribution lens 23 may be integrally formed with the light source.

  Further, the auxiliary light block 8 shown in the first and second embodiments may be an external device that is detachable from the imaging device 1. In that case, for example, characteristic information relating to the light distribution characteristic of the photographing auxiliary light may be stored in an external device, and the characteristic information may be supplied to the CPU 2 from the external device.

  In the first and second embodiments, the first to third brightness areas A, B, and C are set in the irradiation area of the photographing auxiliary light by dividing the brightness in the irradiation area into three stages. In the above description, the configuration in which the amount of the photographing auxiliary light is controlled in three steps according to the brightness region where the moving object is located has been described.

  However, in the case of controlling the light amount of the photographing auxiliary light step by step, it is desirable to control the light amount of the photographing auxiliary light in more stages. Further, the light amount of the photographing auxiliary light is the irradiation region of the photographing auxiliary light. It is preferable to control in a stepless manner according to the position of the moving object.

  That is, if the configuration is such that the light amount of the photographing auxiliary light is controlled step by step with a larger number of steps, the decrease in the peripheral light amount due to the optical characteristics of the light distribution lens 23 in the imaging screen can be reduced by adjusting the light amount of the photographing auxiliary light. Thus, compensation can be made more effectively, and uniform brightness can be ensured by the moving object regardless of the position within the angle of view during moving image shooting. As a result, it is possible to obtain a moving image in which higher quality image quality is ensured throughout the entire period.

  Furthermore, if the configuration is such that the light amount of the photographing auxiliary light is controlled steplessly, the decrease in the peripheral light amount due to the optical characteristics of the light distribution lens 23 in the imaging screen is almost completely compensated by adjusting the light amount of the photographing auxiliary light. Thus, during moving image shooting, uniform brightness can be ensured on the moving object regardless of the position within the angle of view. As a result, it is possible to obtain a moving image in which extremely high image quality is ensured throughout the entire period.

  In addition, when adopting a configuration that controls the amount of shooting auxiliary light steplessly, the decrease in the amount of peripheral light in the shooting auxiliary light is a decrease due to the ratio of the cosine fourth law, so the position of the moving object in the imaging screen The corresponding amount of photographing auxiliary light (the amount of light emitted from the LED 23) can be calculated. That is, the amount of the photographing auxiliary light is, for example, flat according to the horizontal distance and vertical distance between the position (center position) of the moving object in the imaging screen and the center of the imaging screen corresponding to the optical axis, and the flatness of the irradiation area. It can obtain | require by calculation using a coefficient.

  In addition, as described in the first and second embodiments, the amount of photographing auxiliary light (the amount of light emitted from the LED 23) is determined according to the position of the subject and the brightness of a conventional subject is measured. Depending on whether the subject is moving or whether the moving speed is fast or slow, the method that is determined according to the measurement result may be used separately.

  In addition, as a method for determining the amount of photographing auxiliary light (the amount of light emitted from the LED 23), the distance is measured, the determination method is based on the measured distance and position, and the brightness of the entire screen is measured to correspond to the position of the subject. The method of adjusting the position can be considered.

  In the first and second embodiments, the case where there is one moving object that is the main subject has been described. However, when there are a plurality of moving objects, for example, a plurality of moving objects are used according to a predetermined standard. A priority may be set, and the amount of photographing auxiliary light may be controlled according to the position of the moving object having the highest priority. In that case, even if there are a plurality of moving objects, the moving object that the photographer assumed in advance can be used as the main subject, and the subject can be reliably photographed in a good state.

  For example, the moving speed of the moving object can be used as the priority setting criterion. In this case, for example, the priority of the moving object having the fastest moving speed can be maximized. Further, for example, the type of moving object (subject) can be used as the priority setting reference, and in this case, the type of moving object having the highest priority can be used as the face of a person.

  Further, in the present invention, the main subject is not necessarily a moving object. In other words, the present invention is effective not only for moving objects but also for shooting moving images in a state where a stationary object or a person is the main subject and irradiation with auxiliary shooting light with a reduced amount of peripheral light is applied.

  For example, when shooting a moving object or person standing still in a dark environment, the position of the object or person within the angle of view is intentionally changed by changing the orientation of the imaging device in order to obtain a production effect. Even in the case of changing to, good brightness can be secured for the main subject during moving image shooting regardless of the position within the angle of view. Therefore, even in such a case, it is possible to obtain a moving image in which an extremely good image quality is ensured throughout the entire period.

  Further, in the first and second embodiments, when the LED that is the light source of the photographing auxiliary light is single and the irradiation region of the photographing auxiliary light is divided into a plurality of brightness regions, each brightness region Has been described as a continuous structure without being divided by other brightness regions. However, according to the present invention, for example, when the light source of the photographing auxiliary light is a plurality of LEDs and the irradiation region of the photographing auxiliary light is divided into a plurality of brightness regions, the brightness region having the same brightness range is irradiated. Even a configuration in which a plurality of areas are present is effective.

  In the above description, it is assumed that the subject is irradiated with shooting auxiliary light mainly over the entire period from the start to the end of moving image shooting. However, the effect of the present invention is necessary, for example, during moving image shooting. Accordingly, it can be obtained even when the subject is temporarily irradiated with the photographing auxiliary light.

  As an example, if it is detected that a moving object has entered within the angle of view after starting moving image shooting, irradiation of the auxiliary shooting light started at that time, and the moving object has come out of the angle of view. If it is detected, it may be considered that the irradiation of the photographing auxiliary light is terminated at that time. In that case, the effect of the present invention can be obtained regardless of the length of the irradiation time of the photographing auxiliary light.

  As mentioned above, although several embodiment of this invention and its modification were demonstrated, if these are in the range in which the effect of this invention is acquired, it can change suitably, and embodiment after change is also a claim. It is included in the scope of the invention described in the scope of the invention and the invention equivalent to the invention.

The invention described in the scope of the claims of the present application will be appended below.
[Claim 1]
An imaging unit that images the subject, an irradiating unit that irradiates the subject with shooting auxiliary light, and a light amount of the shooting auxiliary light that the irradiation unit irradiates the subject according to the position of the subject in the imaging screen of the imaging unit An image pickup apparatus comprising: a light amount control means for performing the above operation.
[Claim 2]
2. The imaging according to claim 1, wherein the light amount control unit determines the light amount of the photographing auxiliary light according to the position of the subject at the imaging timing in a stage where the brightness measurement of the subject at the imaging timing is not performed. apparatus.
[Claim 3]
2. The light quantity control unit controls the light quantity of the photographing auxiliary light to a light quantity according to a light quantity distribution of the photographing auxiliary light in the imaging screen and a position of a subject in the imaging screen. Or the imaging device of 2.
[Claim 4]
The irradiation unit includes a light distribution control unit that controls a light distribution characteristic of the photographing auxiliary light, and the light amount control unit distributes the light amount of the photographing auxiliary light by the light distribution control unit in the imaging screen. 4. The image pickup apparatus according to claim 3, wherein the light quantity is controlled according to the position of the subject in the imaging screen of the imaging means based on the light quantity distribution of the photographing auxiliary light whose optical characteristics are controlled.
[Claim 5]
The imaging apparatus according to any one of claims 1 to 4, wherein the light amount control means determines the light amount according to the photographing position of the subject at a timing before the subject completes moving to the photographing position.
[Claim 6]
Based on the movement amount acquired by the movement amount acquisition means, the movement amount acquisition means for acquiring the movement amount of the subject within the predetermined time in the imaging screen, the imaging screen at the imaging operation timing of the imaging means Predicting means for predicting the position of the subject in the camera, wherein the light quantity control means controls the light quantity of the photographing auxiliary light to a light quantity according to the position of the subject predicted by the predicting means. The imaging device according to claim 1.
[Claim 7]
The predicting unit calculates a moving speed of the subject based on the moving amount acquired by the moving amount acquiring unit, and based on the calculated moving speed, the object in the imaging screen at the imaging operation timing of the imaging unit. The imaging apparatus according to claim 6, wherein the position is predicted.
[Claim 8]
The movement amount acquisition means periodically acquires the movement amount of the subject within a predetermined time in the imaging screen, and the prediction means, based on the movement amount periodically acquired by the movement amount acquisition means, The imaging apparatus according to claim 6, wherein the position of the subject in the imaging screen at the imaging operation timing of the imaging unit is predicted.
[Claim 9]
The light amount control unit controls the light amount of the photographing auxiliary light to a light amount according to a position of a subject having the highest priority among a plurality of subjects in an imaging screen of the imaging unit. The imaging device according to any one of 1 to 8.
[Claim 10]
An imaging method comprising: determining a light amount of photographing auxiliary light for irradiating a subject imaged by an imaging unit according to a position of a subject in an imaging screen of the imaging unit.
[Claim 11]
A computer having an image pickup apparatus including an image pickup unit that picks up an image of an object and an irradiation unit that irradiates the subject with shooting auxiliary light. The amount of the shooting auxiliary light that the irradiation unit irradiates the subject is set in an image pickup screen of the image pickup unit. Functioning as a light amount control means that is determined according to the position of the subject in the program.

1 Imaging device 2 Main CPU
3 Imaging sensor 4 Imaging lens 5 LCD
6 Image memory 7 Key input block 8 Auxiliary light block 9 Power supply block 11 Image processing block 12 Memory 13 ROM
21 LED
22 LED control block 23 Light distribution lens A 1st brightness area B 2nd brightness area C 3rd brightness area K1 1st passage point K2 2nd passage point L Movement amount X Moving object

Claims (11)

Imaging means for continuously imaging a moving subject;
Irradiating means for continuously irradiating photographing auxiliary light to the moving subject;
The amount of auxiliary photographic light the irradiation unit irradiates continuously to subject to the movement, and a light amount control means for sequentially determined according to the position of the subject changes have you in the imaging screen of the imaging means An imaging apparatus characterized by that. A moving image acquisition unit that acquires a moving image from images continuously captured by the imaging unit that images the moving subject;
The moving subject included in the moving image acquired by the moving image acquisition unit is irradiated with photographing auxiliary light continuously irradiated by the irradiation unit with a light amount sequentially determined by the light amount control unit . The imaging apparatus according to claim 1. The light amount control unit controls the light amount of the photographing auxiliary light to a light amount distribution according to a light amount distribution of the photographing auxiliary light in the imaging screen and a position of the moving subject in the imaging screen. The imaging device according to claim 1 or 2. The irradiation unit includes a light distribution control unit that controls a light distribution characteristic of the photographing auxiliary light,
The light amount control unit is configured to capture the light amount of the photographing auxiliary light based on the light amount distribution of the photographing auxiliary light whose light distribution characteristic is controlled by the light distribution control unit in the imaging screen. The image pickup apparatus according to claim 3, wherein the amount of light is controlled according to the position of the moving subject in the camera. The light quantity control means to claim 1, characterized in that said irradiating means to determine the light intensity according to the position of the object to the moving timing before the timing at which it is necessary to vary the amount of auxiliary photographic light 4. The imaging device according to any one of 4. The imaging means performs imaging continuously at an imaging operation timing of a predetermined cycle,
A displacement acquiring means for acquiring a movement amount in one or more predetermined periods of the object to the movement in the imaging screen,
Prediction means for predicting the position of the moving subject in the imaging screen at the imaging operation timing after the timing at which the movement amount by the imaging means is acquired based on the movement amount acquired by the movement amount acquisition means. And further comprising
The imaging apparatus according to any one of claims 1 to 5, wherein the light amount control unit controls the light amount of the photographing auxiliary light to a light amount according to the position of the moving subject predicted by the prediction unit. . The prediction means, a moving speed of the object which the moving based on the movement amount obtained by the displacement acquiring means calculates, based on the calculated moving speed, the moving amount of the imaging operation of the imaging means is obtained The imaging apparatus according to claim 6, wherein a position of the moving subject in the imaging screen at a timing after the timing is predicted. The moving amount acquisition means acquires the movement amount sequentially in one or more predetermined periods of the object to the movement in the imaging screen,
Said predicting means, on the basis of the movement amount obtained in succession by the moving amount acquisition unit, wherein the movement in the imaging screen of the imaging operation timing of the subsequent movement amount is acquired timing by said image pickup means The imaging apparatus according to claim 6, wherein the position of the subject is predicted.   The light amount control unit controls the light amount of the photographing auxiliary light to a light amount according to a position of a subject having the highest priority among a plurality of subjects in an imaging screen of the imaging unit. The imaging device according to any one of 1 to 8. The amount of auxiliary photographic light continuously by the image pickup means for continuously irradiated with the subject moving being imaged, to sequentially determined according to the position of the subject changes have you in the imaging screen of the imaging means A characteristic imaging method. Imaging means for imaging an object that moves in succession, and irradiating means for irradiating continuously auxiliary photographic light to an object to the mobile, a computer imaging apparatus having equipped with, on the subject in the irradiation unit is the moving the amount of auxiliary photographic light to be irradiated, a program for causing to function as light quantity control means for sequentially determined according to the position of the subject changes at the imaging screen of the imaging means.

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