JP2004064661A - Photographic apparatus and photographic method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographic apparatus and a photographic method using the same in which photographing is accurately performed in accordance with the state of a photographic subject. <P>SOLUTION: In order to photograph a series of changes of the photographic subject, conditions such as a unit photographing time, the number of times of exposure within the unit photographing time and an exposure time are inputted to a control part 11 beforehand for every unit photographing time to control driving of an imaging device 7. Image information for every unit photographing time resulting from photographing is digitally converted by an image processing part 8 and stored in a main storage part 9 after carrying out various kinds of image working processing, and the stored image information is outputted and displayed on a monitor 3 as occasion demands. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-speed imaging apparatus such as a video camera, and in particular, to scientific measurements such as high-speed moving objects such as rockets, explosions, turbulence, discharge phenomena, movement of microorganisms under a microscope, and signal transmission of the brain and nervous system. The present invention relates to a technique for performing photographing by using the camera.
[0002]
[Prior art]
2. Description of the Related Art As a conventional image pickup apparatus, for example, there is a video camera that realizes high-speed photographing at 1 million frames / sec. This imaging apparatus realizes high-speed imaging by including an image sensor called a “pixel peripheral recording solid-state image sensor” as described below. This pixel peripheral recording type solid-state imaging device distinguishes and accumulates a light receiving pixel for photoelectrically converting incident light and a charge signal group generated in the light receiving pixel for each of a plurality of frames (images) at different photographing times. The solid-state imaging device has a plurality of unit pixels including a plurality of storage pixels and outputs a charge signal group of each storage pixel after high-speed shooting.
[0003]
An imaging device (high-speed video camera) using the above-described solid-state imaging device performs one exposure for a predetermined time within a unit imaging time for each frame during a series of imaging, and continuously repeats this operation. ing.
[0004]
When obtaining image information for confirming the change of the imaging target in more detail, that is, when obtaining image information for a plurality of images within a unit imaging time, as shown in the timing chart of FIG. Are illuminated a plurality of times (three times in the figure) within _one exposure time t1. In this case, it is necessary to use a special laser illumination as a light source in order to accurately light and emit light at minute intervals.
[0005]
[Problems to be solved by the invention]
However, the conventional imaging device has the following problems.
Since the unit photographing time and the exposure time are constant (one exposure within the exposure time) in a series of photographing processes, it is not possible to obtain highly accurate image information according to the change of the photographing target. For example, when photographing an explosion phenomenon accompanied by self-emission, a sudden change accompanied by light emission occurs at the moment when the phenomenon occurs. For this reason, an exposure time that does not cause halation due to light entering the element more than necessary is taken into consideration, and the unit photographing time is set short. However, after the occurrence of the phenomenon, the photographing is performed under the same conditions despite the decay of the amount of light due to light emission and the change of the phenomenon becoming gentle. Therefore, there is a problem that a clear moving image cannot be obtained from the series of image information obtained.
[0006]
In the case where image information for a plurality of images is obtained within a unit photographing time, the light source is turned on a plurality of times during one exposure within the unit photographing time to perform multiple exposures. There is a problem that it is difficult to determine the image information to be checked on a moving image, as a result, all the image information to be obtained is superimposed and displayed on one image.
[0007]
Further, in the conventional apparatus, since the unit photographing time and the exposure time are kept constant during a series of photographing processes, it is complicated to set the optimal conditions for photographing the photographing target, and the cost is reduced. However, there is also a disadvantage such as increased bulk. In other words, in order to obtain clear image information, a reproduction experiment in which the exposure time is changed must be performed a plurality of times before the actual shooting.
[0008]
The present invention has been made in view of such circumstances, and a main object of the present invention is to provide an imaging apparatus capable of performing imaging with high accuracy according to the state of an imaging target and an imaging method using the same.
[0009]
[Means for Solving the Problems]
The present invention has the following configuration to achieve such an object.
That is, according to the first aspect of the present invention, a plurality of light receiving elements for photoelectrically converting incident light and a plurality of charge signal groups generated by the light receiving elements for each of a plurality of frames at different photographing times are stored for each frame. (A) a frame interval of the frames, a unit photographing time, a series of photographing processes, and an image pickup device including an image pickup device that outputs a charge signal group accumulated in the charge accumulation unit. And changing means for changing at least one of the exposure conditions a plurality of times for each unit photographing time.
[0010]
According to the first aspect of the present invention, at least one of a frame interval, a unit photographing time, and an exposure condition of a frame can be changed a plurality of times for each unit photographing time in a series of photographing processes. By providing the means, it is possible to accurately shoot in accordance with the change of the imaging target that changes with time, and as a result, a clear moving image can be obtained.
[0011]
For example, when shooting an explosion phenomenon involving self-emission, if the amount of light at the moment when the phenomenon occurs is large and involves a rapid change, the unit shooting time and exposure time should be set short, and then the light amount will decrease over time. Then, the unit photographing time and the exposure time are set for each unit photographing time so as to increase as the phenomenon changes gradually.
[0012]
Therefore, image information can be obtained under the condition of the optimal amount of light for each frame of the unit shooting time, so that a clear series of moving images can be obtained, and image information is obtained more than necessary at a time when the phenomenon is mild. This eliminates the need for efficient imaging.
[0013]
Further, by providing the changing means, it is possible to set the condition of the optimum light amount for each frame of the unit photographing time, so that it is not necessary to use a special light source unlike the conventional apparatus. That is, when a light source is used, generally used light illumination or the like may be used.
[0014]
According to a second aspect of the present invention, in the imaging device according to the first aspect, (b) the exposure condition is the number of exposures per unit photographing time, and the number of exposures per unit photographing time is within the unit photographing time. Image processing means for performing a plurality of exposures each time and combining a plurality of pieces of image information obtained for each unit shooting time as one image; and (c) display means for outputting and displaying the image information subjected to the image processing. It is characterized by having.
[0015]
According to the second aspect of the present invention, a plurality of exposures are performed for each unit photographing time in a series of photographing processes, and a plurality of pieces of image information obtained for each unit photographing time are converted into one frame. By providing the image processing means for combining as one-half image, it is possible to output change information in which the imaging target moves and changes over time on one image. Further, by continuously outputting one image for each frame as a moving image, it is possible to more accurately confirm, on a moving image, change information in which a shooting target moves / changes, for example, a moving direction of an object.
[0016]
According to a third aspect of the present invention, there is provided an imaging method using the imaging apparatus according to the first or second aspect, wherein a plurality of exposures are performed within a unit imaging time during a series of imaging operations. And changing the frame interval.
[0017]
According to the third aspect of the present invention, a plurality of exposures are performed within a unit photographing time during a series of photographing and a plurality of exposures are performed at a constant frame interval by changing the frame interval. With a smaller number of exposures than in the case of performing multiple exposures, it is possible to accurately confirm an imaging object having a large change amount and an imaging object having a small change amount from an image.
[0018]
For example, when comparing image information obtained by setting all frame intervals, which are intervals between consecutive exposures within a unit imaging time, short, the objects to be imaged having a small change amount are substantially equivalent to those on the image when confirmed in the order of imaging. It is reflected in the same position, making it difficult to check for movement or change. Therefore, in order to check the movement / change of the photographing target having a small change amount, the image information of a plurality of images after a lapse of a certain time from the photographing time of the first image is compared. On the other hand, by setting consecutive frame intervals within a unit imaging time to a combination of a short interval and a long interval, a comparison between two pieces of image information obtained at short intervals can result in a large change in the imaging target. By comparing the two pieces of image information obtained at long intervals, it is possible to accurately confirm the movement and change of the photographing object having a small change amount from the image.
[0019]
According to a fourth aspect of the present invention, there is provided an imaging method using the imaging apparatus according to the first aspect, wherein at least one of a unit imaging time and an exposure time which is the exposure condition in a series of imaging operations. Is changed at a fixed ratio.
[0020]
According to the fourth aspect of the invention, at least one of the unit photographing time and the exposure time is changed at a fixed ratio in the course of performing a series of photographing, so that the photographing changes regularly with time. The subject can be photographed with high accuracy.
[0021]
According to a fifth aspect of the present invention, there is provided an imaging method using the imaging apparatus according to the first aspect, wherein one exposure is performed within a certain unit imaging time during a series of imaging operations, and The exposure time is changed for each exposure.
[0022]
According to the fifth aspect of the present invention, a single exposure is performed within a unit photographing time in the course of performing a series of photographing, and the exposure time is changed for each exposure. Can be confirmed by one reproduction experiment.
[0023]
For example, when photographing explosive phenomena accompanied by self-emission, we performed multiple reproduction experiments by changing the exposure time little by little, by obtaining image information for multiple images with the exposure time changed for each unit shooting time. Image information under substantially the same conditions as described above is obtained. Therefore, it is only necessary to perform the reproduction experiment once for setting the photographing conditions.
[0024]
According to a sixth aspect of the present invention, in the imaging method according to any one of the third to fifth aspects, the change of the frame interval or the exposure time is synchronized with an external signal. Things.
[0025]
(Function / Effect) According to the invention described in claim 6, by changing the frame interval or the exposure time in synchronization with an external signal, it is possible to easily perform shooting in which the timing at which the phenomenon occurs is difficult to take. it can.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing an overall configuration of an imaging apparatus according to an embodiment, FIG. 2 is a diagram showing a schematic configuration of an imaging device, and FIG. 3 is a pulse waveform diagram showing timings of photographing intervals and exposure times. (Timing chart).
[0027]
Reference numeral 1 in FIG. 1 denotes an imaging apparatus according to the present embodiment, and the imaging apparatus 1 includes a main body device 2, a monitor 3, and an operation unit 4.
[0028]
The main body device 2 includes an optical lens 5 that captures light from a subject, and a processing unit 6 that converts an optical image captured from the optical lens 5 into an electric signal (charge signal) and performs various processes.
[0029]
The processing unit 6 includes an imaging element 7, an image processing unit 8, a main storage unit 9, a clock generation circuit 10, and a control unit 11.
[0030]
As shown in FIG. 2, the imaging device 7 includes a plurality of photodiodes 12 for performing photoelectric conversion, and a one-dimensional array-like CCD device group 13 for accumulating a photoelectrically converted charge signal group. A charge signal obtained by photoelectrically converting the optical image and accumulating is output from the drain 14 via the charge signal transfer unit 15. The image sensor 7 has a function of operating as an electronic shutter when sequentially storing and reading out the photoelectrically converted charges. The photodiode 12 corresponds to a light receiving element of the present invention, and the CCD group corresponds to a charge storage unit.
[0031]
Note that the CCD element group 13 may be a CCD element group connected not only in a one-dimensional array but also in a two-dimensional array.
[0032]
The image processing unit 8 amplifies the signal by an amplifier or an AD converter (both not shown) and converts the signal from an analog signal to a digital signal. That is, the image processing unit 8 has a function of processing an electric signal output from the image sensor 7 as a captured image. For example, a case in which a phenomenon in which particles contained in a fluid circulate in a flow path are photographed, and image processing is performed by the image processing unit 8 to obtain change information of particles and display the information on a moving image will be described as an example. .
[0033]
In this case, as shown in the timing chart of FIG. 3, unit shooting times T _{1 to} T _n (n is a positive integer, and the same applies hereinafter) is input to the control unit 11 by an input operation from the operation unit 4. In 1 ms, the setting and input are performed such that the exposure with the exposure time of 1 μs is performed three times (t _n , t _n ′, t _n ″) every unit photographing time.
[0034]
When a series of photographing is performed, three pieces of image information are obtained for each unit photographing time. The first of the three pieces of image information is used as reference image information, and the remaining two pieces of image information are binarized, for example, to obtain the contour coordinates of the particles. The obtained outline coordinates are combined and reflected on the first image information to obtain image information of one frame, which is equivalent to one frame when an image is output as a moving image. Therefore, as shown in FIG. 4, images of three particles (indicated by △, Δ, and × in the figure) are displayed on the output one-frame image in the flow direction of the fluid (arrow a in the figure). ) Indicates that it moves over time. By displaying the image information obtained by the series of photographing on the monitor 3 as a moving image, it is possible to more accurately confirm a change in the moving direction of the particles on the output screen.
[0035]
Next, the main storage unit 9 stores the image information obtained by the image processing unit 8 and sequentially outputs and displays the image information on the monitor 3.
[0036]
The clock generation circuit 10 generates a shuttering clock for performing exposure for each frame within a unit photographing time in a series of photographing processes, based on photographing conditions set and input to the control unit 11 described later. For example, as shown in FIG. 3, three clocks are executed within the unit shooting time so that three exposures (t _n , t _n ′, t _n ″) are performed during each unit shooting time T _n. generate.
[0037]
The control unit 11 has a function of totally controlling the image sensor 7, the image processing unit 8, the main storage unit 9, and the clock generation circuit 10. Note that the clock generation circuit 10 and the control unit 11 correspond to changing means in the present invention.
[0038]
In addition, the control unit 11 stores shooting conditions such as a frame interval of a frame, a unit shooting time, the number of exposures within the unit shooting time, and an exposure time in accordance with an input operation from the operation unit 4 for each unit shooting time. Entered in advance. The driving of the image sensor 7 is controlled via the clock generation circuit 10 based on the input conditions. Note that shooting conditions and the like will be described in detail below using a specific example of a shooting method. In the specific example, an imaging device having the above-described configuration is used.
[0039]
<Specific example 1>
In this specific example, a case where a plurality of exposures are performed within a unit photographing time and a frame interval is changed in a process of performing a series of photographing will be described with reference to FIG. In this specific example, for convenience of explanation, the number of light exposure times in a unit recording time 3 times _{(t n, t n ',} t n ") and then, the 1 ms, each exposure time the unit photographing time _T 1 through T _n Is 1 μs.
[0040]
As shown in FIG. 5, for example, from the first t ₁ of the end of exposure in a unit recording time second t _{1 'the} interval time required to exposure of a 20 .mu.s, second t _1' 3 time t ₁ from the end of exposure A series of photographing is performed by changing each frame interval so that the interval until the exposure of “” is 40 μs. The frame interval in this specific example is defined as the time from the start of a certain exposure to the next exposure. The change of the frame interval is not limited to this mode, and may be performed, for example, by adjusting the exposure time.
[0041]
By performing such an imaging method, an object having a large change amount and an object having a small change amount can be accurately confirmed on an image. In other words, when three pieces of image information obtained within a unit time are combined and processed by the image processing unit 8, as shown in FIG. 6, a circle with a large change (movement) amount indicates t at which the frame interval is set short. Comparing the time point _{1 and the} time point t ₁ ′, it can be seen that the position is clearly different and the movement is large in the direction of arrow a. On the other hand, the triangles with a small amount of movement are superimposed and displayed at substantially the same position at times t ₁ and t ₁ ′.
[0042]
However, when comparing the time t ₁ ′ and the time t ₁ ″ at which the frame interval is set long, it can be seen that the △ mark with a small movement amount is clearly moving.
[0043]
Therefore, a change in an object having a different change amount can be determined on an image with a small number of exposures within a unit photographing time. Furthermore, if this image is displayed on the monitor 3 as a moving image, the change of the photographing target, for example, the moving direction can be confirmed more accurately from the screen.
[0044]
<Specific example 2>
In this specific example, a case where each of the unit photographing time and the exposure time is changed at a fixed ratio in the process of performing a series of photographing will be described as an example.
[0045]
As shown in FIG. 7, the unit photographing time is 100 (μs), 200 (μs),... 100 · n (μs), and the exposure time is 10 (μs), 20 (μs),. Is set to change at a constant rate over time.
[0046]
By performing such a photographing method, it is possible to accurately photograph a phenomenon in which the speed of change changes regularly with time, for example, a state in which an iron ball collides with and digs into a wall. In this case, the exposure time may be fixed.
[0047]
<Specific example 3>
In this specific example, a case will be described as an example where one exposure is performed within a certain unit time in the course of performing a series of photographing, and the exposure time for each unit photographing time is changed.
[0048]
As shown in FIG. 8, when performing a series of photographing for n frames, the unit photographing time is always set to a constant value of 100 μs, and the exposure time for each unit photographing time is set to 10 (μs), 20 (μs). ),..., 10 · n (μs).
[0049]
In this way, by changing only the exposure time for each unit shooting time, the optimum shooting conditions according to the shooting target, that is, the exposure time at which the optimum amount of light that does not cause halation in the output image enters the image sensor 7. Can be confirmed.
[0050]
For example, it is suitable for shooting an explosion phenomenon accompanied by self-emission. In other words, while the phenomenon occurs and light is emitted, a plurality of types of image information whose exposure time is changed can be obtained, and from these obtained image information, the exposure time of the image information that is clearly shot can be selected. Good.
[0051]
Therefore, it is sufficient to perform only one reproduction experiment for setting the exposure time, which is a photographing condition.
[0052]
<Specific example 4>
In this specific example, there is a case where one exposure is performed within a certain unit photographing time in the process of performing a series of photographing, and the unit photographing time and the exposure time are changed in synchronization with an external signal (trigger). An example will be described. For example, a case where the exposure time is changed when an arrow sticks into a balloon and an explosion occurs is taken as an example.
[0053]
In order to realize this specific example, as shown in FIG. 9, a trigger generation circuit 16 is added to the device configuration of FIG. 1, and a vibration sensor 17 externally connected to the imaging device 1 is configured.
[0054]
The vibration sensor 17 detects a vibration due to the explosion of the balloon, and the trigger generation circuit 16 captures the detection timing of the vibration sensor 17 as a trigger. This trigger generated from the trigger generation circuit 16 is sent to the clock generation circuit 10.
[0055]
Therefore, when photographing is performed using this apparatus, as shown in FIG. 10, until the arrow is released and pierces the balloon, for example, the photographing is performed with a unit photographing time of 100 μs and an exposure time of 50 μs. When the vibration sensor 17 detects the vibration in which the arrow pierces the balloon and bursts, a trigger is sent to the clock generation circuit 10 and the unit photographing time is changed to 30 μs and the exposure time is changed to 10 μs, and photographing is continuously performed.
[0056]
By capturing an external signal (trigger) in this manner, it is possible to easily and accurately perform shooting in which the timing at which a phenomenon occurs is difficult to take.
[0057]
As described above, in the process of performing a series of shootings, the shooting conditions such as the frame interval of the frame, the unit shooting time, the number of exposures within the unit shooting time, and the exposure time are changed for each unit shooting time according to the shooting target. By inputting the image data to the control unit 11 in advance and controlling the driving of the image pickup device 7 via the clock generation circuit 10, it is possible to perform imaging to obtain a clear moving image without being affected by a change in the imaging target.
[0058]
The present invention is not limited to the above-described embodiment, but can be modified as follows.
[0059]
(1) In the above embodiment, a plurality of pieces of image information obtained within a unit photographing time are binarized to obtain outline coordinates, and the other pieces of image information are reflected on the first piece of reference image information to make one frame. However, the present invention is not limited to this mode, and multi-valued information may be used when reflecting information of an object that is difficult to identify. Also, instead of superimposing and displaying a plurality of pieces of information on one image, approximate center coordinates of the obtained outline coordinates are obtained, and the center coordinates are connected by a line in chronological order to display the movement locus of the object. Alternatively, the moving direction may be indicated by using an arrow.
[0060]
When displaying the trajectory of an object, a moving distance of a predetermined object is obtained by sequentially using two pieces of image information of a plurality of pieces of image information obtained for each unit photographing time, and the obtained moving distance is obtained. The moving speed of the object may be obtained in the order of photographing from the image and the frame interval (time) between the pieces of image information used for obtaining the moving distance. Further, the acceleration of a predetermined object may be obtained by using the obtained moving speed in the order of photographing.
[0061]
(2) In the above embodiment, the case where the light is not irradiated toward the object to be photographed has been described as an example. However, the photographing may be performed using a general lighting means such as a light.
[0062]
【The invention's effect】
As is apparent from the above description, according to the present invention, by providing the changing unit, at least one of the frame interval, the unit shooting time, and the exposure condition of the frame in the process of performing a series of shootings is changed to the unit shooting. Since it can be changed a plurality of times every time, it is possible to accurately shoot a subject that changes rapidly with time, and as a result, a clear moving image can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment.
FIG. 2 is a diagram illustrating a schematic configuration of an image sensor.
FIG. 3 is a pulse waveform diagram showing photographing conditions such as a unit photographing time and an exposure time.
FIG. 4 is a diagram showing image information for one frame subjected to image processing;
FIG. 5 is a pulse waveform showing a photographing condition of a specific example 1.
FIG. 6 is a diagram showing one frame of image information obtained by a specific example 1.
FIG. 7 is a pulse waveform showing a photographing condition of a specific example 2.
FIG. 8 is a pulse waveform showing the imaging conditions of Example 3.
FIG. 9 is a block diagram showing an apparatus configuration used in a specific example 4.
FIG. 10 is a pulse waveform showing the imaging conditions of Example 4.
FIG. 11 is a pulse waveform showing imaging conditions for performing multiple exposure within a unit time using a conventional apparatus.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 imaging device 2 imaging element 3 image processing unit 4 main storage unit 5 clock generation circuit 6 control unit

Claims (6)

A light-receiving element for photoelectrically converting incident light; and a plurality of charge storage sections for storing a group of charge signals generated by the light-receiving element for each of a plurality of frames at different shooting times for each frame. In an image pickup apparatus provided with an image pickup device that outputs a group of charge signals accumulated in a unit, (a) in the course of performing a series of photographing, at least one of a frame interval of the frame, a unit photographing time, and an exposure condition is set to a unit photographing time An imaging apparatus comprising a change unit that can change a plurality of times each time. 2. The image pickup apparatus according to claim 1, wherein (b) the exposure condition is the number of exposures per unit photographing time, and a plurality of exposures are performed within the unit photographing time in a series of photographing steps. An image pickup apparatus comprising: an image processing unit that combines a plurality of pieces of image information obtained for each time as one image; and (c) a display unit that outputs and displays the image processed image information. 3. An imaging method using the imaging apparatus according to claim 1 or 2, wherein a plurality of exposures are performed within a unit imaging time during a series of imaging, and the frame interval is changed. And the shooting method. 2. A photographing method using the image pickup apparatus according to claim 1, wherein at least one of a unit photographing time and an exposure time as the exposure condition is changed at a fixed ratio in a series of photographing. How to shoot. A photographing method using the image pickup apparatus according to claim 1, wherein one exposure is performed within a fixed unit photographing time during a series of photographing, and the exposure time is changed for each exposure. Characteristic shooting method. 6. The imaging method according to claim 3, wherein the change of the frame interval or the exposure time is synchronized with an external signal.

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