JP4288992B2 - Imaging apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image pickup apparatus and method using an image pickup device and generating image data corresponding to a plurality of types of exposure times, particularly one type of moving image data and still image data, at the same timing.
[0002]
[Prior art]
In recent years, digital video cameras capable of recording moving image data and still image data have been developed, and are currently in practical use. In such digital video cameras in general, in the case of moving images, the image information from the imaging means is reduced in pixel density, and after being recorded on a recording medium as a series of moving images, later from the recording medium as needed, After being read out, it is reproduced and displayed as a moving image. In the case of a still image, the image information from the imaging means is recorded on the recording medium as it is as a still image without being reduced in pixel density, and is later read from the recording medium as needed. It is designed to be reproduced and displayed as a still image.
[0003]
Incidentally, Patent Document 1 describes that moving image data and still image data are generated from a single image sensor at non-identical timing. Japanese Patent Application Laid-Open No. 2004-228620 describes that, when a still image recording instruction is issued during moving image recording, high-definition still image data is recorded while the system is standardized.
[0004]
[Patent Document 1]
JP-A-8-298644 [Patent Document 2]
JP-A-10-108121 [0005]
[Problems to be solved by the invention]
However, in general, the optimal exposure time for moving image data is different from the optimal exposure time for still image data. Despite this fact, until now, as shown in Patent Documents 1 and 2, since image data captured at a certain timing is shared as moving image data and still image data, The actual situation is that the result is that the image quality of either one of the moving image and the still image or both images is deteriorated. That is, until now, no consideration has been given to the generation of moving image data and still image data having the optimum exposure time required by each.
[0006]
An object of the present invention is to use an image pickup device and easily perform image data corresponding to a plurality of types of exposure times, particularly one type of moving image data and still image data without losing image quality under the same timing. It is to be able to be generated.
[0007]
[Means for Solving the Problems]
The present invention includes an imaging device for imaging a subject, acquires the image pickup output from the imaging device, the imaging apparatus having an image processing circuit that generates a one of the moving image data and still image data, still image Controlling the image sensor so that the exposure time for data is not less than n (n is a natural number) times and less than (n + 1) times the exposure time for moving image data; After moving image data for n frames is generated from the imaging output sequentially acquired n times with the exposure time for image data, the difference between n times the exposure time for moving image data and the exposure time for still image data It is generated by a combined addition of an imaging output acquired as a response and an imaging output acquired as a response according to the difference between the exposure time for still image data and (n + 1) times the exposure time for moving image data. One frame of moving image data and a moving image exposure time, and a cumulative addition of imaging outputs sequentially acquired n times, and still image data exposure time and moving image data exposure time n times Image data corresponding to a plurality of types of exposure time is included, including a step of generating still image data generated by combination addition with an imaging output acquired as a difference according to the same timing at the same timing. It is made to be generated.
[0008]
Actually, the image data requested to be acquired is, for example, one kind of moving image data and still image data. As the simplest example, the exposure time for still image data is less than the exposure time for moving image data. When moving image data and still image data are generated at the same timing, in the image data generation step, the moving image data is acquired according to the difference between the exposure time for still image data and the exposure time for moving image data. Generated by the combined addition of the imaging output acquired and the imaging output acquired by the exposure time for still image data, and still image data is an image acquired by the exposure time for still image data. What is necessary is just to make it produce | generate as it is from information.
[0009]
Further, for example, when the exposure time for still image data is 1 time or more and less than 2 times the exposure time for moving image data, and the moving image data and the still image data are generated at the same timing, the first moving image The data may be generated as it is from the imaging output acquired with the exposure time for moving image data. However, for the next moving image data, the exposure time for still image data and twice the exposure time for moving image data are used. It is generated by a combined addition of an imaging output acquired as a function of the difference and an imaging output acquired as a function of the difference between the exposure time for the moving image data and the exposure time for the still image data. It is good. On the other hand, with respect to still image data, image information acquired at the exposure time for moving image data and imaging acquired as a difference between the exposure time for still image data and one time of the exposure time for moving image data. It is generated by combination addition with the output.
[0010]
From the above specific examples, the moving image data and the still image data are generated according to the exposure time optimized for each, and are easily generated without impairing the image quality.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
First, prior to specific description of the present invention, image data corresponding to a plurality of types of exposure times referred to in the present invention, that is, a plurality of types of shutter speeds, is defined. In general, image data is roughly classified into moving image data and still image data. Among them, the moving image data is continuously generated with a 1/30 period at a moving image data shutter speed (for example, fixed at 1/30 seconds). In the present invention, moving image data having a different shutter speed is used. Note that data is also taken into account. For example, the present invention is applicable when it is necessary to simultaneously generate moving image data with a shutter speed of 1/60 or 1/120 seconds in addition to moving image data with a shutter speed of 1/30 seconds. Yes.
[0012]
On the other hand, although the shutter speed of still image data can be set variously, it should be noted that it is also considered to generate still image data having different shutter speeds at the same timing. In the present invention, it is considered to generate still image data having a desired shutter speed, particularly during generation of moving image data. Therefore, from this, it is natural that the image data corresponding to a plurality of types of shutter speed includes one type of moving image data (the shutter speed is fixed at, for example, 1/30 seconds). This means mainly the moving image data and still image data (the shutter speed is arbitrarily variable).
[0013]
Now, the present invention will be described in detail. First, a schematic configuration of a main part in an example of an imaging apparatus according to the present invention is shown in FIG. As shown in the figure, a photographing lens 11, an image sensor (CCD image sensor, CMOS image sensor or the like that converts an optical image from the photographing lens 1 into an electrical signal) 12, an image information processing block 13, a moving image recording block 14, a still image recording It consists of block 15. Other constituent elements include a control circuit for performing electronic shutter speed control and various information processing controls for the image sensor 12 and the image information processing block 13, and for temporarily storing image information and image information intermediate processing results. It should be noted that a memory or the like is required, but is omitted for simplification of illustration. First, a general moving image recording operation will be described as follows.
[0014]
That is, recording of moving image data is performed in response to a moving image data recording request from an operator. When there is a request for recording, an A / D converter in the image information processing block 13 is periodically converted into an analog image signal by the image sensor 12 as shown in FIG. In the state converted into the digital image signal by 131, the image information processing circuit 132 sequentially processes. In that process, moving image data is generated by performing white balance adjustment, gamma correction, etc. If necessary, conversion of the number of pixels according to the recording format of the moving image data is also necessary. Done. This is because, in general, recording devices that support both moving images and still images often use image sensors that match the resolution of still images, and moving image data requires data thinning. Because. As described above, the moving image data generated by the image information processing circuit 132 is then compressed by the moving image compression circuit 141 in the moving image recording block 14 and then sequentially recorded on the recording medium 142. It has become.
[0015]
Next, a general still image recording operation will be described. This still image data is also recorded in response to a still image data recording request from an operator. When there is a request for recording, as shown in the figure, the condensing image by the photographing lens 11 is converted into an analog image signal by the image sensor 12, and then converted into a digital image by the A / D converter 131 in the image information processing block 13. The signal is processed by the image information processing circuit 132 in a state converted into a signal. In this processing, still image data is generated by performing white balance adjustment, gamma correction, and the like. As described above, the still image data generated by the image information processing circuit 132 is then compressed by the still image compression circuit 151 in the still image recording block 15 and then recorded on the recording medium 152. ing.
[0016]
Here, it will be as follows if the imaging of moving image data is demonstrated in detail.
That is, in this example, it is assumed that non-interlaced (sequential scanning or progressive scanning) moving image data of 30 frames / second is recorded, and moving image data is captured as shown in FIG. Thus, the exposure time (shutter speed) 21 is desirably set to 1/30 seconds. In this way, the subject is imaged with a slight blur, so that the moving image data can be reproduced as a smooth moving image later.
[0017]
Next, imaging of still image data will be described. In the case of a still image, it is necessary to optimally set the shutter speed according to the application and ambient brightness conditions. Alternatively, in the case of a still image, it is preferable that a faster shutter speed can be selected when shooting a fast-moving subject and a longer shutter speed is desired when panning is desired. For example, the exposure time 22 is 1/125 seconds, or the exposure time 23 is 1/8 seconds. In other words, the shutter speed required for still image data is generally greatly different from moving image data, and the shutter speed required for each still image data is also largely different from each other. is there. Therefore, when both moving image data and still image data are simultaneously imaged with a single image sensor, it is necessary to simultaneously realize imaging with different shutter speeds. This will be described with reference to FIG.
[0018]
The recording operation of the moving image data and still image data described above is a single operation to the last, and therefore the operation is relatively simple. However, a description will be given of a case in which still image data having a desired shutter speed, for example, a shutter speed of 1/125 seconds as shown in FIG. The exposure time 21 of the image sensor 12 in the case of recording and not recording still image data is 1/30 second. In this way, the captured image is subjected to processing such as white balance adjustment and gamma correction by the image information processing circuit 132, and, if necessary, pixel number conversion processing is performed. After being obtained as moving image data 34, it is compressed and recorded.
[0019]
Assuming that a still image data recording request with a shutter speed of 1/125 seconds is generated at timing 31 as shown in the state where moving image data is generated and recorded as described above, imaging is performed. In the element 12, imaging indicated as exposure times 32 and 33 is performed. The exposure time 32 is imaging for still image data, and the shutter speed is 1/125 seconds. However, when the exposure time 33 is 1/30 second, which is the imaging unit time of moving image data, imaging is performed within the remaining time with respect to the imaging unit time. That is, the shutter speed of the exposure time 33 is 19/750 seconds (= 1/30 seconds-1 / 125 seconds).
[0020]
When the image is picked up as described above, the analog image signal from the image pickup device 12 is digitized and processed by the image information processing circuit 132, so that the moving image data and the still image immediately before the compression recording are obtained. The data is generated. The generation method will be described in detail as follows.
[0021]
That is, for the moving image data, it is obvious that the necessary moving image data can be obtained by combining and adding the image data captured at the exposure times 32 and 33 respectively. Thereafter, white balance adjustment, gamma correction, and the like, and conversion of the number of pixels as necessary, can obtain moving image data 35 immediately before compression recording. Eventually, the image is captured at a shutter speed of 1/30 seconds without being affected by the image capture, even though the image capture is performed in the middle to obtain still image data with a shutter speed of 1/125 seconds. Moving image data can be obtained. On the other hand, with respect to still image data, still image data 36 immediately before compression recording can be obtained by simply performing white balance adjustment and gamma correction on the image data captured at the exposure time 32. .
[0022]
The above description is for a case where the shutter speed is still image data having a 1/125 second shutter speed, but the case where the shutter speed is longer than 1/30 second, for example, 1/8 second is shown in FIG. This is as follows.
[0023]
That is, as shown in FIG. 4, it is assumed that a still image data recording request with a shutter speed of 1/8 second is generated at a certain timing 31 in a state where imaging with the exposure time 21 is continuously performed. In this case, the imaging device 12 performs imaging indicated as exposure times 41 to 43. Since the exposure for still image data requires 1/8 second exposure, after three consecutive normal exposures, the image of the portion with insufficient exposure seems to be performed within the exposure time 42. To. That is, the shutter speed 1/8 sec is decomposed as 1/30 sec + 1/30 sec + 1/30 sec + 1/40 sec (= 1/8 sec) and 1/30 sec within each exposure time 41. Imaging is performed within 1/40 second within the exposure time 42. Similarly to the case shown in FIG. 3, the imaging shown as the exposure time 43 is performed as the imaging for the remaining time when 1/30 second, which is the unit time of the moving image data, is considered. The speed is obtained as 1/120 second (= 1/30 second-1 / 40 second).
[0024]
Eventually, from the image data captured as described above, in addition to the moving image data 44 for three frames, the moving image data for one frame is obtained by combining and adding the image data for the exposure time 42 and the image data for the exposure time 43. 45 is obtained. As for still image data, still image data 46 is obtained by combining and adding the cumulative addition of moving image data 44 for three frames and the image data for the exposure time 42.
[0025]
Further, even if moving image data is obtained every 1/30 second period, if the moving image data shutter speed is set to 1/60 seconds, as shown in FIG. Is performed continuously. However, only the image data for the exposure time 52 corresponding to the first half of each 1/30 second period is obtained as the moving image data 58, and the image data for the exposure time 52 corresponding to the second half is not obtained as the moving image data 58. Ignored.
[0026]
Now, a case where a still image data recording request with a shutter speed of 1/16 second is generated at a certain timing 51 in such a state will be described. In this case, the imaging element 12 indicates exposure times 53 to 57. It is obvious that the image data for each of the exposure times 53 and 55 is obtained as the moving image data 59 among the exposure times 53 to 57. However, since the exposure for still image data requires exposure of 1/16 second, after the imaging with each of the exposure times 53 to 55, the imaging for the portion with insufficient exposure is performed within the exposure time 56. That is, the shutter speed 1/16 second is decomposed as 1/60 seconds + 1/60 seconds + 1/60 seconds + 1/80 seconds (= 1/16 seconds) and 1/60 within each exposure time 53 to 55. The second image is taken, and within the exposure time 56, 1/80 second image is taken. Eventually, still image data 60 is obtained by combining and adding image data for exposure times 53 to 55 and image data for exposure time 56. Incidentally, although the exposure time 57 is calculated | required as 1/240 second (= 1/60 second-1/80 second), the image data with respect to this is discarded.
[0027]
Eventually, two frames of moving image data 59 are obtained from the image data captured as described above. As for still image data, still image data 60 is obtained by combining and adding image data for each of the exposure times 53, 54, and 55 and image data for the exposure time 56.
[0028]
As can be seen from the above description, the shutter speed for still image data is rarely an integer multiple of the shutter speed for moving image data. In other words, for example, when the shutter speed for moving image data is set to 1/30 seconds and the shutter speed for still image data is arbitrarily set, a still image is acquired when one frame of moving image data is acquired. Imaging for acquiring data needs to be performed once within 1/30 second. The above-described exposure times 32, 42, and 56 are for imaging, but the exposure times 32, 42, and 56 can be easily calculated as described above by the control circuit. Yes.
[0029]
FIG. 6 shows a flow of an example of shutter speed control by the control circuit when the still image data shutter speed is arbitrarily set. In this case, first, every time moving image data is imaged, whether or not imaging shorter than 1/30 second is necessary, that is, whether or not imaging for acquiring still image data is necessary is required. Determination is made (step 61). If it is determined in this determination that it is still unnecessary, moving image data is captured with the shutter speed set to 1/30 as in the normal case (step 62). However, if it is determined that it is necessary, the necessary exposure time A (seconds) is calculated from the moving image data shutter speed and the still image data shutter speed (step 63). Since the necessary exposure time A corresponds to the exposure times 32, 42, and 56 described above, first, imaging with the exposure time A is performed (step 64). After the imaging with the exposure time A is performed, the imaging with the exposure time (1 / 30-A) (seconds) is performed (step 65).
[0030]
By the way, when still image data is generated together with moving image data under the same timing, an image signal based on the next exposure time is being read out from the image sensor 12 while an image signal based on a certain exposure time is being output. If it is necessary to start the read output, a problem occurs. Such a case is, for example, a case where imaging is performed at a shutter speed of 1/120 seconds immediately after imaging at a shutter speed of 1/40 seconds within 1/30 seconds. In order to avoid such a problem, it is necessary to make some contrivance with respect to the CCD configuration in the image sensor 12.
[0031]
In order to avoid the above problems, it is conceivable to provide two storage units 741 and 742 as the configuration of the CCD as shown in FIG. In the frame interline transfer type CCD, there is an accumulator on the CCD, and the electric charge is transferred from the photodiode to the vertical transfer CCD and then transferred to the accumulator at a high speed. The analog image information is transferred to the storage unit 74, whereas two storage units 741 and 742 are provided.
[0032]
Explaining its configuration and operation, the charge accumulated in the photodiode 71 is transferred to the vertical shift register 73 via the transfer gate 72. Thereafter, the data are transferred to the storage units 741 and 742 at a high speed and can be output to the outside of the CCD at a relatively low speed via the horizontal shift registers 751 and 752. Such a function can be realized by providing two storage units for the frame interline transfer CCD.
[0033]
If the CCD having the above configuration is used, the above problems can be solved. That is, for example, when imaging with a shutter speed of 1/40 seconds, an analog image signal is read out via the storage unit 742 and the horizontal shift register 752 as indicated by an arrow, while the shutter speed is 1/120. At the time of imaging in seconds, an analog image signal is read out via the storage unit 741 and the horizontal shift register 751 as indicated by an arrow in FIG. In this case, an analog image signal may be read from each of the horizontal shift registers 751 and 752 via a dedicated signal line, but can also be read via a common signal line. This is because the necessary analog image signals have already been saved and accumulated in the storage units 741 and 742, and therefore no particular problem occurs even if they are read out at a low speed.
[0034]
As described above, both moving image data and still image data can be easily generated without losing image quality under the same timing using an image sensor. In the above description, 1/30 seconds is mainly assumed as the shutter speed of moving image data, but this value may be set arbitrarily. Furthermore, although one type of moving image data and still image data has been described as a main target, still image data corresponding to a plurality of types of shutter speeds can be easily captured using a single image sensor. It can be applied.
[0035]
As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0036]
【The invention's effect】
There is an effect that image data corresponding to a plurality of types of shutter speeds, in particular, one type of moving image data and still image data can be easily generated without losing image quality at the same timing using an image sensor. .
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a main part in an example of an imaging apparatus according to the present invention.
FIG. 2 is a diagram illustrating examples of shutter speeds required for moving image data and still image data.
FIG. 3 is a diagram for explaining a method of generating moving image data and still image data when the shutter speed for still image data is lower than the shutter speed for moving image data.
FIG. 4 is a diagram for explaining a method of generating moving image data and still image data when the shutter speed for still image data is longer than the shutter speed for moving image data.
FIG. 5 is a diagram for explaining a method of generating moving image data and still image data when the shutter speed for still image data is longer than the shutter speed for moving image data.
FIG. 6 is a diagram illustrating a flow of an example of shutter speed control by a control circuit when a still image data shutter speed is arbitrarily set.
FIG. 7 is a diagram showing a CCD configuration having two storage units and its operation.
FIG. 8 is a diagram similarly showing the operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Shooting lens, 12 ... Image sensor, 13 ... Image information processing block, 132 ... Image information processing circuit

Claims (2)

An image sensor for imaging a subject;
And acquiring imaging output from the image pickup device, an image processing circuit that generates a one of the moving image data and still image data,
The image sensor is controlled such that the exposure time for still image data is not less than n (n is a natural number) times and less than (n + 1) times the exposure time for moving image data. On the other hand, after the moving image data corresponding to n frames is generated from the imaging output sequentially acquired n times with the moving image data exposure time, n times the moving image data exposure time and the stationary Captured output acquired as a function of the difference with the exposure time for image data, and acquired as a function of the difference between the exposure time for the still image data and (n + 1) times the exposure time for the moving image data. One frame of moving image data generated by combination addition with the imaging output, and the cumulative addition of the imaging output sequentially acquired n times with the moving image exposure time, and the still image Performs control to the still image data generated by the combination addition of the imaging output to be obtained as corresponding to the difference between the n times the exposure time for the image data and the moving image data for exposure time, to produce at the same time An imaging device including a control circuit. An imaging device for imaging a subject, acquires the image pickup output from the imaging device, an imaging method in an imaging apparatus and an image processing circuit that generates a one of the moving image data and still image data,
Controlling the image sensor so that the exposure time for still image data is not less than n (n is a natural number) times and less than (n + 1) times the exposure time for moving image data;
The moving image data exposure time after the moving image data for n frames has been generated from the imaging output sequentially acquired n times with the moving image data exposure time for the image information processing circuit. The difference between the imaging output acquired as a function of the difference between n times the exposure time for still image data and the exposure time for still image data and (n + 1) times the exposure time for moving image data A cumulative addition of one frame of moving image data generated by a combined addition with an imaging output acquired as a response, and the above imaging output sequentially acquired n times with the exposure time for moving images; The still image data generated by the combined addition of the imaging output acquired as the difference between the exposure time for the still image data and n times the exposure time for the moving image data is the same. Imaging method comprising the steps of generating at timing.

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