JP2006215379A - Imaging apparatus and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically find out a subject to be monitored and pick up the image thereof even when two or more subjects are present at different distances respectively. <P>SOLUTION: When a monitoring mode is set, all the area scanning operation that the focusing feasible area of a lens 1 is driven from an infinity end to a closest-distance end and a maximal value position where a focus evaluated value becomes maximum is set and stored as a lens position corresponding to an index (n) is performed in S3. The number (n) of the maximal value positions being the number of indexes stored is decided in S4. When (n) is two or more, operation progresses to S5. When (n) is one, image pickup by ordinary AF processing is performed in S2. The imaging time is set in S5, and whether or not the number (n) of indexes is maximum is decided in S8. When NO in S8, operation progresses to S9 and n=n+1 is set, and when YES in S8, n=1 is set in S10. The lens 1 is driven in S11, and operation progresses to S13 after imaging the subject in S12, then whether or not the imaging pickup time elapses is decided. When the time does not elapse yet, operation returns to S12 and imaging is continued. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus such as a surveillance camera having a focus adjustment function and an imaging method.

  2. Description of the Related Art Conventionally, in surveillance cameras, video cameras, and the like, a method is used in which a lens position where a wide-range component of a luminance signal obtained from an image sensor such as a CCD is maximized is a focus position. The focus evaluation value is stored while driving the lens over the entire range of the distance measurement range, or the hill-climbing method in which the position where the focus evaluation value, which is the wide-area component of the luminance signal obtained from the image sensor, is the maximum is the in-focus position. A scanning method is known in which the lens position corresponding to the maximum stored value is the in-focus position.

  In these methods, normally, the center portion of the shooting screen is a distance measuring frame, and the lens position at which the focus evaluation value is maximum for the subject in this range is the focusing position. In addition, when the infinite focus area is scanned from the infinity end to the close end, and there are two or more in-focus points, that is, in the case of a subject that is in perspective, the focus position of the focus lens is set to infinity. A method is known in which a priority or closest priority mode can be set, and a photographer selects a mode to capture an image focused on a desired subject.

JP 2001-255450 A

  However, in the case of a surveillance camera, the user rarely monitors images to be captured at all times. Even if the above-mentioned mode is set, if the subject changes, the focusable area is periodically restored. In some cases, it takes time to scan, and a desired image cannot be obtained even if the mode is set.

  An object of the present invention is to solve the above-described problems and to enable imaging of a subject to be automatically monitored without requiring a user's effort even when there are two or more subjects at different focal lengths. An apparatus and an imaging method are provided.

  In order to achieve the above object, the technical features of the imaging apparatus according to the present invention include a focus lens that adjusts the focus of a subject image, a driving unit that drives the focus lens, a timing unit that counts an imaging time, A photoelectric conversion means for converting the subject image formed by the focus lens into an electrical signal, an extraction means for extracting a high-frequency component of the luminance of the subject image from an output signal of the photoelectric conversion means, and the extracted by the extraction means Storage means for storing the position of the focus lens when the signal representing the high-frequency component takes a maximum value, and shooting for a predetermined imaging time for each position of the focus lens when the signal representing the high-frequency component takes a maximum value And control means for controlling the driving means so as to perform the above.

  A technical feature of the imaging method according to the present invention is that a focus lens that adjusts the focus of a subject image, a driving unit that drives the focus lens, a time measuring unit that measures an imaging time, and an imaging position by the focus lens. Represents the photoelectric conversion means for converting the adjusted subject image into an electrical signal, the extraction means for extracting the high frequency component of the luminance of the subject image from the output signal of the photoelectric conversion means, and the high frequency component extracted by the extraction means And a storage unit that stores a position of the focus lens when the signal has a maximum value, and a predetermined imaging time for each position of the focus lens when the signal representing the high-frequency component has a maximum value. The drive means is controlled so as to perform photographing only.

  According to the imaging apparatus and the imaging method of the present invention, even when there are two or more subjects at different distances or when the subject changes, it is possible to image each in-focus position in a time-sharing manner. A desired subject can be automatically imaged without applying.

The present invention will be described in detail based on the embodiments shown in the drawings.
FIG. 1 is a block diagram of an image pickup apparatus according to the present embodiment. An image pickup element 2 made of, for example, a CCD for converting reflected light from an object into an electric signal is arranged behind the focus lens 1. The output of the element 2 is connected to an A / D converter 3, an image processor 4, and a network 6 for transmitting image data via an interface 5 for receiving input image data transmission and driving commands. Are sequentially connected with an interface 7 for transmitting and receiving data, a recording medium 8 for displaying image data and an operation screen, and a display unit 9.

  On the other hand, the output of the CPU 10 is connected to the image sensor 2 and the A / D converter 3 through a timing signal generation circuit 11 that generates a timing signal, and further drives to drive the focus lens 1 through a focus lens drive circuit 12. It is connected to the motor 13.

  The CPU 10 also stores an image processor 4 for performing predetermined processing on image data, an interface 5, a mode switch 14 for switching between a monitoring mode and a normal mode, and a program memory 15 in which a program executed by the CPU 10 is described. A work memory 16 is connected to write and read various data necessary for the CPU 10 to perform processing according to the program.

  FIG. 2 shows a flowchart of the operation. First, in step S1, the state of the mode switch 14 is determined. If the monitoring mode is off, that is, the normal mode, the process proceeds to step S2, and normal imaging processing by autofocus is performed. If the monitoring mode is on, the process proceeds to step S3, the focusable region of the focus lens 1 is driven from the infinity end to the close end, and the local maximum position where the focus evaluation value is maximized corresponds to the index n. The entire area scanning operation stored in the work memory 16 as the lens position is performed.

  For the index number, the initial value is set to 0. For example, when there are three local maximum positions as shown in FIG. 3, the numbers 1 to 3 are assigned from the local maximum on the infinity side, and the focus lens 1 Remember the position. This scanning operation is performed by driving the focus lens 1 from the closest end to the infinity end, and one of them is performed as a start point and the other as an end point.

  Subsequently, in step S4, the number n of local maximum positions, which is the index number stored in step S3, is determined. If n is 2 or more, the process proceeds to step S5. If n is 1, the process proceeds to step S2. Proceed and perform imaging by normal autofocus processing.

  If n is 0, the process proceeds to step S6, and an error indicating that the display focus position cannot be extracted is displayed on the display unit 9. Thereafter, in step S7, it is determined whether or not the previous focus position is stored. If the focus position is stored, the process proceeds to step S5. If not, the process proceeds to step S2.

  In step S5, the user presets the time for imaging at each local maximum position, the time for rescanning, and whether the infinity side priority or the near side priority is prioritized. The time set here may be set to be the same at each maximum value position or different for each maximum value position. In FIG. 3, the imaging time is set such that, for example, the local maximum position A is 5 minutes, the local maximum position B is 5 minutes, and the local maximum position C is 10 minutes.

  Subsequently, in step S8, it is determined whether or not the index number is the maximum number n, that is, whether or not n is maximum. If NO, the process proceeds to step S9, and the index is incremented. If YES, the process proceeds to step S10. Proceed with n = 1. Subsequently, in step S11, the local maximum position corresponding to the index number is acquired from the work memory 16, the focus lens 1 is driven to that position, the subject is imaged in step S12, and then the process proceeds to step S13. It is determined whether or not the captured imaging time has elapsed.

  If it has not elapsed, the process returns to step S12 to continue imaging, and if it has elapsed, the process proceeds to step S14. In step S14, it is determined whether or not rescanning is necessary. If it is not necessary, the process returns to step S8. If rescanning is performed, the process returns to step S3 to perform the scanning operation.

  In this way, even if the position of the subject changes, the in-focus point can be automatically found and an image can be taken at the desired in-focus position, so that the effect as a surveillance camera can be enhanced.

  Also, a storage medium in which a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and the system or computer reads and executes the program code stored in the storage medium. It goes without saying that the present invention is achieved. In this case, the program code itself read from the storage medium realizes the described embodiment, and the storage medium storing the program code constitutes the present invention.

  Further, by executing the program code read out by the computer, not only the functions of the above-described embodiments are performed, but also the operating system or the like running on the computer is actually processed based on the program code instruction. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the above and the processing thereof is included.

It is a block block diagram of an imaging device. It is a flowchart figure of an imaging process operation. It is a graph of the focus evaluation value acquired in the imaging processing operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Focus lens 2 Image pick-up element 3 A / D converter 4 Image processor 8 Recording medium 9 Display part 10 CPU
11 Timing signal generation circuit 14 Mode switch 15 Program memory 16 Work memory

Claims (9)

  A focus lens that adjusts the focus of the subject image; a drive unit that drives the focus lens; a timing unit that measures an imaging time; a photoelectric conversion unit that converts the subject image formed by the focus lens into an electrical signal; An extraction means for extracting a high-frequency component of the luminance of the subject image from the output signal of the photoelectric conversion means; and a position of the focus lens when the signal representing the high-frequency component extracted by the extraction means takes a maximum value Storage means for controlling, and control means for controlling the driving means so as to perform photographing for a predetermined imaging time for each position of the focus lens when the signal representing the high-frequency component takes a maximum value. An imaging device.   2. The imaging apparatus according to claim 1, wherein the timing unit drives the focus lens over the entire range of ranging when a predetermined imaging time is measured, and re-stores the position of the focus lens. .   The imaging apparatus according to claim 1, further comprising: a display unit capable of displaying that when the extraction unit cannot extract the high-frequency component.   The imaging apparatus according to claim 1, wherein when the extraction unit cannot extract the high-frequency component, the driving unit is controlled based on a position of the focus lens detected previously.   A focus lens that adjusts the focus of the subject image, a drive unit that drives the focus lens, a timing unit that measures the imaging time, and a photoelectric that converts the subject image whose imaging position has been adjusted by the focus lens into an electrical signal. Conversion means, extraction means for extracting high-frequency components of the luminance of the subject image from the output signal of the photoelectric conversion means, and the focus lens when the signal representing the high-frequency components extracted by the extraction means takes a maximum value An image pickup apparatus including a storage unit for storing a position, wherein the driving unit is controlled so as to perform shooting for a predetermined imaging time for each position of the focus lens when the signal representing the high-frequency component takes a maximum value. An imaging method characterized by the above.   6. The imaging method according to claim 5, wherein when the predetermined time is measured, the time measuring unit drives the focus lens over the entire distance measuring range to re-store the position of the focus lens.   6. The imaging method according to claim 5, wherein when the extraction unit cannot extract the high-frequency component, a message to that effect is displayed.   6. The imaging method according to claim 5, wherein when the extraction unit cannot extract the high-frequency component, the focus lens is driven based on the position of the focus lens detected previously.   A storage medium storing the imaging method according to any one of claims 5 to 8 as a program.

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