JP2007068097A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate an image wherein illumination non-uniformity is eliminated, without mechanically or electrically driving an illumination means. <P>SOLUTION: An illumination non-uniformity detection means is provided which detects an illumination non-uniform area (S108) in an illumination means for illuminating an object (S107), and when the illumination non-uniform area detected by said illumination non-uniformity detection means is equal to a predetermined size or larger (S109), an image is generated (S110, S111) by image signals within a light distribution range of said illumination means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including illumination unevenness detection means for detecting an illumination unevenness area of illumination means for illuminating a subject.

  2. Description of the Related Art Conventionally, in order to obtain a good imaging screen under low illuminance, an imaging device incorporating a lighting device such as a lamp or white LED for illuminating a subject is known.

  Normally, as shown in FIG. 8, in an imaging apparatus incorporating an illuminating unit, an imaging lens 2 and an optical system 4 constituting a part of the illuminating unit are arranged with an interval L in the imaging apparatus main body 1. An image of the subject obtained by the imaging lens 2 is formed on the imaging element 3. The illumination means includes an optical system 4 and a light emitting unit 5 such as a lamp or a white LED. When the light emitting unit 5 emits light, the optical system 4 efficiently irradiates the emitted light onto the subject. In this way, the light distribution characteristic of the illumination means for illuminating the subject is set by the optical system 4, and in many cases, an appropriate light amount distribution is obtained during normal photographing with a subject distance of 2 to 3 m in accordance with the angle of view of the imaging lens 2. Is set to be.

  In the imaging device incorporating the illumination means, the optical axis 2a of the imaging lens 2 and the optical axis 4a of the optical system 4 are arranged with a distance L as shown in FIG. When the subject is far from the position 6a with respect to the imaging device, almost the entire field of view is illuminated by the illumination means, and a clear image can be taken. Therefore, there is no problem in normal shooting for a person or landscape. However, when the subject approaches the imaging apparatus main body 1 side, parallax occurs between the illumination range of the illumination unit and the imaging range of the imaging lens 2. In this case, the illumination range of the illumination unit cannot cover the entire photographing range, and the photographed image has a large illumination unevenness. For example, in FIG. 8, when the subject is at position 6b, the half area on the illumination means side of the subject is illuminated, but the half area on the imaging lens 2 side is not illuminated.

  Further, when the imaging lens 2 is a zoom lens, even if the entire photographing field angle is the subject position 6a illuminated by the illumination means, illumination unevenness occurs when the zoom operation is further performed on the wide angle side. . For this reason, it has been difficult to obtain good results without uneven illumination in macro photography in a room or the like that requires illumination.

Therefore, many proposals have been made to solve the above problems. For example, Patent Document 1 discloses a technique for changing an irradiation direction by mechanically rotating an illumination unit according to a subject distance. Further, in Patent Document 2, in a video camera with a built-in video light for illuminating a subject, the first and second video lights are made variable in conjunction with the focal length of the zoom lens. For wide-angle shooting, the angle formed by the irradiation direction is widened to illuminate the wide-angle range more efficiently.For narrow-angle shooting, the video light is directed inward to narrow the angle formed by the irradiation direction and the illumination range A technique for matching and illuminating the same subject brighter is disclosed.
JP-A-57-122423 JP-A-9-200604

  However, in any of the above imaging apparatuses, it is necessary to drive the illumination means mechanically or electrically, so that the mechanism is complicated, the cost is increased due to an increase in the number of parts, and the imaging apparatus main body is increased in size. Had problems.

(Object of invention)
An object of the present invention is to provide an imaging device capable of generating an image without illumination unevenness without mechanically or electrically driving an illumination unit.

  In order to achieve the above object, the present invention according to claim 1 includes illumination unevenness detection means for detecting an illumination unevenness area of illumination means for illuminating a subject, and the illumination unevenness area detected by the illumination unevenness detection means. Is an image pickup apparatus that generates an image using an image signal within a light distribution range of the illumination unit.

  In order to achieve the above object, the present invention according to claim 2 is an illumination unevenness detection unit that detects an illumination unevenness region of an illumination unit that illuminates a subject, and an area setting that sets an image generation region by a user operation. And an imaging device that issues a warning when the image generation area set by the area setting means overlaps the illumination unevenness area detected by the illumination unevenness detection means.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which can produce | generate an image without illumination nonuniformity can be provided.

  The best mode for carrying out the present invention is as shown in the following examples.

  1 is a block diagram showing a circuit configuration of a video camera which is an example of an imaging apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the video camera of FIG. 1 viewed from the front direction (subject side), and FIG. FIG. 4 is a perspective view of the video camera of FIG. 1 viewed from the right rear, and FIG. 4 is a perspective view of the video camera of FIG. 1 viewed from the left rear.

  As shown in FIG. 1, the video camera 100 includes a lens 101, an imaging unit 102, a zoom control unit 123, a camera signal processing unit 103, a compression / decompression processing unit 104, and a display unit 105. Furthermore, a recording / playback processing unit 106, a memory card 107, a recorder control unit 108, a tape medium 109, a microphone 110, an audio signal processing unit 111, a strobe control unit 112, and a strobe 113 are provided. Furthermore, a video light control unit 114, a video light 115, a memory 116, a memory control unit 117, a CPU 118, an operation unit 119, a power control unit 120, and a battery 121 are provided. The functional blocks are connected to each other via a data bus 122 so that data communication is possible.

  In the video camera 100 configured as described above, the memory 116 is used by time sharing in each functional block via the data bus 122, and is controlled and managed by the memory control unit 117. The lens 101 includes an optical lens group such as focus and zoom and an aperture, and captures an image of a subject. The imaging unit 102 includes an imaging element such as a CCD that converts an optical image into an electrical signal, an A / D converter that converts an analog signal output into a digital signal, and the like. The zoom control unit 123 controls zooming of the lens 101 in accordance with an instruction from the operation unit 119.

  The camera signal processing unit 103 performs signal processing such as color separation, gradation correction, white balance adjustment, and digital zoom on the image signal sent from the imaging unit 102. The audio signal processing unit 111 outputs the audio signal as audio data by gain-controlling the audio signal input from the microphone 110 to gain a predetermined level.

  The compression / decompression processing unit 104 compresses and encodes the image data output from the camera signal processing unit 103 and the audio data output from the audio signal processing unit 111 using a predetermined compression encoding method. Further, at the time of reproduction, the data output from the recording / reproduction processing unit 106 is subjected to a decompression process corresponding to a predetermined compression encoding method to obtain image data and audio data before compression encoding.

  The display unit 105 includes a liquid crystal panel 105a and an electronic viewfinder (EVF) 105b shown in FIG. 3, and the compression / decompression processing unit 104 displays image data to be compressed and encoded. During reproduction, the reproduction data obtained by the compression / decompression processing unit 104 is displayed. Further, the operation status of the video camera body 100 is displayed as on-screen display information as necessary.

  The recording / playback processing unit 106 performs error correction coding processing, modulation processing, and the like on the data after compression coding obtained by the compression / decompression processing unit 104. Further, data such as synchronization and ID is added and converted into a form suitable for recording, and then recorded on a recording medium such as the tape medium 109 or the memory card 107. At the time of reproduction, the original digital data is detected from the data read from the tape medium 109 or the memory card 107, and processing such as error correction and demodulation is performed. At this time, the recorder control unit 108 controls the running of the tape medium 109.

  The strobe control unit 112 causes the strobe 113 to emit light when it is determined that the subject brightness is equal to or lower than a predetermined value during still image shooting. If the video light control unit 115 determines that the subject brightness is equal to or lower than a predetermined value during moving image shooting, the video light control unit 115 causes the video light 115 to emit light.

  The power control unit 120 includes a battery detection circuit, a DC / DC converter, a switch circuit that switches blocks to be energized, and the like. Then, the presence / absence of a battery, the type of battery, and the remaining battery level are detected. The battery 121 is a lithium ion battery or the like and supplies power to the video camera 100.

  The operation unit 116 includes operation members indicated by 116a, 116b, 116c, 116d, 116e, 116f, 116g, 116h, and the like shown in FIGS. 3 and 4 (details will be described later). In addition, the CPU 118 has a function of instructing the operation based on a key operation from the user.

  Reference numeral 116a denotes a multi-dial, which can be selected by various rotation operations and determined by a pressing operation. Reference numeral 116b denotes a mode dial which switches between power-off, shooting mode, and playback mode. Here, the power-off is a mode for turning off the main power of the video camera 100, and the shooting mode is a mode whose main purpose is shooting. The reproduction mode is a mode whose main purpose is to reproduce image data recorded on the memory card 107 or the tape medium 109. Reference numeral 116c denotes a trigger button for starting / stopping shooting, and is a button for generating a moving image recording start and recording end event each time it is pressed in the shooting mode. Reference numeral 116d denotes a menu button for displaying a menu. Reference numeral 116e denotes a cross key for designating an area. For example, an area for trimming an image is designated. Reference numeral 116f denotes an area determination button for determining an area designated by the cross key 116d. Reference numeral 116g denotes a photo button for generating a still image shooting event in the shooting mode. Reference numeral 116h denotes a zoom lever for performing a zooming operation of the lens 101 in the photographing mode.

  Next, the operation of the video camera 100 configured as described above in the shooting mode will be described with reference to the flowchart of FIG.

  When the user performs shooting, the shooting mode is selected by the mode dial 116b. When the shooting mode is selected, the CPU 118 determines in step S101 in FIG. 5 that the trigger button 116c has been pressed, and proceeds to step S102. In step S102, the video light control unit 114 measures the brightness of the subject. In the next step S103, the brightness of the subject measured in step S102 is determined. As a result, if it is determined that the subject is bright, the process proceeds to step S104.

  In step S104, recording of the captured image on the tape medium 109 is started. Then, in the next step S105, it is determined whether or not the trigger button 116c is pressed again. If it is determined that the trigger button 116c is pressed again, it is determined that the recording end is instructed, a recording end process is performed in step S106, and this process ends.

  On the other hand, if it is determined in step S103 that the subject brightness is equal to or lower than the predetermined value, the process proceeds to step S107, where the video light control unit 114 turns on the video light 115 shown in FIG. Then, in the next step S108, the illumination unevenness region is specified. Specifically, the contribution due to illumination is calculated based on the difference in luminance value for each pixel of the image data before and after turning on the video light 115 (image data with illumination and image data without illumination). Here, when the difference value is equal to or smaller than a certain threshold value, it is determined that the contribution due to illumination is small, thereby specifying the illumination unevenness region in the shooting angle of view. Conversely, when the difference value is greater than or equal to a certain threshold value, the light distribution range of the video light 115 at the shooting angle of view is specified by determining that the contribution due to illumination is large.

  In the next step S109, the degree of illumination unevenness is determined based on the information on the illumination unevenness region created in step S108. As a result, if it is determined that the illumination unevenness area is equal to or smaller than a predetermined range, the process proceeds to step S104, and recording of the captured image is started. Here, the predetermined range may be determined by setting a threshold value, for example, 80% of the shooting area.

  On the other hand, if it is determined in step S109 that the illumination unevenness area is greater than or equal to a predetermined range, the process proceeds to step S110, where the zoom operation of the lens 101 to the wide angle side is prohibited. Then, in the next step S111, a predetermined angle of view that is maximum within the light distribution range of the video light 115 specified in step S108 is automatically cut out. Then, digital zoom processing for electronically enlarging the resolution to the format is performed, and the process returns to step S104.

  Here, the reason for prohibiting the optical zoom operation of the lens 101 toward the wide angle side in step S110 will be described.

  FIG. 6 is a diagram illustrating a state in which the light distribution range of the video light 115 is approximately half of the shooting area. In this figure, reference numeral 200 denotes a photographing area, 201 denotes a digital zoom area, 202 denotes a video light distribution area, and 203 denotes an illumination unevenness area. The digital zoom area 201 is an area that is automatically set so that the angle of view is maximized within the light distribution range of the video light 115, and the image signal in that area is automatically cut out.

  If the zoom operation to the wide angle side of the lens 101 is further performed from this state, the state as shown in FIG. 7 is obtained, and the photographing region 200 becomes larger. However, since the video light distribution area 202 does not change, the illumination unevenness area 203 becomes large as a result. Further, since the video light distribution area 202 becomes relatively small, the digital zoom area 201 that performs the digital zoom processing in step S111 also becomes small as a result.

  As described above, when the zoom operation to the wide angle side of the lens 101 is performed, the illumination unevenness region 203 becomes large and the digital zoom region 201 becomes small. Therefore, in step S110, the zoom operation to the wide angle side of the lens 101 is performed. Is prohibited.

  In this embodiment, a process for prohibiting the zoom operation of the lens 101 to the wide angle side in step S110 of FIG. 5 when it is determined that the illumination unevenness area is greater than or equal to a predetermined range is described. However, in addition to the process of prohibiting the zoom operation, for example, a warning such as “If the zoom operation is performed on the wide-angle side, the illumination unevenness range is widened” may be displayed on the display unit 105 to alert the user. Good.

  In step S111, a digital zoom process is performed in which a predetermined angle of view that is the maximum within the light distribution range of the video light 115 is automatically cut out and enlarged to the resolution on the format. However, the present invention is not limited to this. For example, the digital zoom area may be freely specified by the user using the cross key 116d and the area determination button 116f. At this time, for example, when the area specified by the user is in the uneven illumination range, a warning message such as “The specified area is in the uneven illumination range” may be displayed on the display unit 105. Alternatively, the user may be alerted by changing the color of the selected area to a warning color such as red, or generating a warning sound such as a beep sound.

  Thus, in this embodiment, when illumination means such as the video light 115 is used, the presence or absence of illumination unevenness is detected, and when there is illumination unevenness, a predetermined maximum within the light distribution range of the video light 115 is obtained. A digital zoom process for automatically cutting out the angle of view and enlarging the resolution to the format is performed. Therefore, it is possible to generate a good captured image without illumination unevenness.

  Further, when there is illumination unevenness, zoom operation to the wide-angle side of the lens 101 is prohibited, so that it is possible to prevent the illumination unevenness from further increasing.

  Therefore, it is not necessary to mechanically or electrically drive the illumination means as in the prior art to improve the illumination unevenness of the photographed image, and it is not necessary to make the mechanism of the video camera 100 complicated. An increase in size can be prevented.

  In the embodiment described above, the warning operation is performed by displaying on the display unit 105. However, the present invention is not limited to this, and the user can be audibly informed by, for example, warning by voice. Further, the video light 115 may be detachable from the imaging device.

It is a block diagram which shows the circuit structure of the video camera concerning the Example of this invention. It is the perspective view seen from the front direction (subject side) of the video camera concerning the example of the present invention. It is the perspective view seen from the left rear of the video camera concerning the Example of this invention. It is the perspective view seen from the right rear of the video camera concerning the Example of this invention. It is a flowchart which shows the operation | movement at the time of imaging | photography mode in the video camera concerning the Example of this invention. It is a figure which shows the state in which the light distribution range of a video light has become about half of the imaging | photography area | region in the video camera concerning the Example of this invention. It is a figure which shows the state which performed the zoom operation | movement to the wide angle side further from the state of FIG. It is a figure for demonstrating the imaging device incorporating the general illumination means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Video camera 101 Lens 102 Image pick-up part 103 Camera signal processing part 104 Compression / decompression processing part 105 Display part 105a Liquid crystal panel 105b EVF
106 Recording / playback processing unit 118 CPU
119 Operation unit 123 Zoom control unit 200 Shooting area 201 Digital zoom area 202 Video light distribution area 203 Illumination unevenness area

Claims (6)

Illumination unevenness detecting means for detecting an illumination unevenness area of the illumination means for illuminating the subject,
An imaging apparatus that generates an image based on an image signal within a light distribution range of the illumination unit when the illumination unevenness area detected by the illumination unevenness detection unit is a predetermined size or larger. Illumination unevenness detecting means for detecting an illumination unevenness area of the illumination means for illuminating the subject; and
Area setting means for setting an image generation area by a user operation;
Have
An imaging apparatus that warns when an image generation region set by the region setting unit overlaps an illumination uneven region detected by the illumination unevenness detection unit.   The illumination unevenness detection unit detects an illumination unevenness region by obtaining a difference value between image data in a state where the subject is irradiated with the illumination unit and a state where the subject is not irradiated with the illumination unit. The imaging device described.   The imaging apparatus according to claim 1 or 3, wherein an imaging angle of view is restricted within the light distribution range when the detected illumination unevenness area is a predetermined size or more.   The imaging apparatus according to claim 4, wherein when the detected uneven illumination area has a size greater than or equal to a predetermined size, the zooming operation to the wide angle side of the lens is restricted. The imaging apparatus according to claim 1, wherein when the detected illumination unevenness area is larger than a predetermined size, an image signal within the light distribution range is cut out and enlarged to a resolution of a predetermined format. .

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