JP2006033291A - Imaging apparatus, method of controlling the same and processing program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera which can automatically set a trimming region and can output the RAW data of a plurality of different resolutions. <P>SOLUTION: A pre-luminance is performed, and a reflected light from a subject is measured. Consequently, a main subject region is presumed from a photography screen. A file capacity is reduced by trimming and saving the RAW data of the region presumed to be the main subject. Next image processing is made easy. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging measure capable of performing a measurement operation on a subject.

  In general digital cameras, image signals obtained from image sensors such as CCD sensors and CMOS sensors are A / D converted, subjected to various image processing, and then compressed using a compression method such as JPEG encoding. Record on a recording medium.

  In this type of digital camera, irreversible compression is performed when recording on a recording medium, so that a sufficiently good image quality may not always be obtained during reproduction or printing. In addition, since the recorded image has already been subjected to various image processing, the image quality may deteriorate if the user performs further image processing after shooting.

  On the other hand, a method (RAW method) has been proposed in which an analog signal for each pixel output from the image sensor is A / D converted and recorded without performing image processing.

  In this RAW method, RAW data that is image data before image processing such as development is recorded, and image reproduction (development) processing is not performed in the camera but is performed using an external processing device such as a personal computer. ing. Thereby, the degree of freedom of image processing such as white balance and color processing can be given to the user after shooting.

  However, as the number of pixels of the image sensor increases, there is a problem that the recording capacity per image increases and the number of images that can be recorded decreases.

  Further, when the amount of RAW data recorded on the recording medium increases, the amount of data to be image processed by the external processing device after shooting increases accordingly, which increases the burden on the user.

Therefore, in the RAW format, as a method for reducing the amount of recording data, for example, a method of performing a trimming process for deleting unnecessary portions in an image and recording with a smaller number of pixels (resolution) than the maximum number of pixels is proposed. (For example, refer to Patent Document 1).
JP 2003-309796 A (paragraph 0229, FIG. 35)

  However, Patent Document 1 does not mention a trimming area designation method.

  In order to solve the above problems, one of the objects of the present invention is to set the trimming area automatically so that the user does not need to set the area, and to reduce the recording capacity and save the post-processing. The object is to provide a digital camera capable of outputting data.

  In order to solve the above problems, a first configuration of an imaging apparatus according to the present invention includes an image generation unit that generates an image using an imaging element (for example, a CCD sensor or a CMOS sensor), and a subject in a plurality of subject areas. Measurement means for performing a measurement operation (for example, photometry operation, distance measurement operation), a determination means for determining a specific subject area from the plurality of subject areas based on a measurement result by the measurement means, and the generated image An image pickup apparatus comprising: a control unit that records an image region corresponding to the specific subject region in an image recording unit.

  In the first configuration of the present invention, an image area corresponding to the specific subject area is stored in the image recording means, and this specific subject area is determined based on the measurement result by the measuring means. As a result, the user of the photographing apparatus does not need to set a specific subject area for all the photographed images, and can set the specific subject area using information used for imaging. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1 is a block diagram showing the overall configuration of a digital camera (imaging device) 10 that is an embodiment of the present invention. In the figure, reference numeral 100 denotes a control circuit that controls the entire digital camera. The control circuit 100 includes a central processing circuit. Reference numeral 101 denotes a photographic lens that advances and retreats in the optical axis direction based on a drive signal from the control circuit 100.

  Reference numeral 102 denotes a light shielding member including a diaphragm, a shutter, and the like, which is opened and closed in a plane substantially orthogonal to the photographing optical axis to change the amount of light passing through.

  Reference numeral 103 denotes an image sensor (for example, a CCD sensor or a CMOS sensor) that converts light from a subject into an electrical signal. The analog signal output from the image sensor 103 is converted into a digital signal by the A / D converter 104.

  Hereinafter, a signal output from the A / D converter 104 is referred to as a RAW data signal. Note that the RAW data signal means a signal that has undergone A / D conversion and has not undergone image processing such as white balance adjustment, pixel interpolation, gradation conversion, and color correction. The image data signal obtained by performing the defect correction process for interpolating the data is included in the point that the image process related to the image quality adjustment is not performed.

  The buffer memory 105 has a capacity capable of storing a plurality of pieces of image data for one screen read from the image sensor 103 as a unit. Furthermore, the capacity of the buffer memory 105 is such that the speed of the continuous shooting operation that performs a plurality of shooting operations in a short time is not limited to the speed of subsequent processing (format conversion, compression encoding, recording on the recording medium 107). It is set to be large.

  The image processing circuit 106 performs image processing such as white balance adjustment, pixel interpolation processing, gradation processing, and color conversion processing on the RAW data signal. As the recording medium 107 (image recording means), a semiconductor memory that can be attached to and detached from the camera is used.

  The photometric sensor 108 (measuring means) is a multi-segment photometric sensor that can divide the imaging screen into a plurality of areas and measure the luminance for each area as shown in FIG. Here, FIG. 3 is a division diagram in which the photographing screen is divided into 35 photometric areas. In the figure, 30 represents the entire photographing screen, and 31 represents the division state of the photometric sensor 108 on the photographing screen.

  In this way, the photometric sensor 108 associated with the photographing screen can divide the photographing screen and measure and output each luminance value.

  Reference numeral 112 denotes SW1 operated to start a shooting preparation operation (ranging operation and photometry operation), and 113 denotes a shooting operation (such as exposure to the image sensor 103 for recording an image signal). SW2 to be operated.

  Reference numeral 110 denotes an operation unit that is operated for setting a shooting mode of the camera, setting of a trimming area, and the like, and 111 is an image display unit including a liquid crystal panel 111a that displays a shot image.

  A trimming processing circuit 114 extracts RAW data corresponding to a main subject region (specific subject region), which will be described later, from an image displayed on the entire liquid crystal panel 111 a and is driven by the control circuit 100.

  Next, trimming processing in the digital camera of this embodiment will be described with reference to FIG. Here, FIG. 2 is a flowchart showing a control procedure of the trimming process. The control circuit 100 reads out and executes a program from a memory (not shown).

  When SW1 is operated by the photographer, a photometric operation by the photometric sensor 108 described below is started (step S201). That is, first, the photometric sensor 108 measures the light for each area in the shooting screen under natural light, and stores the photometric result in the buffer memory 105 as the luminance value E1i (i = 1 to 35) (step S202).

  Next, a lighting device (not shown) is driven to perform pre-light emission toward the subject (step S203). Then, the reflected light of the subject based on this pre-emission is measured again by the photometric sensor 108 in each area, and the photometric result is stored in the buffer memory 105 as a luminance value E2i (i = 1 to 35) (step S204).

  Next, a difference ΔEi between the luminance value at the time of pre-emission of each area in the photographing screen and the luminance value in the natural light state is calculated.

ΔEi = E2i−E1i (i = 1 to 35)
In this calculation, the luminance when the subject is irradiated with pure pre-emission energy is obtained, but in many cases the luminance under pre-emission is much higher than the luminance under natural light. Therefore, in order to simplify the calculation, the difference calculation result may be approximated to a luminance value under pre-emission.
ΔEi = E2i (i = 1 to 35)
Based on this difference value, the weighting coefficient in each area is calculated to estimate the main subject area (step S205). This main subject region estimation method will be described with reference to FIG. Here, FIG. 4 is a flowchart showing a main subject region estimation method.

First, the maximum value of ΔEi (i = 1 to 35) measured in each area is obtained (step S301).
maxE = max (ΔEi)
However, when the luminance value of one area is much larger than the luminance values of the remaining other areas, the maximum value may be obtained by excluding the luminance value of the one area.

  By excluding areas with extremely large luminance values, it is possible to prevent the object from being erroneously estimated as the main subject when there is an object with a very high reflectance in the background.

  Next, the weighting coefficient ki (i = 1 to 35) in each area is calculated from the upper left area (i = 1) from the difference between maxE and ΔEi (steps S302 and S303). When the weighting coefficient is equal to or greater than the threshold value t0, the area flag Fi is set to 1 (steps S304 and S305). The main subject area is set to a rectangular area including all areas where the flag Fi is 1.

  On the other hand, when the weighting coefficient is smaller than the threshold value t0, the flag Fi of the area is set to 0 (steps S304 and S306). Next, i is incremented (step S307), and the routine from step S304 to step S307 is executed (step S308) until the flags Fi of all 35 divided areas are determined (that is, until i> 35). When all the flags Fi are determined, a rectangular area including all areas where Fi = 1 is estimated as the main subject area.

  FIG. 5 is a diagram in which the main subject area is estimated based on the above-described flowchart. When the SW1 is operated in the composition as shown in FIG. 5A and the photographing preparation operation is started, the photometric sensor 108 measures the luminance value in each area.

  Next, based on the photometric result, the weighting coefficient in each area is calculated as shown in FIG. At this time, if the threshold value t0 is 50, the Fi of the dark gray area is 1. In this example, the gray area is divided into two areas according to the density, but a rectangular area that includes all of these areas and that retains the aspect ratio (3: 2) of the original image is estimated as the main subject area. (FIG. 5C).

  An appropriate exposure amount is calculated based on the photometric value of the area estimated to contain the main subject (step S206). When SW2 is operated (step S207), the light shielding member 102 is driven and controlled based on the calculation result, and exposure control is performed. Is started (step S208, step S209).

  Next, the RAW data output from the image sensor 103 is developed in the image processing circuit 106, where a preview image to be displayed on the image display unit 111 is generated (step S210). The preview image is displayed on the image display unit 111 together with a frame indicating the main subject area estimated in step S205 (step S211).

  At the same time, selection information (not shown) such as “trimming” or “not trimming” is displayed below the liquid crystal panel 111 a of the image display unit 111. The user can select one of the selection information by operating the left key 61L and the right key 61R of the cross key 61. Then, the selection information selected by pressing the set key 62 can be confirmed. Thereby, it is possible to determine whether or not to perform image trimming (step S212).

  If “Do not trim” is selected, the RAW data of the captured image displayed on the entire liquid crystal panel 111a is stored in the recording medium 107 (step S214), and the process is terminated. Thus, in this embodiment, the main subject (mainly the subject targeted by the photographer at the time of photographing) stored in the recording medium 107 can be automatically set, so the burden on the photographer can be reduced.

  When “trimming” is selected, “change area” and “do not change area” are further displayed on the liquid crystal panel 111a as selection information. The user can select one of the selection information by operating the left key 61L and the right key 61R of the cross key 61. Then, the selection information selected by pressing the set key 62 can be confirmed. Thereby, it is possible to determine whether or not to change the setting of the trimming area (step S213).

  When “Do not change the area” is selected, the process of resetting the area (step S215) is skipped, and the RAW data of the main subject area determined in step S205 is stored in the recording medium 107 and processed. Exit. Note that RAW data relating to an area other than the main subject area may be discarded or recorded on a recording medium different from the recording medium 107. Thereby, the amount of data recorded on the recording medium 107 can be reduced.

  When “change area” is selected, an operation guide as shown in FIG. 6 is displayed at the bottom of the liquid crystal panel 111a. Here, the trimming region can be enlarged / reduced by operating the enlargement / reduction key 60. Further, by operating the cross key 61, the trimming area can be moved in a direction corresponding to the operation direction.

  Then, the trimming area can be rotated by simultaneously pressing the left key 61L and the right key 61R of the cross key 61. For example, by simultaneously pressing the left key 61L and the right key 61R, the trimming region having a vertical / horizontal length ratio of 2: 3 as shown in FIG. 5C is rotated 90 degrees, and the vertical / horizontal length ratio is set to 3 : The trimming area can be changed to 2.

  When the trimming area is reset by the user pressing the set key 62 (step S215), RAW data relating to the set area is stored in the recording medium 107 (step S216).

(Example 2)
In the present embodiment, unlike the first embodiment, the main subject region is specified based on the measurement result of the distance measuring sensor 109 (see FIG. 1). Here, the distance measuring sensor 109 (measuring means) is a multi-distance distance measuring sensor that divides the imaging screen into a plurality of areas as shown in FIG. 3, for example, and measures the distance for each area.

  A trimming process in the photographing apparatus of the present embodiment will be described with reference to FIG. Here, FIG. 7 is a flowchart showing the control procedure of the trimming process. The program is read from the memory (not shown) by the control circuit 100 and executed.

  First, when SW1 is operated (step S401), a shooting preparation operation, that is, a distance measuring operation by the distance measuring sensor 109, etc. is started.

  By this distance measuring operation, the distance to the subject displayed in each shooting area is measured, and the focus adjustment state for the subject is detected (step S402).

  Then, a weighting coefficient corresponding to the distance to the subject is calculated for each of the plurality of shooting areas divided as shown in FIG. 3, and the main subject region is estimated based on the calculation result (S403).

  Then, an appropriate exposure amount is calculated based on the photometric result obtained by the above-described photometric operation (step S404). Based on the calculated result, the light shielding member 102 is controlled and the focus lens is driven according to the above-described focus detection state. Then, by operating SW2 (step S405), the illumination device irradiates the main light (step S406) and the image sensor 103 is exposed (step S407).

  About step S408-step S414, since it is the same as that of step S210-step S216 mentioned above, description is abbreviate | omitted.

  Note that the trimming process may be applied to the RAW data recorded on the recording medium 107 instead of immediately after the photographing operation.

1 is a functional block diagram of a digital camera according to an embodiment. 3 is a flowchart showing a control procedure of trimming processing executed by the digital camera of Embodiment 1. It is a photometry division | segmentation figure of a photometry sensor. 5 is a flowchart showing a procedure for estimating a main subject area. FIG. 6 is a diagram illustrating an estimated main subject area. It is the figure which displayed the main subject field and operation guidance on the liquid crystal panel. 6 is a flowchart illustrating a control procedure of trimming processing executed by the digital camera of Embodiment 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 100 Control circuit 101 Shooting lens 102 Light-shielding member 103 Image pick-up element 104 A / D converter 105 Buffer memory 106 Image processing circuit 107 Recording medium 108 Photometric sensor 109 Distance sensor 110 Operation unit 111 Image display unit 112 SW1
113 SW2
114 Trimming Processing Circuit 30 Shooting Screen 31 Metering Area 60 Enlargement / Reduction Key 61 Cross Key 62 Set Key

Claims (7)

Image generating means for generating an image using an image sensor;
Measuring means for performing a measuring operation on a subject in a plurality of subject areas;
Determining means for determining a specific subject area from the plurality of subject areas based on a measurement result by the measuring means;
An image pickup apparatus comprising: a control unit that records an image region corresponding to the specific subject region in the generated image in an image recording unit. The measuring means is a photometric means;
The determining unit is configured to determine the specific subject based on a difference between a photometric result obtained in each subject region by irradiating the subject with illumination light and a photometric result obtained in each subject region without irradiating the illumination light. The imaging apparatus according to claim 1, wherein an area is determined. The measuring means is a distance measuring means,
The imaging apparatus according to claim 1, wherein the determination unit determines the specific subject region based on a distance measurement result obtained in each subject region.   4. The method according to claim 1, wherein the determination unit performs a weighting operation between the plurality of subject regions based on the measurement result, and determines the specific region based on the calculation result. The imaging device described in 1. Generating an image using an imaging device;
A measurement step for performing a measurement operation on a subject in a plurality of subject areas;
A determination step of determining a specific subject region from the plurality of subject regions based on the measurement result of the measurement step;
And a step of recording an image region corresponding to the specific subject region in the generated image in an image recording unit.   6. The method according to claim 5, wherein the image data of the image recorded in the recording unit is RAW data output from the image sensor.   A processing program for causing a computer in an imaging apparatus to execute the control method according to claim 5 or 6.

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