JP4991511B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus capable of selectively setting a maximum digital zoom amount.

  Conventionally, the zoom function of an image pickup apparatus can be broadly classified into two types: an optical function and an electronic function. In general, the former is called “optical zoom” and the latter is called “digital zoom”.

  In the optical zoom, the size of the subject image is changed by changing the combination of the optical lenses, so that the image quality does not deteriorate due to the change in zoom magnification.

  On the other hand, unlike the optical zoom, the digital zoom cuts out and enlarges a part of a pixel in the image sensor. For this reason, when the number of pixels to be cut out falls below the number of pixels of the image to be recorded, the shortage is compensated for by complementation processing, and deterioration in image quality is inevitable.

Users have a desire to shoot with as high image quality as possible. For this reason, there has been proposed an imaging apparatus that performs a display that can quantitatively and intuitively recognize how much image quality is captured using a digital zoom (see, for example, Patent Document 1).
JP 2006-2111434 A

  However, in an imaging apparatus such as that disclosed in Patent Document 1, even if the user wants to take a picture with a desired image quality or higher, he / she sees a display relating to the picture quality which changes every moment during a sudden zoom operation. However, it is difficult to stop the zoom operation at the limit of the desired image quality. In addition, if the consciousness is concentrated on confirmation of the composition or the like, it is sufficiently considered that the display relating to the image quality is overlooked, and as a result, there is a possibility that the image is taken with an image quality less than desired.

  In order to prevent the above-described shooting not intended by the user, the digital zoom has a setting function for the maximum zoom amount. However, the conventional setting method is a format in which selection candidates are expressed by zoom magnification (for example, “× 40”, “× 100” (meaning 40 times and 100 times, respectively)). Therefore, in order to determine the degree of image quality from the zoom magnification, it is necessary to perform photographing with digital zoom many times and learn the relationship empirically, which is not suitable for intuitive operation.

(Object of invention)
An object of the present invention is to provide an imaging apparatus that can allow a user to intuitively determine how much image quality degradation has occurred when setting a maximum digital zoom amount.

In order to achieve the above object, the present invention provides a digital zoom processing unit that performs digital zoom processing on an image captured by an imaging unit, and a maximum digital zoom amount candidate display unit that allows a user to select a maximum digital zoom amount. in the imaging apparatus having the the maximum digital zoom amount candidate display means, which selection candidates displayed on the display together with corresponding to the selection of the maximum digital zoom amount is set to an imaging apparatus is intended to represent the number of recording pixels It is.

  According to the present invention, it is possible to provide an imaging apparatus that allows a user to intuitively determine how much image quality degradation has occurred when setting the maximum digital zoom amount.

  The best mode for carrying out the present invention is as shown in Examples 1 to 3 below.

  FIG. 1 is a block diagram showing a schematic configuration of an image pickup apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes an image pickup unit, which includes an image pickup element, a lens, a diaphragm, an optical zoom mechanism, and the like, and converts an imaged subject into an electrical signal. An image processing unit 2 performs various signal processing on the electrical signal received from the imaging unit 1 to generate a predetermined image signal. A control unit 3 performs processing related to operation control of the imaging apparatus, and performs processing control of various input switches, drive control of an optical lens, an instruction to the image processing unit 2, and the like.

  Reference numeral 4 denotes a digital zoom processing unit that performs a process of selecting and cutting out a part of information obtained by the image pickup device of the image pickup unit 1 in cooperation with the image processing unit 2 during the digital zoom process. Reference numeral 5 denotes a recording unit that records the image signal generated by the image processing unit 2 in an internal memory or an external memory. Reference numeral 6 denotes a display unit such as an LCD, which displays a photographed image and image information directed to the user. Reference numeral 7 denotes a release switch, which is a shutter button for taking a still image. Reference numeral 8 denotes a zoom switch for operating zoom up and zoom back. Based on this operation information, the optical lens is driven and the digital zoom cut-out size is changed. Reference numeral 9 denotes an input switch for obtaining some input information from the user, such as a push switch or a touch panel.

  The image processing unit 2, the control unit 3, the digital zoom processing unit 4, and the like described above may exist independently, or may be included in any representative portion.

Some image pickup apparatuses having a digital zoom function can enable / disable the digital zoom function and can set a maximum digital zoom amount when the digital zoom function is enabled. FIG. 2 shows an example in which selection candidates expressed by the number of pixels are displayed on the display unit 6 when the maximum digital zoom amount is set. The number of pixels indicates the number of pixel range (clipped area) of the information obtained by the imaging element in the imaging unit 1 is selected by the digital zoom processing unit 4 during digital zoom processing (signal information to be used as an image). The number of pixels in the range of information obtained by the image sensor selected by the digital zoom processing unit 4 is hereinafter referred to as a read pixel number.

  Here, an example of a process of selecting and cutting out a part of information obtained by the image sensor by the digital zoom processing unit 4 or the like will be described in detail.

  Based on the selected setting value, the cut-out pixel range of the image sensor included in the imaging unit 1 is determined. This is a calculation including the aspect ratio of the recorded image. For example, when “6M (6 million pixels)” is set, “the number of long side pixels × the number of short side pixels = approximately 6 million”, and the aspect ratio of the recorded image is “4: 3”. Then, “the number of long side pixels × (3/4) = the number of short side pixels”. The cutout pixel range at this set value is the solution of the above two equations, and an example is a value of “2840 × 2130 (= 650,000)”.

When pixel coordinates are assigned with reference to one corner of a rectangular image sensor having a total number of long sides = Xmax and a total number of short sides = Ymax, the center pixel coordinate is [x = Xmax / 2, y = Ymax / 2]
It becomes. Note that x is the horizontal direction (long side), and y is the vertical direction (short side).

Here, it is assumed that the number of cut-out pixels by digital zoom is long-side cut-out pixel number = Xzoom, and short-side cut-out pixel number = Yzoom. The center of zoom enlargement is the center of the image sensor. The coordinates of the cutout pixel range at this time are as shown in FIG.
[X = (Xmax / 2) − (Xzoom / 2),
y = (Ymax / 2)-(Yzoom / 2)]
[X = (Xmax / 2) − (Xzoom / 2),
y = (Ymax / 2) + (Yzoom / 2)]
[X = (Xmax / 2) + (Xzoom / 2),
y = (Ymax / 2) + (Yzoom / 2)]
[X = (Xmax / 2) + (Xzoom / 2),
y = (Ymax / 2)-(Yzoom / 2)]
This is an area surrounded by four points.

  An example of operation using specific numerical values is shown below. The total number of pixels of the image sensor is 7.92 million pixels of “3300 × 2400”, and the number of cut-out pixels is “2840 × 2130 (= 650,000)” mentioned in the previous example. The center pixel coordinates of the image sensor are “x = 1650, y = 1200”, and the cutout pixel range is an area surrounded by the following four coordinates.

[X = 230, y = 135]
[X = 230, y = 2265]
[X = 0307, y = 2265]
[X = 3070, y = 135]
As an applied operation, it may be possible to set the zoom magnification center to a different coordinate from the center of the image sensor. For example, it is a case where the coordinates are recognized as having a human face.

  The above operation is a joint operation of the imaging unit 1, the image processing unit 2, and the digital zoom processing unit 4 in FIG. When the image sensor is a CCD, the image processing unit 2 and the digital zoom processing unit 4 cut out only the area necessary for recording from the data obtained by reading all the pixels. When the image sensor is a CMOS, the digital zoom processing unit 4 determines a region necessary for recording and notifies the image capturing unit 1 of the region, so that signals can be read out only from pixels in the necessary region. In either case, the digital zoom processing unit 4 selects an area.

  Hereinafter, settings and operations in an image pickup apparatus having an image pickup device having a total number of pixels of 8 million pixels will be described.

  When the user selects a digital zoom limit setting item in the setting change menu of the imaging apparatus, selection candidates as shown in FIG. In FIG. 2, only the number of pixels is displayed, but a color expression that can be intuitively imagined for the degree of deterioration is added, or a magnification expression that is displayed on a conventional imaging device. It is also effective to use them together.

  The user uses the input switch 9 to select the number of recording pixels as the image quality level of the digital zoom that is determined to be acceptable by the user. Here, it is assumed that “6M (mega)” meaning 6 million pixels is selected (see FIG. 2). Information that the user has decided to select using the input switch 9 is recognized by the control unit 3, and then the fact that “6M” has been selected is transmitted to the digital zoom processing unit 4. Then, the digital zoom processing unit 4 sets this as a limit pixel number (maximum digital zoom amount), for example, and limits the number of read pixels to 6 million pixels. Here, the image quality level of the digital zoom is set to “6M” which is equal to the number of readout pixels, but may be a number which is an approximation of “6M” or more and “6M” or less. For example, “2800 × 2100 = 5,880,000” may be treated as an approximation of “6M”.

  The operation executed by the control unit 3 when taking a still image after the above digital zoom limit setting is completed will be described with reference to the flowchart of FIG. Note that this flowchart shows only operations relating to the zoom operation and photographing. In the imaging apparatus, the optical zoom is preferentially processed, and the digital zoom processing is performed only for the zoom beyond the telephoto end.

  In FIG. 3, first, in step S101, it is determined whether or not the release switch 7 has been pressed. If the pressing operation has been performed, the process proceeds to the process after step S114 described later. If the release switch 7 is not pressed, the process proceeds to step S102, where it is determined whether the zoom operation using the zoom switch 2 has been performed. If the zoom operation has not been performed, the process returns to step S101 to wait for input of the release switch 7 and zoom operation.

  When it is determined in step S102 that the zoom operation has been performed, the zoom processing operation is started. In the next step S103, it is determined whether or not the zoom processing at this time is zoom-up. If it is not zoomed up, the process proceeds to step S109 and later. If the zoom is up, the process proceeds to step S104 to determine whether the optical lens is at the tele end. If it is not at the tele end, the process proceeds to step S105 to drive the optical lens to the tele end side. Thereafter, the process returns to step S102.

  If it is determined in step S104 that the optical lens is located at the tele end, digital zoom processing is started. In the next step S106, the current number of read pixels is compared with the number of limit pixels (for example, 6M) selected by the user in the digital zoom limit setting. As a result, when the current number of read pixels is larger than the limit pixel number, the process proceeds to step S107, where the number of read pixels is decreased and digital zoom-up processing is performed. On the other hand, if the read pixel number is equal to the limit pixel number, the process proceeds to step S108, and the digital zoom-up process is not performed. At this time, some message by display or sound may be issued.

  If it is determined in step S103 that the zoom-up is not performed but the zoom-back is performed, the process proceeds to step S109, and the current readout pixel number is compared with the maximum readout pixel number (hereinafter, maximum pixel number) when digital zoom is not processed. As a result, if the number of readout pixels is smaller than the maximum number of pixels, it can be determined that the digital zoom processing is in progress, and thus the process proceeds to step S110, and zoom back processing is performed by increasing the number of readout pixels. On the other hand, if the number of read pixels is equal to the maximum number of pixels, it can be determined that the optical zoom region or the optical lens is located at the telephoto end, and the process proceeds to step 111. In step S111, it is determined whether or not the optical lens at that time is positioned at the wide end. If it is positioned at the wide end, the process proceeds to step S112, and no further zoom back is performed. If it is located in the movable region of the optical zoom, the process proceeds to step S113, and only in this case, driving to the wide end side is performed.

  After the above zoom adjustment is completed, the user performs a pressing operation on the release switch 7.

  When the release switch 7 is pressed, this is determined in step S101 in FIG. 3, the process proceeds to step S114, and the subject is photographed. As a result, in the next step S115, an electrical signal is read from the imaging unit 1 to the image processing unit 2, and an image to be recorded in the recording unit 5 is generated from the read pixel signal, and the next step S116 is performed. The generated image is recorded in the recording unit 5.

  The size of the image recorded in the recording unit 5 is determined separately according to user settings. FIG. 4 is an example of a recording image size setting screen. Here, it is expressed in the format of “the number of horizontal pixels × the number of vertical pixels” of the recorded image. The result of multiplying these lengths and widths is the number of recording pixels. “3300 × 2400” is 7.92 million pixels, and “2600 × 1900” is 4.94 million pixels, which are sequentially 1.92 million pixels, 960,000 pixels, and 300,000 pixels.

  Here, processing according to the relationship between the number of read pixels and the number of recorded pixels included in the image processing in step S115 will be described with reference to the flowchart of FIG.

  FIG. 6 shows the relationship between the case where the number of read pixels is 6 million pixels and “2600 × 1900” is selected as the recorded image size in the state during the digital zoom process.

  In step S201 in FIG. 5, the number of pixels, that is, the number of read pixels and the number of recorded pixels are compared. In this example, since the number of read pixels is larger than the number of recorded pixels, the process proceeds to step S202, and a thinning process for 1.06 million pixels as the difference is performed.

  Further, the relationship when “3300 × 2400” is selected as the recording image size is as shown in FIG. 7, and in this case, the number of recording pixels is larger than the number of readout pixels, and therefore, the process proceeds from step S201 to step S203. Then, the complementary processing for 1.92 million pixels as the difference is performed.

  Although the thinning process and the complementary process are not particularly specified, a known technique can be used.

  As shown in FIG. 6, when the number of read pixels is larger than the number of recorded pixels, the image quality deterioration due to the complement processing does not occur, so that the photographing result expected by the user can be obtained. On the other hand, when the number of readout pixels is lower than the number of recorded pixels as shown in FIG. However, even in this case, post-processing such as reduction processing is performed on a personal computer or the like, so that the image quality equivalent to the recorded image by the imaging device having the number of pixels equivalent to the number of pixels set to the maximum zoom amount is secured. it can.

  Therefore, the selection candidates for setting the maximum digital zoom amount are expressed in terms of the number of pixels, that is, the expression format based on the number of recorded pixels as the image quality level. Can be judged.

  In the zoom operation processing in FIG. 3, the position of the optical lens is confirmed every time. As a derivative example, FIG. 8 shows a flowchart when the digital zoom processing is handled as flag information. The digital zoom processing flag portion in steps S304, S309, and S314 in FIG. Since the basic operation is the same as in FIG. 3, details thereof are omitted.

  FIG. 9 shows a flowchart when there is no optical zoom. This is the same as that obtained by deleting the item relating to the optical zoom in FIG.

  Next, an image pickup apparatus according to Embodiment 2 of the present invention will be described. The first embodiment is a display method that is particularly effective in still image shooting. On the other hand, in the case of a moving image, there is a format that defines the resolution for television, so it is easier to understand intuitively if an expression based on this resolution is used. Such an example will be described as a second embodiment of the present invention.

  FIG. 10 shows a display example on the display unit 6 according to the second embodiment of the present invention, and is a digital zoom limit setting screen expressed in an expression suitable for moving images. Note that the configuration of the imaging apparatus is the same as that of the first embodiment, and thus the description thereof is omitted.

  In FIG. 10, “HD” is an abbreviation for High Definition, and there are standards for scanning lines such as 1080i and 720p, and the above examples are 1080 lines and 720 lines, respectively. “SD” is an abbreviation for Standard Definition, which is 525 in the NTSC format and 625 in the PAL format.

  In FIG. 10, only three of “OFF”, “HD”, and “SD” are described as selection candidates, but “HD” is further increased to several types, or the number of pixel number candidates is increased. It is also possible.

  A case where 1080i is set for “HD”, NTSC for “SD”, and 16: 9 is set as the screen aspect ratio will be described below. These settings are preferably linked to the video recording format of the imaging apparatus.

  First, a case where the user selects “HD” will be described. In this case, the number of limit pixels in the vertical direction is set to a value equal to the number of scanning lines. In this example, it is 1080. Next, the limit pixel number in the horizontal direction is calculated from the screen aspect ratio. Since 1080/9 × 16 = 1920, the limit number of pixels when “HD” is selected is 1920 × 1080.

  Therefore, when the user selects “HD” in the digital zoom limit setting, it is possible to perform shooting without deterioration in image quality due to the complementary processing up to the number of pixels. Therefore, the same image quality can be maintained in the recorded video, and at the same time, a high-quality video can be viewed on a television screen having the same resolution. Similarly, when “720p” is set in “HD”, 1280 × 720 is the limit pixel number.

  Next, a case where the user selects “SD” will be described. In this case, since the number of scanning lines is 525, the limit pixel number in the vertical direction is 525. Further, since the limit pixel number in the horizontal direction is 525/9 × 16 = 933 (rounded down), the limit pixel number when “SD” is selected is 933 × 525. When High Definition such as 1080i is selected as the recording video format, the video that has been subjected to the complementary processing is recorded. Therefore, when this is viewed on the 1080i TV screen, the image quality is deteriorated. You will feel it. However, this is the same level as when an image based on the existing Standard Definition is projected. When Standard Definition such as NTSC is selected as the video recording format, it is possible to perform shooting without causing image quality degradation due to the complementary processing. Therefore, on the standard definition television screen, a high-quality image within the performance limit of the television monitor can be viewed.

  Therefore, the selection candidate for setting the maximum digital zoom amount is expressed by a name associated with the resolution of the video signal, that is, an expression format based on the degree of image quality. This makes it possible for the user to intuitively determine the degree of image quality degradation during maximum digital zoom during moving image shooting.

  Next, an image pickup apparatus according to Embodiment 3 of the present invention will be described. The first embodiment is effective when the user is strongly aware of the number of pixels. However, in the case of an imaging device built in a mobile phone, for example, the maximum digital zoom amount setting based on the number of pixels is not always intuitive. It can not be said. Rather, in such an apparatus, it may be easier to handle the relative degree of deterioration. Such an example will be described as a third embodiment of the present invention.

  FIG. 11 is an example of displaying the digital zoom image quality limit on the screen of the image pickup apparatus built in the mobile phone according to the third embodiment of the present invention by relative notation of the degree of deterioration. Here, since the degree of image quality is displayed, the number of readout pixels of “low” is the smallest. An example of the read limit pixel number defined by the expressions “high”, “medium”, and “low” is shown in FIG. Also, the recorded image size can generally be selected from a plurality of candidates.

  Also in the third embodiment of the present invention, a series of processing is performed according to the flowcharts of FIGS. 3, 5, 8, and 9, which are the same as in the above-described embodiment.

  In the third embodiment, even if the product has a digital zoom function and the user's recognition of the number of pixels is relatively weak, the user can intuitively determine the degree of image quality degradation due to the digital zoom.

  According to the imaging apparatus in each of the embodiments described above, the image processing unit 2 that performs image processing of an image captured by the imaging device included in the imaging unit 1, and the image that has been subjected to image processing by the image processing unit 2 are recorded. A control unit 3 is included. Furthermore, it has a digital zoom processing unit 4 that performs digital zoom processing on an image captured by the image sensor, and a display unit 6 for a maximum zoom amount candidate that allows the user to select a maximum zoom amount during digital zoom. In such an image pickup apparatus, the selection candidate displayed on the display unit 6 for the maximum zoom amount candidate is conventionally the zoom magnification, and the image quality is set.

  The number of recorded pixels as the image quality degree of the selection candidate is expressed by a numerical quantity expression that is equal to or approximate to the number of pixels in the range of information obtained by the image sensor selected by the digital zoom processing means. I try to do it.

  Thus, when setting the maximum digital zoom amount, since the selection candidates are expressed by the number of pixels, the degree of image quality deterioration at that time is compared with an imaging device having an image sensor with a lower number of pixels. The user can intuitively judge. In other words, since the selection candidates expressed by the degree of image quality are expressed by the number of pixels, the degree of image quality degradation at the time of the maximum digital zoom is intuitively used compared with an imaging device having an image sensor with a lower number of pixels. Can be judged.

  The image quality level of the selection candidate is the name or abbreviation of a standard defined by a resolution that is equal to or approximate to the number of pixels in the range of information obtained by the image sensor selected by the digital zoom processing unit 4. Or, it is expressed by a name representing the fineness of the resolution. For example, “OFF”, “HD”, “SD”, and the like.

  In this way, when setting the maximum digital zoom amount, the selection candidate is expressed by a name related to the resolution, so the degree of image quality degradation at that time is used intuitively compared with the resolution of the video signal Can be judged. In other words, since the selection candidates expressed by the degree of image quality are expressed by a name related to the resolution, the user can intuitively determine the degree of image quality degradation at the time of maximum digital zoom compared to the resolution of the video. Can do.

  In addition, the image quality level of the selection candidates is selected by the digital zoom processing unit 4 in a plurality of grades (“high”, “medium”, “Low” etc.).

  In this way, when setting the maximum digital zoom amount, the selection candidates are expressed in relative notation between the respective shooting image quality candidates, and how much image quality degradation at that time is compared to others. Can be intuitively determined by the user.

  In addition, since the selection candidates expressed in terms of image quality are expressed in relative notation between each of the shooting image quality candidates, it is intuitive to see how much the image quality degradation at the maximum digital zoom is compared to others. The user can be judged.

(Correspondence between the present invention and the embodiment)
The digital zoom processing unit 4 corresponds to digital zoom processing means for performing digital zoom processing on a captured image according to the present invention. The display unit 6 corresponds to the maximum digital zoom amount candidate display means for allowing the user to select the maximum digital zoom amount according to the present invention.

It is a block diagram which shows schematic structure of the imaging device concerning each Example of this invention. It is a figure which shows the setting screen regarding the digital zoom limit which concerns on Example 1 of this invention. It is a flowchart which shows the operation | movement at the time of zoom operation and imaging operation in the imaging device concerning each Example of this invention being performed. It is a figure which shows the setting screen regarding the recording image size which concerns on Example 1 of this invention. It is a flowchart which shows the pixel number conversion process in the image process which concerns on each Example of this invention. It is a figure which shows an example of the relationship between the number of read pixels which concerns on Example 1 of this invention, and the number of recording pixels. It is a figure which shows the other example of the relationship between the number of read pixels which concerns on Example 1 of this invention, and the number of recording pixels. FIG. 4 is a flowchart illustrating an operation when a zoom operation and an imaging operation in which a part of FIG. 3 is changed are performed. 4 is a flowchart showing an operation when a zoom operation and an imaging operation in which a part of FIG. 3 is changed are performed. It is a figure which shows the setting screen regarding the digital zoom limit which concerns on Example 2 of this invention. It is a figure which shows the setting screen regarding the image quality limit of the digital zoom which concerns on Example 3 of this invention. FIG. 11 is a diagram showing a conversion relationship between display characters and the number of read pixels on the setting screen related to the image quality limit of digital zoom according to the third embodiment of the present invention. It is a figure for demonstrating the cutout pixel number which concerns on each Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up part 2 Image processing part 3 Control part 4 Digital zoom processing part 5 Recording part 6 Display part 7 Release switch 8 Zoom switch 9 Input switch

Claims (4)

Digital zoom processing means for performing digital zoom processing on an image captured by the imaging means;
In an imaging apparatus having a maximum digital zoom amount candidate display means for allowing a user to select a maximum digital zoom amount,
In the maximum digital zoom amount candidate display means, the image pickup apparatus, wherein the selection candidate displayed on the display together with corresponding to the selection of the maximum digital zoom amount is intended to represent the number of recording pixels.   The representation of the number of recorded pixels is a number that is equal to or approximate to the number of pixels in the range of information obtained by the imaging means selected by the digital zoom processing means when digital zoom processing is being performed. The imaging apparatus according to claim 1, wherein:   The number of recorded pixels is defined by a resolution that is equal to or approximate to the number of pixels in the information range obtained by the imaging means selected by the digital zoom processing means when digital zoom processing is being performed. The imaging apparatus according to claim 1, wherein the imaging apparatus is expressed by a name or abbreviation of a standard that has been set, or a name that represents a fine sense of the resolution.   The number of recorded pixels is expressed by a plurality of grades set in advance according to the number of pixels in the range of information obtained by the imaging unit selected by the digital zoom processing unit when digital zoom processing is performed. The imaging apparatus according to claim 1, wherein the imaging apparatus is a device.

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