JP2005198035A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera in which an auxiliary line can be legible by making the color and brightness of the auxiliary line changeable. <P>SOLUTION: Auxiliary lines of a black color 71Bk and a white color 71W are stored in a ROM 72. An auxiliary line indicator 70 analyzes through image data, averages tone values of all pixels which constitute the through image data, and calculates a tone mean rate. In the case that a tone mean rate is 128 or less and the through image is presumed to be a dark image, the auxiliary line indicator 70 selects the auxiliary line 71W so that the auxiliary line is legible when displayed on the dark image. On the other hand, in the case that the tone mean rate is 128 or more and the through image is presumed to be a bright image, the auxiliary line indicator 70 selects the auxiliary line 71Bk so that the auxiliary line is legible when displayed on the bright image. The auxiliary line indicator 70 makes an LCD 27 display the auxiliary line 71 of a selected color. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital camera including an electronic viewfinder that displays a through image captured for framing a subject.

  2. Description of the Related Art There is known a digital camera that captures an object image obtained through a photographing lens with an individual image sensor such as a CCD or a CMOS. Many digital cameras include an electronic viewfinder such as a liquid crystal monitor, and display a so-called through image. The photographer performs framing while confirming the through image, determines the photographing range, and performs photographing.

  Patent Document 1 listed below discloses a digital camera in which a grid-like auxiliary line for assisting framing is displayed on an electronic viewfinder in order to prevent a problem that a captured image becomes an inclined image. Has been described. According to this digital camera, when the framing is performed, the camera can be held at an appropriate position where the captured image does not tilt by holding the camera so that the vertical and horizontal portions of the subject overlap the auxiliary line.

  However, with a grid-like auxiliary line, when the auxiliary line is separated from the horizontal or vertical part of the subject, it is difficult to hold the camera so that they overlap. For this reason, the following Patent Document 2 discloses a digital camera that displays auxiliary lines composed of vertical lines and horizontal lines, and that enables the display positions of the vertical lines and horizontal lines to be translated in parallel. According to this digital camera, since the auxiliary line moves, it is easy to superimpose the horizontal and vertical parts of the subject and the auxiliary line, and the camera can be quickly set at an appropriate position.

JP 2000-270242 A JP 2000-333045 A

  However, the conventional digital camera has a problem in that it is difficult to see the auxiliary line if the auxiliary line and the through image are similar in color to the image due to lack of consideration regarding the visibility of the auxiliary line. An object of this invention is to provide the digital camera which can solve such a problem.

  In order to achieve the above object, the digital camera of the present invention comprises a vertical line and a horizontal line, a display means for displaying an auxiliary line for assisting framing on the electronic viewfinder, and the vertical line and the horizontal line moved in parallel. And an auxiliary line moving means for changing the color and brightness of at least one of the auxiliary lines.

  The display switching means may automatically change at least one of the color and brightness of the auxiliary line so that the auxiliary line is easily visible according to the color density information of the through image. In addition, image processing means may be provided for adjusting the color density of the through image so that the auxiliary line can be easily seen in accordance with at least one of the color and brightness of the auxiliary line.

  Further, an angle detection means for detecting a tilt angle of the camera with respect to a horizontal position is provided, and the display means displays the horizontal line and the tilt angle of the camera on the electronic viewfinder in addition to the auxiliary line. Good.

  Since the digital camera of the present invention can change the color and brightness of the auxiliary line, the auxiliary line can be easily seen. In addition, an operation for changing the color and brightness of the auxiliary line is performed by automatically changing the color and brightness of the auxiliary line so that the auxiliary line is easy to see according to the color density information of the through image. There is no need to do it. Furthermore, by adjusting the color density of the through image so that the auxiliary line can be easily seen according to the color and brightness of the auxiliary line, the auxiliary line can be seen more easily.

  In addition, since the camera tilt angle with respect to the horizontal position is detected and the horizontal line and the camera tilt angle are displayed, for example, the photographer is unstable such as on a ship and the horizontal or vertical portion of the subject is displayed. Even if it is difficult to align with the auxiliary line, it is possible to prevent the photographed image from being tilted by photographing with reference to the horizontal line and the camera tilt angle display.

  1 and 2, a lens barrel 15 that holds the photographing lens 13 is incorporated in the front surface of the digital camera 10, and a strobe light emitting unit 16 is exposed. On the side surface of the digital camera 10, a lid 19 is provided to cover a memory card slot into which a memory card 17 (see FIG. 3) is detachably loaded.

  An operation unit 25 and a liquid crystal display (LCD) 27 are provided on the back surface of the digital camera 10. The operation unit 25 includes a power switch 28 for switching on / off the power, a zoom lever 29 for changing the magnification by moving the zoom lens of the taking lens 13 to the wide side and the tele side, a shooting mode, a playback mode, and a menu mode for performing various settings. And a cursor key 33 for moving a cursor displayed on the menu screen and moving an auxiliary line 71 (see FIG. 4) to be described later.

  The LCD 27 displays an image recorded on the memory card 17 and various menu screens. When the digital camera 10 is set to the shooting mode, a so-called through image is displayed on the LCD 27, and framing can be performed by confirming the through image.

  A shutter button 35 is provided on the upper surface of the digital camera 10. The shutter button 35 is a two-step push switch. When the shutter button 35 is lightly pressed (half-pressed) during the shooting mode, the flash is charged according to the illuminance of the subject, automatic exposure adjustment (AE), Various shooting preparation processes such as automatic focus adjustment (AF) are performed. In this state, when the shutter button 35 is pressed once more (fully pressed), the main shooting is performed, and the image signal for one screen prepared for shooting is converted into image data, and then various image processing and compression are performed. The processing is performed and recorded in the memory card 17.

  As shown in FIG. 3, the digital camera 10 is provided with a CPU 55 and connected to each component of the digital camera 10. The CPU 55 drives and controls each connected unit in response to an operation signal input from the operation unit 25 or the shutter button 35.

  A diaphragm 37 and a CCD 40 are arranged behind the photographic lens 13. The photographing lens 13 includes a zoom lens 43 and a focus lens 45, to which a zoom motor 47 and a focus motor 49 are connected, respectively. An iris motor 50 is connected to the diaphragm 37.

  The zoom motor 47 performs zooming by moving the zoom lens 43 to the wide side or the tele side in conjunction with the operation of the zoom lever 29. The focus motor 49 moves the focus lens 45 according to the subject distance and the zoom lens 43, and performs focus adjustment so that the photographing conditions are optimized. The diaphragm 37 is driven by an iris motor 50 and adjusts the exposure by adjusting the size of the opening that opens the photographing optical axis. These motors 47, 49, 50 are stepping motors, and their operation is controlled by drive pulses transmitted from the motor driver 57.

  As is well known, the CCD 40 includes a photoelectric surface in which a large number of light receiving elements are arranged in a matrix, and photoelectrically converts subject light that passes through the photographing lens 13 and the diaphragm 37 and forms an image on the photoelectric surface. In front of the photocathode, a microlens array for condensing light on each pixel and a color filter array for each color are arranged so that each pixel corresponds to one of R, G, and B.

  The CCD 40 acquires the electric charge accumulated for each pixel as an imaging signal in synchronization with the vertical transfer clock and the horizontal transfer clock supplied from the CCD driver 58. The CCD 40 acquires an imaging signal as a through image with a reduced number of pixels when the digital camera 10 is set in the imaging mode, and acquires an imaging signal as a main image when the shutter button 35 is fully pressed during the imaging mode. . The analog imaging signal thus captured is output to the analog signal processing circuit 59.

  The analog signal processing circuit 59 is provided with a correlated double sampling circuit (CDS) and an amplifier (AMP) A / D converter (A / D) (not shown). After being amplified, it is converted into digital image data. This image data is CCD-RAW data having a gradation value of 8 bits (256 levels) indicating the density of R, G, and B for each pixel, and is output to the frame memory 61 via the data bus 60.

  In addition to the frame memory 61 and the analog signal processing circuit 59, the CPU 36, the digital signal processing circuit 62, the auxiliary line display unit 70, the LCD 27, and the like are connected to the data bus 60, and these transmit and receive information via the data bus 60. Can be done. The frame memory 61 is a working memory used when the digital signal processing circuit 62 and the auxiliary line display unit 70 perform various signal processing on the image data, and temporarily stores the image data.

  The digital signal processing circuit 62 performs various image processing such as sharpness correction, contrast correction, white balance correction, and γ correction on the image data stored in the frame memory 61. Thereafter, the image data acquired as the main image is subjected to image compression in a predetermined compression format (for example, JPEG format) and then recorded on the memory card 17 via the media controller 63.

  On the other hand, the image data acquired as a through image is subjected to various image processing by the digital signal processing circuit 62, and then subjected to auxiliary line synthesis processing by the auxiliary line display unit 70 and displayed on the LCD 27. As shown in FIG. 4, when the auxiliary line synthesis processing is performed, an auxiliary line 71 for assisting framing is displayed on the LCD 27 so as to overlap the through image. Hereinafter, the auxiliary line synthesis process will be described.

  The auxiliary line display unit 70 is provided with a ROM 72, and stores image data (auxiliary line data) representing the auxiliary line 71 composed of a vertical line 73 and a horizontal line 74. The auxiliary line display unit 70 generates composite image data obtained by combining the auxiliary line data and image data (through image data) acquired as a through image and stored in the frame memory 61, and displays the combined image data on the LCD 27. An operation signal for the cursor key 33 is input to the auxiliary line display unit 70. The auxiliary line display unit 70 translates the vertical line 73 in conjunction with the left / right operation of the cursor key 33 and the horizontal line 74 in conjunction with the up / down operation of the cursor key 33.

  The ROM 72 stores two types of auxiliary line data having different display colors. One is for displaying the black auxiliary line 71Bk on the LCD 27, and the other is for displaying the white auxiliary line 71W on the LCD 27. Then, when generating the composite image data, one of the auxiliary line 71Bk and the auxiliary line 71W is selected.

  As shown in FIG. 5, in the selection of the auxiliary line 71, the auxiliary line display unit 70 analyzes the through image data, averages the gradation values of all the pixels constituting the through image data, and calculates the gradation average value. Is calculated. When the gradation average value is 128 or less and the through image is estimated to be a dark image, the auxiliary line display unit 70 selects the auxiliary line 71W so that it is easy to see when displayed on the dark image. To do. On the other hand, when the average gradation value is 128 or more and it is estimated that the through image is a bright image, the auxiliary line 71Bk is selected so that it is easy to see when displayed on the bright image. Then, the auxiliary line display unit 70 displays the auxiliary line 71 of the selected color on the LCD 27.

  The operation of the present invention having the above configuration will be described below. When the digital camera 10 is set to the photographing mode, the image capture by the CCD 40 is started, and a through image is displayed on the LCD 27. The photographer performs framing by confirming the through image, and determines the photographing range.

  An auxiliary line 71 is displayed on the LCD 27 so as to overlap the through image (see FIG. 4), and the vertical line 73 and the horizontal line 74 can be translated by the operation of the cursor key 33. The photographer holds the digital camera 10 by moving the auxiliary line 71 so that the vertical portion and the vertical line 73 of the subject overlap each other or the horizontal portion and the horizontal line 74 of the subject overlap each other. In this way, the digital camera 10 can be held so as not to tilt with respect to the subject, and the captured image does not tilt.

  The auxiliary line 71 is set with two types of auxiliary lines, a white auxiliary line 71W and a black auxiliary line 71Bk. And, when the brightness of the through image is estimated from the gradation values of the pixels constituting the through image, and the through image is estimated to be a dark image, it is easy to see even if it is displayed simultaneously with the dark image. When the white auxiliary line 71W is displayed and it is estimated that the through image is a bright image, the black auxiliary line 71Bk is displayed so that it is easy to see even if the through image is displayed simultaneously.

  As described above, the digital camera 10 estimates the brightness of the through image based on the color density information of the through image, and makes the auxiliary line easy to see according to the estimated brightness of the through image. Since the display color is switched, the auxiliary line is easy to see. Further, since the display color is automatically switched, it is not necessary to perform an operation for switching the display color of the auxiliary line.

  In the said embodiment, although demonstrated by the example which displays two types of auxiliary lines, white and black, this invention is not limited to this. Since the display color of the auxiliary line can be freely set, for example, a red or blue auxiliary line may be displayed. Also, the brightness of the auxiliary line can be set freely.

  In the above-described embodiment, an example in which an auxiliary line is always displayed during the display of a through image has been described. However, for example, display / non-display of an auxiliary line may be switched by operating a button. In the above embodiment, the example in which the color and brightness of the auxiliary line automatically change according to the color density of the through image has been described. However, the color and brightness of the auxiliary line are manually changed. Also good. In this case, for example, two operation buttons may be provided, the display color of the auxiliary line is switched by one operation, and the brightness of the auxiliary line is switched by the other operation.

  In the above-described embodiment, the example in which the color and brightness of the auxiliary line are changed according to the brightness of the through image has been described. However, the present invention is not limited to this. For example, if the through image is an image with a strong red color, the auxiliary line is changed to green, which is complementary to the red color, and if the through image is an image with a strong yellow color, the auxiliary line is changed. Depending on the color of the through image, the color or brightness of the auxiliary line may be changed so that it is easy to see, such as changing the line to purple, which is complementary to yellow.

  In this case, the gradation values of the pixels constituting the through image are classified for each of R, G, and B, and the gradation average value for each color is calculated. Subsequently, from the calculated gradation average value for each color, it is detected what color image the entire through image is. Then, the color and brightness of the auxiliary line may be changed so as to have a complementary color relationship with the color of the through image. Even if it does in this way, the effect similar to the said embodiment can be acquired.

  In the above embodiment, the example of changing the color and brightness of the auxiliary line to make the auxiliary line easy to see has been described, but in addition to this, the auxiliary line is added by performing image processing on the through image. It may be easy to see. In this case, for example, in the digital signal processing circuit, image processing such as contrast enhancement and halftone enhancement may be performed to make the auxiliary line easy to see.

  In addition, for example, when photographing on a ship or the like, it is conceivable that the photographer is unstable and it is difficult to align the horizontal or vertical part of the subject with the auxiliary line. In order to solve such a problem, a tilt angle detection sensor may be provided in the digital camera, and information such as the tilt angle of the digital camera obtained from the angle detection sensor may be displayed in addition to the auxiliary line. .

  In this case, for example, as shown in FIG. 6, the horizontal line 80 is displayed on the LCD 27 based on the tilt angle of the digital camera obtained from the angle detection sensor. The horizontal line 80 is displayed so as to rotate, for example, at the intersection of the vertical line 73 and the horizontal line 74 or one end of the horizontal line 74 as a fulcrum. Also, camera angle information 81 for the horizontal line 80 is displayed.

  The camera angle information 81 includes, for example, tilt direction information, tilt angle information, and angle warning information. The tilt direction information indicates whether the camera is tilted in the left or right direction, and in this example, a triangular index whose one side is substantially parallel to the horizontal line is displayed. The tilt angle information represents the tilt angle of the camera with respect to the horizontal line 80, and in this example, the tilt angle of the camera is displayed with the case of tilting to the right as the positive direction.

  In addition, the angle warning information displays a circular index, for example, blue when the camera angle is less than ± 2 °, yellow when the camera angle is ± 2 ° or more and less than ± 5 °, and the camera angle is When the angle is ± 5 ° or more, the display color is changed to red. In the case shown in FIG. 6, since the camera is tilted by + 6 ° with respect to the horizontal line 80, a circular index representing the angle warning information is displayed in red.

  In this way, by displaying the information obtained from the angle detection sensor, even if it is difficult to align the horizontal or vertical part of the subject with the auxiliary line, if the image is taken with reference to the horizontal line and angle warning information, the captured image Can be prevented from tilting. In this example, a horizontal line is displayed. Of course, a vertical line can also be displayed. In addition, a warning sound corresponding to the camera angle may be emitted from a speaker to notify the photographer of the camera angle.

  Furthermore, it is possible to detect the camera angle by performing image analysis of the through image and detecting the horizontal or vertical degree of the image without using the angle detection sensor. In this case, it is selected whether to detect the horizontal or vertical degree of the through image, the inclination of the through image in the selected direction is detected by binary analysis or the like, and the camera angle is detected based on this. Then, a horizontal line, a vertical line, and camera angle information may be displayed.

It is an external view of the front side of a digital camera. It is an external view of the back side of a digital camera. It is a block diagram showing the structure of a digital camera. It is explanatory drawing showing a mode that an auxiliary | assistant line is displayed on a through image. It is explanatory drawing showing the example which displayed the horizontal line and the camera angle information in addition to the auxiliary line. It is explanatory drawing showing a mode that a horizontal line and camera angle information are displayed.

Explanation of symbols

10 Digital Camera 27 LCD
33 Cursor keys 70 Auxiliary line display 71 Auxiliary line 72 ROM
73 Vertical line 74 Horizontal line 80 Horizontal line 81 Camera angle information

Claims (4)

In a digital camera with an electronic viewfinder that displays a through image captured for framing the subject,
Display means for displaying the auxiliary line for assisting the framing on the electronic viewfinder, auxiliary line moving means for moving the vertical line and horizontal line in parallel, and the color or brightness of the auxiliary line. A digital camera comprising display switching means for changing at least one of the lengths.   The display switching means automatically changes at least one of the color and brightness of the auxiliary line so as to make the auxiliary line easy to see according to color density information of the through image. The digital camera described.   The image processing means for adjusting the color density of the through image so as to make the auxiliary line easy to see according to at least one of the color and brightness of the auxiliary line is provided. The digital camera described.   An angle detection unit that detects a tilt angle of the camera with respect to a horizontal position, wherein the display unit displays the horizontal line and the tilt angle of the camera on the electronic viewfinder in addition to the auxiliary line. The digital camera according to claim 1.

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