JP3826949B2 - Digital camera - Google Patents

Description

  The present invention relates to a digital camera, and more particularly to a digital camera having a function of electronically enlarging a captured image.

  The digital camera repeatedly captures images at a substantially constant period, and records image data representing the captured images on a recording medium in response to a recording instruction given by the user. Many digital cameras are provided with a display device such as a liquid crystal display, and the display device is used for reproducing and displaying a photographed and recorded image and displaying an image being photographed. The user can set the composition or confirm the in-focus state while viewing the displayed image being captured, that is, the live view, and the display device functions as an electronic viewfinder.

  In general, the charge accumulated by the image sensor by photoelectric conversion is read out for each pixel column and used to generate image data. The aspect ratio of the size of the display device is the same as the aspect ratio of the image sensor, but the number of pixels of the display device is about 1/16 to 1/25 of the number of pixels of the image sensor, and therefore the number of pixel columns is It is about 1/4 to 1/5. For this reason, when the photographed image is used for display only without being recorded, the charge of the image sensor is read while thinning out so as to have a ratio of one pixel column to four to five pixel columns.

  Some digital cameras have a function of generating image data for recording using stored charges in only a part of the image sensor in order to provide an image with a narrow angle of view as taken with a telephoto lens. There is something. This function is called a digital tele function. Some digital cameras have a function of generating image data with a narrower angle of view than recording image data and enlarging and displaying the image in order to facilitate confirmation of the in-focus state. This function is called a magnifier function.

  With the magnifier function, it is possible to observe a part of the photographed image by magnifying it several times or more, but the enlargement ratio is determined and fixed on the basis of the overall size of the image sensor. Therefore, when the digital tele function is used, the enlargement ratio for the recorded image is lower than when the digital tele function is not used. For this reason, when used together with the digital tele function, the purpose of the magnifier function of facilitating confirmation of the in-focus state cannot be sufficiently achieved.

  In addition, when taking an image for display only, regardless of whether the magnifier function is used or not, images are read out while thinning out the charge of the image sensor at a constant rate. Becomes rough. In this respect as well, the purpose of the magnifier function is not fully achieved.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a digital camera that can sufficiently exhibit a magnifier function of facilitating confirmation of a focused state.

  In order to achieve the above object, the present invention includes an image sensor in which pixels are two-dimensionally arranged, and reads out the charges accumulated by photoelectric conversion of each pixel of the image sensor to generate image data for display. A digital camera that repeatedly displays an image represented by the image data, and generates and records image data for recording in accordance with a recording instruction given in the meantime. The entire recording mode with an angle of view corresponding to almost the entire image, the partial recording mode with the angle of view of image data for recording corresponding to a part of the image sensor, and the angle of view of image data for display Same view angle as that of the image data for recording, the same size display mode that displays the image at a predetermined size, and the angle of view of the image data for display is made smaller than the angle of view of the image data for recording. To display the same size The display image data in the enlarged display mode has an angle of view in both the whole recording mode and the partial recording mode. It is assumed that a predetermined value is set for the angle of view of the data.

  This digital camera has a partial recording mode for realizing a digital tele function and an enlarged display mode for realizing a magnifying function, in addition to a whole recording mode and an equal magnification display mode for displaying an entire recording image. The angle of view of the image data for display generated in the enlarged display mode is determined with respect to the angle of view of the image data for recording regardless of whether it is the full recording mode or the partial recording mode. That is, the magnification of the magnifier function is based on the size of the recorded image regardless of whether the digital tele function is used together. Therefore, it can be surely known from the enlarged display mode whether or not the in-focus state is suitable for the size of the image to be recorded.

  In the above digital camera, the angle of view of the image data for recording in the partial recording mode is variable, and the angle of view of the image data for display in the partial recording mode is a lower limit determined based on the size of the image sensor. You may make it always keep above the value.

  Since the angle of view in the enlarged display mode is set to a predetermined value with respect to the angle of view of the image data for recording, the image displayed when the angle of view of the image data for recording is reduced in the partial recording mode. The range of becomes smaller. However, if an extremely small range is enlarged and displayed, it is not possible to know which part of the imaging target corresponds, and the boundary of the pixels of the image sensor appears clearly, so that the in-focus state can be confirmed. Can not be. By setting the lower limit of the angle of view of the image data for display generated in the enlarged display mode based on the size of the image sensor, the range of the image to be displayed can be limited to a size that allows confirmation of the in-focus state with certainty. Is possible.

  Whole recording mode in which the angle of view of the image data for recording corresponds to almost the entire image sensor, and partial recording mode in which the angle of view of the image data for recording corresponds to a part of the image sensor The same angle of view of the image data for display as the angle of view of the image data for recording, and the same size display mode for displaying the image in a predetermined size and the angle of view of the image data for display are recorded. And an enlarged display mode for displaying the image in substantially the same size as the normal magnification display mode, and the angle of view of the image data for display in the enlarged display mode is In both the whole recording mode and the partial recording mode, the digital camera of the present invention in which the angle of view of the image data for recording is set to a predetermined value actually records the enlargement ratio in the enlarged display mode. To be determined based on the size of the image Ri, regardless of whether a combination of partial recording mode, it is possible to confirm reliably focus state in the enlarged display mode.

  Here, the angle of view of the image data for recording in the partial recording mode is variable, and the angle of view of the image data for display in the partial recording mode is greater than or equal to the lower limit value determined based on the size of the image sensor. If it is always kept, it is possible to shoot and record images of various angles of view, greatly improving usability, and avoiding enlarging and displaying a very small range, and focusing. It is possible to always provide an image that can be surely confirmed.

  Hereinafter, an embodiment of a digital camera of the present invention will be described with reference to the drawings. The external appearance of the digital camera 1 of this embodiment is shown in FIGS. 1 to 3, and the outline of the circuit configuration is schematically shown in FIG. 1 is a front view of the digital camera 1, FIG. 2 is a rear view, and FIG. 3 is a top view.

  The digital camera 1 has a photographing lens 11 on the front surface and two display units 12 and 13 on the rear surface. A push button type shutter switch 14, a push button type switch 15 and a slide type switch 16 are provided on the upper surface, and a slide type switch 17 is provided on the rear surface. Although not shown, an insertion slot for mounting a memory card 18 (see FIG. 4) as a recording medium is provided on the bottom surface of the digital camera 1.

  As shown in FIG. 4, a stop 11 a is provided at the pupil position of the photographic lens 11, and an image sensor 21 is disposed behind the photographic lens 11. The digital camera 1 captures an image by photoelectrically converting light from a subject to be transmitted that has passed through the photographing lens 11 into an electric charge by the image sensor 21, and processes the electric charge accumulated in the image sensor 21 by various circuits described later. Thus, image data representing the image is generated. The image represented by the generated image data is displayed on the display units 12 and 13, and the image data is recorded on the memory card 18 in accordance with a recording instruction given by operating the shutter switch 14. Images are captured and displayed repeatedly at a substantially constant period, for example, 1/30 seconds.

  One display unit 12 is composed of a large liquid crystal display (LCD), and displays an image having the same angle of view as the image data for recording. The user can observe the image displayed on the display unit 12 from a distance of several tens of centimeters or more. Hereinafter, the display unit 12 is also referred to as a monitor.

  The other display unit 13 includes a small LCD 13a, a convex lens 13b, and a reflection mirror 13c. The LCD 13a displays an image having the same angle of view as the image represented by the recording image data or a smaller angle of view. The user can further enlarge and observe the displayed image by viewing the LCD 13a through the lens 13b and the mirror 13c from a distance of several centimeters or less. The lens 13b is an eyepiece. Hereinafter, the display unit 13 is also referred to as an electronic viewfinder or a fan finder.

  The user can set the composition while viewing the image displayed on the monitor 12 or the electronic viewfinder 13, and can confirm the in-focus state of the photographing lens 11 with respect to the photographing target. Whether the image is displayed on the monitor 12 or the viewfinder 13 can be switched, and this switching is performed by the setting of the switch 17. Each of the LCDs of the monitor 12 and the viewfinder 13 has 640 pixels in the horizontal (lateral) direction and 480 pixels in the vertical (vertical) direction.

  The image sensor 21 is an area sensor having 2560 pixels in the horizontal direction and 1920 pixels in the vertical direction. Each pixel is provided with a filter that selectively transmits red (R) light, green (G) light, or blue (B) light, and all the pixels are for R light, G light, and B light. It is classified into three types for light. These three types of pixels are arranged in a Bayer type (see FIG. 7).

  The circuit configuration of the digital camera 1 will be described with reference to FIG. The digital camera 1 includes a correlated double sampling (CDS) circuit 22 and an automatic gain control (AGC) circuit 23 that process charges output as an analog signal from the image sensor 21, and an A / D converter that converts the analog signal into a digital signal. 24. An image processing CPU 25 that processes digital signals to generate image data representing a photographed image, and an image memory 26 that the image processing CPU 25 uses for temporary storage are provided.

  The CDS circuit 22 reduces the noise of the analog signal output from the image sensor 21, and the AGC circuit 23 adjusts the level of all signals from the CDS circuit 22 by its gain. The A / D converter 24 converts the analog signal from the AGC circuit 23 into a 10-bit digital signal.

  The image processing CPU 25 performs pixel interpolation 25a, resolution conversion 25b, color balance adjustment 25c, and gamma correction 25d on the digitized signal to generate image data representing the photographed image. Further, the image data to be recorded in the memory card 18 is subjected to image compression 25e processing. The image processing CPU 25 first writes the digital signal from the A / D converter 24 into the image memory 26, and then reads out the signal from the image memory 26 and writes the signal into the image memory 26 while performing pixel interpolation 25a to image compression 25e. We will proceed with the process.

  The pixel interpolation 25a generates a signal missing at each pixel position of the image sensor 21 (for example, R and B signals at the G light pixel position) from signals of surrounding pixels. Thereby, three signals of R, G, and B are obtained corresponding to each pixel. For the G signal, the average value of the intermediate binary values of the four pixel signals is obtained, and for the R and B signals, the average value of the two pixel signals is obtained.

  The resolution conversion 25b extracts a predetermined number of signals for each of the horizontal direction and the vertical direction from the signal after pixel interpolation. The signal extraction is performed according to the use of the image data composed of the extracted signal, and a continuous signal within a predetermined range may be extracted or a signal separated from the entire range at a predetermined interval may be extracted. That is, it may be thinned out. Thereby, the range of the image represented by the image data is determined. In the resolution conversion 25b, the horizontal and vertical signal trains are also copied. The copy of the signal train is used for converting the resolution of an image to be displayed in an enlarged display mode to be described later.

  The color balance adjustment 25c adjusts the intensity for each of the R, G, and B signal groups so as to achieve an appropriate white balance. Specifically, a portion that is originally white is estimated based on the intensity and distribution of the R, G, and B signals, and an average value for each of the R, G, and B signals is obtained for the portion, and G The intensity of each of the R, G, and B signals is corrected from the intensity ratio of / R and the intensity ratio of G / B.

  The gamma correction 25d performs non-linearization on the signal intensity so as to be compatible with an external device that uses image data via the monitor 12, the finder 13 or the memory card 18. The image compression 25e compresses image data by performing discrete cosine transform (DCT) and Huffman coding according to the JPEG method. It is also possible to read out the image data recorded in the memory card 18 and reproduce and display it on the monitor 12. In this case, the image processing CPU 25 performs a reverse process of the compression on the read out image data to obtain an image before compression. Play the data.

  In addition, the digital camera 1 includes a camera control CPU 31, an aperture driver 32, a sensor driver 33, a video encoder 34, and a card driver 35. The camera control CPU 31 controls the entire digital camera 1. The camera control CPU 31 is connected to the operation unit 36 including the above-described various switches including the shutter switch 14, and controls the operation of the digital camera 1 in accordance with a signal given from the operation unit 36. The aperture driver 32 drives the aperture 11 a, and the sensor driver 33 generates a control signal indicating the output timing of the charge accumulated by the photoelectric conversion and gives it to the image sensor 21.

  In photographing until a recording instruction is given by the shutter switch 14, the aperture 11a is opened, and the exposure amount is controlled by adjusting the photoelectric conversion time (electronic shutter speed) of the image sensor 21. When a recording instruction is given, that is, when an image for recording is taken, the aperture of the diaphragm 11a and the photoelectric conversion time are set according to a predetermined relationship to control the exposure amount. The exposure amount is controlled based on the intensity of a signal from a partial area at the center of the image sensor 21.

  The video encoder 34 encodes the image data given from the image processing CPU 25 by the NTSC method or the PAL method, and outputs the encoded image data to the monitor 12 and the finder 13. The card driver 35 writes the image data given from the image processing CPU 25 to the memory card 18, reads the image data from the memory card 18, and gives it to the image processing CPU 25.

  The digital camera 1 has two modes for recording image data: a whole recording mode and a partial recording mode. The whole recording mode is for generating image data representing an image with a large angle of view corresponding to the entirety of the image sensor 21, and the partial recording mode is an image having a small angle of view corresponding to a part of the image sensor 21. Image data is generated. The digital tele function is realized by the partial recording mode.

  The angle of view of the partial recording mode can be selected from three angles of view of 2/3, 1/2 and 1/4 of the angle of view of the entire recording mode. That is, the magnification in the partial recording mode is 1.5 times, 2 times, or 4 times (2.25 times, 4 times, or 16 times in area). The angle of view is switched by operating the switch 15. Each time the switch 15 is operated, the angle of view changes in order, and the enlargement ratio corresponding to the selected angle of view is displayed on the monitor 12 or the finder 13 for a while.

  The digital camera 1 also has two modes for displaying images, the same size display mode and the enlarged display mode. In the same size display mode, an image having the same angle of view as the image for recording is displayed on the entire monitor 12 or the finder 13. In the enlarged display mode, an image having an angle of view smaller than the image for recording is displayed in the finder 13. It is displayed on the whole. The magnifier function is realized by the enlarged display mode. The same size display mode and the enlarged display mode are switched by the setting of the switch 17.

  The angle of view in the enlarged display mode can be selected from two angles of view that are 1/2 and 1/4 of the angle of view in the normal magnification display mode. That is, the enlargement ratio in the enlargement display mode is 2 times or 4 times (4 times or 16 times in area). The angle of view is switched by operating the switch 16.

  A combination of the whole recording mode and the partial recording mode, the same magnification display mode, and the enlarged display mode is arbitrary, and the user can freely select from four combinations. In the enlarged display mode, a central range corresponding to 1/2 or 1/4 of the angle of view of the image data for recording is displayed regardless of whether the recording mode is the full recording mode or the partial recording mode. . That is, the enlargement ratio in the enlargement display mode is determined based on the actual image size, not the physical size of the image sensor 21.

  However, when the partial recording mode with a magnification factor of 4 and the magnified display mode with a magnification factor of 4 are combined, the imaging device 21 has a magnification factor of 16 times, which is inappropriate for checking the in-focus state. A too small range will be displayed. That is, the user cannot know which part of the imaging target is displayed, and the boundary of the pixels of the image sensor 21 appears clearly. Therefore, the digital camera 1 restricts the angle of view of the enlarged display mode so that it does not become less than 1/10 of the angle of view of the entire recording mode when combined with the partial recording mode having a magnification ratio of 4 times. That is, the enlargement ratio in the enlargement display mode in this case is 2.5 times.

  The configuration of the image sensor 21 is schematically shown in FIG. The image sensor 21 includes a photodiode 21a as a pixel. As described above, the photodiodes 21a are arranged in 2560 in the horizontal direction and 1920 in the vertical direction. Each vertical column of photodiodes 21a is provided with a vertical transfer register 21b formed as a charge coupled device (CCD), and each photodiode 21a is a vertical transfer register for storing charges (signals) accumulated by photoelectric conversion. It outputs to the corresponding part of 21b.

  Each vertical transfer register 21b is connected to a horizontal transfer register 21c which is also formed as a CCD, and sequentially outputs a signal output from each photodiode 21a to a corresponding portion of the horizontal transfer register 21c. The horizontal transfer register 21c is connected to the amplifier 21d, and the output of the horizontal transfer register 21c is amplified by the amplifier 21d and supplied to the CDS circuit 22 (not shown).

  Signal output from the photodiode 21a to the vertical transfer register 21b, signal transfer in the vertical transfer register 21b, and signal transfer in the horizontal transfer register 21c are performed by the control signal supplied from the sensor driver 33 as described above. Be controlled. On the other hand, the camera control CPU 31 controls the sensor driver 33, depending on whether it is the whole recording mode or the partial recording mode, and depending on whether it is the same size display mode or the enlarged display mode. The transfer speed of the photodiode 21a for outputting charges, the vertical transfer register 21b, and the horizontal transfer register 21c is changed.

  Hereinafter, processing from reading of electric charges of the image sensor 21 to recording of image data on the memory card 18 or display of an image on the monitor 12 or the finder 13 will be described with specific examples. Among the codes used in each example, P1 represents a process of reading out charges from the image sensor 21, P2 represents a process of generating image data representing an image, and P3 represents a process of displaying an image on the monitor 12 or the viewfinder 13. Further, S1 represents electric charges accumulated in the image sensor 21, S2 represents a signal read and digitized in the process P1, and S3 represents a signal converted into image data representing an image in the process P2.

  The signal processing of the first example is shown in FIG. This example is signal processing when a recording instruction is given in the overall recording mode. In this example, the charges of all the pixel columns in the horizontal direction of the image sensor 21 are read out, and all the read signals S2 are set as signals S3 representing an image in the image data generation process P2. The signal S3 is recorded on the memory card 18. FIG. 7 shows a pixel column from which charges are read in the reading process P1.

  Further, a control signal given from the sensor driver 33 to the image sensor 21 in the readout process P1 is schematically shown in FIG. VD is a pulse for instructing the photodiode 21a to output an electric charge, and is given to all the photodiodes. VT is a pulse for instructing transfer to the vertical transfer register 21b. The transfer command pulse VT is given at a constant cycle over the entire period.

  The signal processing of the second example is shown in FIG. This example is processing until a recording instruction is given in the entire recording mode and the equal magnification display mode. In this example, the charges in the horizontal pixel columns of the image sensor 21 are read at a ratio of one column to four columns, and the thinning process in the vertical direction is performed. Further, when reading, the charges of pixels of the same color adjacent on the vertical transfer register 21b are added.

  FIG. 10 shows a pixel column from which charges are read. The charges of 4 pixel columns are read out every 16 pixel columns. Among these pixel columns, two pixel columns including G light pixels and R light pixels, G light pixels, and B light Two pixel columns including pixels for light are included. The charges of the two pixels for R light are added, the charges of the two pixels for B light are added, and the charges of the four pixels for G light are also added by two pixels. Eventually, the number of horizontal columns of the signal S2 after reading is 240. This read process P1 can be performed at a speed eight times that of the read process of the first example.

  In the image data generation process P2, signals are extracted at a rate of one pixel per four pixels for each horizontal signal sequence, and the number of signals S3 is set to the horizontal direction 640 and the vertical direction 240. The number of signals in the horizontal direction coincides with the number of pixels in the horizontal direction of the LCD of the monitor 12 and the finder 13, and the number of signals in the vertical direction is half the number of pixels in the vertical direction of the LCD. Therefore, in the display process P3, each signal sequence in the horizontal direction is output twice. As a result, an image having an angle of view corresponding to the entire image sensor 21 is displayed on the entire monitor 12 and the finder 13.

  The signal processing of the third example is shown in FIG. This example is signal processing when a recording instruction is given in the partial recording mode with a magnification of 2 times. In the reading process P1, the charges of all the pixel columns 960 at the center in the vertical direction of the image sensor 21 are read. In the image data generation process P2, all 1280 signals at the center of each signal sequence included in the read signal S2 are extracted and set as a signal S3 representing an image. The signal S3 is recorded on the memory card 18.

  FIG. 12 schematically shows a control signal given from the sensor driver 33 to the image sensor 21 in the reading process P1. In FIG. 12, the portion of the drive command pulse VT marked with H has a shorter cycle than the other portions and commands high-speed driving. Electric charges are output from all the pixel columns to the vertical transfer register 21b by the output command pulse VD. However, the charges corresponding to the upper 480 pixel columns and the lower 480 pixel columns drive the vertical transfer register 21b at high speed (H) and do not read. On the other hand, the charges in the center 960 pixel columns are read out by driving the vertical transfer register 21b at a normal speed in synchronization with the horizontal transfer register 21c. Therefore, the time required for the reading process is about half that of the first example.

  The signal processing of the fourth example is shown in FIG. This example is signal processing until a recording instruction is given in a partial recording mode with an enlargement ratio of 2 and an enlarged display mode with an enlargement ratio of 2 times. The read process P1 is performed as in the second example. That is, charges are read at a rate of one pixel column to four pixel columns, and the charges of two pixels of the same color are added. In the image data generation process P2, the signals in the horizontal direction 640 and the vertical direction 120 at the center of the read signal S2 are extracted, and further, each signal string in the horizontal direction is duplicated to be a signal S3 representing an image. . In the display process P3, each signal sequence included in the signal S3 is output twice. FIG. 14 shows the relationship between the angle of view A1 of the image sensor 21, the angle of view A2 of the image to be recorded, and the angle of view A3 of the image to be displayed.

  In this signal processing, since the reading process P1 is performed in the same manner as in the whole recording mode, it is not necessary to prepare a separate control signal from the sensor driver 33 to the image sensor 21, and the configuration of the sensor driver 33 and the image sensor 21 is complicated. Never become. In addition, since the sensitivity is not changed, switching between the normal magnification display mode and the enlarged display mode can be easily performed. Although the vertical resolution of the image to be displayed is only half that of the image photographed for recording, the horizontal resolution is the same, so that the function of facilitating confirmation of the in-focus state is not greatly reduced.

  FIG. 15 shows the signal processing of the fifth example. This example is also signal processing until a recording instruction is given in the partial recording mode with an enlargement ratio of 2 and the enlarged display mode with an enlargement ratio of 2 times. In the reading process P1, the charges of the pixel columns at the center in the vertical direction of the image sensor 21 are read out for 240 pixel columns at a ratio of one column to two columns. In the image data generation process P2, 640 signals at the center of each signal sequence included in the signal S2 are extracted and set as a signal S3 representing an image. In the display process P3, each signal sequence included in the signal S3 is output twice. FIG. 16 shows a pixel column from which charges are read in the reading process P1. The relationship between the angle of view A1 of the image sensor 21, the angle of view A2 of the image to be recorded, and the angle of view A3 of the image to be displayed is the same as that shown in FIG.

  The read process P1 is performed by the same method as in the third example. That is, the charges in the upper and lower 720 pixel columns of the image sensor 21 are transferred at high speed, and only the charges in the central pixel column are output to the horizontal transfer register at a normal speed. Therefore, the reading process can be performed in a very short time.

  The signal processing of the sixth example is shown in FIG. This example is signal processing until a recording instruction is given in the partial recording mode with an enlargement ratio of 2 and the enlarged display mode with an enlargement ratio of 4 times. In the reading process P1, all the charges in the 240 pixel columns at the center in the vertical direction of the image sensor 21 are read. In the image data generation process P2, 320 signals at the center of each signal sequence included in the signal S2 are extracted, and each signal sequence in the vertical direction included in the extracted signal is copied to obtain a signal S3 representing an image. . In the display process P3, each horizontal signal sequence included in the signal S3 is output twice. FIG. 18 shows the relationship between the angle of view A1 of the image sensor 21, the angle of view A2 of the image to be recorded, and the angle of view A3 of the image to be displayed.

  In the reading process P1, the charges of the pixel columns of the upper and lower portions of the image sensor 21 are transferred at a high speed, and only the charges of the central pixel line are output to the horizontal transfer register at a normal speed. Therefore, the reading process is completed in a very short time. Although the vertical pixel column is copied in the process P2, since the image can be displayed with the same resolution as the recording image, there is no deterioration in the function that facilitates confirmation of the in-focus state. is there.

  The signal processing of the seventh example is shown in FIG. This example is signal processing when a recording instruction is given in the partial recording mode with a magnification of 4 times. In the readout process P1, all charges in the 960 pixel columns in the center in the vertical direction of the image sensor 21 are read out. In the image data generation process P2, signals in the horizontal direction 640 and the vertical direction 480 in the central portion are extracted from the signal S2 and set as a signal S3 representing an image. The signal S3 is recorded on the memory card 18.

  Also in this example, the charges in the upper and lower 480 pixel columns of the image sensor 21 are transferred at high speed, and only the charges in the central pixel column are output to the horizontal transfer register at a normal speed. Therefore, the time required for the reading process P1 is short.

  The signal processing of the eighth example is shown in FIG. This example is signal processing when a recording instruction is given in the partial recording mode with an enlargement ratio of 1.5. In the reading process P1, the charges of all the pixel columns of the image sensor 21 are read. In the image data generation process P2, the signal in the horizontal direction 1706 and the vertical direction 1280 in the central portion is extracted from the signal S2 and set as a signal S3 representing an image. The signal S3 is recorded on the memory card 18.

  The signal processing of the ninth example is shown in FIG. This example is signal processing until a recording instruction is given in the entire recording mode and the enlarged display mode with an enlargement ratio of 4 times. In the reading process P1, the charges of the pixel columns at the center in the vertical direction of the image sensor 21 are read out for 240 pixel columns at a ratio of one column to two columns. In the image data generation process P2, 640 signals at the center of each signal sequence included in the signal S2 are extracted and set as a signal S3 representing an image. In the display process P3, each signal sequence included in the signal S3 is output twice. The pixel column from which charges are read in the reading process P1 is the same as that shown in FIG.

  The signal processing of the tenth example is shown in FIG. This example is also signal processing until a recording instruction is given in the entire recording mode and the enlarged display mode with an enlargement ratio of 4 times. However, the enlargement ratio in the vertical direction is slightly smaller than four times. In the reading process P1, the charges of the pixel columns at the center in the vertical direction of the image sensor 21 are read for 220 pixel columns at a ratio of one column to two columns. In the image data generation process P2, 640 signals at the center of each signal sequence included in the signal S2 are extracted and set as a signal S3 representing an image. In the display process P3, each signal sequence included in the signal S3 is output twice. The image to be displayed is obtained by removing about 4% of the upper end portion and the lower end portion from the image displayed in the ninth example. The pixel column from which charges are read in the reading process P1 is the same as that shown in FIG.

  In this example, the reason why the vertical enlargement ratio is set to be slightly smaller than 4 times is to allow an image to be displayed in the enlargement display mode at the same speed or higher than the same magnification display mode. In the digital camera 1 of the present embodiment, the number of pixels in the vertical direction of the image sensor 21 is 1920, which is not particularly large. Therefore, even in the ninth example, the display speed of the enlarged display mode is slower than the normal display mode. Absent. However, this signal processing method is useful for increasing the display speed in the enlarged display mode in a configuration using an image sensor 21 having a very large number of pixels.

  In the digital camera 1 of the present embodiment, the monitor 12 and the finder 13 are provided as the display unit, but the finder 13 may be omitted. In that case, the image to be displayed on the monitor 12 is switched in accordance with switching between the same size display mode and the enlarged display mode. Although specific numerical values such as pixels, signals to be processed, and enlargement ratio are shown here, these are merely examples, and other values may be used. Although it is expected that image sensors having more pixels will be developed in the future, the number of signals to be processed and the enlargement ratio may be determined according to the number of pixels of the image sensor.

1 is a front view of a digital camera according to an embodiment of the present invention. The rear view of the said digital camera. The top view of the said digital camera. FIG. 2 is a block diagram schematically showing an outline of a circuit configuration of the digital camera. The figure which shows typically the structure of the image pick-up element of the said digital camera. The figure which shows the 1st example of the signal processing of the said digital camera. The figure which shows the pixel arrangement | sequence read in 1st example and arrangement | positioning of the pixel of the said image pick-up element. The figure which shows typically the control signal given to an image pick-up element by the read-out process of a 1st example. The figure which shows the 2nd example of the signal processing of the said digital camera. The figure which shows the pixel row read in the 2nd example. The figure which shows the 3rd example of the signal processing of the said digital camera. The figure which shows typically the control signal given to an image pick-up element by the read-out process of a 3rd example. The figure which shows the 4th example of the signal processing of the said digital camera. The figure which shows the view angle of the image pick-up element in the 4th example, the view angle of the image to record, and the view angle of the image to display. The figure which shows the 5th example of the signal processing of the said digital camera. The figure which shows the pixel row read in the 5th example. The figure which shows the 6th example of the signal processing of the said digital camera. The figure which shows the view angle of the image pick-up element in the 6th example, the view angle of the image to record, and the view angle of the image to display. The figure which shows the 7th example of the signal processing of the said digital camera. The figure which shows the 8th example of the signal processing of the said digital camera. The figure which shows the 9th example of the signal processing of the said digital camera. The figure which shows the 10th example of the signal processing of the said digital camera.

Explanation of symbols

1 Digital Camera 11 Shooting Lens 11a Aperture 12 Monitor 13 Electronic Viewfinder 13a LCD
13b Eyepiece 14 Shutter Switch 15-17 Switch 18 Memory Card 21 Image Sensor 21a Photodiode 21b Vertical Transfer Register 21c Horizontal Transfer Register 22 CDS Circuit 23 AGC Circuit 24 A / D Converter 25 Image Processing CPU
25a Pixel interpolation process 25b Resolution conversion process 25c Color balance adjustment process 25d Gamma correction process 25e Image compression process 26 Image memory 31 Camera control CPU
32 Aperture driver 33 Sensor driver 34 Video encoder 35 Card driver 36 Operation unit

Claims (2)

It is equipped with an image sensor in which pixels are arranged in a two-dimensional manner, and each pixel of the image sensor reads out the electric charge accumulated by photoelectric conversion, generates display image data, and repeatedly displays an image represented by the image data , A digital camera that generates and records image data for recording in accordance with a recording instruction given in the meantime, and performs overall recording in which the angle of view of the image data for recording is an angle of view corresponding to substantially the entire image sensor Mode, partial recording mode in which the angle of view of the image data for recording corresponds to a part of the image sensor, and the angle of view of the image data for display is the same as the angle of view of the image data for recording The same size display mode that displays the image at a predetermined size, and the angle of view of the image data for display is smaller than the angle of view of the image data for recording, and the image is substantially the same as the normal size display mode. Enlarged display to display in size In those with and over de,
The angle of view of the image data for display in the enlarged display mode is set to a predetermined value with respect to the angle of view of the image data for recording in both the whole recording mode and the partial recording mode. Digital camera.   The angle of view of the image data for recording in the partial recording mode is variable, and the angle of view of the image data for display in the partial recording mode is always kept above the lower limit value determined based on the size of the image sensor. The digital camera according to claim 1.

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