JP3513833B2 - Electronic camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera for outputting original image data extracted from an image sensor to an external electronic device. 2. Description of the Related Art Conventionally, in an electronic camera, exposure control is performed by an AE mechanism at the time of photographing. For example, a shutter speed and an aperture value are set so that the brightness of a subject near the center of a screen becomes a predetermined value. Set and execute shooting. When reading out a part of the image captured in this way, the subject in the cut out part is different from the subject whose exposure was adjusted at the time of shooting,
There is a drawback that the output image is not properly exposed. Recently, it has been considered to connect an electronic still camera as an image input terminal to various external electronic devices and take in images. However, since image processing capability differs for each external electronic device, image data input according to the specifications of the electronic still camera cannot be efficiently processed. For example, when image data is output after being binarized, an optimal error diffusion method differs depending on the characteristics of a display device used in an external electronic device, the type of an original image, and the use of an output image. Further, the amount of image data required by the external electronic device differs depending on the memory capacity and display size of the external electronic device. Further, when a part of the image data is cut out and output by the external electronic device, the exposure value of the cut out image data is different from the proper exposure value set at the time of shooting because the cut out image data is different from the photographed subject image. For the reasons described above, there arises a problem that required image data differs depending on the external electronic device connected to the electronic still camera. The present invention has been made in view of the above circumstances, and in the case of reading out a part of a captured image, there is provided an electronic camera which performs exposure correction so that a subject in a cut out part has proper exposure and outputs the image. The purpose is to provide. In order to achieve the above object, an electronic camera according to the present invention comprises: an image pickup device; photographing means for driving the image pickup device to take an image; and outputting an output of the image pickup device to a digital value. A memory for storing the converted data, a CPU for processing the stored data, and an external device.
Connect has a communication means for outputting the data processed with braking <br/> Gosuru based on specification of the CPU from an external device to the external device, the above photographing means exposure control means has, to control this as above the CPU to appropriate exposure based on the obtained data, based on the designation from the external device <br/>, external cut out any portion of the original image data In addition to having a function of outputting to a device , the cut-out image data is subjected to gain correction control to output the image data in a state substantially equivalent to the proper exposure. According to the present invention, by changing image data taken corresponding to an image form inputted from the outside,
Image data can be output in an image format corresponding to an external device. For example, in order to perform a binarization process using an error diffusion method on the original image data stored in the memory corresponding to the external device, the characteristics of the display device used for the external device, the type of the original image, and the output image Optimum binarization processing can be performed depending on the application. In particular, how to distribute dots can be arbitrarily adjusted by changing the binarization threshold value and the diffusion coefficient in accordance with an instruction from an external device. Also, since a predetermined area of the captured image data is converted into a predetermined data amount and output, an arbitrary portion of the captured image data can be output with an arbitrary number of pixels.
It can be configured to be compatible with external devices of various specifications, and can be converted into a data amount corresponding to the memory capacity and display size of the external device. [0010] Further, in order to perform gain correction on image data obtained by cutting out a predetermined portion of the appropriately exposed captured image data and output the image data in a state equivalent to the appropriate exposure, the image data in the view area is gain corrected. Since the cropped image can be output in a state equivalent to the proper exposure at the time of shooting, and especially when the view area changes every moment due to zooming in / out, vertical / horizontal scroll, etc., an appropriate image can always be output. High functionality can be achieved. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of an electronic still camera according to the present invention. In this figure, an electronic still camera includes an A / D converter 31, a CDS circuit 3,
2, memory control unit 33, timing generator 34, register 35, integration processing circuit 36, counter 37, timer 3
8, CPU 39, parallel I / O 40, ROM 41,
RAM 42, I / O port 43, interrupt processing unit 44, serial I / O 45, and system clock generating unit 46
, A memory controller 33, a register 35, a counter 37, a timer 38, a CPU 39, a parallel I / O
40, ROM 41, RAM 42, I / O port 43,
The interrupt processing unit 44 and the serial I / O 45 are connected to a bus 47
Connected to. The A / D converter 31 receives an A / D signal from a processing timing signal input from a timing generator 34.
The conversion processing timing is controlled, and the image signal amplified and output from the CCD 11 by the amplifier 51 is converted into a predetermined digital image signal and output to the CDS circuit 32. The CDS circuit 32 includes a timing generator 34
Is controlled by a sampling timing signal input from the A / D converter and a predetermined control signal input via the register 35, and is superimposed on a digital image signal input from the A / D converter 31 at the output unit of the CCD 11. Correlation double sampling processing for removing reset noise, 1 / f noise, and the like is performed, and the digital image signal from which the noise has been removed is output to the memory control unit 33 and the integration processing circuit 36 as image data. The memory control unit 33 includes the timing generator 3
The image data input from the CDS circuit 32 is controlled by an access timing signal input from the input terminal 4 and a predetermined access request signal input from the register 35.
The image data is read from the SRAM 52 and transferred to the parallel I / O 40, the I / O port 43, and the serial I / O 45 via the bus 47. The timing generator 34 generates a processing timing signal for the A / D converter 31 based on the master clock signal input from the master clock generator 46,
Various timing signals for controlling various processing timings in the image processing circuit 30, such as a sampling timing signal for the CDS circuit 32, an access timing signal for the memory control unit 33, and an integration processing timing signal for the integration processing circuit 36, are generated. At the same time, it outputs a predetermined timing signal for controlling the operation timing of the CCD 11 in the CCD driver 53 connected to the outside. The register 35 is connected to the CPU via a bus 47.
Various control signals input from 39 are temporarily stored, and the various control signals are output to the CDS circuit 32, the memory control unit 33, and the integration processing circuit 36 according to the timing signal input from the timing generator 34. The integration processing circuit 36 includes the timing generator 3
4 according to the integration processing timing signal input from
The image data input from the S circuit 32 is integrated, and the integration result is output to the counter 37. The counter 37 counts up based on the integration result input from the integration processing circuit 36, and notifies the CPU 39 of the count value via the bus 47. The timer 38 sets a delay time of a shutter operation at the time of image capturing and the like, and sets the set time via the bus 47 to the interrupt processing unit 4.
Notify 4. The CPU 39 executes error diffusion processing of image data and the like based on a predetermined program stored in the ROM 41 to generate binary image data, and transfers the accumulated charges in the CCD 11 described later. A timing control process is executed to control an electronic shutter operation in the CCD 11. The parallel I / O 40 transmits and receives image data and control data to and from a parallel I / O of an externally connected electronic device in accordance with a predetermined parallel data communication procedure. The ROM 41 stores a program executed by the CPU 39 and the like, and the RAM 42 forms a data area for temporarily storing data when the CPU 39 executes an error diffusion process and the like. The I / O port 43 is connected to an I / O port of an external electronic device or the like, and controls transfer of image data according to a predetermined data communication control procedure. The interrupt processing unit 44
An interrupt process such as a shutter delay operation is executed according to the delay time set by the timer 38. The serial I / O 45 is connected to a serial I / O of an electronic device connected to the outside via a bus 47.
Image data and control data are transmitted and received according to a predetermined serial communication procedure (for example, RS232C). The SRAM 52 forms a memory area for temporarily storing image data by the memory control unit 33. The CCD driver 53 outputs a frame shift pulse signal and a line transfer pulse signal for controlling operations such as a photoelectric conversion / accumulation period and a transfer timing of accumulated charges in the CCD 11 in accordance with a timing signal input from the timing generator 34. It is generated and output to the CCD 11. The electronic still camera is connected to an external electronic device through each I / O port, and receives an output image form from the external electronic device, so that the CPU 39 can take a captured image based on the received output image form. Optimize your data. First, optimization of the error diffusion process will be described. FIG. 2A is a principle diagram showing an example of the error diffusion method, and is a method in which when a certain pixel is binarized, a difference from the original luminance is diffused to surrounding unprocessed pixels. Here, the bit width of the original image data is 8 bits (256 gradations). That is,
Pixel X is binarized X ₀ by binarization threshold T, and X <T
If X ₀ = 0 (black) if X ≧ T and X ₀ = 255 (white) if X ≧ T, then X−X ₀ is the error component. This is diffused to surrounding pixels at a predetermined ratio. In this embodiment, the diffusion amount is controlled by multiplying the error component by the diffusion coefficient K. Diffusion is performed in four directions as shown in the error diffusion filter of FIG. 2B, and the value D ′ (n) of the surrounding pixels D (n) after diffusion is obtained by calculating the coefficient of the corresponding error diffusion filter. Assuming β (n), D ′ (n) = D (n) + β (n) ^* K ^* (X−X ₀ ), and an error is included when binarizing the pixel D ′ (n). By performing the same processing on the value D '(n), a natural image close to the density gradient of the original image can be obtained. FIG. 2 (b)
In the example of the error diffusion filter, the error of the binarization performed at the pixel X is calculated by using the ratios 7/16, 1/16, 5/16, and 3/16.
To add to surrounding pixels. When the threshold value T is changed, the brightness of the entire output image changes. The smaller the threshold value T, the brighter the image. Also, the diffusion coefficient K
When (0 ≦ K ≦ 1) is changed, the total amount of diffusion increases or decreases and the tone of the output image changes. When K = 0, the image becomes a completely binary image without error diffusion, and becomes closer to a halftone image as the diffusion coefficient K increases. However, the threshold value T and the diffusion coefficient K are set as shown in FIG. The change can be made to look more natural by changing the relation with each other. As described above, since the threshold value T is changed in conjunction with the diffusion coefficient K, there is an advantage that the halftone adjustment of the image can be performed more naturally.
Since half-tone adjustment can be achieved with a simple operation. That is, the ROM 41 of the electronic still camera 1
If there is a table as shown in FIG. 3, the external electronic device may receive either the threshold value T or the diffusion coefficient K. As described above, when error diffusion processing is performed on captured image data, error diffusion processing is performed based on a threshold value or a diffusion coefficient input from an external electronic device. Optimal image data can be output to an external electronic device regardless of the characteristics of the display device of the device, the type of the original image, and the use of the output image. In this embodiment, the pseudo halftone processing is realized by the error diffusion processing. However, the present invention is not limited to this. Pseudo halftone processing such as dither processing may be used. In this case, the threshold value of the dither matrix of a predetermined size, the size of the dither matrix, and the like are input from the external electronic device. Next, a description will be given of an electronic still camera in which the data amount for outputting all or a part of the original image can be arbitrarily changed according to designation from an external electronic device. The external electronic device has a horizontal pixel number H, a vertical pixel number V, a viewpoint (C _x , C _y ), an aspect ratio A,
The CPU 39 converts the image data of a portion required by the external electronic device into a required data amount based on these parameters, and sends the image data to the external device via each I / O port. The basis of this operation is pixel interpolation calculation as shown in FIGS. 4 (a) and 4 (b). That is, as shown in FIG. 4A, the interpolation data S is obtained by linear approximation of the data P and Q of two pixels. S = (1−d) P + dQ Therefore, as shown in FIG. 4B, in order to obtain the interpolation data S of one point in the area from the data A, B, C, and D of the four neighboring pixels, first, Interpolation data P and Q at two points in the horizontal direction are obtained, and P = (1−x) A + xB Q = (1−x) C + xD Next, a similar operation is performed in the vertical direction to obtain target interpolation data S. S = (1−y) P + yQ In the present embodiment, the space between pixels is divided into 256, and a virtual space of 61440 ^* 30720 pixels is generated from the effective pixel number 240 ^* 120 of the original image data. Next, as shown in FIG. 5, an area K _x ^* centered on the viewpoint (C _x , C _y ) in this virtual space ^.
The extraction of an image space to be output after converting _Ky to H ^* V pixels will be described. Assuming that the horizontal direction is the main scanning direction and the vertical direction is the sub-scanning direction from the upper left end of the output screen, data transmission is performed. The first transmission data D (0,0) is as follows.
A point on the virtual space _{(C x -K x / 2,} C y -K y / 2), the next transmission data D (1, 0) becomes K _x / H pixels right of the data. Because the vertical direction is the same, transmission data D (i, j) is, D (i, j) = (C x -K x / 2 + i * K x / H, C
represented by ^{_{y -K y / 2 + j *}} K y / V). Providing a constant: where, K _x, K the K _y with the aspect ratio A and the magnification Z mentioned above ^{_{x = k * A * H /}} Z K y = k * a * V / Z k. However, the aspect ratio A is defined as A = px / py when the horizontal pixel pitch is px and the vertical pixel pitch is py. A in the equation is the aspect ratio of the CCD itself. When the magnification Z is changed, zoom-in / out is performed. When the view points C _x and C _y are changed, vertical / zoom-out is performed.
Horizontal scrolling can be easily realized. As described above, an arbitrary portion of the original image data can be output with an arbitrary number of pixels, so that an electronic camera capable of supporting external electronic devices of various specifications can be configured. Next, a description will be given of an electronic still camera in which when a part of a captured image is read out, the subject in the cut out part is subjected to exposure correction so as to be properly exposed and output. That is, as shown in FIG.
39 calculates an average value A of the central portion AE calculation area of the photographed original image data, and performs exposure control so that the average value A becomes equal to a predetermined appropriate exposure value. As shown in FIG. 7, the original image data in the designated view area is enlarged / reduced as necessary with respect to the image data subjected to the exposure control by the proper exposure, and is output as a cut-out image.
For the cut-out view area, the average value B of the central portion AE calculation area in the view area is calculated in the same manner as at the time of shooting. By performing gain correction of the image data in the view area by A / B times, the cut-out image can be output in a state equivalent to the proper exposure. in this case,
Limit the gain so that the image is not unnatural due to extreme light and darkness. As described above, since the function for correcting the gain of the image data in the view area is provided, there is an advantage that the cut-out image can be output in a state equivalent to the proper exposure, such as zoom-in / out and vertical / horizontal scroll. Accordingly, an appropriate image can be always output even when the view area changes every moment, so that the electronic still camera can be enhanced in function. FIG. 8 shows an example in which the electronic still camera 1 of the present invention is connected to a label printer 61. In the figure, a label printer 61 includes a liquid crystal display screen 62 for displaying image data input from the electronic still camera 1, an operation state of the label printer 61, a contrast dial 63 for adjusting the brightness of the liquid crystal display screen 62, and a label. An operation key unit 64 for inputting a print operation, a communication operation with the electronic still camera 1 and the like, a character input unit 65 for inputting characters, a power key unit 66 for turning on / off the power, and the like. And it is connected to the electronic still camera 1 of the present invention by a cable. In the above configuration, the error diffusion coefficient K depends on the characteristics of the liquid crystal panel (display device) of the liquid crystal display screen 62, the type of the original image (for example, a natural image) and the use of the output image, and the image memory of the label printer 61. (C _x , C _y ), area (K _x , K _y ), aspect ratio A, magnification based on the capacity of the liquid crystal panel, the display size that can be displayed on the liquid crystal panel of the liquid crystal display screen 62, the area required as image data, and the like. Z and the like are input to the electronic still camera 1 via a cable, and based on the input data, the electronic still camera 1 performs optimal error diffusion processing and view processing for the label printer 61 based on the error diffusion coefficient K as described above. point (C _x, C _y), the area (K _x, K _y), the aspect ratio a, the output image data of the optimum data amount and the optimum exposure value based on the ratio Z It is possible to force. FIGS. 9 and 10 show the electronic still camera 1 of the present invention connected to electronic notebooks 67 and 69.
FIG. 10 shows an electronic still camera 1 formed integrally with an electronic organizer 67. FIG.
Is connected to the electronic organizer 69 by a cable. Also in this embodiment, as described above, the error diffusion coefficient K according to the characteristics of the liquid crystal display panels 68 and 70, the type of the original image (for example, a natural image) and the use of the output image, and the image memories of the electronic notebooks 67 and 69 Of the viewpoint (C _x , C _x) based on the capacity of the
C _y ), area (K _x , K _y ), aspect ratio A, magnification Z
Electronic still camera 1 directly or via a cable
, And based on the input data, the electronic still camera 1 performs the optimal error diffusion processing for the electronic notebooks 67 and 69 based on the error diffusion coefficient K as described above, the view points (C _x , C _y ), Output image data having an optimal data amount and an optimal exposure value can be output based on the area ( _Kx , _Ky ), the aspect ratio A, and the magnification Z. Thus, the electronic still camera 1 of the present invention can
It may be formed integrally or detachably. As described above, according to the present invention, the function of correcting the gain of the data in the view area is provided.
This has the advantage that the cropped image can be output in the same state as the appropriate exposure, and the appropriate image can always be output even when the view area changes every moment due to zooming in / out, vertical / horizontal scrolling, etc. Can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory view showing one embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating an example of an error diffusion method according to the present invention. FIG. 3 is a characteristic diagram showing an example of a relationship between a diffusion coefficient and a threshold according to the present invention. FIG. 4 is an explanatory diagram showing an example of a pixel interpolation calculation according to the present invention. FIG. 5 is an explanatory diagram showing an example of clipping a pixel space according to the present invention. FIG. 6 is an explanatory diagram showing an example of an AE calculation area according to the present invention. FIG. 7 is an explanatory diagram showing another example of cutting out a pixel space according to the present invention. FIG. 8 is a configuration diagram showing an example in which the electronic still camera of the present invention is connected to a label printer. FIG. 9 is a configuration diagram showing an example in which the present invention is connected to an electronic organizer as another example of use of the present invention. FIG. 10 is a configuration diagram showing an example in which a cable is connected to an electronic organizer as another use example of the present invention. [Description of Signs] 1 ... Electronic still camera, 11 ... Frame transfer type CCD, 31 ... A / D converter, 32 ... CDS circuit, 33 ... Memory control unit, 34 ... Timing generator, 3
5 register, 36 integration circuit, 37 counter
38 timer, 39 CPU, 40 parallel I / O,
41 ROM, 42 RAM, 43 I / O port, 4
4 interrupt processing circuit, 45 serial I / O, 46 system clock generator, 47 bus, 51 amplifier, 5
2 ... SRAM, 53 ... CCD driver.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/228 H04N 5/225 H04N 5/243

Claims (1)

(57) [Claim 1] An imaging device, imaging means for driving the imaging device to capture an image, means for converting the output of the imaging device into a digital value, and storing the converted data. A memory, a CPU that processes accumulated data, and an external device are connected, and the CPU can be specified by the external device.
The external machine processed data controls based
A communication means for outputting to the vessel, and the above photographing means has an exposed control means, for controlling the so that the CPU becomes appropriate exposure based on the data obtained
Together, on the basis of the specification from an external device, and has a function of cutting out any portion of the original image data to output to the external device, the proper exposure by performing gain correction control for clipped image data substantially An electronic camera characterized by outputting in an equivalent state.