JP2001197358A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a detection area generation circuit is complicated since a detection area on an image for calculating an evaluation value for deciding the image pickup condition of automatic white balance(AWB), an automatic focus(AF) and automatic exposure control(AE) differs by an image pickup condition and a problem that a photographing interval becomes long since the evaluation values for deciding the image pickup conditions cannot simultaneously be calculated in the image pickup device of a digital camera. SOLUTION: A means for generating the detection area from a pixel clock for driving imaging device and a horizontal synchronizing signal is installed. The evaluation values of the imaging devices are calculated on the respective detection areas. Picture data from imaging devices is inputted to respective evaluation generation means in parallel and processing speed is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus adapted to a digital camera, a microscope, etc., which converts light from a subject into an electric signal and performs an image pickup process.

[0002]

2. Description of the Related Art Digital cameras, which convert light into electric signals using a solid-state image pickup device such as a CCD, process the signals as digital signals, and pick up images, have rapidly become widespread. With digital cameras, auto focus (auto focus control; hereinafter referred to as AF), auto exposure (auto exposure control; hereinafter referred to as AE), and auto white balance (auto color adjustment; hereinafter referred to as AWB) so that users can easily take high-quality images. Many are equipped with automatic control functions.

The AF integrates a signal component from an image pickup device by using a contrast method or the like, obtains a correlation between the contrast and the defocus amount, and drives a lens to perform focusing. The AE integrates the signal components and sets an aperture or the like in accordance with a change in luminance of the subject to obtain an optimal exposure amount. AW
B is for correcting the color signals from the image sensor by integrating the color signals and correlating the respective colors to obtain a color balance.

The evaluation value such as the integral value used for the automatic control is obtained by dividing the image screen into several regions and detecting the evaluation value for each region. Many methods of dividing the detection area have been proposed. One example is shown in FIG. The detection area (solid line) for AF is arranged near the center of the imaging screen, and the signal within this detection area is integrated to obtain an evaluation value used for AF. The AE and AWB detection areas (broken lines) are arranged at the top and bottom (A area, C area) and the center (B area) of the screen.
The signals in the C region are detected, and evaluation values in the respective detection regions are obtained and reflected in the AE and AWB control operations.

On the other hand, another prior art is disclosed in
There is an apparatus as shown in FIG. 1
Reference numeral 01 denotes an optical unit including a lens and a solid-state imaging device, a driving circuit for driving the solid-state imaging device, and an imaging unit including a driving mechanism (not shown) for conveying a lens and a diaphragm to a predetermined position. A drive unit for generating a drive signal for driving the size of the diaphragm and the solid-state imaging device;
An analog signal processing unit that clamps and amplifies the signal output from 1; an A / D conversion processing unit 104 that performs digital conversion; a digital signal processing unit 105 that performs γ processing and AWB adjustment; A recording / reproducing processing unit 107 for recording / reproducing a signal, a D / A conversion processing unit 107,
The signal is converted to an analog signal and the monitor 1 of the display unit 108
09 is visually displayed. Reference numeral 111 denotes a control unit, and 112 denotes an operation switch. An AF integration block 113 calculates an evaluation value for performing automatic focus adjustment. 114 is AE /
This is a common integration block for calculating an evaluation value for performing AF by AWB and mode.

The signal from the imaging unit 101 is processed by the analog signal processing unit 103 and is processed by the digital signal processing unit 10.
5 is input. A signal from the digital signal processing unit 105 is supplied to a recording / reproducing process 106 according to a command from the switch 112.
Via the D / A conversion processing unit 107 and displayed on the monitor 109 of the display unit 108. At this time, the signal from the A / D conversion processing unit 104 is
It is also input to the AF integration block 113 and the common integration block 114. The AF integration block 113 calculates a contrast evaluation value indicating the contrast of the image signal in a predetermined detection area. In the common accumulation block 114, A
Each evaluation value of F, AE, and AWB is generated. As shown in FIG. 14, the common integration block 114 calculates each imaging adjustment function in a time-division manner for each field corresponding to the screen output of the solid-state imaging device, and performs desired imaging adjustment.

[0007]

In the former former example,
When the AF, AE, and AWB detection areas are different, it is necessary to independently have setting means for setting the detection areas, and to enable the detection areas to be set in different shapes. Therefore, a circuit for generating the detection areas However, there was a problem that it became complicated. Also, if the AF detection area is only at the center of the screen, it is possible to focus only on the center of the screen. In the case of a digital camera, the user must first turn the center of the screen to the position to focus before pressing the shutter. did not become.

In the latter example, A
Since the evaluation values of F, AE, and AWB are generated and the imaging adjustment is performed in a time-division manner, the number of pixels increases with the recent increase in the definition of the image sensor, and the speed ( Field rate) and the display speed and shutter interval become slow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can simplify a circuit configuration and detect an evaluation value used for each processing in real time.
Moreover, it is an object of the present invention to obtain an imaging device that can efficiently use the evaluation value and obtain a high-quality image.

[0010]

An image pickup apparatus according to the present invention is an image pickup apparatus having an optical system for determining a plurality of image pickup conditions and picking up an image, and has a plurality of pixels arranged on a plane. An imaging element that outputs image data generated by imaging a subject in pixel units; and an evaluation value generation unit that generates an evaluation value of the imaging condition that is referred to when determining the imaging condition. A plurality of evaluation value generating means for generating an evaluation value of a condition from the image data; and a control means for determining each imaging condition by referring to the evaluation value of each imaging condition generated by the plurality of evaluation value generation means. The plurality of evaluation value generating means are configured to input the image data in parallel.

The image pickup apparatus according to the present invention sets a plurality of regions in a plane on which pixels of the image pickup device are arranged,
The image sensor further includes detection area generation means for generating area information indicating the image data of a pixel in which area, and the plurality of evaluation value generation means include area information generated by the detection area generation means. Generating an evaluation value of each imaging condition for each area from the image data output by the imaging element, and the control unit refers to the evaluation value of each imaging condition generated for each area, and determines each imaging condition. The decision is made.

In the imaging apparatus according to the present invention, the control means refers to evaluation values of the imaging conditions in a plurality of areas when determining one imaging condition.

In the imaging apparatus according to the present invention, a combination of the plurality of areas is variable.

Further, in the imaging apparatus according to the present invention, the control means associates a predetermined weighting factor with each of the regions, and when determining the imaging condition, assigns the weighting factor to an evaluation value of the imaging condition for each region. Is to be multiplied.

Further, in the imaging apparatus according to the present invention, when the control means determines one predetermined imaging condition, the evaluation value of the imaging condition generated for each area by the evaluation value generation means is set in advance. The selected one imaging condition and the other imaging conditions are selected by referring to the evaluation value of the predetermined one imaging condition and the evaluation value of another imaging condition of the selected region. The conditions are determined.

Further, in the imaging apparatus according to the present invention, the plurality of imaging conditions are at least two of white balance, focal length of the optical system, and exposure amount of the optical system.

Further, in the image pickup apparatus according to the present invention, the plurality of image pickup conditions include a focal length of an optical system, and a filter constant for emphasizing a change in the image data. A filter that changes in accordance with the evaluation value of the focal length referred to when determining the focal length, and the control means changes the filter constant and applies the filter constant to the filter. .

Further, in the imaging apparatus according to the present invention, the plurality of imaging conditions further include an exposure amount of an optical system, and the control means defocuses from an evaluation value of the focal length referred to when determining the focal length. Calculate the amount and calculate the depth of focus from the evaluation value of the exposure amount used when determining the exposure amount of the optical system, and the calculated defocus amount is larger than the calculated depth of focus and the difference is larger, The filter constant is changed so that the degree of enhancement of the change in the image data is increased.

In the imaging apparatus according to the present invention, the detection area generating means receives a pixel clock synchronized with an output signal of the imaging element and a horizontal synchronization signal, and outputs image data from the input number of pixel clocks. Horizontal gate signal generating means for outputting a horizontal gate signal indicating the horizontal position of the pixel being output, and indicating the vertical position of the pixel outputting image data from the input number of horizontal synchronization signals. Vertical gate signal generating means for generating a vertical gate signal, wherein the area information is generated by a combination of the horizontal gate signal and the vertical gate signal.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an imaging device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing an example of the imaging apparatus according to the first embodiment. In the figure, 1A is a control unit, a CPU having a ROM, a RAM, etc., 1B is an operation panel for setting the operation of an imaging device such as a power switch and a shutter switch, 2 is a lens, 3 is an aperture, and 4 is an imaging device such as a CCD. 5, an A / D converter; 6, a memory capable of storing at least one screen; 7, an AWB processing circuit for performing white balance processing on a signal from the A / D converter 5; 8, A / D conversion An AF processing circuit for performing automatic focus control using a signal from the device 5; an AE processing circuit 9 for performing automatic exposure control using a signal from the A / D converter 5; A detection area generation circuit for generating a detection area by dividing the detection area into a plurality of areas, an AF motor 11 for moving a lens in the optical axis direction, an aperture control circuit 12 for opening and closing the aperture 3,
13 is an element control circuit for driving the image sensor 4, 14 is an image processing circuit having various filters and a screen enlargement / reduction function, and 15 is equipped with a D / A converter, a drive control for a display and video memory. A display processing circuit 16 using a liquid crystal or the like; 17 a recording processing circuit for storing a captured image in a recording medium 18; and 18 a recording medium such as a magnetic medium, an optical disk, or a flash memory.

The control section 1A is a control means in the present invention, and the lens 2 and the aperture 3 form an optical system in the present invention. Further, the detection range generation circuit 10
Is a detection area generating means in the present invention. Also AWB
The processing circuit 7, the AF processing circuit 8, and the AE processing circuit 9 are evaluation value generation means in the present invention.

Next, the operation will be described. Light from a subject passes through a lens 2, passes through a stop 3 serving as a light amount limiting unit, and forms an image on an image sensor 4. The imaging element 4 uses, for example, a two-dimensional CCD having 2048 horizontal pixels × 1024 vertical pixels and outputting red (R), green (G), and blue (B) color signals in a Bayer array in pixel units. A signal that is analog image data photoelectrically converted by the image sensor 4 is A /
It is quantized by the D converter 5. The signal S, which is the digitized image data output from the A / D converter 5, is A
The signals are input to the WB processing circuit 7, the AF processing circuit 8, and the AE processing circuit 9 in parallel. These processing circuits include a detection range generation circuit 1
A detection area is designated by 0, and signal detection is performed within the designated detection area to calculate an evaluation value (details will be described later).
The signals processed as the optimal imaging signals by these processing circuits are input to the image processing circuit 14. Image processing circuit 1
In No. 4, filter processing for edge enhancement of the imaging signal,
In accordance with an instruction from the operation panel 1B, enlargement / reduction processing of the imaging screen is performed. After that, the display processing circuit 15 performs a predetermined process for displaying the image on the display 16, and then displays an image confirmation screen on the display 16. Here, when the shutter of the operation panel 1B is pressed by the user, the signal S of the A / D converter 5 is output.
Are temporarily stored in the memory 6. The images in the memory 6 are sequentially read out according to the speed of the image processing circuit 14, the recording speed of the recording medium 18, and the like, and are again processed by the AWB processing circuit 7 and the image processing circuit 14. The data is converted and recorded on the recording medium 18. The subject is imaged by such a series of operations.

Here, the detection range generation circuit 10 will be described.
FIG. 2 is a diagram illustrating an example of the detection range generation circuit 10. The detection area shown in FIG. 3 is generated by this detection area generation circuit. In the present embodiment, the screen is divided into 16, and one detection area is 512 pixels horizontally and 256 pixels vertically. The detection area in FIG. 3 is an area according to the present invention.

In FIG. 2, reference numeral 19 denotes a horizontal gate signal generating section (horizontal gate signal generating means). 20 is a horizontal address counter, 21a, 21b. . 21
n is a horizontal direction gate signal generation circuit corresponding to each detection area in the horizontal direction, and in the case of this embodiment, there are four (n)
Is 4). Horizontal gate generation circuits 21a, 21b. . 2
1n, first, 22a, 22b. . , A register for storing the horizontal start or horizontal end position of each detection area, and 23 logical operation units.
4a and 24b and an AND gate 25.
On the other hand, reference numeral 26 denotes a vertical gate signal generator (vertical gate signal generator). Reference numeral 27 denotes a vertical address counter which is constituted by a down counter and has an 8-bit width capable of counting 256 vertical pixels (lines) in one detection area. 28 is a vertical direction gate signal generation circuit. Reference numeral 29 denotes an OR gate which takes the logical sum of all bits of the output VAD of the vertical address counter 27.

The generation of the detection area 1 will be described. A pixel clock synchronized with the signal S is input to the horizontal address counter 20 from the element control circuit 13. The horizontal address counter 20 counts the number of horizontal 2048 pixels of the image sensor 4 and generates a horizontal address HAD. Horizontal address HAD
Is the logical operation unit 2 of the horizontal direction gate signal generation circuit 21a.
3 is input. The comparator 24a compares the horizontal address HAD with a register 22a indicating the start position of a predetermined horizontal detection area of the detection area 1. The horizontal address HAD counts up as the pixel reading from the image sensor 4 progresses. When the horizontal address HAD is equal to or larger than the horizontal start position register 22a, the comparator 24a outputs an "H" signal. Further, the horizontal address HAD is compared with the horizontal end position register 22b of the detection area 1 by the comparator 24b, and the horizontal address HA is more than the end position register 22b.
When D is as follows, "H" is output from the comparator 24b.
The outputs of the comparators 24a and 24b are input to an AND gate 25, and the AND gate outputs an "H" signal only when both outputs are "H". As a result, the horizontal gate signal W in the detection area 1 is output.
EH1 is obtained.

On the other hand, a horizontal synchronizing signal for each line is input to the vertical address counter 27 from the element control circuit 13.
The vertical address counter 27 has an initial value of 255 set in advance, counts the number of vertical 256 lines in the detection area, and generates a vertical address VAD. Vertical address VAD
Are input to the vertical gate generation circuit 28. The vertical address VAD is decremented by one according to the horizontal cycle from the image sensor 4. At the vertical boundary line between the detection area 1 and the detection area 5 shown in FIG. 3, that is, the 256th line, the vertical address VAD becomes 0 and all 8 bits become “L”. Therefore, the OR gate 29 outputs "L" and the detection range 1
The gate signal WEV which becomes "L" is obtained only in the vertical end line.

The horizontal direction gate signal WEH1 and the vertical direction gate signal WEV in the detection area 1 provide an area signal WE indicating that the area is within the detection area 1. Detection range 2-4
Similarly, the signals indicating the horizontal gate generation circuits 21b. . The area can be specified from the outputs WEH2 to WEHn of the 21n and the output WEV of the vertical gate generation circuit 28. Further, the signal WE of the next detection area 5 is returned to 255 by the vertical address counter 27 and starts counting.
Gate signal WE indicating the vertical end line of detection area 5
The region is specified by V and the horizontal direction gate signal WEH1. By repeating this operation, a signal WE capable of specifying the entire detection range can be obtained.

The gate signals WEH1 to WEHn are the horizontal gate signal and the gate signal WEV in the present invention.
Is the vertical gate signal in the present invention, and the signal WE obtained by combining the horizontal gate signal and the vertical gate signal is the area information in the present invention.

Next, the AWB processing circuit 7, the AF processing circuit 8, and the AE processing circuit 9 will be described.

FIG. 4 shows the AWB processing circuit 7. 33a ~
Reference numeral 33d denotes a detection unit that calculates an average value, a maximum value, and a minimum value for each of R, G, and B colors used as evaluation values of the AWB process.
Is a correction unit for multiplying the signal S by a correction coefficient. In this embodiment, the number of the detection units is four in the horizontal detection area in the present embodiment, so that four detection units are provided. 35 is a vertical gate signal WE
A signal R that becomes “L” at the point where V changes from “L” to “H”
This is a differentiating circuit that outputs ST. This is to prevent the pixel on the last line from being unable to detect the WEV signal because it becomes “L” at the vertical end line of each detection area. The detector performs detection according to the WE signal. The detector 33a uses the WEH1 signal as an operation enable signal.
The detection is performed only at the time of H ". The detection units 33b to 33d operate in the same manner according to WEH2 to WEHn.
When the output signal RST of the differentiating circuit 35 of the vertical gate signal WEV indicating the end in the vertical direction of .about.4 becomes "L", the respective evaluation values W1 to W4 obtained by the respective detectors are transmitted to the controller 1A through the data bus D. Sent to Then, RST
Each detector is reset by the signal. Next, the detection unit 33
a to 33d detect AWB evaluation values in the detection ranges 5 to 8.
Thus, detection for one screen is performed. Each evaluation value W1
W4 represents R (red) and G in detection ranges 1 to 4, respectively.
(Green) and the average, maximum, and minimum values of the intensities of B (blue).

Note that the number of detection sections may be any number as long as the detection areas do not overlap at least in the horizontal direction, and of course, may have the number of detection areas. When the detection area may be discontinuous in the vertical direction, the differentiating circuit 35 becomes unnecessary. Further, in this embodiment, for the sake of simplicity, fine timing adjustment is omitted, but transmission of the evaluation values W1 to W4 and resetting of the detection unit are performed by using a predetermined delay line, flip-flop, or the like.
After the signal is delayed and the transmission of the evaluation value is completed, the reset may be performed.

With reference to each evaluation value obtained through the data bus D, the control section 1A selects an evaluation value in a predetermined detection range. At the time of selection, for example, the maximum value and the minimum value of each color in which AWB (auto white balance) operates optimally are set in advance, and the evaluation value is compared with the above evaluation value to select an evaluation value from a detection area suitable for the condition. . When performing white balance adjustment based on the output of G, the correction coefficient of R is calculated using the average value of R and the average value of G in the selected detection area.
Similarly, the correction coefficient of B is calculated by using the average value of B and the average value of G in the selected detection area.
It is calculated by the average value / G average value. The correction coefficient calculated in this way is sent to the AWB processing circuit 7 via the data bus D, and is applied to each detection area by multiplying the correction coefficient by the correction coefficient by the correction unit 34 to balance each color.

Similarly, the AF processing circuit 8 has detection sections for at least the number of detection areas in the horizontal direction, and integrates the signal S by these detection sections. The AF processing circuit 8 has a configuration in which the correction unit 34 is deleted from the AWB evaluation circuit 7 in FIG. Therefore, an AF (autofocus) evaluation value is obtained at the same timing as the AWB evaluation value, using the integrated value for each detection area as the evaluation value. Here, the integration interval of the signal S to be integrated is changed at least two times so that the AF following speed and accuracy can be selected.
The type of AF evaluation value, AF detection 1 and AF detection 2 are obtained. For example, AF detection 1 is obtained by integrating the signals S for all the pixels in the detection area, and AF detection 2 is obtained by integrating the signals S every other pixel in the detection area in the horizontal direction. Of course, other integration methods may be used.

When the object is out of focus (out of focus), the integrated value of the signal S becomes small, and when the object is in focus, the integrated value becomes large. This integrated value is transmitted to the control unit 1A via the data bus D. The control unit 1A selects a predetermined detection area set in advance, or selects an optimal detection area by referring to the maximum, minimum, and average values of the AWB evaluation values, and further selects an arbitrary detection area from the selected detection area. One of the two AF evaluation values (AF detection 1 and AF detection 2) is selected according to the AF following speed and the like. Based on the selected AF evaluation value and the defocus amount correlated with the selected AF evaluation value, the control unit 1A drives the AF motor 11 attached to the lens 2 so as to be in focus and performs automatic focusing.

Similarly, the AE processing circuit 9 has a detection section for at least a horizontal detection area, and each detection section integrates the signal S. The AE processing circuit 9 also has a configuration in which the correction unit 34 is deleted from the AWB evaluation circuit 7 in FIG. This integrated value varies depending on the brightness of the subject. This AE (auto exposure: automatic exposure) evaluation value is also an AWB evaluation value, AF
It can be obtained at the same timing as the evaluation value. The obtained integrated value, which is the AE evaluation value, is sent to the control unit 1A via the data bus D, and the control unit 1A selects the AE evaluation value in a predetermined detection range and controls the aperture 3 so that the optimum exposure amount is obtained. The aperture control circuit 12 is operated. Or image sensor 4
Is transmitted to the element control circuit 13 for controlling the control so as to obtain a desired charge accumulation time. Further, the shutter speed of a shutter (not shown) may be changed according to the exposure amount. The above AWB, AE, and AF are a plurality of imaging conditions in the present invention.

Here, further explanation will be given using a timing chart. FIG. 5 is a timing chart showing the above operation. V indicates a screen (field), an “H” section indicates an effective section of the image sensor 4, and an “L” section is a so-called vertical retrace period in which a transition is made to the next screen. First, time T
AF, AE, A in the detection range 1 to 4 in the interval 0 to T1
Each detection of WB is performed. At time T1, the evaluation values of AF, AE, and AWB detected in the detection ranges 1 to 4 are sent to the control unit 1A via the data bus D, and the control unit 1A
Is stored in the internal register. In the next section from time T1 to T2, detection is performed by the detectors 5 to 8, and at time T2, the evaluation value in this section is sent to the controller 1A. Detection is sequentially performed in this manner. At time T4, the evaluation values in the entire detection area of the screen 1 are aligned. The control unit 1A operates at time T4
A predetermined evaluation value is selected using these evaluation values in the period from T0 'to a time period and reflected in each process. Therefore, on the next screen 2, it is possible to obtain an image for which predetermined automatic processing has been completed. Note that the vertical flyback period (time T4 to T0 ') is equivalent to about ten horizontal synchronization signals, so that the control unit can sufficiently perform calculations within this period.

As described above, the screen is divided into a plurality of detection ranges, and each evaluation value used for each of the AF, AE, and AWB processes can be detected simultaneously for each detection range. Since the circuit can be simplified and the evaluation values in a plurality of detection ranges can be detected simultaneously, high-speed processing can be performed, and the obtained evaluation values can be efficiently reflected in each processing. In addition, since the evaluation value is reflected on each processing operation at least within the vertical blanking period up to the next screen, real-time processing can be performed and the processing speed can be improved. Furthermore, since an evaluation value can be obtained for each detection area, these can be combined and reflected in each processing, and an imaging device capable of obtaining a high-quality image can be obtained.

The number of pixels of the image sensor 4 and the number of detection areas used are arbitrary, and are not limited to the present embodiment. It goes without saying that the imaging device 4 may use not only a CCD but also a CMOS sensor or the like.

In the detection area generating means shown in FIG. 2, the horizontal size of the detection area can be changed by changing the set values of the horizontal start position registers 22a and 22c and the horizontal end registers 22b and 22d. It is also possible to change the vertical size of the detection area by changing the number of bits of the vertical address counter 27 or changing it to, for example, a programmable counter capable of setting an initial value for each vertical detection area. It is possible. The setting value of each register may be arbitrarily set by the user, and the detection areas arranged in the horizontal direction may not be equal in size in the horizontal direction, and the detection areas arranged in the vertical direction may not be equal. May not be equal. Further, although the vertical address counter 27 is constituted by a down counter, it goes without saying that it can be constituted by an up counter.

In this embodiment, the control section controls the AF, AE, and AWB during the vertical flyback period. However, when the evaluation value of the detection area 5 is selected, for example, at time T2 When the evaluation value of the detection area 5 is obtained, the control unit 1A may perform the calculation, and control the lens and aperture and rewrite the AWB correction coefficient within the vertical flyback period. Also, in the case where the processing operation is performed with reference to the AWB evaluation value (maximum / minimum / average value) as in the example shown in the above-described AF processing operation, the control is performed at the time when the evaluation value of the detection area is obtained. The processing may be sequentially performed by the unit, and each processing operation may be completed by the time the imaging of the next screen is started. Further, for example, the detection area 1
The evaluation values of (1) to (4) are not sent to the control unit 1A at the time T1, but are sent out to the control unit 1A at the time of completion of each detection, and the control unit sequentially refers to the evaluation values and sequentially processes the evaluation values. You may.

When an image is read from the memory 6 after the shutter is pressed, AF, AE, A
WB detection may be performed, and an imaging signal in which an AWB correction coefficient, a filter intensity coefficient described later, or the like is changed using the evaluation value may be recorded on the recording medium 18.

Although the reflection in each automatic processing is performed in the vertical retrace interval, when performing imaging while observing the imaging state on the display or performing high-speed tracking, a lens or aperture is required in the middle of the screen. And the rewriting of the AWB correction coefficient may be performed. This is because, for example, when the display is based on NTSC, the frame rate is visually high at 1/30 seconds, and there is almost no effect even if the processing changes in the middle of the screen. This is the same even if it complies with another method such as PAL.

The detection of AF, AE, and AWB is performed by hardware using a circuit.
And may be detected by the control unit 1A.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6, which is a new diagram, is a diagram illustrating a detection area and an evaluation area according to the second embodiment. The detection ranges 1 to 16 are the same as those of the first embodiment shown in FIG.
Is a detection range generated by the detection range generation circuit 10 described with reference to FIG. AWB processing circuit 7, AF
The processing circuit 8 and the AE processing circuit 9 detect the respective evaluation values in the respective detection ranges as in the first embodiment. The obtained evaluation value is sent to the processing unit 1 via the data bus D. In the control unit 1A, evaluation areas used for the AF, AE, and AWB processes are set in advance as shown in FIG. Evaluation area 1
Is used by adding or averaging the evaluation values of the detection ranges 1, 5, 9, and 13. The evaluation area 2 includes detection areas 6, 7, 10,
The evaluation value of 11 is processed, and the processing area 3 is the detection area 4, 8, 12, 16
Combine the evaluation values of Therefore, in the processing area 2, a result substantially equal to the result of photometry at the center of the screen is obtained. Similarly, the processing areas 1 and 2 are the same as the result of photometry of the left and right peripheral portions of the screen. The AF, AE, and AWB operations are performed using the evaluation values thus combined.

First, the imaging state is observed on the display 16. Next, the evaluation area 1 combining the detection areas is selected by the operation panel 1B. The control unit 1A reflects the evaluation value of the evaluation area 1 in the left part of the screen in the AF, AE, and AWB processes according to the instruction on the operation panel 1B. Then, an imaging screen using the evaluation value of the evaluation area 1 is displayed on the display 16. When a desired imaging screen is obtained, a shutter on the operation panel 1B is pressed to save data in the recording medium 18. If a desired imaging screen cannot be obtained, the evaluation area 2 at the center of the screen is selected next. By repeating the above operation until a desired screen is obtained, an imaging screen is obtained.

As described above, A in the multi-divided detection area
AF, A by combining the evaluation values of F, AE, and AWB
E, since it is reflected in the AWB processing, for example, center-weighted photometry or peripheral photometry can be facilitated without increasing the circuit scale.

In this embodiment, the combined evaluation area used for each processing is selected while observing on the display. However, a predetermined evaluation value range is determined in advance, and the evaluation area within that range is determined by the control unit. And the evaluation value may be automatically selected.

Note that the combination of the detection ranges is not limited to this, and any combination is possible.
What is necessary is just to calculate the average value by adding the evaluation values of up to 16 and obtain the average value.

Further, a selection switch or the like may be provided on the operation panel 1B so as to select a detection area, so that the user can arbitrarily select the detection area in accordance with the subject and the photographing situation. Since the photographer can arbitrarily set the processing areas of AF, AE, and AWB in this manner, the processing intended by the photographer can be performed, and an easy-to-use imaging device can be obtained.

Although the detection areas are combined on the operation panel, the detection areas to be combined may be prepared in advance so that the evaluation value as the result of the combination can be selected by the user.

Embodiment 3 FIG. Hereinafter, a third embodiment of the present invention will be described with reference to FIG. As described in the first embodiment, each evaluation value obtained from each detection area is sent to control section 1A via data bus D, and control section 1A
Once stored in an internal register, the control section 1A refers to the register to determine an optimal operation. FIG. 7 is a diagram showing the evaluation values stored in the internal register 40 of the control unit 1A at that time. FIG. 7 shows the relationship between the address of the internal register of the control section 1A and the evaluation values detected by the AWB processing circuit 7, the AF processing circuit 8, and the AE processing circuit 9. At address 0, the maximum value, minimum value, average value and AF evaluation value 1 of the R component of the detection area 1 detected by the AWB processing circuit 7
Are stored in the address 1, the maximum value / minimum value / average value of the G component in the detection area 1 and the AF detection value 2 and the address 2 the maximum value / minimum value / average value of the B component in the detection area 1 and the AE. The evaluation value is stored. Addresses 3 to 5 store the evaluation values of the detection area 2.

The operation of the AWB control will be described as an example. The control unit 1A accesses the address 0. Then the maximum value of R
The minimum / average value and the AF detection value 1 can be referred to simultaneously.
The control section 1A has a predetermined range set in advance, and compares the predetermined range with the maximum value / minimum value. If the maximum value and the minimum value are within the predetermined range, the average value of R in the detection area 1 is used for calculating the AWB correction coefficient. If not within the range, the evaluation value of the detection area 1 is not reflected in the AWB processing,
The same operation as above is performed with reference to the address 3 in which the evaluation value of the next detection area 2 is stored. By performing such an operation, unnecessary increment of the address becomes unnecessary.

As described above, since a plurality of evaluation values can be referred to at the same time, the efficiency of software for controlling the control unit is improved, and high-speed processing can be performed.

Further, an identifier or the like may be provided in the evaluation value so that the obtained evaluation value can be easily identified or discriminated.
As the identifier, for example, any detection area (detection areas 1 to 16)
Of the evaluation value (R, 4 bits)
G, B maximum value, minimum value, average value, AF detection 1, AF
4 bits total 8 indicating detection 2 and AE detection (total 12 types)
Bits may be added before the evaluation value.

The combination of the evaluation values stored in the internal register 40 and simultaneously referred to by the control unit is not limited to this, and may be determined based on the processing priority of AF, AE, and AWB. Also, the internal register 40
It goes without saying that M or the like may be used.

Embodiment 4 Embodiment 4 will be described with reference to FIG. 1 and FIG. The configuration of the imaging device in this embodiment is the same as that in FIG. 1 described in the first embodiment.
In the present embodiment, the AE evaluation value is reflected in the AF operation. As shown in FIG. 8A, a case where a subject includes a high-luminance part such as the “sun” and a “house” for the purpose of focusing on the screen will be described as an example. Since the integrated value of such a high-luminance portion is originally a high value of the imaging signal level, a large value is obtained as the AF evaluation value even if the image is not in focus, and the control unit 1A determines that the image is in focus. It becomes a factor. This also causes a malfunction in the AE and AWB operations, and also causes a malfunction in a case where a low luminance portion exists.

Next, the operation will be described. As shown in FIG. 8B, the AE processing circuit 9 calculates an evaluation value for each detection area. Here, for the sake of simplicity, it is assumed that the relative values are standardized such that the high-luminance portion has an evaluation value of 10. Here, an appropriate AF operation range is set in advance. In this case, the AE evaluation value of 3 to 6 is set as the AF proper operation range. The control section 1A determines an evaluation value within the AF proper operation range from the obtained evaluation value. Accordingly, as shown in FIG. 8C, only the evaluation value obtained from the detection area (the area where the house is captured) at the lower right of the screen is reflected in the AF operation, and the evaluation obtained from the detection area outside the AF proper operation range. The value is not used for the AF operation.
Thereafter, an AF process is performed by averaging the evaluation values of the appropriate operation range. This operation is the same as in the first embodiment.

As described above, the proper operation range of each process of the automatic control operation is set in advance, and when the evaluation value obtained from each detection area is out of the range, the evaluation value is applied to each control operation. Since it is not used, there is an effect that malfunction of AF, AE, and AWB can be prevented.
E, AWB operation can be obtained.

In this embodiment, the AE evaluation value is reflected in the AF operation. However, the AF evaluation value may be reflected in the AE operation. The appropriate range of each of the AF, AE, and AWB operations may be held independently, or an optimal operation range that correlates a plurality of operations may be set as in the above embodiment. For example, a proper operation range of the maximum, minimum, and average values of each of the R, G, and B colors is set as an appropriate range of the AWB operation, and only the evaluation value of the detection range within this range is subjected to the AW operation.
What is necessary is just to reflect on the B operation and the AE operation.

Further, the user may be allowed to set an arbitrary value through the operation panel for the proper operation range. For example, the appropriate AF range shown in the fourth embodiment is set using a keyboard or the like on operation panel 1B. The AWB / AE proper range is also set on the operation panel in the same manner.

As described above, since the user can set the appropriate operation ranges of AF, AE, and AWB, there is an effect that the user can obtain a desired captured image according to the subject.

Embodiment 5 Embodiment 5 will be described with reference to FIG. The configuration of this embodiment is the same as the configuration shown in FIG. 1 described in the first embodiment. FIG. 9 is a diagram illustrating an example of a weighting coefficient for an evaluation value obtained from each detection area of the imaging screen. (A) shows the detection result, and (B)
Is a weighting coefficient, and the number “1” indicates that the obtained detection result is used as it is as the evaluation value, and “3” is used.
Indicates that the obtained detection result (A) is multiplied by a relative value of “3” to obtain an evaluation value. This weighting is performed by the control unit 1A.
Performed by After weighting each detection result according to the weighting coefficient, the control unit 1A reflects the weighted result (C) as an evaluation value in each process. For example, when the AF operation is performed, the evaluation value at the center of the screen is weighted with respect to the evaluation values at the periphery by using the weighting coefficient of (B), so that the center is focused. .

As described above, the evaluation values obtained from the respective detection ranges are weighted, and the AF, AE, and AWB processing operations are performed based on the weighted results. It is possible to obtain an imaging device that can freely perform the edge-weighted method or the like.

Although only an example of the AF operation has been described, AE and A
A similar operation is possible for the WB operation. The weighting coefficient may be arbitrarily determined according to the subject or the user's intention, and is not limited to the coefficient as shown in FIG. Further, although the weighting process is performed by the control unit 1A, the detection unit of each process may be provided with a multiplier or the like, and the detection result may be multiplied by a weighting coefficient and output to the control unit. Further, the manner of associating the weighting coefficients with the respective detection ranges may be different depending on the imaging conditions AF, AE, and AWB, or may be the same.

Further, an identifier such as a flag may be added to the weighted evaluation value so that the weighted evaluation value can be easily identified.

Embodiment 6 FIG. Embodiment 6 will be described with reference to FIG. The configuration of this embodiment is the same as the configuration described in Embodiment 1 with reference to FIG. FIG. 10 is a schematic configuration diagram illustrating a part of the image processing circuit 14 of the imaging device according to the sixth embodiment. 45 is a high-pass filter which is an edge correction means for correcting a signal change point of the imaging signal S;
Is a line buffer and includes two line memories.
The image processing circuit 14 includes three registers (not shown) each having a capacity of three pixels. Further, the control section 1A gives the high-pass filter 45 an intensity coefficient which is a filter constant according to the AF evaluation value.

Next, the operation will be described. Note that the present embodiment will be described with an example of edge enhancement in edge correction. The operation in which the imaging signal is input to the AF processing circuit 8 and the AF evaluation value that is the detection result is sent to the control unit 1A is the same as in the first embodiment. When the AF evaluation value in the predetermined detection area is a large value, the control unit 1A decreases the intensity coefficient of the high-pass filter 45 or sets the intensity coefficient to 0 because the subject is near the focus. On the other hand, when the AF evaluation value is a small value, the camera is in an out-of-focus state. At this time,
By increasing the intensity coefficient of the high-pass filter 45, the edge (signal change point) of the imaging screen is emphasized.

In the present embodiment, the surrounding pixels of the target pixel are referred to as the high-pass filter 45, for example, 3 pixels × 3
An example in which a Laplacian filter of pixels is used will be described. FIG.
The calculation of the target pixel B1 of 3 × 3 pixels shown in FIG. Here, B1 ′ is a value of the target pixel B1 after the intensity conversion, and Kx, Ky, and Kz are intensity coefficients in the xyz directions, respectively. The degree of emphasis of the edge (emphasis degree) is changed by this intensity coefficient.

(Equation 1)

First, the pixels in the line direction of A0, A1, and A2 are stored in one line memory of the line buffer 46. The pixels of the next lines B0, B1, and B2 are also stored in other line memories of the line buffer 46. Further, when C0, C1, and C2 of the next line are spatially aligned with the pixel data, the pixel data from A0 to B2 stored in the line buffer 46 is read out to two registers. Using the read pixel data of A0 to B2 and the pixel data of C0, C1, and C2 stored in another register, the arithmetic operation according to the equation (1) is performed. At this time, the relationship between the AF evaluation value and the filter strength is determined in advance. The control unit 1A determines the filter strength coefficients Kx, Ky, K based on the correlation.
The operation described above is performed by rewriting z.

As described above, since the image signal intensity of the filter for emphasizing the image is changed from the obtained AF evaluation value, even if the lens is slightly deviated from the in-focus position, a sharp imaging screen with little blur is obtained. There is an effect that can be obtained.

In the present embodiment, an example during the imaging operation has been described. However, the present embodiment can also be used during the assembly at the time of manufacturing the device. An image of a predetermined subject is taken, the focus is manually adjusted to the in-focus position, and an AF evaluation value at that time is obtained. Compared with the designed AF evaluation value, if the obtained AF evaluation value is lower than that value, the intensity coefficient given to the filter is increased, and the intensity coefficient (filter intensity) of this filter is set as the initial setting value.

By doing so, an imaging apparatus capable of guaranteeing a desired MTF (modulation transfer function) even for a static error due to an assembly error or a variation error of parts such as lenses is obtained. There is an effect that can be.

Further, in the present embodiment, the detection area is divided into 16 areas of the screen. However, by increasing the number of divisions, there is an effect that finer MTF correction can be performed.

In the present embodiment, a Laplacian filter of 3 × 3 pixels is used. However, any filter may be used as long as the filter sharpens the image, and the number of reference pixels around the target pixel is not limited to this.

Although an example of an edge emphasis filter has been described, a low-pass filter or the like for smoothing edges may be used as an edge correction means if necessary. In this case, noise removal of signal components is possible. .

Further, in the above embodiment, the filter strength reflects the AF evaluation value. However, the filter strength may be changed to include the AE evaluation value.
In this case, the following operation is performed. The control unit 1A is A
The optimum aperture is determined from the E evaluation value. With this optimum aperture value, when the subject is bright (the AE evaluation value is large), the aperture is narrowed down and the depth of field becomes deep. Conversely, when the subject is dark (the AE evaluation value is small), the aperture is opened and the depth of field is reduced. The correlation between these AE evaluation values and the aperture (depth of field) is determined in advance. On the other hand, the control unit 1A
Estimates the defocus amount from the obtained AF evaluation value.
The optimum filter strength is determined from the relationship between the estimated defocus amount and the aperture. Specifically, when the defocus amount is larger than the depth of field (aperture value based on the brightness of the subject) (the AF evaluation value is small) (at the time of out-of-focus), the intensity coefficient of the filter is increased to increase the image quality. Is sharpened. vice versa,
When the defocus amount is smaller than the depth of field (the AF evaluation value is large) (near focus), the necessary sharpness can be obtained without emphasizing the edge portion. Alternatively, imaging is performed with the filter coefficient set to 0.

As described above, since the image signal intensity of the filter for emphasizing the image is changed based on the AF evaluation value and the AE evaluation value, the defocus is small even when out of focus according to the brightness of the subject. There is an effect that a sharp imaging screen can be obtained. Further, it is needless to say that the aperture operates only when the shutter is depressed, and that there is a remarkable effect in the so-called open photometry in which the photometry is performed with the aperture opened.

[0078]

As described above, the imaging apparatus according to the present invention is an imaging apparatus which has an optical system and determines a plurality of imaging conditions to perform imaging, and has a plurality of pixels arranged on a plane. An imaging element that outputs image data generated by imaging a subject in pixel units; and an evaluation value generation unit that generates an evaluation value of the imaging condition that is referred to when determining the imaging condition. A plurality of evaluation value generating means for generating an evaluation value of a condition from the image data; and a control means for determining each imaging condition by referring to the evaluation value of each imaging condition generated by the plurality of evaluation value generation means. However, since the plurality of evaluation value generation means are configured to input the image data in parallel, a plurality of evaluation values are generated at the same time, and the processing can be speeded up.

Further, in the image pickup apparatus according to the present invention, a plurality of areas are set in a plane in which the pixels of the image pickup element are arranged,
The image sensor further includes detection area generation means for generating area information indicating the image data of a pixel in which area, and the plurality of evaluation value generation means include area information generated by the detection area generation means. Generating an evaluation value of each imaging condition for each area from the image data output by the imaging element, and the control unit refers to the evaluation value of each imaging condition generated for each area, and determines each imaging condition. Since the determination is made, it is possible to refer to the evaluation value of a predetermined area as needed, and it is possible to flexibly control the image quality.

Further, in the imaging apparatus according to the present invention, the control means refers to the evaluation values of the imaging conditions of a plurality of areas when determining one imaging condition, so that only the evaluation value of a specific area is used. Irrespective of this, the imaging conditions are determined and there is an effect that an image with good image quality can be obtained.

Further, the image pickup apparatus according to the present invention has an effect that the image quality can be flexibly controlled because the combination of the plurality of areas is variable.

Further, in the imaging apparatus according to the present invention, the control means associates a predetermined weighting factor with each of the regions, and when determining the imaging condition, adds the weighting factor to the evaluation value of the imaging condition for each region. Is multiplied by a factor, there is an effect that it is possible to reflect the evaluation value of the area to be emphasized when determining the imaging conditions.

Further, the imaging apparatus according to the present invention has
When determining one imaging condition, the evaluation value generation means selects an area in which the evaluation value of the imaging condition generated for each area is within a preset range, and selects the predetermined one of the selected areas. The predetermined one imaging condition and the other imaging condition are determined with reference to the evaluation value of one imaging condition and the evaluation value of another imaging condition. Therefore, the evaluation value from a region having a unique evaluation value is excluded. It is possible to obtain an image with good image quality.

In the imaging apparatus according to the present invention, the plurality of imaging conditions are at least two of white balance, focal length of the optical system, and exposure of the optical system. There is an effect that can be applied to.

In the image pickup apparatus according to the present invention, the plurality of image pickup conditions include a focal length of an optical system, and a filter for emphasizing a change in the image data. A filter that changes in accordance with the evaluation value of the focal length referred to when determining the focal length, and applies the filter constant to the filter so that the contour is clear. There is an effect that an image can be obtained.

Further, in the imaging apparatus according to the present invention, the plurality of imaging conditions further include an exposure amount of the optical system, and the control means performs defocusing from the focal length evaluation value referred to when determining the focal length. The depth of focus is calculated from the evaluation value of the exposure amount used in determining the exposure amount of the optical system while calculating the amount, and the calculated defocus amount is larger as the calculated focal depth is larger and the difference is larger, Since the filter constant is changed so that the degree of enhancement of the change in the image data is increased, there is an effect that an image having a clear outline can be obtained.

In the imaging apparatus according to the present invention, the detection area generating means receives a pixel clock synchronized with the image sensor output signal and a horizontal synchronization signal, and outputs image data from the input pixel clock number. Horizontal gate signal generating means for outputting a horizontal gate signal indicating a horizontal position of a pixel which is present, and a vertical direction indicating a vertical position of a pixel which is outputting image data based on the number of input horizontal synchronization signals. Vertical gate signal generating means for generating a gate signal, and the area information is generated by a combination of the horizontal gate signal and the vertical gate signal. Therefore, the detection area generating means is constituted by a counter and a small number of elements. This has the effect of realizing a simple circuit configuration.

[Brief description of the drawings]

FIG. 1 is a diagram showing an imaging apparatus of the present invention.

FIG. 2 is a diagram showing a processing area generation circuit according to the present invention;

FIG. 3 is a diagram showing detection ranges of AF, AE, and AWB of the present invention.

FIG. 4 is a diagram showing an AWB processing circuit of the present invention.

FIG. 5 is a timing chart of the present invention.

FIG. 6 is a diagram illustrating AF, AE, and AW according to the second embodiment of the present invention.
Diagram showing B evaluation area

FIG. 7 is a diagram showing a control unit internal register according to the third embodiment of the present invention;

FIG. 8 is a diagram showing the operation of the fourth embodiment of the present invention.

FIG. 9 is a diagram showing an operation of the fifth embodiment of the present invention.

FIG. 10 is a diagram showing an imaging device according to a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a target pixel according to a sixth embodiment of the present invention;

FIG. 12 is a diagram showing a conventional detection area.

FIG. 13 is a diagram showing a conventional imaging device.

FIG. 14 is a diagram showing the operation of a conventional imaging device.

[Explanation of symbols]

 Reference Signs List 1A Control unit 1B Operation panel 2 Lens 3 Aperture 4 Image sensor 5 A / D converter 6 Memory 7 AWB processing circuit 8 AF processing circuit 9 AE processing circuit 10 Processing area generation circuit 14 Image processing circuit 19 Horizontal gate signal generation unit 20 21n Horizontal address counter 21a Horizontal gate generator 26 Vertical gate signal generator 27 Vertical address counter 28 Vertical gate signal generator 33a... 33d AWB detector 34 AWB correction unit 40 Internal register 45 Filter 46 Line buffer.

Continued on front page F term (reference) 5C022 AA13 AB06 AB30 AC01 AC42 AC69 5C065 AA03 BB02 BB08 BB11 CC01 DD01 GG02 GG18 GG22 GG24 GG26 5C066 AA01 CA23 EA14 KC03 KD04 KE01 KE07 KE19 KE21 KE24 KM02

Claims (10)

[Claims] 1. An imaging apparatus having an optical system and determining a plurality of imaging conditions to perform imaging, comprising: a plurality of pixels arranged on a plane; An image sensor that outputs the image data in units; and an evaluation value generation unit that generates an evaluation value of the imaging condition that is referred to when the imaging condition is determined. Evaluation value generation means, and control means for determining each imaging condition by referring to the evaluation value of each imaging condition generated by the plurality of evaluation value generation means, wherein the plurality of evaluation value generation means An imaging apparatus characterized in that data is input in parallel. 2. A detection area generation method for setting a plurality of regions in a plane on which pixels of the image sensor are arranged, and generating region information indicating which region of the image sensor outputs image data of the pixels. Means for generating an evaluation value of each imaging condition for each area from the area information generated by the detection area generation means and the image data output by the imaging element; The imaging apparatus according to claim 1, wherein the means determines each imaging condition by referring to an evaluation value of each imaging condition generated for each of the regions. 3. The imaging apparatus according to claim 2, wherein the control unit refers to evaluation values of the imaging conditions of a plurality of areas when determining one imaging condition. 4. The imaging device according to claim 3, wherein a combination of the plurality of regions is variable. 5. The control unit according to claim 1, wherein a predetermined weighting factor is associated with each of the regions, and when determining an imaging condition, an evaluation value of the imaging condition for each of the regions is multiplied by the weighting factor. The imaging device according to claim 2. 6. The control means, when deciding one predetermined imaging condition, determines an area in which the evaluation value of the imaging condition generated for each area by the evaluation value generation means is within a preset range. Selecting, referring to the evaluation value of the predetermined one imaging condition and the evaluation value of another imaging condition of the selected area,
The imaging apparatus according to claim 2, wherein the one predetermined imaging condition and another predetermined imaging condition are determined. 7. The imaging apparatus according to claim 1, wherein the plurality of imaging conditions are at least two of white balance, a focal length of the optical system, and an exposure amount of the optical system. An imaging device according to any one of the preceding claims. 8. A filter that includes a focal length of an optical system in the plurality of imaging conditions, and further includes a filter that enhances a change in the image data, the filter having a degree of enhancement that varies according to a filter constant externally provided. 7. The method according to claim 1, wherein the control unit changes the filter constant according to an evaluation value of the focal length referred to when determining the focal length, and applies the filter constant to the filter. An imaging device according to any one of the above. 9. The plurality of image pickup conditions further include an exposure amount of an optical system, wherein the control means calculates a defocus amount from an evaluation value of a focal length referred to when determining the focal length, and calculates the defocus amount. Depth of focus is calculated from the evaluation value of the amount of exposure used in determining the amount of exposure of the system, and the degree of emphasis of the change in the image data is greater as the calculated defocus amount is larger than the calculated depth of focus and the difference is larger. The image pickup apparatus according to claim 8, wherein the filter constant is changed so that is larger. 10. The detection area generation means receives a pixel clock synchronized with an output signal of the image sensor and a horizontal synchronization signal, and outputs a pixel which outputs image data in the horizontal direction from the input pixel clock number. Horizontal gate signal generating means for outputting a horizontal gate signal indicating the position of the pixel, and generating a vertical gate signal indicating the vertical position of the pixel outputting the image data from the input number of horizontal synchronization signals. 10. The imaging apparatus according to claim 2, further comprising a vertical direction gate signal generating unit, wherein the area information is generated by a combination of the horizontal direction gate signal and the vertical direction gate signal. .