JPH10155106A - Electronic image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic image pickup device whose cost is reduced and whose power consumption is saved by using image data orthogonally transformed on a frequency axis and realizing a control system to obtain each image pickup condition parameter through the use of a conventional microcomputer. SOLUTION: This image pickup device is provided with an image pickup lens 1, an image pickup element 3, a storage means 6, an orthogonal transformation means 8 that reads a video signal corresponding to one image stored in the storage means 6 and applies orthogonal transformation processing to each 2-dimensional unit block BL to obtain orthogonal transformation data for each unit block BL, a means 11 that obtains a high frequency component denoted by orthogonal transformation data corresponding to specified discretely in the image among all the orthogonal transformation data corresponding to each unit block BL as a focus evaluation index, and an automatic focus adjustment means 12 that provides an adjustment displacement to the optical system element 1 for focus adjustment in response to the focus evaluation index of the means 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic image pickup apparatus such as a still video camera for obtaining various image pickup condition parameters using image information orthogonally transformed on a frequency axis.

[0002]

2. Description of the Related Art When adjusting focus, exposure, white balance, and the like in an electronic imaging device such as a still video camera, a subject image obtained through an optical system such as a lens is converted into an electric signal, and the electric signal is converted. Performing using orthogonally transformed data on the frequency axis is described in, for example, "Automatic Focus Adjustment Device" in JP-A-4-405 and "Image Data Encoding Circuit" in JP-A-4-248767.
It is conventionally known as disclosed in, for example, Japanese Patent Application Laid-Open No. H11-157572.

FIG. 11 is a block diagram showing only the main components of a conventional electronic image pickup apparatus. In the figure, 1 is an imaging lens, 2 is an aperture mechanism, 3 is a CCD as an imaging device
(Charge-coupled device), and a subject image is formed on the image forming surface of the CCD 3 through the lens 1 and the aperture mechanism 2. Reference numeral 4 denotes an imaging process circuit, which controls an input video signal.
Processing such as amplification, correlated double sampling (CDS), and color separation (luminance and color difference signals) are performed. Reference numeral 5 denotes an A / D conversion circuit (ADC), and reference numeral 6 denotes a buffer memory (BUF). 7
Denotes a pulse generation circuit (SSG), which controls the CCD 3, the imaging process circuit 4, the A / D conversion circuit 5, the buffer memory 6, and a DCT circuit 8, an integration circuit 20, a lens / video signal control circuit 11, etc. Various pulses such as a horizontal synchronizing signal (HD) and a vertical synchronizing signal (VD) are generated and output.

Reference numeral 8 denotes a DCT circuit (discrete cosine transform circuit)
The orthogonal transformation process is performed on the input data of each block divided into unit blocks each having N pixels vertically and horizontally. That is, a DCT operation is performed on data of a unit block of, for example, 8 pixels in the vertical and horizontal directions in the entire screen or the AF target area input from the buffer memory 6 to obtain a DC (DC) conversion coefficient and an AC (AC) conversion coefficient. DCT circuit 8
The direct current (DC) conversion coefficient obtained by performing the orthogonal transformation processing is supplied to the quantization circuit 9 and the integration circuit 20. An alternating current (AC) transform coefficient obtained by the orthogonal transform processing by the DCT circuit 8 is converted into a quantized circuit 10 and an integrating circuit 20.
And supplied to.

The quantization circuit 9 quantizes the DC conversion coefficient,
Output to a subsequent circuit (not shown). Also quantization circuit 1
A value of 0 quantizes the AC conversion coefficient and outputs it to a subsequent circuit.

In the circuit at the subsequent stage, the prediction error of the DC conversion coefficient and the AC conversion coefficient are recorded in the recording device.

The integration circuit 20 integrates the absolute value of each of the AC conversion coefficient and the DC conversion coefficient, and supplies the integrated values, that is, the DC evaluation value and the AC evaluation value, to the lens / video signal control circuit 11.

A lens / video signal control circuit 11 controls a lens drive circuit 12 upon receiving an AC evaluation value for one screen of a luminance signal or an AC evaluation value (AF evaluation value) in a block (AF area) to be AF-selected. Then, the focus is automatically adjusted by controlling the movement of the lens 1 on its optical axis so that the AF evaluation value obtained by the DCT circuit 8 is maximized.

On the other hand, the video signal control circuit 11 controls the aperture drive circuit 13 to variably adjust the aperture mechanism 2 so that the exposure level of the video signal is optimized, and performs automatic exposure adjustment (AE). Alternatively, the exposure level is adjusted by variably adjusting the element shutter speed of the CCD 3.

[0010]

In the above-mentioned conventional electronic imaging apparatus, in order to perform focus adjustment and the like using the AC conversion coefficient and the DC conversion coefficient of the DCT circuit 8, these coefficients are integrated. , It is necessary to provide hardware such as the integration circuit 20. For this reason, there is a disadvantage that the mounting area, mounting volume, and the like become large.

As a method for solving this, the DCT circuit 8
Is not directly input to the integrator 20 but directly input to the lens / video signal control circuit 11. That is,
In general, since the lens / video signal control circuit 11 is often configured by a microcomputer or the like, a necessary integration operation is performed using an integration function in the microcomputer.

FIG. 12 is a diagram showing an example of the integration process. In the example shown in FIG. 12A, DCT (1), DCT (2), DCT which are DCT coefficients within one vertical retrace period (for one screen)
This is an example in which T (3)... DCT (n + 3) are all taken into the microcomputer, and finally integration and AF processing are collectively performed. The example shown in FIG. 12B is an example in which each time a DCT block in one vertical blanking period is read one by one, successive integration processing is performed, and finally AF processing is performed.

However, the integration processing by the above method has the following problems. That is, the DCT block is set to 8
In the case of a pixel × 8 pixel unit, it is necessary to perform an integration process on each block in one screen for a maximum of 64 data items. This means that one screen is, for example, 64
If 0 pixels × 480 pixels, the DCT block is 480 pixels.
0 blocks can be obtained. Therefore, the number of integration times is (64 data × 4800 blocks) = 307200 times, and this must be executed within a predetermined time. In this case, when the number of pixels on one screen is further increased, the amount of calculation is further increased, and in the worst case, the processing time is short, and the system may be broken. In addition, in the example shown in FIG. 12A, it is necessary to select a microcomputer compatible with high-speed arithmetic processing, and a large-capacity memory (built-in or external) capable of storing all DCT data in one screen. Also, in the example of FIG. 12B, selection of a microcomputer corresponding to high-speed arithmetic processing is an essential requirement. Since such a microcomputer is very expensive and consumes a lot of power, there are problems in terms of cost and power supply.

An object of the present invention is to convert a subject image obtained through an optical system into an electric signal, and to perform various photographing operations such as focus, exposure, and white balance using image data obtained by orthogonally transforming the electric signal on a frequency axis. It is an object of the present invention to provide an electronic imaging apparatus which can realize a control system for obtaining condition parameters by using a relatively inexpensive general-purpose microcomputer and can reduce costs and save power.

[0015]

In order to solve the above-mentioned problems and achieve the object, the present invention is configured as described below.

(1) An electronic image pickup apparatus according to the present invention is provided with an image pickup lens for forming a subject image, and a light beam on the image pickup plane which is arranged so that an image formed by the image pickup lens can be formed on its own image pickup plane. An image sensor that photoelectrically converts an image, and storage means for storing a video signal that is a photoelectric conversion output of the image sensor,
A video signal corresponding to one screen stored in the storage means is read, and a predetermined 2
Orthogonal transformation means for performing orthogonal transformation processing for each of a plurality of unit blocks of dimension to obtain orthogonal transformation data corresponding to each of the unit blocks; and one of the orthogonal transformation data of all orthogonal transformation data corresponding to each of the plurality of unit blocks. Focus evaluation index formation that obtains, as a focus evaluation index, a value of a high-frequency component represented by the data based on orthogonal transformation data corresponding to a specific unit block or unit block group discretely selected in the screen of FIG. Means, and automatic focus adjustment means for applying an adjustment displacement to an element of the optical system for focus adjustment according to the focus evaluation index of the focus evaluation index forming means. .

(2) The electronic image pickup apparatus according to the present invention is the electronic image pickup apparatus described in (1) above, wherein the focus is obtained by the focus evaluation index forming means only when an automatic focus adjustment operation is performed. An evaluation index is generated, and video data corresponding to all orthogonal transform data corresponding to each unit block is supplied to the recording means as recording data at a predetermined timing after the end of the automatic focusing adjustment operation. It is characterized by comprising control means for controlling.

(3) The electronic image pickup apparatus of the present invention is the electronic image pickup apparatus described in (1) above, wherein the specific unit block selected discretely is placed in the one screen. Alternatively, it is characterized by being discretely selected so as to correspond to a region set in a row.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1 and 2 are block diagrams showing the configuration of an electronic imaging apparatus according to a first embodiment of the present invention. Note that FIG. 1 and FIG. 2 are connected to each other at locations indicated by reference signs A to D surrounded by circles.

The position of the imaging lens 1 on the optical axis is adjusted by the lens driving circuit 12. The aperture mechanism 2 is controlled by an aperture drive circuit 13 to adjust the aperture amount. Thus, a subject image is formed on the imaging surface of a CCD (charge coupled device) 3 as an imaging device through the lens 1 and the aperture mechanism 2. The subject image formed on the CCD 3 is converted into an electric signal by the CCD 3 to become a video signal, which is input to the imaging process circuit 4. The imaging process circuit 4 performs signal amplification, correlated double sampling (CDS), color separation (luminance,
(Color difference signal). The output of the imaging process circuit 4 is converted into digital data by an A / D conversion circuit (ADC) 5 and then input to a buffer memory (BUF) 6 for recording.

A pulse generation circuit (SSG) 7 generates a horizontal synchronizing signal (HD), a vertical synchronizing signal (VD) and other various control pulses, and outputs the above-mentioned CCD 3, imaging process circuit 4, A / D conversion circuit 5 , A buffer memory 6, a DCT circuit 8, a lens / video signal control circuit 11, and the like, which will be described later.

The data read from the buffer memory 6 and divided into unit blocks each composed of N pixels vertically and horizontally are input to a DCT circuit (discrete cosine transform circuit) 8. The DCT circuit 8 outputs, for example, “8 pixels ×
A DCT operation (orthogonal transformation process) is performed on the data of the unit block of "8 pixels" to obtain a direct current (DC) transform coefficient and an alternating current (AC) transform coefficient.

FIG. 3 shows a transform coefficient (Cu) obtained by performing a DCT operation on block data consisting of 8 × 8 pixels.
It is a figure showing an example of v). In FIG. 3, as u and v increase, the frequency component becomes higher. That is, C00 represents the magnitude of the DC component (DC conversion coefficient), and as it goes rightward (from u: 0 to 7),
It shows a higher horizontal frequency component and C00
As going downward (v: 0 to 7), higher vertical frequency components are shown. Here, the remaining transform coefficients excluding the DC transform coefficient (C00) are called AC transform coefficients. Each unit of C00, C01 to Cuv is called one data.

Returning to FIG. 1 and FIG. The direct current (DC) transform coefficient obtained by the orthogonal transform processing by the DCT circuit 8 is supplied to the quantization circuit 9 on one side, and is supplied to the lens / video signal control circuit 11 on the other side. On the other hand, an alternating current (AC) conversion coefficient obtained by the orthogonal transform processing by the DCT circuit 8 is supplied to the quantization circuit 10 on the one hand and to the lens / video signal control circuit 11 on the other hand.

The lens / video signal control circuit 11 has a DCT
It is mainly composed of a microcomputer capable of performing the integration process of the block BL. That is, the lens / video signal control circuit 11 is based on the integral value of the AC evaluation value for one screen of the luminance signal or the integral value (AF evaluation value) of the AC evaluation value in the block BL (AF area) to be AF. By operating the lens drive circuit 12,
The focus is adjusted by variably controlling the position of the lens 1 on the optical axis so that the AF evaluation value obtained by the DCT circuit 8 is maximized.

The lens / video signal control circuit 11
Integral value of DC conversion coefficient of CT block BL (DC evaluation value) or integration value of DC conversion coefficient from each photometry area arbitrarily divided for divided photometry (DC evaluation value)
The automatic exposure adjustment (AE) is performed by controlling the aperture drive circuit 13 to adjust the aperture amount so as to optimize the exposure level of the video signal. Or C
The element shutter speed of the CD 3 is variably adjusted to adjust the exposure level. At this time, control is performed by using the integral value of the DC evaluation value for one screen of the luminance signal or the integral value (AE evaluation value) of the DC evaluation value from each photometry block arbitrarily divided for divided photometry. It will be easier.

FIG. 4 is a view showing the principle of the automatic focus adjustment. As shown in FIG. 4, the lens position at which the AF evaluation value (corresponding to a high-frequency component) becomes maximum at the in-focus position is determined by using the principle that the lens position becomes the in-focus position so that the AF evaluation value becomes maximum. AF is performed by controlling (called a hill-climbing method).

Returning to FIG. 1 and FIG. The quantization circuit 9 quantizes the DC transform coefficient input from the DCT circuit 8 and supplies the quantized DC transform coefficient to the delay circuit 21 and the subtraction circuit 22 shown in FIG.
Further, the quantization circuit 10 receives the AC input from the DCT circuit 8.
The transform coefficients are quantized and applied to a so-called zigzag scan scanning circuit 24 shown in FIG.

In the subtraction circuit 22, the DC conversion coefficient and the delay output from the delay circuit 21 are subtracted, and the difference, that is, the prediction error is obtained. This prediction error is supplied to the synthesizing circuit 26 after being encoded by the encoding circuit 23. In the zigzag scan scanning circuit 24,
A coefficient rearrangement process is performed on the input AC conversion coefficients. The output of the zigzag scan scanning circuit 24 is supplied to a synthesizing circuit 26 after being encoded by an encoding circuit 25.

The synthesizing circuit 26 includes encoding circuits 23 and 2
5 is synthesized. Synthesized D
The signal indicating the prediction error of the C conversion coefficient and the AC conversion coefficient is recorded in the recording device 27.

The system control circuit 28 shown in FIG. 2 includes the recording device 27 and the pulse generation circuit (SSG) 7.
And the sequence control of the entire circuit including the lens / video signal control circuit 11.

Originally, the DCT circuit is often used when encoding an image. For this reason, if the DCT circuit 8 detects AF information, AE information, and the like as described above,
Since the DCT circuit 8 can be shared, the configuration is simplified and the cost is reduced.

As described above, in this embodiment, unlike the conventional apparatus shown in FIGS. 11 and 12,
The DCT coefficient of the DCT circuit 8 is not integrated by the integrator 20, but is directly input to the lens / video signal control circuit 11. The lens / video signal control circuit 11 mainly composed of a microcomputer performs the integration processing of the DCT block BL. In particular, in the present embodiment, when reading DCT block data from the DCT circuit 8,
The configuration is such that CT blocks BL are discretely acquired and the number of acquired DCT blocks BL is reduced.

FIGS. 5A and 5B are explanatory diagrams of the functions.
12A is a diagram showing a pattern of an integration process in the embodiment, and FIG. 12B is a diagram showing a pattern of an integration process in a comparative example (conventional example) cited from FIG. 12B for comparison. is there. As is clear from the comparison between FIGS. 5A and 5B, in the case of the present embodiment, DCT blocks BL are acquired every other block. By doing so, the reading speed of the DCT block data is reduced to approximately １ ／, and it is possible to secure about twice the integration time as compared with the conventional case. Therefore, the calculation load applied to the microcomputer or the like can be greatly reduced.

FIG. 6 is a schematic diagram showing an example of a method of selecting a DCT block BL selected to obtain AF information and the like. The method of acquiring the DCT block BL shown in FIG. 5A corresponds to using only the information of the DCT block BL indicated by hatching in FIG. In addition, as shown in FIG.
In the case of acquiring the T block BL, if the subject is a special case such as “one vertical line”, there is a possibility that false focusing may occur depending on conditions. However, this point can be easily solved by uniformly obtaining the DCT block BL over the entire screen so as to prevent bias.

FIG. 7 is a schematic diagram showing another example of a method of selecting a DCT block BL selected to obtain AF information and the like. This example is a case where the DCT block BL is acquired in a so-called checkered pattern as indicated by oblique lines. According to this example, even if the subject is a special case such as “one vertical line” as described above, focusing can be always stably performed.

FIGS. 8A, 8B and 8C are schematic diagrams showing a modification of the method of selecting the DCT block BL. As shown by oblique lines in FIGS. 8A to 8C, a block of several DCT blocks BL may be captured as one block, and data may be obtained from each block.

If the object is a general object and the DCT block BL has a size of about 8 × 8 pixels, the pattern of the object of the adjacent DCT block BL in the screen rarely keeps changing rapidly. . For this reason, information necessary for AF can be sufficiently obtained even with a DCT block BL that is discrete to some extent. This point could be easily confirmed by experiments.

The obtained discrete pattern of the DCT block BL may be varied so as to be adapted to the photographing environment.

[Operation at Automatic Focusing (AF)] FIGS. 9 and 10 are flowcharts showing the procedure of the AF processing of this embodiment. 9 and FIG. 10 are connected to each other at locations indicated by reference symbols E and F surrounded by circles.
Hereinafter, the procedure of the AF process will be described with reference to this flowchart.

"Step ST1" The program starts.

[Step ST2] The acquisition pattern of the DCT block BL is set to, for example, a checkered pattern as shown in FIG.

"Step ST3" VD (vertical synchronization signal)
Is detected.

[Step ST4] When the rising edge of VD is detected, the AC evaluation value of the imaging screen is input.

[Step ST5] When the AC evaluation value is larger than a predetermined value, the DCT block BL
Select

[Step ST6] The sum of the DCT blocks BL selected in step ST5 is "DC in the AF area".
It is determined whether the number is greater than １ ／ of the number of T blocks BL (checkered pattern). If the number is small, the process proceeds to step ST7. If the number is large, the process proceeds to step ST8.

[Step ST7] D having a large AC evaluation value
"DCT block BL in AF area"
(1/2 of the number of (checkered patterns)) is selected, and step ST
Proceed to 8.

"Step ST8" The DCT block selected in step ST6 or step ST7
BL is set as an AF DCT block BL used for AF. Step ST6 or step ST7
Is "1/2 of the number of DCT blocks BL (checkerboard pattern) in the AF area".
“2” is merely an example, and an optimal value may be set according to parameters caused by AF, such as the size of the AF area and the size of the AC evaluation value.

[Step ST9] An AF evaluation value is obtained using the DCT block BL set in step ST8. "Step ST10" The rising of VD is detected again.

[Step ST11] An AC evaluation value (the used DCT block BL is the block set in step ST8) of the imaging screen is input.

[Step ST12] The AF evaluation value is obtained by integrating the AC evaluation value obtained in step ST11.

[Step ST13] The lens drive circuit 12 is controlled to move and adjust the position of the lens 1 on the optical axis so that the AF evaluation value becomes the maximum, and the AF process is performed by the hill-climbing method.

[Step ST14] It is determined whether or not the AF processing has been completed. If the AF processing has not been completed, the process returns to step ST10. If the AF processing has been completed, the process proceeds to step ST15.

[Step ST15] If the AF process has been completed, the program ends. However, when performing a recording operation or the like after the end of AF, DCT calculation is performed for all blocks on one screen. By doing so, the number of DCT blocks acquired in one screen during AF is reduced, and AF accuracy is improved by selecting a block BL having many high frequency components. These can reduce the DCT block acquisition time and the integration time, which leads to power saving of the system. Further, since the lens / video signal control circuit 11 can be constituted by a low-speed microcomputer, the cost can be reduced. If a high-speed microcomputer can be used, it is possible to cope with a case where a CCD having a higher pixel number than the conventional one is used.

[Operation at Automatic Exposure (AE)] Integral value of DC conversion coefficient of DCT block BL (DC evaluation value) or integration of DC conversion coefficient from each photometry area arbitrarily divided for divided photometry. Using the value (DC evaluation value), the aperture driving circuit 13 is controlled by the lens / video signal control circuit 11 so that the exposure level of the video signal is optimized, and the aperture mechanism 2 is adjusted.

For example, if the DC evaluation value is within a certain predetermined range, the AE is determined to be the optimum exposure state.
The operation will be described. First, it is determined whether or not the obtained DC evaluation value is within a predetermined range. If the DC evaluation value is less than the predetermined value range, the diaphragm mechanism 2 is driven to the open side, and if it is more than the predetermined value range, the diaphragm mechanism 2 is driven to the closed side. Also, if the aperture mechanism 2 is within the predetermined range, the optimal exposure state can always be maintained by fixing the aperture mechanism 2 in that state. Of course, if the DC evaluation value is equal to or less than the predetermined value range even when the aperture mechanism 2 is fully opened, the gain of the video signal may be increased. Alternatively, the exposure state may be changed by changing the timing of the element shutter of the CCD 3 without using the aperture mechanism 2. Of course, the information of the discrete DCT block BL can be used similarly to AF.

[Operation at White Balance Adjustment] In the white balance adjustment, similarly to the AF processing and the AE processing, the information of the DCT block BL in which the color difference signals (RY, BY) are discrete is used. White balance can be easily adjusted.

As described above, since both the automatic exposure (AE) adjustment and the white balance adjustment use the discrete DCT block BL, similarly to the AF adjustment, the data acquisition time required for control can be reduced, and the integration time can be reduced. The time can be reduced, and the power consumption of the system can be reduced. Further, since a low-speed microcomputer can be used as the lens / video signal control circuit 11, the cost can be reduced. If a high-speed microcomputer can be used, CCD3 with a higher pixel
Can also be handled.

In recent years, there has been a camera that directly converts the output of the CCD 3 from analog to digital by the A / D conversion circuit 5 without performing, for example, color separation in the imaging process 4 of FIG. 1, and compresses and records the data. Are known. In the case of this camera, recorded data is taken into a personal computer, and processing such as color separation is performed on the personal computer side.

Normally, AF processing and AE processing are performed using a luminance signal. The output of the CCD 3 is directly subjected to A / D conversion without depending on the luminance signal, and a value obtained by subjecting the data to DCT processing is used. May be used. In this case, since the imaging process circuit 4 or a circuit for color separation processing or the like becomes unnecessary, the cost can be further reduced.

(Summary of Feature Points of Embodiment) The feature points of the electronic imaging apparatus shown in the above-described embodiment are summarized as follows.

[1] The electronic image pickup apparatus shown in the embodiment is such that an image pickup lens (1) for forming a subject image and an image formed by the image pickup lens (1) can be formed on its own image pickup surface. Imaging device (3) arranged in the camera and photoelectrically converting a light image on the imaging surface (3)
A storage means (6) for storing a video signal which is a photoelectric conversion output of the image pickup device (3); and a video signal corresponding to one screen stored in the storage means (6). The read video signal is subjected to an orthogonal transformation process for each of a plurality of predetermined two-dimensional unit blocks (BL), and the respective unit blocks are processed.
Orthogonal transformation means for obtaining orthogonal transformation data corresponding to each (BL)
(8) and orthogonal transform data corresponding to a specific unit block or unit block group discretely selected in the one screen among all orthogonal transform data corresponding to each of the plurality of unit blocks (BL). The focus evaluation index forming means (11) for obtaining the value of the high-frequency component represented by the data as a focus evaluation index based on the data, and according to the focus evaluation index of the focus evaluation index forming means (11). Automatic focus adjusting means (12) for applying an adjustment displacement to the optical system element (1) for focusing adjustment.

In the above electronic imaging apparatus, DCT is performed discretely, so that the processing time is greatly reduced and the high-speed processing is performed as compared with the conventional method in which AF is performed using data obtained by orthogonally transforming the entire AF area. Can be It is also very advantageous in terms of power consumption.

[2] The electronic image pickup apparatus described in the embodiment is the electronic image pickup apparatus described in the above [1], and the focus evaluation index forming means is used only when the automatic focus adjustment operation is performed. A focusing evaluation index is generated according to (11), and video data corresponding to all orthogonal transform data corresponding to each of the unit blocks (BL) is recorded at a predetermined timing after the completion of the automatic focusing adjustment operation. And a control means (28) for controlling supply to the recording means (27).

The electronic image pickup apparatus has the same operation and effect as the above [1], and can record a normal image at the time of recording even if the image signal becomes discrete during the AF processing.

[3] The electronic image pickup apparatus shown in the embodiment is the electronic image pickup apparatus described in the above [1], and the specific unit block BL discretely selected is one of the ones. It is characterized by being discretely selected so as to correspond to an area set in rows or columns in the screen.

In the above electronic imaging apparatus, the same operation and effect as in the above [1] can be obtained, and the control algorithm is simplified because of the simple pattern.

[4] The electronic image pickup device shown in the embodiment is the electronic image pickup device described in the above [1], and the specific unit block (BL) which is discretely selected is the above-mentioned one. It is characterized by being discretely selected so as to correspond to an area set in a checkered pattern on one screen.

In the above electronic imaging device, the same operation and effect as in the above [1] are obtained, and the DCT block BL
And the accuracy can be improved because it can be obtained without bias. [5] The electronic imaging apparatus according to the embodiment is arranged such that an imaging lens (1) for forming a subject image and an image formed by the imaging lens (1) can be formed on its own imaging surface. An image sensor (3) for photoelectrically converting the light image on the imaging surface; a storage unit (6) for storing a video signal that is a photoelectric conversion output of the image sensor (3); and the storage unit (6). A video signal corresponding to one screen stored in is read out, and the read-out video signal is subjected to an orthogonal transformation process for each of a plurality of predetermined two-dimensional unit blocks (BL). BL) and orthogonal transform means (8) for obtaining orthogonal transform data corresponding to each of the unit blocks (BL). High-frequency data represented by the data based on the orthogonal transformation data corresponding to the unit block or the unit block group; A focus evaluation index forming means (11) for obtaining the value of the component as a focus evaluation index, and an element of an optical system for focusing adjustment according to the focus evaluation index of the focus evaluation index forming means (11) ( 1) an automatic focus adjustment means (12) for applying an adjustment displacement to the specific unit block (B) selected discretely.
L) to the unit block group are selected as containing a relatively large amount of high frequency components, and after the selection is made once, the focus adjustment adjustment operation by the automatic focus adjustment means (12) is performed. The selection is characterized in that the selection is not changed until substantially completed.

In the above electronic imaging apparatus, since the DCT block (BL) having a large number of high frequency components is used, an AF is performed by using data obtained by orthogonally transforming (for example, DCT) the entire AF area. And the AF accuracy is improved. Further, since DCT is not performed in all areas, it is advantageous in terms of speed and power consumption.

[6] The electronic image pickup apparatus shown in the embodiment is the electronic image pickup apparatus described in the above [5], and further includes the discrete unit blocks (BL), which are discretely selected. It is characterized in that the selection of the unit block group is made at the time when the focus detection operation is started in the electronic imaging apparatus.

In the electronic imaging apparatus, the same operation and effect as in the above [5] are obtained, and since no selection is made during the AF process, there is no possibility that an abnormal operation occurs in the AF process.

[7] The electronic image pickup apparatus shown in the embodiment has an image pickup lens (1) for forming a subject image and an image formed by the image pickup lens (1) can be formed on its own image pickup surface. An image pickup device (3) which is arranged in the optical pickup and photoelectrically converts a light image on the image pickup surface.
A storage means (6) for storing a video signal which is a photoelectric conversion output of the image pickup device (3); and a video signal corresponding to one screen stored in the storage means (6). The read video signal is subjected to an orthogonal transformation process for each of a plurality of predetermined two-dimensional unit blocks (BL), and the respective unit blocks are processed.
Orthogonal transformation means for obtaining orthogonal transformation data corresponding to each (BL)
(8) and, based on data corresponding to a specific unit block or a unit block group discretely selected in the one screen among all orthogonal transform data corresponding to each unit block (BL). White balance adjusting means (11) for performing a white balance adjusting operation based on the obtained white balance detection value.

In the above electronic imaging apparatus, since the DCT is performed discretely, the processing time can be greatly reduced and the processing speed can be increased as compared with the related art in which the entire area within the AF area is orthogonally transformed (for example, DCT). it can. It is also advantageous in terms of power consumption.

[8] The electronic imaging device according to the embodiment is the electronic imaging device described in [7], and the white balance detection value is discretely selected within the one screen. The data is obtained by relying on data including at least DC component data among the data corresponding to the specified specific unit block or unit block group.

In the electronic imaging apparatus, the same operation and effect as the above [7] are obtained, and the accuracy is improved because the white balance control is performed using the DC component.

[9] The electronic image pickup apparatus shown in the embodiment has an image pickup lens (1) for forming a subject image and an image formed by the image pickup lens (1) can be formed on its own image pickup surface. An image pickup device (3) which is arranged in the optical pickup and photoelectrically converts a light image on the image pickup surface.
A storage means (6) for storing a video signal which is a photoelectric conversion output of the image pickup device (3); and a video signal corresponding to one screen stored in the storage means (6). The read video signal is subjected to an orthogonal transformation process for each of a plurality of predetermined two-dimensional unit blocks (BL), and the respective unit blocks are processed.
Orthogonal transformation means for obtaining orthogonal transformation data corresponding to each (BL)
(8) and, based on the data corresponding to a specific unit block or unit block group discretely selected in the one screen, of all the orthogonal transform data corresponding to each unit block (BL). Exposure adjusting means (11) and (13) for performing an exposure adjusting operation based on the photometric value obtained as described above.

In the above electronic imaging apparatus, since the DCT is performed discretely, the processing time can be greatly reduced and the speed can be increased as compared with the related art in which the entire AF area is orthogonally transformed (for example, DCT). . It is also advantageous in terms of power consumption.

[10] The electronic imaging device according to the embodiment is the electronic imaging device described in the above [9],
The photometric detection value is obtained based on data including at least a DC component data among data corresponding to a specific unit block or a unit block group discretely selected in the one screen. It is characterized by.

In the electronic imaging apparatus, the same operation and effect as in the above item [9] are obtained, and since the exposure control is performed using the DC component, the accuracy is improved.

[0081]

According to the present invention, a subject image obtained through an optical system is converted into an electric signal, and the electric signal is subjected to various transformations such as focus, exposure, white balance, etc., using image data obtained by orthogonally transforming the electric signal on a frequency axis. It is possible to realize a control system for obtaining the photographing condition parameters by using a relatively inexpensive general-purpose microcomputer, thereby reducing costs,
It is possible to provide an electronic imaging device capable of saving power and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a part of the configuration of an electronic imaging device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing another part of the configuration of the electronic imaging device according to the first embodiment of the present invention.

FIG. 3 is a functional explanatory diagram of the electronic imaging apparatus according to the first embodiment of the present invention, showing an example of a transform coefficient (Cuv) obtained by performing a DCT operation on block data composed of 8 pixels × 8 pixels.

FIG. 4 is a functional explanatory diagram of the electronic imaging apparatus according to the first embodiment of the present invention, illustrating the principle of automatic focus adjustment.

FIGS. 5A and 5B are explanatory diagrams of functions of the electronic imaging apparatus according to the first embodiment of the present invention, in which FIG. 5A shows a pattern of an integration process in the embodiment, and FIG. The figure which shows the figure which shows the pattern of the integration process in a comparative example (conventional example).

FIG. 6 is a functional explanatory diagram of the electronic imaging apparatus according to the first embodiment of the present invention, and is a DC selected to obtain AF information and the like.
The schematic diagram which shows an example of the method of selecting a T block.

FIG. 7 is an explanatory diagram of functions of the electronic imaging apparatus according to the first embodiment of the present invention, in which DC selected to obtain AF information and the like;
The schematic diagram which shows the other example of the method of selecting a T block.

FIGS. 8A to 8C are explanatory diagrams of functions of the electronic imaging apparatus according to the first embodiment of the present invention, wherein FIGS. 8A to 8C are schematic diagrams illustrating a modification of a method of selecting a DCT block.

FIG. 9 is a diagram showing a part of a flow showing an AF processing procedure of the electronic imaging apparatus according to the first embodiment of the present invention.

FIG. 10 is a diagram showing another part of the flow showing the AF processing procedure of the electronic imaging apparatus according to the first embodiment of the present invention.

FIG. 11 is a block diagram extracting and showing only a main part configuration of an electronic imaging apparatus according to a conventional example.

FIG. 12 is a diagram showing a pattern of an integration process of an electronic imaging apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Imaging lens 2 ... Aperture mechanism 3 ... CCD as an imaging element 4 ... Imaging process circuit 5 ... A / D conversion circuit (ADC) 6 ... Buffer memory (BUF) 7 ... Pulse generation circuit (SSG) 8 ... DCT circuit ( Discrete cosine transform circuit) 9, 10 quantization circuit 11 lens / video signal control circuit 12 lens drive circuit 13 aperture drive circuit 20 integration circuit 21 delay circuit 22 subtraction circuit 23, 25 encoding circuit 24 ... Zigzag scan scanning circuit 26 ... Synthesis circuit 27 ... Recording device 28 ... System control circuit

Claims (3)

[Claims] An imaging lens for forming an image of a subject, an imaging device arranged so that an image formed by the imaging lens can be formed on its own imaging surface, and an photoelectric device for photoelectrically converting a light image on the imaging surface; A storage unit for storing a video signal which is a photoelectric conversion output of the image pickup device; a video signal corresponding to one screen stored in the storage unit, and a predetermined 2
Orthogonal transformation means for performing orthogonal transformation processing on each of a plurality of unit blocks in a dimension to obtain orthogonal transformation data corresponding to each of the unit blocks; Focus evaluation index formation that obtains, as a focus evaluation index, a value of a high-frequency component represented by the data based on orthogonal transformation data corresponding to a specific unit block or unit block group discretely selected in the screen of FIG. Means, and automatic focus adjustment means for applying an adjustment displacement to an element of the optical system for focusing adjustment according to the focus evaluation index of the focus evaluation index forming means. Electronic imaging device. 2. A focusing evaluation index is generated by said focusing evaluation index forming means only when an automatic focusing adjustment operation is performed.
A control means for controlling to supply video data corresponding to all orthogonal transform data corresponding to each of the unit blocks as recording data to the recording means at a predetermined timing after the completion of the automatic focus adjustment operation. The electronic imaging device according to claim 1, wherein: 3. The specific unit block discretely selected is discretely selected so as to correspond to an area set in a row or a column in the one screen. The electronic imaging device according to claim 1.