JP3273326B2 - Imaging device - Google Patents

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, and more particularly to an image pickup apparatus having a zoom function (zoom lens) in an image pickup optical system.

[0002]

2. Description of the Related Art In recent years, with the advance of electronic technology, miniaturization and high performance of imaging devices have been remarkably advanced, and all functions (optical system, recording system, finder system) have been realized in a size that can be completely accommodated in one hand. Built-in, high-quality imaging devices are being introduced to the market one after another.

In these imaging apparatuses, a zooming function for continuously enlarging a main subject at the time of photographing, etc. exerts a great power, and a small-sized imaging optical system has a zoom lens and a high-magnification lens as much as possible. It is required to mount a zoom lens .

[0004]

When a small and high-magnification zoom lens is mounted on an image pickup apparatus, if the operation is made compatible with both a manual zoom and a power (motorized) zoom, the operation becomes complicated mechanically and the shape becomes complicated. In addition to the size increase, it also causes cost increase.

[0005] Therefore, at present, in the imaging apparatus which has been greatly reduced in size, the zoom operation only using the power zoom is becoming mainstream. However, in the case of the power zoom, it is difficult to change the speed because of the strength (margin) of the mechanical system, the complexity of the electric / mechanical system, the power consumption, and the like. As a result, when it is desired to determine the composition by changing the magnification at a high speed, it is not possible to sufficiently cope with the situation, which is inconvenient for the photographer .

[0006]

According to the present invention , there is provided an image pickup apparatus which uses a zoom lens as an image pickup optical system and has an electronic magnification changing function for electronically changing a read signal from an image pickup element. Changing the magnification of the zoom lens to the magnification by the electronic zoom function after determining the magnification of the composition by the electronic zoom function.
Features.

[0007]

The operation of the present invention will be described below.

In recent years, a so-called “electronic zoom” that electronically provides a variable magnification function by performing thinning and interpolation on reading from an image sensor has been put to practical use in some products.

[0009] Since the "electronic zoom" involves thinning out the reading from the image pickup device, some image quality deterioration is inevitable. On the other hand, since the magnification can be completely electronically changed, the speed can be arbitrarily increased (slower), and there is almost no restriction on the setting of the speed.

According to the present invention, the restriction on the zooming speed of the conventional zoom lens which hinders the photographer from swiftly deciding the composition is instantly reduced by using an electronic zoom which can freely set the zooming speed. In addition to allowing the composition to be determined, the image quality is eventually degraded by the electronic zoom by taking the image with the optical zoom set to the value of the electronic zoom .

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an electric circuit diagram showing the structure of a first embodiment of an image pickup apparatus according to the present invention . In the figure, reference numeral 1 denotes an image of a subject on a photoelectric conversion surface of an image pickup device to be described later. Optical system. The optical system 1 has a magnification (focal length) change (zoom) capability. Reference numeral 2 denotes a zoom motor for driving a zooming mechanism, 3 denotes a circuit (zoom driver) for driving the zoom motor 2, and 4 denotes a zoom encoder for detecting a current magnification (focal length) value. .

Reference numeral 5 denotes an image sensor (constituted of a CCD sensor, a MOS sensor, an image pickup tube, etc.) for converting an optical image of a subject into an electric signal. A sample-and-hold (S / H) circuit for holding, a process circuit for pre-processing the signal, an A / D conversion circuit for converting the processed signal into a digital signal, and an A / D converter for converting the processed signal into a digital signal. An image memory 10 for storing an image signal, which has been A / D converted by the D conversion circuit 8 into a digital signal, on one screen, is a memory controller for controlling writing and reading of the image memory 9.

Reference numeral 11 denotes a D / A for converting a digital signal of an image read from the image memory 9 into an analog signal.
It is a conversion circuit. Numeral 12 denotes an arithmetic circuit for performing an interpolation operation for reading (thinning out) a part (thinning-out) of the image memory 9 for enlargement described later. Numeral 13 converts an analog signal after operation to a standard video signal such as an NTSC signal. Encoder circuit. A signal line 14 outputs a standard video signal.

Reference numeral 15 denotes an electronic viewfinder (EVF) for determining the composition and confirming the subject being photographed. Reference numeral 16 denotes a system controller for detecting and controlling the state of each part of the circuit element, which can be configured using a general-purpose microprocessor.

Reference numeral 17 denotes a zooming operation member, which has three states of a tele (telephoto) side, a wide side, and no operation.
Reference numeral 8 denotes an operation member for designating a zoom operation mode.
It is specified whether zooming is performed using only the normal zoom motor 2 or so-called “electronic zoom” for changing the magnification of reading from the image memory 9 is also used.

The electric circuit configuration of the first embodiment of the imaging apparatus according to the present invention has been described above. Hereinafter, the operation will be described with reference to the electric circuit configuration diagram of FIG. 1 and the flowcharts of FIGS. 2 and 3.

For the sake of simplicity, the present embodiment uses the image memory 9 for storing the information of one entire screen. However, the circuit configuration is simplified by using only one or several line memories. It can also be cheaper.

FIG. 2 is a flow chart for explaining the operation of the image pickup apparatus of the first embodiment shown in FIG.

Note that, except for the case where the operation member 18 is set to the electronic zoom combined mode, a known circuit and a known operation are performed. Therefore, the case where the operation member 18 is set to the electronic zoom combined mode will be mainly described.

As shown in FIG. 2, first, the system controller 16 checks the state of the operation member 18 to determine whether or not the mode is the electronic zoom combined mode (step 10).
1). If not (NO in step 101), the operation ends because the operation mode is the known operation mode.

If the mode is the electronic zoom combined mode (YES in step 101), the operation state of the operation member 17 is detected, and it is determined whether the operation state is the operation on the tele side (step 102). If the operation member 17 is operated on the tele side (YES in step 102), the system controller 16
To the electronic zoom on the n-step tele side (enlargement)
(Step 103). Here, n is an integer greater than 1. If the operation member 17 is not the tele side operation (NO in step 102), step 103 is skipped.

Next, it is determined whether or not the electronic zoom state is operating based on the state of an internal variable of the system controller 16 (step 104). If the electronic zoom is being operated (YES in step 104), the optical zoom is shifted to the one-step tele side (step 105), and at the same time.
The electronic zoom is shifted to the smaller side (wide side) by one step (step 106) by the amount just canceling the shift of the optical zoom to the tele side (step 106), and the process returns to step 101.
If the electronic zoom is not in operation (NO in step 104), the process returns to step 101.

When the operation member 18 is operated to the telephoto side in the mode in which the operation member 18 is used together with the electronic zoom by the above operation,

[0025]

(Equation 1) , The zooming is performed quickly mainly by the electronic zoom.

After the zooming by the electronic zoom is completed, if the operation of the operation member 17 is returned to the non-operation state,

[0027]

(Equation 2) The electronic zoom is changed over by the optical zoom around the loop of step, and when the change of the electronic zoom by the optical zoom is completed, step 104 becomes NO and thereafter,

[0028]

(Equation 3) , But does not do anything.

FIG. 3 is a flowchart showing a second embodiment of the image pickup apparatus according to the present invention . In contrast to the first embodiment which is effective only on the telephoto side, only the electronic zoom is used in this embodiment. Using it, high-speed zooming can be performed in both tele-wide mode. The configuration of the imaging apparatus of the present embodiment is shown in FIG.
Has the same configuration as the imaging device shown in FIG.

Hereinafter, the operation will be described with reference to FIG.

First, in the image pickup apparatus shown in FIG. 1, an optical focal length is set to the widest usable side (not the wide end) without using the electronic zoom.

Next, as shown in FIG. 3, the system controller 16 checks the state of the operation member 18 and determines whether or not the electronic zoom mode is set (step 201).
If not (NO in step 201), the operation ends to shift to a known operation mode.

If the electronic zoom mode is set (YES in step 201), then the system controller 16 checks whether or not the operation state of the operation member 17 is operated toward telephoto (step 202). If it is operated for telephoto (YES in step 202), the system controller 16 issues a command to the memory controller 10 and the arithmetic circuit 12 to shift the electronic zoom to the one-step telephoto side (step 203). 20
Return to 1.

If it is determined in step 202 that the operation member 17 is not telephoto (NO in step 202), it is next checked whether the operation is wide (step 204). If the zoom is operated wide (YES in step 204), the electronic zoom is shifted to the wide side by one step as in step 203 (step 20).
5) Then, return to step 201.

If it is determined in step 204 that the operation member 17 has not been operated wide (N in step 204).
O), the operation is terminated because the operation member 17 has not been operated in the telephoto or wide-angle mode.

Next, a reference example of the image pickup apparatus of the present invention will be described. FIG. 4 is an electric circuit configuration diagram of a reference example of the imaging apparatus of the present invention .

In FIG. 1, reference numeral 21 denotes an optical system for forming a subject image on an image pickup device surface, which will be described later; and 22, a CCD for converting the subject image obtained by the optical system 21 from an optical signal to an electric signal. An image sensor such as a type sensor or a MOS type sensor. Reference numeral 23 denotes a signal processing circuit for processing a time-series signal related to a subject image obtained from the image sensor 22, and 24 denotes a signal for converting an electric signal (analog signal) processed by the signal processing circuit 23 into a digital signal. A
/ D converter, 25 is an image memory for storing image information for one screen, 26 is an image processing circuit for performing image processing conversion similar to the operation of a tilt (shift) lens, and such coordinate conversion processing Can be realized in a capacity by using a known digital operation circuit, and therefore a detailed description is omitted.

Reference numeral 27 denotes a D / A converter for returning the digital signal after image processing to an analog signal again;
Reference numeral 28 denotes a D / A converted analog signal in NTSC / PA
This is an encoder circuit for converting into a standard video signal 29 such as L. Reference numeral 30 denotes an electronic viewfinder (EVF) for confirming a photographing screen. Reference numeral 31 denotes a system controller for checking an operation state of an operation member or the like to be described later and controlling each element in accordance with the operation state, and can be easily realized by using a general-purpose microprocessor.

Reference numeral 32 denotes a tilt (shift) operation (O
N) or an operation member for selecting not to perform (OFF), 33 is an operation member for performing a tilt operation when the operation member 32 is ON, and this is an independent operation member. Alternatively, an existing operation member having an up / down function (for example, power zoom, power focus) may be shared. If the operation member 33 is a member dedicated to the tilt operation, the operation member 32 can be omitted.

The above is the configuration of the electric circuit of one example of the image pickup apparatus of the present invention , and the operation thereof will be described below.

The configuration of the present embodiment is a very ordinary configuration of a known image pickup apparatus except for the operation members related to the tilt operation and the image processing unit therefor. The operation will be described.

FIG. 5 is a flowchart for explaining the operation of the imaging apparatus of the reference example shown in FIG.

As shown in the figure, first, the system controller 31 checks the state of the operation member 32 for selecting the tilt operation, and determines whether or not the tilt operation is ON (step 301).

If the operation member 32 for selecting the tilt operation does not indicate that the tilt operation is ON (N in step 301).
O) Terminate the operation.

If the operation member 32 for selecting the tilt operation indicates that the tilt operation is ON (Y in step 301).
ES), and then the system controller 31
Check the status of.

First, it is determined whether or not the operation member 33 is pointing up (step 302). If it is pointing up (YES in step 302), the tilt is increased by one step. That is, the correction amount is increased (step 30).
3). Then, the process returns to step 301.

If the operation member 33 does not indicate "up" (NO in step 302), it is determined whether the operation member 33 indicates "down" (step 304).

If the operation member 33 indicates down (YES in step 304), the tilt is reduced by one step. That is, the correction amount is reduced (step 3
05), and return to step 301.

If the operation member 33 has not instructed down (NO in step 304), the operation member 33 does not perform any of the up / down operations, and therefore returns to step 301 without doing anything.

Next, the display on the EVF 10 during the tilt adjustment will be described.

The function of generating the reference vertical line as shown in FIG. 6 in the image processing circuit 26 of FIG. 4 can be easily realized by a known technique. In this case, since the vertical (tilt) adjustment can be performed with reference to the reference vertical line, the tilt adjustment can be performed easily and with high accuracy.

Although the number of reference vertical lines is set to two here, the number can be set arbitrarily, and the position can be easily changed by an operation member by a known method.

As shown in FIG. 7B, FIG.
If the area around the reference vertical line is enlarged and displayed in the horizontal direction from the state described above, the deviation from the vertical direction can be enlarged and displayed by the EVF, so that the adjustment is easy. It is needless to say that the image can be enlarged and displayed in the vertical direction.

If the reference point for adjustment is only a small part of the screen as shown in FIG.
As shown in the above, it is easier to match when the display is enlarged in both the vertical and horizontal directions.

Also, a grid-like reference pattern may be used as shown in FIG.

In the above description, the image processing circuit 26 has a reference line generating function.
If it is not preferable to insert these reference lines, a reference line insertion circuit may be provided at a position 26 'in FIG. 4 (immediately before the EVF 30).

[0057]

As is apparent from the above description, when the image pickup apparatus of the present invention is used, it is possible to quickly determine a composition by the electronic zoom, and at the same time, gradually replace the electronic zoom with the optical zoom while maintaining the composition. Therefore, image quality degradation due to the electronic zoom is only required for a very short time. In particular, when quick composition adjustment is the highest priority, it is possible to replace the optical zoom and use the electronic zoom for both telephoto and wide .

[Brief description of the drawings]

FIG. 1 is an electric circuit configuration diagram showing a configuration of a first embodiment of an imaging device of the present invention .

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a flowchart showing a second embodiment of the imaging apparatus of the present invention .

FIG. 4 is an electric circuit configuration diagram of a reference example of the imaging apparatus of the present invention .

FIG. 5 is a flowchart for explaining the operation of the imaging device of the reference example shown in FIG. 4;

FIG. 6 is a diagram for explaining a tilt adjustment according to a reference example of the imaging apparatus of the present invention .

FIG. 7 is a diagram for explaining a tilt adjustment according to a reference example of the imaging apparatus of the present invention .

FIG. 8 is a diagram for explaining a tilt adjustment according to a reference example of the imaging apparatus of the present invention .

FIG. 9 is a diagram for explaining a tilt adjustment according to a reference example of the imaging apparatus of the present invention .

FIG. 10 is a schematic explanatory diagram illustrating an operation in a case where a tilt (shift) function is optically added.

FIG. 11 is a schematic explanatory diagram illustrating an operation in a case where an optical tilt (shift) function is added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical system 2 Zoom motor 3 Zoom driver 4 Zoom encoder 5 Image sensor 6 Sample hold (S / H) circuit 7 Process circuit 8 A / D conversion circuit 9 Image memory 10 Memory controller 11 D / A conversion circuit 12 Operation circuit 13 Encoder circuit 14 Signal line 15 Electronic viewfinder (EVF) 16 System controller 17 Operation member 18 Operation member 21 Optical system 22 Image sensor 23 Signal processing circuit 24 A / D converter 25 Image memory 26 Image processing circuit 26 'Reference line insertion circuit 27 D / A converter 28 Encoder circuit 29 Signal 30 Electronic viewfinder (EVF) 31 System controller 32 Operation member 33 Operation member

Claims (3)

(57) [Claims] 1. An image pickup apparatus using a zoom lens as an image pickup optical system and having an electronic magnification function for electronically changing a read signal from an image pickup device. An image pickup apparatus, wherein, after the determination is made, the magnification of the zoom lens is changed to the magnification by the electronic magnification function. 2. The imaging apparatus according to claim 1, wherein the electronic magnification function is operated in a direction to cancel the magnification change by the zoom lens while the magnification is changed by the zoom lens, so that the imaging magnification is constant. An imaging device adapted to be 3. The image pickup apparatus according to claim 1, wherein a variable speed of the electronic variable function is higher than an optical variable speed by the zoom lens .