JPH07131700A - Image pickup display device - Google Patents

Abstract

PURPOSE:To provide an image pickup display device with an auto-zooming function which can photograph a subject set in an optional size in a fixed size in response to the subject's movement. CONSTITUTION:An image pickup display device is provided with an automatic focus control means, a subject distance calculating means which calculates the distance from a subject, an image pickup frame setting means GW, an LPF 5 which extracts a luminance signal, a field memory 7 which stores the luminance information. Furthermore a gate circuit 8 is added to set an area in order to check the movement of the subject, together with an arithmetic circuit 10 which calculates a subject occupying area ratio PER against an image pickup frame, a distance change detecting circuit 12 which confirms whether the subject distance is changed or not, and a comparator 9 which compares the ratio PER with an initial subject occupying area ratio FPER when the change of the subject distance is confirmed and gives an instruction to the automatic focus control means to set both ratios PER and FPER equal to each other and then to adjust the zooming ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup display device having an auto zoom function.

[0002]

2. Description of the Related Art Generally, an image pickup display device such as a video camera has a lens section for capturing an image as light, a photoelectric conversion section for electrically converting an image of light, and a signal processing section for processing the obtained electric signal. And a signal recording unit for recording the processed signal as a video signal. Further, in recent home video cameras, a CCD (Charge Coupled) is formed on the image plane of the subject image incident through the lens unit.
An image sensor (abbreviation of Device) is provided,
Therefore, photoelectric conversion is performed.

The CCD image pickup device has a structure in which a large number of pixels serving as a light receiving portion (a combination of a photosensor and a vertical register) are arranged like a grid. It should be noted that in a general popular type camera, a total of about 250,000 pixels, which are 510 horizontally and 492 vertically, are arranged on a silicon substrate of about 10 mm. Then, in each pixel, an electric charge is generated according to the intensity of the imaged light, and the generated electric charge is
It is sent to the corresponding vertical register every 1/60 seconds (1 field). Further, this charge is successively transferred one pixel column at a time in the vertical register to the horizontal register every 63.5 μs. Therefore, the charges that have reached the horizontal register are transferred to the output section at a high speed of 14.3 MHz, and finally converted into a voltage and output. That is, first, one horizontal row (VT
The electric charge of one horizontal scanning (in the case of reproducing an image on the R screen) is vertically transferred, guided to the horizontal register, and sequentially output from there. Subsequently, the electric charge for the next horizontal row is similarly continuously output. In this way, the electric charge for one horizontal line becomes one unit and is continuously output from the CCD image pickup device.

Further, the output from the CCD image pickup device is subjected to the following processing in the signal processing section in order to be recorded as a video signal. First, only the signal component is extracted by the correlated double sampling, and then the AGC (Automa) is extracted.
Abbreviation for tic Gain Control, and has the function of correcting the magnitude of the selected signal to an appropriate level.)
It is amplified by the amplifier. Further, the output from the AGC amplifier is separated into two series of signals by a color separation sampling and holding circuit (having a function of extracting a component of a desired signal from the output from the CCD), and a 1H delay line (scanning time of one horizontal scanning line). Only has the function of delaying and transmitting the signal)
RGB signals are formed by the synchronization processing using the above and the matrix calculation. After that, the RGB signals are subjected to white balance and gamma correction (processing for matching the characteristics when viewed on a television Braun tube) to form color difference signals (RY, BY). Finally, it is output as a color signal (also called a chroma signal) obtained by modulating a subcarrier (which is a frequency required for superimposing colors on a black and white screen in a color television system).

Separately, the output from the AGC amplifier is passed through an LPF (low-pass filter) to remove color signal components, and then gamma-corrected.
After passing through the 1H delay line, a horizontal contour compensation signal and a synchronizing signal are further added and finally output as a luminance signal. In this way, the color signal and the luminance signal output from the signal processing section are transmitted to the signal recording section, where they are converted into magnetic signals by the magnetic head and recorded on the magnetic tape. There is.

On the other hand, a home video camera has an automatic exposure function (AE: automatic exposure function, that is, an automatic brightness adjustment function) and an automatic focusing function (AF: automatic focus function, that is, an automatic focusing function). ),
Automatic white balance function (AWB: automatic white balance function, that is, automatic hue adjustment function), zoom function (even when the focal length changes continuously,
Some functions are provided as standard for the convenience of the photographer's operation, such as the function to prevent the focal plane from always moving from a fixed position.

The autofocus function is an automatic focus detection mechanism that automatically detects whether or not the lens is in focus, and a lens and a CC when it is detected that they are not in focus.
It is realized by a combination with an automatic adjustment mechanism that automatically adjusts the positional relationship with the D image pickup device. The automatic focus detection mechanism is composed of a distance measurement mechanism that measures the distance to the subject and a focus detection mechanism that detects the focus. It should be noted that as the distance measuring method, a method such as a triangulation method, a reflection intensity method, or a propagation time method is adopted, and as a focus detection method, a method such as a contrast method or a phase method is individually adopted. .

Although the zoom function is not yet automated at present, its frequency of use is extremely high.
The photographer manually operates the zoom switch attached to the video camera body to drive the zoom motor and move the position of the zoom lens to perform zoom photography. The zoom lens is usually equipped with a focusing function for focusing and a zooming function for changing the angle of view from wide angle to telephoto, which makes the image refracting and converging light and excellent image performance. In order to achieve a good result, it is composed of a plurality of convex and concave lenses. The contents are "focusing component" which has each function of focusing and zooming, "variator (lens group which plays a leading role in zooming action)" and "compensator (moving in conjunction with variator lens, from wide-angle side to telephoto, Correction lens for making the image forming position of the image constant) ”and the like.

The purpose of zoom photography is to change the magnification of the image while the position of the camera with respect to an arbitrary subject is fixed. Then, when using a video camera to capture a scene such as "a subject approaches from a distance and then moves away again", the photographer can see the movement of the subject approaching or moving away. While chasing with the viewfinder (a device for observing the subject itself or its real or virtual image and overlapping it with the field of view frame to determine the shooting range), manually operate the zoom switch attached to the video camera. It is designed to take zoom shots.

[0010]

However, such a zoom operation is considerably troublesome for the photographer and causes camera shake. In some cases, the size of the subject may change in the captured image, which may result in a very unstable image that is difficult to see.

Therefore, as one measure for solving such a problem, for example, Japanese Patent Laid-Open No. 2-87876 discloses the following technique. That is,
In this technique, a target monitoring area smaller than the viewfinder is set, the image area of the subject is calculated based on the binarized video signal obtained from this area, and this is compared with the target size, and the result is calculated. It is fed back to the zoom ratio control circuit (the zoom ratio means the rate of change of the focal length). In this way, the display size of the subject can be kept constant and continuously displayed.

However, the above-mentioned JP-A-2-8787.
According to the technique disclosed in Japanese Patent Laid-Open No. 6, the object size is controlled only by the image area of the object in the set target monitoring area, and the image area does not change when the object is a stationary object. Although it does not cause any particular problem, the image area changes when the subject is a moving object (for example, when a person standing at a certain position is photographed, the person can bend his arms, spread his arms, or When the person stands, sits down, or turns sideways, the image area of the subject changes, and the zoom ratio, which should be unchanged, is changed. As a result, the image of the subject may even become a difficult image to see.

Further, with respect to the subject size, at present, it is necessary to set a predetermined size in advance before photographing, and it is impossible to change the size during photographing. Therefore, it must be said that it is extremely difficult to perform zoom photography with a sense of stability in response to the movement of the subject by manual operation. The present invention has been made in view of the above circumstances, and an image pickup display apparatus having an auto-zoom function that enables a subject set to an arbitrary size to be photographed at a fixed size in accordance with the movement of the subject. Is intended to provide.

[0014]

In order to achieve the above object, the invention according to claim 1 is an automatic focus control means,
An image pickup display device including a subject distance calculating unit that calculates a distance to a subject, the image pickup frame setting unit setting an image pickup frame to be picked up by an image pickup element, and an image pickup signal obtained for the set image pickup frame, A brightness signal extracting unit that extracts a brightness signal and a brightness information storage unit that stores information about the extracted brightness signal are provided, and an area for checking a subject motion is set in the set imaging frame. Based on the brightness information stored in the check area setting means and the brightness information storage means, the object area in the set check area is measured, and the object occupied area ratio for the set image pickup frame is calculated. A ratio calculation means,
A subject distance change confirming means for confirming whether or not there is a change in the subject distance calculated by the subject distance calculating means, and an object if the subject distance change confirming means confirms that the subject distance has changed. A zoom ratio for comparing the occupied area ratio and the initial object occupied area ratio, and instructing the automatic focus control means so that the object occupied area ratio becomes equal to the initial object occupied area ratio, and adjusting the zoom ratio. It is characterized by having an adjusting means.

The invention according to claim 2 is the image pickup display device according to claim 1, further comprising a minimum reference value setting for setting an allowable minimum reference value for the initial subject occupied area ratio. And the initial object occupation area ratio calculated by the object occupation area ratio calculating means is smaller than the minimum reference value at the start of image pickup when the zoom ratio is set to the maximum, the initial object occupation area ratio is set to The first initial object occupation area ratio updating means for updating the minimum reference value and the initial object occupation area ratio may be changed as necessary during the adjustment of the zoom ratio by the zoom ratio adjusting means. A second initial subject occupied area ratio updating means for updating the subject occupied area ratio at the time point is provided.

[0016]

According to the above construction, the image pickup display apparatus according to the present invention is provided with the automatic focus control means and the subject distance calculation means for calculating the distance to the subject. Then, the image pickup frame setting means sets an image pickup frame to be picked up by the image pickup element. Further, the brightness signal extracting unit extracts the brightness signal from the image pickup signal obtained for the set image pickup frame. Further, the brightness information storage means stores information on the extracted brightness signal.

On the other hand, the check area setting means sets an area in the set image pickup frame for checking the subject motion. In addition, based on the brightness information stored in the brightness information storage means, the object occupation area ratio calculation means measures the object area in the set check area, and the object occupation area ratio for the set imaging frame is calculated. It is calculated. Further, the subject distance change confirmation means confirms whether or not there is a change in the subject distance calculated by the subject distance calculation means.

When it is confirmed by the subject distance change confirming means that the subject distance has changed, the zoom ratio adjusting means compares the object occupying area ratio with the initial object occupying area ratio, The automatic focus control unit is instructed so that the occupation area ratio becomes equal to the initial subject occupation area ratio, and the zoom ratio is adjusted.

Further, the image pickup display device according to the present invention can be further provided with a function of updating the initial subject occupied area ratio. In this case, the minimum reference value setting means sets an allowable minimum reference value for the initial subject occupation area ratio. Then, when the initial subject occupying area ratio calculated by the subject occupying area ratio calculating means is smaller than the minimum reference value at the start of imaging when the zoom ratio is set to the maximum, the first initial subject occupying area ratio The initial subject occupation area ratio is updated by the updating means with the lowest reference value. In addition, during the execution of the zoom ratio adjustment by the zoom ratio adjusting means, if necessary, the second
The initial subject occupied area ratio updating means updates the initial subject occupied area ratio with the subject occupied area ratio at that time.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration for realizing an auto zoom function in an image pickup display device according to the present invention. In this circuit, lens group 1
(Note that each lens position is adjusted by the focus motor drive circuit 13 and the zoom motor drive circuit 14) → CCD image pickup element 2 → AGC circuit 3 →
Video signal processing circuit 4 → In addition to the conventional video signal processing system circuit that takes the signal processing flow from the signal recording circuit,
An auto-zoom control circuit (consisting of circuits 5 to 12 and 15) for realizing the auto-zoom function is provided.

In this auto-zoom control circuit, the output signal from the CCD image pickup device 2 is passed through the LPF (low-pass filter) 5, the color signal is removed and only the luminance signal Y is taken out. Subsequently, the extracted luminance signal Y is digitally converted by the A / D conversion circuit 6 and taken into the field memory 7 as digital data. In this way, the field memory 7 stores the image data for one screen taken by the lens group 1.

Next, the recording mode of the video camera is "AU
A case where the recording is started by setting "TO (automatic)" will be described. That is, the zoom operation for fixing the subject image to a desired size within the frame is performed as follows. First, the image data already captured in the field memory 7 is stored in the gate circuit 8 (here, 2).
It has one input terminal and one output terminal, and forms a gate circuit whose output state is determined by the input state.)
Is sent to the arithmetic circuit 10 via. And the arithmetic circuit 1
At 0, the initial occupation area ratio F of the subject in the frame
PER (FPER is abbreviated as first abbreviation for first percent, and specifically, "FPER"
= Initial occupied area of subject / frame area ") is calculated. Also, the calculated F
The value of PER is held in the FPER holding circuit 11.

Similarly, during recording, the arithmetic circuit 10
The occupation area ratio PER of the subject is calculated. Here, how to obtain the occupation area ratio PER of the subject during recording will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic diagram showing a subject image in a frame taken by the lens group 1 shown in FIG. 1, and FIG. 3 is a subject on the measurement line (shown by a broken line in the figure) shown in FIG. It is a graph which shows the luminance signal level with respect to an image. In the graph of FIG. 3, the horizontal axis represents the horizontal pixel position with the left end as the reference, and the vertical axis represents the luminance signal level with the lower end as the reference.

Here, normally, in the state where the focus is on the subject, the largest change in luminance is at the contour portion of the subject. Therefore, as shown in FIG. 3, a reference change amount R set in advance (note that the reference luminance signal level for determining the reference change amount R is indicated by a chain line in the figure. , The optimum value is set as an empirical value based on the brightness information of the captured image) If the minimum value of the horizontal pixel position indicating the above brightness change is a and the maximum value is b, the subject image The horizontal pixel area “ba” of the above is obtained. Therefore, the subject area can be obtained by digital integration for "b-a" obtained for each measurement line. Further, based on this result, the initial occupied area ratio FPER of the subject is calculated.

In this way, once the FPER is obtained, the gate circuit 8 is applied according to the value (for example, when FPER is 30%, about 60%). When calculating the subject area, erroneous judgments on the values of a and b are prevented. Here, returning to FIG. 1 again, the description of the automatic zoom operation during recording is continued. In the comparison circuit 9, the occupation area ratio PER of the subject at that time calculated by the arithmetic circuit 10 and the initial occupation area ratio FPE of the subject held in the FPER holding circuit 11
The values R and R are compared. Then, the zoom control signal for making the both coincide with each other is the distance change detection circuit 1
2 (here, the focus sensor is used to detect the change in the distance to the subject), and the result is output to the zoom motor drive circuit 14, and the automatic zoom operation is executed.

However, the automatic zoom operation is performed as a result of detection by the distance change detection circuit 12,
Only when the subject distance changes, and when the subject distance does not change, it is determined that the occupancy area ratio PER of the subject is not changed due to the change of the subject position even if PER and FPER do not match. Then, the zoom operation is not performed. In that case, the calculated PER value is set to FP
It is reset as ER and held in the FPER holding circuit 11. After that, the automatic zoom operation is continued in the same manner.

Further, the present image pickup display device is provided with a frame size setting switch SW so that an arbitrary frame size can be set even during a zoom operation, and a new FPER value at that time is calculated by the arithmetic circuit 10. The FPER value held in the FPER holding circuit 11 can be updated while instructing the calculation.

Incidentally, in parallel with the above auto zoom operation,
Based on the detection result of the distance change detection circuit 12,
The focus motor drive circuit 13 is turned on to control automatic focus adjustment. FIG. 4 is a schematic diagram for explaining the process of the zoom operation performed on the subject image captured in the frame by the image pickup display apparatus according to the present invention. (A) is a subject (here,
(B) shows an image when a subject is approaching, (c) shows an image when there is no change in the subject distance, respectively. Also, (a)-
An image within a range (frame) surrounded by a rectangular frame shown in (c) is taken in as image data in the field memory 7 shown in FIG.

In the schematic view of (a), an internal region surrounded by a broken line (a region excluding the shaded portion in the frame) is a portion extracted by the gate circuit 8. Then, in this state, the arithmetic circuit 10 calculates the initial occupation area ratio FPER of the subject by the method described with reference to FIGS. In the schematic diagram of (b), the image data of the region other than the portion extracted by the gate circuit 8 (the hatched region in the figure) is ignored in this case. Then, the occupation area ratio PER of the subject at that time is calculated by the arithmetic circuit 10, the comparison circuit 9 compares the values of FPER and PER, and control is performed so that FPER = PER.

In the schematic view of (c), the subject area changes when the person who is the subject raises both hands, but the subject distance does not change. In such cases,
Although FPER ≠ PER, the zoom operation is not performed.
FIG. 5 is a schematic diagram for explaining the process performed by the image pickup display apparatus according to the present invention when the subject image captured in the frame is small. (D) shows an image of a subject (here, a passenger car) in the case where the zoom is maximum (that is, the maximum telephoto state) at the start of shooting. In such a state, FPER is a certain standard occupied area ratio SPER (standard percen
Characters are displayed as an abbreviation for t, and a fixed value is set in advance for the comparison circuit 9 by the SPER setting circuit 15.)
If smaller, FPER is forcibly set to the set fixed value SPER.

Further, (e) shows an image when the occupied area ratio PER of the subject shown in (d) becomes equal to the set SPER value. Note that the automatic zoom operation is not performed until such a state is reached. And when PER exceeds SPER, this time F
It is controlled so that PER = SPER. By doing this, even if the subject approaches, the subject size will not be photographed as it is small, and when the subject approaches and enters the variable range of the zoom, the subject size is zoomed to a predetermined value. After that, you will be able to shoot with a certain size.

Further, even while the auto-zoom operation is being executed, the operator can update the FPER by operating the frame size setting switch SW, and the subject size can be arbitrarily changed. Is able to. FIG. 6 is a flowchart showing the control relating to the auto zoom performed by the image pickup display device according to the present invention. Recording is started (S1), and it is confirmed whether or not a frame size setting switch SW for determining a frame size for accommodating a subject is turned on (S1).
2). When the frame size setting switch SW is turned on (Yes in S2), the arithmetic circuit 1
FPER is calculated at 0, and at the same time, FPER holding circuit 1
The FPER held in 1 is updated (S3). In this way, the frame size is determined. Then, the gate condition of the gate circuit 8 (which is the condition for extracting the subject image in the frame) is set (S4).

Further, it is confirmed whether or not the zoom condition is set to the maximum telephoto (MAX) (S5),
If the maximum telephoto is set (Yes in S5), the SPER setting circuit 15 sets the reference occupied area ratio SPER (S69). And FPER>
Confirm whether or not it is SPER (S
7), if FPER> SPER is not satisfied (N in S7)
If o), set FPER to SPER (S
8) Then, the process proceeds to the subsequent step S9.

Also, in the case of No in the above step S2 and in the case of No in the above step S5, the process similarly shifts to the step S9. Step S
In 9, the subject distance is calculated by the existing distance measuring mechanism (S9), and the distance change detection circuit 12 further confirms whether or not there is a change in the subject distance (S10).
When the subject distance has changed (Yes in S10), the PER at that time is calculated by the arithmetic circuit 10 (S11), and the comparison circuit 11 continues.
Confirms whether FPER = PER or not (S1
2). Then, if FPER = PER is not satisfied (No in S12), the zoom motor drive circuit 14 is turned on to drive the zoom lens to perform the zoom operation (S13), and further the focus motor drive circuit 13 is turned on. Then, focusing is performed (S14), and thereafter, the process returns to step S2.

If No at step S10 and Yes at step S12, the process proceeds to step S15. In step S15, it is confirmed whether or not the recording is finished,
If it is not ended (No in S15), the process returns to step S2. If it is ended (Yes in S15), the FPER and the gate condition are reset (S16), and the above-described auto zoom control is performed. Ends the series of processing for.

[0036]

As described above, according to the present invention, an auto-zoom function for automatically photographing a subject set to an arbitrary size in a fixed size is realized, and a photographer can perform a hand shake with a simple operation. You will be able to shoot images that are minimal and easy to see. Also, when shooting a person standing at a certain position, that person can cross his arms, spread his arms,
Even if you stand, sit, or turn sideways, the zoom operation is not performed unless the subject distance changes, so you can take a stable zoom shot that corresponds to the movement of the subject. It becomes possible to do.

Further, at the start of photographing, if the subject is still small even if the maximum telephoto state is set, the subject is approached and the zoom operation is not performed until the zoom variable range is reached. It is possible to prevent the problem of being photographed while the size is small. In addition, regarding the subject size, during zoom shooting, if necessary,
Since the change can be performed, it is possible to perform more optimal zoom shooting.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration for realizing an automatic zoom function in an image pickup display device according to the present invention.

FIG. 2 is a schematic diagram showing a subject image in a frame captured by the lens group 1 shown in FIG.

FIG. 3 is a graph showing a luminance signal level for a subject image on the measurement line shown in FIG.

FIG. 4 is a schematic diagram for explaining a process of a zoom operation performed by the image pickup display apparatus according to the present invention on a subject image captured in the frame.

FIG. 5 is a schematic diagram for explaining processing performed by the image pickup display apparatus according to the present invention when the subject image captured in the frame is small.

FIG. 6 is also a flowchart showing control relating to auto zoom performed by the image pickup display apparatus according to the present invention.

[Explanation of symbols]

 1 Lens Group 2 CCD Image Sensor 5 LPF 6 A / D Converter 7 Field Memory 8 Gate Circuit 9 Comparison Circuit 10 Arithmetic Circuit 11 FPER Holding Circuit 12 Distance Change Detection Circuit 13 Focus Motor Drive Circuit 14 Zoom Motor Drive Circuit 15 SPER Setting Circuit SW frame size setting switch

Claims (2)

[Claims] 1. An image pickup display device comprising automatic focus control means and subject distance calculation means for calculating a distance to a subject, the image pickup frame setting means for setting an image pickup frame to be picked up by an image pickup device, and setting. A luminance signal extraction unit that extracts a luminance signal from the image pickup signal obtained for the image pickup frame and a luminance information storage unit that stores information about the extracted luminance signal are provided. A check area setting unit that sets an area for checking the subject movement, and based on the brightness information stored by the brightness information storage unit, measures the subject area in the set check area,
Subject occupancy area ratio calculation means for calculating a subject occupancy area ratio for the set imaging frame; subject distance change confirmation means for confirming whether or not there is a change in the subject distance calculated by the subject distance calculation means; When it is confirmed by the distance change confirmation means that the subject distance has changed, the subject occupied area ratio is compared with the initial subject occupied area ratio, and the subject occupied area ratio is equal to the initial subject occupied area ratio. And a zoom ratio adjusting unit for instructing the automatic focus control unit to adjust the zoom ratio. 2. The image pickup display device according to claim 1, wherein:
Further, a minimum reference value setting means for setting an allowable minimum reference value for the initial subject occupation area ratio, and at the start of image pickup when the zoom ratio is set to the maximum,
First initial subject occupation area ratio updating means for updating the initial subject occupation area ratio with the lowest reference value when the initial subject occupation area ratio calculated by the subject occupation area ratio calculating means is smaller than the lowest reference value. Secondly, if necessary, the initial object occupying area ratio is updated with the object occupying area ratio at that time while the zoom ratio adjusting means is executing the adjustment of the zoom ratio.
2. An image pickup display device, comprising: