JPS6139011A - Camera - Google Patents

Abstract

PURPOSE:To expand effectively a tracking range and to process the complex picture constitution of animation with simple operation by automatically tracking a subject included in a photographing picture or a specific area in the picture, and when the subject is located on the border of the area, adjusting an optical system on a comparatively short focal distance. CONSTITUTION:When the subject is moved into a waiting position TFa, a range finding field is moved to a tracking field position TFb, i.e. the position of the subject, as shown on FFb in Fig. b and the focal distance of the zoom lens is adjusted. The focal distance is the longest at the position in Fig. b and then becomes shorter in accordance with the left movement of the subject. When the tracking field reaches the end part of a limit area by moving the subject as shown on TFf in Fig. f, the focal distance of a zoom lens is adjusted so as to be shorter, i.e. its picture angle is expanded up to a wide end, and the subject is regarded as if it is fixed on the position as shown in Fig. g, so that the tracking range is expanded effectively.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a camera equipped with an automatic focus detection device,
In particular, the present invention relates to means for effectively expanding the tracking range when the object being tracked reaches a position that coincides with the boundary of a photographic screen or a specific area thereof.

(Background Art) In a conventional camera equipped with an automatic focusing device with negligible difference, such as a video camera, the distance measurement field of view is fixed at the center of the shooting screen as shown in Figure 14 (B). ), if the subject you want to focus on (hereinafter referred to as the target subject) (in this example, a person) moves, an object (in this example, a house) that is at a different distance from the target subject will move.
is in focus, and the person who is the target subject becomes blurred, so the disadvantage is that the target subject must always be placed at the center of the screen due to the screen configuration. For this reason, methods have been proposed to make the distance measurement field position variable, but these methods require the photographer to change the distance measurement field position by operating a knob or the like, which is difficult to do when the subject moves during shooting. ,
It is difficult to always maintain the distance measurement position above the focus detection target object using these knobs.

In order to eliminate the above drawbacks, the applicant first sets a movable tracking field of view, extracts the features of the object to be ranged with respect to this tracking field of view, stores the extracted features,
The presence or absence of movement of the object is detected based on the memorized characteristics and the newly extracted characteristics of the object to be ranged, and the distance measurement field of view is tracked to the movement of the object according to the relative movement of the object. We have proposed a moving automatic tracking focus detection device (Patent Application No. 105897 of 1981, title of the invention "Automatic tracking focus detection device"). It is desirable to effectively widen the range in which the tracking operation is performed as much as possible with respect to the specific area set as the range in which the tracking operation is performed within the photographic screen.

(Objective) Therefore, the present invention eliminates the above-mentioned drawbacks of cameras equipped with conventional automatic focus detection devices, automatically detects the moving position of a moving subject, and tracks the distance measurement field of view with the movement of the subject. When the subject being tracked reaches a position that almost coincides with the boundary of the shooting or shooting screen or a specific area thereof, the tracking range is effectively expanded and the focus is adjusted. An object of the present invention is to provide a camera capable of composing a complicated one-page moving image by a simple operation.

(Description based on Examples) Hereinafter, with reference to FIGS. 1E to 13, etc., the means taken in this invention to achieve the above object will be explained by way of example. The following is an overall explanation of the embodiment of the camera according to the present invention, with respect to an example of extracting the color characteristics of a tracked subject using color information, and the limit area setting means, subject movement detection means, and automatic focus in the embodiment. The detection means, the focal length adjustment means, and the operation and operation method of the same embodiment will be described in this order.

(Overall description of an embodiment of the camera according to the present invention) (Fig. 1) Fig. 1 shows a main part of an embodiment of the camera according to the present invention, and in the figure, 1 indicates the focal point in the photographing lens. This is a lens group for adjustment, and is usually helicoidally fitted into a lens barrel (not shown), and its position is changed back and forth by the rotational movement of the lens barrel. 2 is a lens group for changing the focal length ( For example, a zoom lens), which includes a variable power lens and a correction lens, and in most cases, its position is changed according to a cam (not shown) to change the focal length.Furthermore, 3
is an imaging system lens group, which is used to accurately form an image of an object at a predetermined position at a shooting distance determined by the position of the lens group l for focus adjustment. Reference numeral 4 denotes a solid-state image sensor such as C, D, etc., which is an example of an imaging means, and is provided on the imaging plane of the lens group 3, and an image sensor driving circuit 5
It photoelectrically converts the light from the subject that is driven by the camera and enters its light-receiving surface. The image sensor driving circuit 5 is controlled by a clock pulse generated by a clock generation circuit 6 or a signal obtained by frequency-dividing the clock pulse. Ml is a focusing (AF) motor that is linked to the lens barrel holding the lens group 1, and Ml is a zoom motor that is linked to a cam (not shown) for moving the lens group 2. Since the configuration and function of each of the above parts are well known, detailed explanation thereof will be omitted.

7 is a signal processing circuit. The time series signal photoelectrically converted by the image sensor 4 is subjected to correction processing such as blanking correction and gamma correction in the same circuit 7, and color difference correction is performed in a matrix circuit in the same circuit. Signals (RY) and (B-Y) and a luminance signal Y are created. These color difference signals and luminance signals are combined with a synchronization signal generated by the synchronization signal generation circuit 10 in an encoder (not shown) to form an output video signal, for example, an NTSC signal, and the NTSC signal is sent to a usage device, for example, a video deck. Supplied. Note that in the following description, it is assumed that the output video signal is an NTSC signal.

The above color difference signals (R-Y) and (B-Y), and if necessary, the luminance signal Y are input to the subject movement detection circuit 9 via the tracking dart circuit 8, and the same circuit detects the movement of the subject. A direction or amount of movement is detected. Here, since the movement between the subject and the camera is relative, the above-mentioned movement of the subject refers to cases where the camera is fixed and the subject moves, as well as cases where the subject moves.
This refers to a case where the subject stops and the camera moves, or a case where both move together, and the invention of this application is applicable to any of the above cases. Reference numeral 10 denotes a synchronizing signal generating circuit, which is controlled by the clock pulse generated by the clock generating circuit 6 or a signal obtained by dividing the clock pulse. 1 no is) f −) no J? The tracking r-) circuit 8 and the distance measurement gate circuit 1 are controlled in synchronization with the horizontal synchronization signal and vertical synchronization signal generated by the synchronization signal generation circuit 10, and are also controlled by the microprocessor 16 described later.
Generate a dart pulse for 2.

In the tracking dart circuit 8, the dart position for the color difference signal and the like is set by the dart pulse generated by the gate pulse generating circuit 11. With this, the characteristics of the subject,
Furthermore, the position of the tracking field of view for extracting background features, for example, in the manner shown in FIGS. 5 to 9, which will be described later, is determined.

In other words, a range of the color difference signals and the like to be input to the movement detection circuit 9 is determined, and movement of the subject is detected based on a change in this signal. This subject movement detection signal is input to the microprocessor 16 and sent to the tracking dart circuit 8. -) A signal (for example, a signal instructing the moving direction) for moving the position, that is, the position of the tracking field of view in accordance with the movement of the tracked object, is generated 6. This signal is supplied to the ff-) pulse generation circuit 11 to form a dart pulse for extracting a color difference signal at a position corresponding to the movement of the tracked subject.

On the other hand, the luminance signal Y is input to the automatic focus detection circuit 13 via the distance measurement gate circuit 12, and a focus detection or focus adjustment signal is generated by the same circuit. In the ranging gate circuit 12, the dart pulse generated by the dart pulse generation circuit 11 sets the f-) position with respect to the luminance signal Y during the tracking operation to the same relative position as the tracking f-), and thereby the luminance A range (hereinafter referred to as distance measurement field of view) of the signal Y that is input to the automatic focus detection circuit 13 for detecting the focus of the subject is determined. Note that in the embodiments of the invention of this application, the field of view, tracking field of view, and/or distance measurement field of view can be displayed on a display device such as an electronic viewfinder if necessary, but this is not an essential means.

In FIG. 1, the tracking f-) circuit 8 and the ranging gate circuit 12 are provided separately, but both dirt circuits may be provided in common, or the latter may be connected after the former and the distance measuring gate circuit 12 may be provided separately. The distance measurement field of view may be further set in a portion of the φ range within the tracking field of view that is previously set.

However, in any case, during the tracking operation, both fields of view must be set at the same relative position, in particular with the same center position. In the example shown in FIG. 1, the tracking field of view and the distance measurement field of view can each be set to arbitrary sizes. Furthermore, the tracking field size determination circuit 14 is responsive to the outputs of a position sensor P1 that detects the absolute position of the lens group 1 for focus adjustment and a position sensor P2 that detects the absolute position of the lens group 2 for changing the focal length. Therefore, the size of both fields of view can be adjusted to the optimum size for the subject, regardless of changes in the shooting distance of the subject and the focal length of the lens.

An automatic focus detection circuit 13 is provided after the distance measurement gate circuit 12.
is connected, automatic focus detection is performed according to known means, and its output signal controls the AF motor drive device 15,
Lens group 1 is driven by F motor M1. Then, when the in-focus point is detected, the above control loop stops one operation,
Lens group 1 also stops at that position. A specific example of the automatic focus detection means will be described later with reference to FIG. 10.

The microprocessor 16 receives a clock pulse from the clock generation circuit 6, a subject movement detection signal from the subject movement detection circuit 9, a tracking field of view from the tracking field of view size determination circuit 14, or a signal for determining the size of the ranging field of view. In addition, a limit area setting signal from a limit area setting circuit 17 and a time setting signal from a time setting circuit 18, which will be described later, as well as focal length information set by the photographer according to the shooting distance from the input terminal 1, and input terminal I2. Tracking field position setting information etc. from the tracking dart circuit 8 is inputted, and the tracking dart circuit 8
, object movement detection circuit 9, dirt pulse generation circuit 1,
It controls the distance measurement gate circuit 12, the AF motor drive device 15, a zoom motor drive device 19, a character generator 20, etc., which will be described later.

Next, the tracking field of view return means in the embodiment shown in FIG. 1 will be explained. The limit area setting circuit 17 is an example of a main component that cooperates with the microprocessor 16 to return the tracking field of view to a position within the screen when the subject moves out of the shooting screen or a specific area thereof. It is a thing,
Under the control of the horizontal synchronization signal and vertical synchronization signal generated by the synchronization signal generation circuit 10, a specific area, for example, indicated by BA in FIG. Set the limit area. The limit area BA is provided for the purpose of performing a tracking operation only within the limit area BA, and the current position of the tracking field of view is determined in the microprocessor 16 according to the output signals of the limit area setting circuit 17 and the movement detection circuit 9. It is determined whether it is within a limit area BA that is manually set in advance.

Next, we will explain the means for returning the tracking field of view to the standby position when it is determined that the position of the tracking field of view, and therefore the position of the tracked subject on the screen, has left the limit area BA. A control signal a is transferred to the subject movement detection circuit 9 to reset the circuit, and a control signal C is transferred to the dart pulse generation circuit 11 and a control signal d is transferred to the tracking dart circuit 8 to perform tracking f-) circuit 8.
The dart position is moved to a settable position within the photographing screen, for example, a position corresponding to the standby position indicated by TFh in FIG. 13(h). As a result, the tracking field of view moves to, for example, the above-mentioned standby position, and shifts to a tracking mode for the subject expected to enter the photographic screen next.

In order to perform the tracking operation stably when the subject moves rapidly, etc., the method for returning the tracking field of view described above is not to return to the standby position immediately after the subject leaves the limit area BA, but rather to make adjustments. It is possible to perform this after a possible predetermined time has elapsed. The time setting circuit 17 is provided for this purpose and sets the above-mentioned predetermined time based on timer time information inputted by the photographer. When it is determined that the tracked subject has left the limit area BA, the microprocessor 16F! Movement detection circuit 9
The control signal a' is transferred to the character generator 20 and the AF to stop its operation, and the control signal a' is transferred to the character generator 20 and the AF
In the former case, the display operation of the focus detection mark is stopped, and in the latter case, the drive device 15 is stopped and the focus detection state determined by the position of the lens group 1 at that time is maintained. Furthermore, a control signal may be transmitted to a warning circuit (not shown) to warn the photographer that the tracked subject has moved out of the limit area BA or that the tracking operation is currently stopped. good.

Possible means for this purpose include flashing the boundary line (frame) of the limit area, which will be described later, or generating an audible sound signal.

In the above, the character generator 20 receives position information of the tracked subject from the microprocessor 16, forms a focus detection mark signal, adds this signal and the output video signal in the adder circuit 2, and adds the signal to the electronic viewfinder ( EVF) x st, etc., to display a mark indicating the focus detection target object in addition to the video signal.

As for the means for forming the focus detection mark signal, it is possible to use, for example, the means disclosed in Japanese Patent Application No. 59-82709 filed by the present applicant, entitled "Distance Measuring Field of View Selection Device."

When the predetermined time set by the time setting circuit 18 has elapsed, control signals C and d are sent from the microprocessor 16 to f-) pulse generation circuit 11 and tracking dart circuit 8, respectively.
is controlled to return the dart position of the tracking dart circuit 8 to a position equivalent to the above-mentioned standby position, thereby moving the tracking field of view to the standby position, the movement detection circuit 9 starts the object movement detection operation again, and the control signal character by the end of the
Generator 20. The operation of the AF motor drive device 16 is restarted, the operation of the warning circuit line is stopped, and the automatic tracking mode is restarted.

In the embodiments described above, the limit area is a means for determining the range in which a tracking operation is performed, and does not necessarily need to be displayed on a finder or the like.

Further, the limit area is usually set as a narrower range within the entire surface of the photographic screen, or as a narrower range within a part of the photographic screen. However, if the area setting circuit 17 sets the entire shooting screen as the limit area by the photographer's operation, or if the entire shooting screen is fixedly set as the limit area, the tracked subject will be outside the shooting screen. When it is determined that the tracking field has moved out, the above-mentioned tracking field of view is restored and related operations are performed.

Regarding the distance measuring field of view recovery means in the embodiment shown in FIG.
During the tracking operation, as described above, the dart position of the ranging dart circuit 12 follows the movement of the subject and moves to the same relative position as the gate position of the tracking f-) circuit 8, so that the ranging field of view is the same as the tracking field of view. If the subject moves to the same related position, but goes outside the shooting screen or outside the limit area, the tracking field of view is returned to the standby position, and the distance measurement field of view is moved to the center of the shooting screen, for example. to return to the area or its vicinity.

To do this, the microprocessor 16 sends a control signal C' to the f-)/# pulse generation circuit 11 and the distance measuring dart circuit 12.
The dart position of the distance measuring gate circuit J2 may be moved to a position corresponding to the center of the photographing screen or its vicinity by transmitting the control signal e to.

(Limit area setting means in the embodiment of this invention) (First
(FIGS. 2 to 4) Next, the limit area setting means in the embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4. In FIG. 2, 30.31 indicates the boundary line in the X direction of the limit area BA, and 3! , 33 similarly indicate the boundary line in the y direction, and by manual operation of the knob 40 shown in Figure 3, the boundary #3θ, 3 which determines the position in the X direction moves left and right, and μ
The position is fixed by operating the knob 41. Similarly, the boundary 932.38 that defines the position in the y direction moves up and down by manual operation of the knob 42 in FIG.

That is, by operating the knobs 40 and 42, the limit area BA
The position of can be set variably, but the position of
Add one more knob in both directions, and set the border lines 30 and 31.
Similarly, 32 and 33 may be set independently, and the size of the limit area BA may also be set variably.

Boundary line 3 depending on the operation of the above knob and lock button.
In order to generate a signal indicating the positions 0 to 33, the positions of the horizontal scanning lines corresponding to these boundary lines (corresponding to 32 and 33) and the respective horizontal scanning lines whose upper and lower ends are these horizontal scanning lines are required. What is necessary is to select a specific position (corresponding to 30 and 31) inside. To do this, for the former, count the number of horizontal scanning lines in one field and select the horizontal scanning line with the number corresponding to the position of the boundary line 32.83 set by knob 42, etc., and for the latter, count the number of horizontal scanning lines in one field. A pulse train is generated by multiplying the synchronizing signal frequency, and the pulse number corresponding to the position of the boundary @30.31 set by the knob 40 or the like is selected by counting from the start of each horizontal scanning period. Alternatively, triangular waves synchronized with the horizontal and vertical synchronizing signals are generated, and these triangular waves are connected to the boundary lines (
JO, JJ) and (32, 33) to generate a square wave by clipping at the voltage level corresponding to the position, and generate a pair of pulses corresponding to the front and rear end positions of these square waves. , the logical sum of one rectangular wave and the other pair of pulses can be calculated (Japanese Patent Application Laid-Open No. 59-4384 filed by the present applicant, title of the invention is "Video Camera")
reference).

Figure 4 shows the timing relationship of the signals created as described above for one horizontal scanning period.
(a) shows the video signal in a simplified manner, (b) shows the limit area, specifically the position where the boundary line 30°31 in Fig. 2 intersects with the horizontal scanning line, and (C) shows the limit area (a). ) signal and (
b) The composite signal with the signal, (d) the limit area width in the X direction (defined by the boundaries so and si) in Figure 2, (e)
is the dart position by the tracking f-) circuit in Figure 1, (f)
indicate the time axis.

In this example, the signal line limit area showing the limit area width in (d) is at a low level, and the other parts are at a high level. Further, the position of the tracking field of view is determined by the signal (,) indicating the dart position. Although FIG. 4 does not show a signal representing the limit area in the y direction of FIG. 2, this limit area is also set in the same manner as shown in FIG. The limit area BA described above does not necessarily need to be displayed on a display device, but in order to display it on a display device such as the electronic viewfinder 22, the output signal of the expansion limit area setting circuit 18 is sent to the character generator 2o or directly to the electronic display device. What is necessary is to supply it to the viewfinder 22 and display it.

In the microprocessor 16, in order to determine whether the dart position by the tracking dart circuit 8, that is, the tracking field of view exists within the limit area, the position on the time axis of the signal (e) or the signal (d) in FIG. This is done by examining the temporal relationship between and signal (e).

That is, in the former case, if the tracked object, in other words, the signal indicating the dart position, moves from right to left in FIG. 4, 'r2-'ri<'rK, or if it moves from left to right, T4-T. The microprocessor 16 calculates whether the relationship 's<'rK (where TK is a positive constant determined by design) is satisfied. Generally, the position within the limit area BA of the tracking field of view is (Tz
This can be determined by calculating Tl)/(T4 Tl). In the latter case, signal (d) and signal (e)
If the logical sum is a low level, it is determined that it is within the limit area BA, and if it is a high level, it is determined that it is outside the limit area BA. When it is determined that the tracking field of view falls outside the limit area BA, or moves from the center of the limit area BA to the outside of the area, and approaches the boundary line within a certain range (for example, the above-mentioned TK). , the micro 7 Or:

In this specification, the term "the subject reaches a position that almost coincides with the boundaries of the shooting screen or the limit area (specific area)" means that the subject is at a position that completely coincides with these boundaries, or when the subject is relatively Move to the above (Tl-TI
)<TK or (T4 TI)<TK.

(Subject movement detection means in an embodiment of the present invention) (Fig. 1, Fig. 5 to Fig. 9) Next, the movement of the object to be tracked is detected and tracked, and the tracking dart circuit 8 of Fig. 1 A specific example of the movement detection circuit 9 for moving the dart position, that is, the tracking field of view, will be described with reference to FIGS. 5 to 9. The specific example below is an example in which the features of the tracked object are extracted as color signal information, but the features of the object can also be extracted using information such as a luminance signal, the shape of the object, temperature, or characteristic contrast in the object. This can be done using .

The following object movement detection and automatic tracking means can be summarized as follows:
Some kind of no J that expresses the characteristics of the subject? The color of the object and the background in this example are extracted with respect to the tracking field of view set by the tracking means, the extracted features are stored, and the stored features are combined with the newly extracted features of the object. Detects whether or not the subject is moving, and if the subject moves, the moving direction or moving position, and moves the tracking field of view to follow the movement of the subject, and also The distance measuring field of view is moved in the same positional relationship.

In principle, the tracking field of view has a two-dimensional extension, but to simplify the explanation, here, as shown in Figure 5, the one-dimensional extension of the tracking field of view extending in the horizontal direction is 9. Suppose that it has . It is also assumed that the tracking visual field is divided into three parts A, B, and C (each part is hereinafter referred to as a pixel). Note that in order to configure a two-dimensional tracking field of view, for example, pixels may be provided that extend vertically above and below pixel B or A, B, and C in the same figure as the center. Color difference signals (R-, Y) and (B-) obtained as time-series signals from each pixel above.
Y), as shown in FIG.
h, 50b, sample hold Cf37H) circuit 51g
, 51b and the conversion circuits 52a, 52b perform integration, sample hold, and ~Φ conversion processing, and store them in the memories 53a, 53b, respectively. When these stored values are plotted on the orthogonal coordinates of (RY) and (B-Y) for each pixel A, B, and C, they are displayed as shown in FIG. 7, for example. In the figure, AO+BO and co
Each point represents a signal obtained from each pixel A, B, and C in FIG. 5, respectively.

Here, it is assumed that from pixel B, a signal representing only the clothes of the person who is the subject is obtained, and from pixels Person and C, a signal is obtained in which signals representing the clothes of the subject and the background are added. Furthermore, assume that the background colors on the left and right sides of the subject in the figure are different. Therefore, points Ao and Co have different positions on the color difference signal coordinates.

Next, when the subject shown in Fig. 5 moves to the right in the screen as shown in Fig. The signals obtained from the image change as shown in Figures 7A and C. On the other hand, since pixel B remains within the subject as shown in Figure 5(B), it is unclear whether the person is wearing the same clothes. If it is monochromatic, the signal obtained from pixel B will hardly change.

Therefore, here, El = B for simplicity.

shall be. In this case, as shown in FIG. 7, point C1 is point B
o (=Bt), and point A1 becomes point B.

(=Bt), so line segments B, C, are smaller than line segment BoCo, and line segments A, B1 are smaller than line segment AoBo.
It gets bigger. Conversely, line segment BI C1 is line segment BoCo
If the larger line segment AI B is smaller than the line segments A and Bo, it means that the subject is moving to the left in FIG. 5(B). If the background color is the same on both sides of the subject, the subject will appear in the screen as shown in Figure 5 (B).
When moving to the right, the above point A1 will be located on the extension line of the line segments A and Bo, and the point C1 will be located on the line segment BoCo. This invention can be applied to either of the above cases.

In order to detect the movement of the tracked object using the above-mentioned phenomenon, it is sufficient to detect, for example, a change in length of one line segment AB and BC. For that purpose, mobile inspection tPi
The pixels A and B are connected to the O color detection circuit in the circuit 5.

The movement detection circuit 5 detects the color of the subject with respect to C.
The signal representing the newly extracted color of the object is compared with the signal stored in the memory at the next point in time. Then, the presence or absence of movement of the subject and, if the subject moves, the direction of movement, for example, is detected. The above processing is performed for 1 field period of the television signal.
This is done according to its average value during a period of 760 seconds or several fields thereof. In the following, both will be explained as being processed in one field period.

FIG. 8 shows an example of a specific circuit for carrying out the above processing, and this circuit is also similar to the movement detection circuit 9 of FIG.
This shows the details. In the figure, 60 is the distance between the signals An and Bn obtained from the pixels An and B (Figure 7 shows the case where n = 1) when the subject moves within the screen, that is, the length of the line segment AnBn. SADAn,B
The change in n, specifically the length D A of the line segment AoBo
Ratio with Q-BQ DAn, Bn/DA0. B.

Similarly, No. 6 shows the ratio Dc1. of the length DCfi-Bi of the line segment CnBn and the length DcO-BQ of the line segment CoBo. A device for comparing nH/Dcg0m□ with a threshold value is shown.

(RY), (B-Y) The values on the coordinates of points A and B, which represent the color characteristics of pixels and B, respectively, on the orthogonal coordinates are stored in the memory 63 when the switch 62 is not turned on by default. be remembered. That is, the values stored in the memory 63 are Ao for the pixel and Bo for the pixel B. Note that the above initial settings, that is, the registration of reference values for tracking, are performed using a specially provided color designation circuit, as will be described later with reference to Figure 9, instead of using a video signal obtained by photoelectrically converting the light from the subject. Alternatively, at the time of initial setting, a reference color plate of a color corresponding to the color of the subject may be placed in front of the photographing optical system, and the color may be stored in the memory 63.

On the other hand, after the scanning line scan in this case n = O, approximately n/6
(RY) of An and Bn obtained every 0 seconds.

(B-Y) The value on the orthogonal coordinates is directly transferred to the distance calculation circuit 64. Therefore, the distance calculation circuit 64 has ^IBo
The information of each point of and An * B n is combined and DA
The values of o, Bo and DAn-Bn are (R-
Y).

It is calculated from the difference in position regarding each (B-Y) coordinate. Based on these values, the divider 65 calculates DAn, Bn
/Da. , no are calculated and compared with a threshold value KA set by a threshold value setter 66 in a comparator circuit 67.

If there is a change exceeding the threshold value KA, 1'' is output to the movement determination circuit 68.Similarly, the comparator 61
pcn, Bn/DCQ, and B□ are calculated, and if there is a change exceeding the threshold value Kc, 1' is output to the movement determination circuit 68. In many cases, the switches 62 of the comparators 60 and 61 are turned on at substantially the same time, and KA=KC.

(R-Y) of the point representing the color characteristics of pixels A, B, and C,
(B-Y) Assuming that the movement situation on the orthogonal coordinates is the situation shown in FIG. 7, DAn+BnZDAO TakashiBO, DCn, and Bn/Dc.

, Bo=B1, and KA2Ko=2, DAl
・B1/DA0.110 = 2.2Dc1, n1/
Dc6. When n6 = 0.36, only the comparator circuit 67 in the comparator 60 outputs 1'' to the movement determination circuit 68. In this case, the movement determination circuit 68 sets the tracking? In the case of
(e-) Controls the pulse generation circuit 1 and the tracking dart circuit 8 to move the tracking field of view in the direction of movement of the subject, that is, to the right in the screen of FIG. 5(B). On the other hand, if only the corresponding comparison circuit in the comparator 6 outputs 'IN' to the movement determination circuit, the movement determination circuit 68 outputs a signal that advances the tracking dart setting timing by the predetermined time described above, and The visual field is moved to the left within the screen of FIG. 5(B).

In this way, the movement determination circuit 68 adjusts the tracking dart setting timing according to whether DAn, Bn/DAO'BO exceeds the threshold value KA or whether Dcn-BJDc6-m6 exceeds the threshold value Kc. In response to this signal, the microprocessor 16 controls the pulse generating circuit 1, the tracking dart circuit 8, and the distance measuring dart circuit 12 to adjust the tracking field of view and the tracking dart circuit 12. The distance measurement field of view can be moved to track the movement of the subject, and focus detection can be performed at that position.

As a modification of the above-described subject movement detection means, for pixel B, BO, which is information at the stage of initializing (registering) the characteristics of the subject, is used instead of information Bn based on the momentary position based on the movement of the pixel B, and DAn- 111 and Dcn
, DAwa, n in place of Bn, respectively.

and Dcn, B. By detecting movement using the above method, tracking can be performed without malfunction even when the subject moves at high speed.

As a means of initializing (registering) the characteristics (color) of the object in the above-mentioned object movement detection, if the color of the object can be detected in advance or can be predicted, ) can be performed using a color designation circuit. FIG. 9 shows an example of a configuration for this purpose, in which the color difference signal in the video signal is used for tracking? −
) The detected color characteristics are input to the color detection circuit 9a through the circuit 8, and the detected color characteristics are compared with the initial setting value designated by the color designation circuit 23 in the movement determination circuit 9b, and a signal representing the determination result is sent to the microprocessor 16. be transferred. Furthermore, the 8th
The switch 62 shown in the figure is switched between the output signal of the signal processing circuit 7 and the output signal of the color specifying circuit 23 of FIG.
If the configuration is configured such that the signals are input to each other, initial settings can be performed using either of these signals as necessary. Furthermore, in FIG. 8, the movement determination circuit 6
The reason why ``1'' is outputted to 8 is to perform a tracking operation that does not cause hunting or overshoot.

(Automatic focus detection means in the embodiment of this invention) (First
10) The automatic focus detection device 13 shown in FIG.
■Technical Research” Volume 17, No. 1 (Total Volume No. 86) (Showa 4
(Refer to page 21 "Automatic focus adjustment of a television camera using the mountain climbing Kusade method"). In FIG. 10, 70 is a bandpass filter, 71 is a level detection circuit, and 22 is a focusing direction detection circuit, which extracts the contour component, that is, the high frequency component, from the output luminance signal of the ranging gate circuit 12 in FIG. The high-frequency component is extracted by a bandpass filter 70, the level of this high-frequency component is detected by a level detection circuit 7, and the detection level is controlled by a focusing direction detection circuit 72 so that the detection level becomes maximum. A signal representing the moving direction for focus detection is output to the AF motor drive device 15 described above.

In carrying out the present invention, in addition to the above-mentioned means, suitable known means such as infrared TT
L focus detection means or the like can be used.

(Focal length adjustment means in the embodiment of this invention) (First
(FIG. 11) The embodiment of the present invention shown in FIG. 1 is configured to change the focal length of the lens group 2 according to the position of the subject within the limit area BA or within the photographic field. FIG. 11 is for explaining the above-mentioned change in focal length, and x1xxFi in the figure shows the length of one side of the limit area BA in the X-axis direction in FIG. Assuming that the tracked subject enters the limit area BA from the right in FIG. 11 and exits from the limit area BA from the left, the position of the subject within the area is (Tt Tl )/( in FIG. 4). According to this value, the microprocessor 16 transfers a control signal to the zoom motor N driving device 19 to drive the zoom motor M3, and the lens group 2
, and its focal length is changed according to the four turns shown in FIG. 11, for example. In this example, when the subject is at the center of the limit area BA, the focal length is the longest.

As an example of means embodying the main features of this invention,
When the tracking field of view almost coincides with the left end X of the limit area BA, that is, for example, when the tracking field of view coincides with the left end
When the relationship t Ti ) <Tx is satisfied, the focal length of lens group 2 is further adjusted to a shorter focal length, that is, in the direction of widening the angle of view to the wide end. As a result, the subject appears to be stuck at the end of the limit area, and the tracking operation range can be effectively widened. As shown in FIG. 11, the right end of the limit area BA is also adjusted to a short focal length, but the feature of this invention is that the subject can move in any direction within or outside the shooting screen or the limit area BA. Taking this into consideration, the object is set at a relatively short focal length at a position where the subject almost coincides with at least a part of the boundary of the shooting screen or the limit area BA (for example, at least one side of the screen frame FR or the limit area BA in FIG. 13). It's a matter of adjustment. In addition, in Fig. 11, the limit area BA
Although the focal length is changed according to the position of the subject within the boundary, the focal length may be constant at positions other than at least part of the boundary.

(Function and operating method of the embodiment of the invention of this application) (Part 1
(Fig. 12, Fig. 13) Next, 5j! of this invention shown in Fig. 1! The effect of the example will be explained. The following explanation will mainly be made with reference to FIGS. 12 and 13 regarding an example of the operating method of the embodiment. In this example, it is assumed that photographing is started with the subject out of the frame and the tracking field of view in the standby position. The tracking field of view position is set manually by the photographer based on information input to the microprocessor 16 from the input terminal 2 shown in FIG. A specific means for this purpose may be a means similar to the limit area setting means explained in FIGS. 2 to 4. In this example, the size of the tracking field of view is variably set by the tracking field of view size determination circuit 14 shown in FIG. In FIG. 13(a), the position of the tracking field of view during standby is indicated by TFa. On the other hand, in the standby state, the distance measurement field of view F
Fa is, for example, the screen frame FR of the electronic viewfinder 22.
In this example, the size is assumed to be constant throughout all steps. Further, the setting of the limit area BA is performed by the means explained in FIGS. 2 to 4 based on information inputted from the input terminal 3 in FIG. 1 to the limit area setting circuit 17 by manual setting by the photographer. .

The tracking operation shown in the flowchart in Figure 12 is, in principle, carried out in accordance with what has been explained in connection with Figures 5 to 9, and the initial setting of the reference color of the subject for tracking is done by the photographer's operation. This is done through the color designation circuit 23 shown in FIG. Further, in a normal tracking operation, it is assumed that pixel B in FIG. 5 is included in the object.

At step 81 in FIG. 12, the photographer first selects B as a reference color representative of the characteristics of the subject.

Specify and import this value. At this stage, the initial values (Ao and Co) for pixels A and C are not taken. The reason for this is that if the background color when setting the angle of view and starting shooting is different from the background color when capturing B above, there is a risk of malfunction when starting tracking. . Next, the initial position of the tracking field of view (
A standby position TFa) is set (step 82), and the tracking field of view waits at that position until the subject comes into the tracking field of view. Then, calculate the absolute value IBBol of the difference between the value B taken in from pixel B at this standby position TFa (which corresponds to the background color at this standby position until the subject enters) and the above-mentioned B6 (step 83). Compare the result with a predetermined dead band width ΔB (step 84);
This operation is repeated until the relationship IB-BOI<ΔB is established. In other words, the tracking field of view is at its standby position TF.
At point a, it is continuously checked to see if the subject enters the same position.

When the relationship IB-Bo%<ΔB is satisfied, it is determined that the subject has entered the standby position TFa, and the distance measurement field of view is set to the first position.
As shown in FF≦ in Fig. 3(b), the tracking field of view position TFb,
That is, it moves to the subject position (step 85). Furthermore, in order to start the tracking operation, the background (including a part of the subject)
The colors A and co that represent the characteristics of
86), (RY), (B-Y) The lengths of the line segment AoB on the coordinates DAo, Bo and the length D of the line segment C0B0
CQ−BQ is calculated (step 87). here,
When it is determined that IB-BOI<ΔB, for example, l/60
If the configuration is such that AO and CO9 are designated in the next field after a second and the tracking operation is started from the next field, then the actual tracking mode starts from step 88. In other words, each pixel A, B after one frame after a yes determination is made in step 84.
, C is captured in step 88. In addition, in case the subject that once entered the tracking field of view goes out of the screen again, 1BBol and ΔB are further compared (step 89), and in the above case, the tracking field of view returns to the standby position and the measurement is performed. The distance field returns to its initial position again (step 97.9a, FIG. 13(h)).

As long as IB-Bol<ΔB, the tracking operation progresses (steps 90 to 92), and if the subject is within the limit area BA,
The focal length of lens group 2 in FIG. 1 is adjusted according to the pattern shown in FIG. 11 (steps 93 and 94).
Figures (e) to (e) show this situation, with the longest focal length at position (d), and then towards the shortest focal length again as the subject moves to the left in Figures 11 and 13. (Figure 13(e)). Then, as shown in TFf in the same figure (f), the tracking field of view reaches the limit area BA due to the movement of the subject.
When the end of the lens group 2 is reached, the focal length of the lens group 2 is further adjusted to a shorter focal length, that is, in a direction that widens the angle of view to the wide end (step 95). By further widening the angle of view, the subject appears to be fixed at that position, as shown in FIG. 5(g), and the tracking range is effectively expanded. When the focal length of lens group 2 reaches the wide end (the shortest focal length in lens group 2) and the subject leaves the limit area BA, the tracking field of view is at the standby position TFh in FIG. 13(h).
Then, the distance measurement field of view also returns to the initial position FFh, and the device enters the standby state. Note that in this state, the operation may be slightly changed from the above-mentioned Bo specification for a new subject.

In the above explanation, when the subject leaves the limit area BA, it has the same meaning as explained in relation to FIG. can.

The above operating method is an example of the operating method of the camera of the invention of this application, and the operating method is not limited to the above method. In addition, in the above, the position detection of the subject is
In addition to the color information, it is also possible to use other information representing the characteristics of the subject described above. In addition to the position shown in FIG. 13, the standby position of the tracking field of view can be set at any position within the screen according to the photographer's drawing intention.

(Effects) As described above, according to the present invention, means for automatically tracking a subject within the photographic screen or a specific area thereof;
means for adjusting the optical system to a relatively short focal length when the subject reaches a position that relatively coincides with at least a part of the boundary of the photographing screen or the limit area, so that the subject is When the position is reached, the tracking range is effectively expanded, and this allows complex screen configurations of moving images to be created with simple operations.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the main parts of an embodiment of the camera of the invention of this application, and FIGS. 2 to 4 illustrate the limit area setting means in the embodiment of FIG. Figure 2 is an explanatory diagram of the limit area, Figure 3 (N and (B) is an explanatory diagram of the knob and lock button for setting the boundary line of the limit area in the X direction and y direction, respectively, in Figure 2, Figure (a
) or f) is an explanatory diagram for explaining the timing of the signal for setting the limit area, and FIGS. 5 to 8 are explanatory diagrams for explaining the subject movement detection means in the embodiment of FIG. (4) and (B) are explanatory diagrams showing the relationship between the divided tracking fields of view and the subject image; FIG. 6 is a block diagram of a device that processes signals obtained from the divided tracking fields of view in FIG. 5; 7 is an explanatory diagram showing a situation in which signals obtained from the device of FIG. 6 are plotted on a two-dimensional plane, FIG. 8 is a block diagram showing details of the movement detection circuit 5 in FIG. 1, and FIG. 1 is a block diagram showing a modification of the movement detection circuit 5 in FIG.
0 is a block diagram showing details of the automatic focus detection circuit 13 in FIG. 1, and FIG. 11 is an explanatory diagram showing a manner in which the focal length is adjusted according to the position of the subject in the screen in the embodiment of FIG. Fig. 12 is a flowchart explaining the operation method and function of the device shown in Fig. 1, and Fig. 13 (a) to h) shows the positions of the tracking field of view and distance measurement field of view as the subject moves in the device of Fig. 1. Fig. 14 (4) and (B) are explanatory diagrams showing the relationship between the distance measurement field of view and the subject image in a conventional camera. It is a diagram. Explanation of symbols 1: Lens group for focus adjustment, 2: Lens group for changing focal length, 3: Imaging system lens group, 4: Solid-state image sensor, which is an example of imaging means, 7: Signal processing circuit , 8:
Tracking dart circuit, 9: Subject movement detection circuit, 11: Dart noise generation circuit, 12: Ranging f-) circuit, 13: Automatic focus detection circuit, 14: Tracking field of view size determination circuit, 15
: AF motor drive device, 16: Microprocessor, 1
7. Two limit area setting circuits, 19: Zoom motor drive device,
23: Color specification circuit, BA: Limit area, TF: Tracking field of view,
FF: Distance field of view. ¥2 Figure Figure 3 (A) (B) Figure 5 Figure 6 Figure 7

Claims (2)

[Claims] (1) means for automatically tracking a subject within the photographing screen or a specific area thereof; A camera comprising means for adjusting the system to a relatively short focal length; (2) Claims in which the specific area can be set (
1) The camera described.