KR100515205B1 - Zooming speed control of zoom camera - Google Patents

Abstract

The present invention relates to a zooming speed control method of a zooming camera for setting an optimal zooming speed by improving zoom tracking performance to a fixed focus track for a fixed and moving subject in zooming.

In other words, by setting the optimal zooming speed during zooming, the performance of zoom tracking to the in-focus track for fixed and moving subjects is improved.

It is to determine whether the subject is moving during zooming, and to improve the performance of zoom tracking on the moving object by adding or subtracting the zooming speed according to the amount of movement of the subject.

With the minimum trace trajectory curve data for zoom tracking stored in the internal memory of the zoom camera, the zoom lens is used to determine the moving position of the focus lens according to the movement of the zoom lens.

In addition, the present invention relates to a method of increasing the zooming speed at the start of zooming, and to determining whether a subject moves by using a tracking trajectory of the focus lens, and controlling the zooming speed accordingly.

Description

Zooming speed control of zoom camera}

The present invention relates to a method for controlling zooming speed of a zoom camera. Particularly, a zoom camera zooming performance is improved to set an optimal zooming speed by improving zoom tracking performance to a fixed focus track for a fixed and moving subject in zooming. It relates to a control method.

In general, it is well known that an image acquisition apparatus using a zoom lens such as a surveillance zoom camera, a camcorder, a general zoom camera, and the like should be accurately photographed when the subject is enlarged or reduced.

When the subject is to be photographed using the zoom camera, the zooming control is performed by determining the movement of the subject when the distance to the zoom camera changes according to the state in which the subject moves back and forth.

As shown in FIG. 1, an automatic focus control apparatus during zooming of a conventional general zoom camera is provided.

A lens group 1 including a zoom / focus lens for receiving an image having a magnification adjusted according to information for enlarging or reducing the subject;

An imaging unit 2 for converting an image signal input from the lens group 1 into an electrical signal;

A sampling / gain control unit 3 for sampling and gain controlling the image captured by the imaging unit 2,

An analog / digital converter 4 for digitizing the gain-controlled video signal in field units;

A digital signal processor (5) for processing the image converted into the digital signal to calculate the auto focus data;

A digital / analog converter 6 for converting a digital video signal from the digital signal processor 5 back into an analog video signal;

An image output unit 7 receiving the converted analog image signal and outputting the same to the monitor 14;

A microprocessor (8) for receiving the focus data from the digital signal processor (5) and controlling the automatic focusing operation during zooming;

A memory 9 for storing and outputting data according to an operation including various image signals and focus data while being controlled by the microprocessor 8;

A zoom motor driver 10 for driving the zoom motor 11 under the control of the microprocessor 8,

A focus motor driver 12 driving the focus motor 13 while being controlled by the microprocessor 8,

A zoom motor 11 for moving the zoom lens 1a of the lens group 1;

The focus motor 13 moves the focus lens 1b of the lens group 1.

And when the zoom camera is zoomed, the automatic focus control device should zoom in and out while the focus lens accurately tracks the trace trajectory when the zoom lens moves, but since the trajectory curve is nonlinear, the zoom position Since the relative amount of movement of the focus lens appears differently, it is important to control the proper movement speed of the zoom lens and the focus lens.

That is, the zooming speed control method uses the zoom speed (zoom speed) designated for each zoom position stored in the zoom camera internal memory by the automatic focus control apparatus during zooming of a general zoom camera. As can be seen in the graph of FIG. 2, the zooming speed for each zoom position is generally designed to have a slow zoom speed at a high magnification of a long distance and a fast zoom speed at a low magnification of a wide area. If the zoom speed is high at high magnification, the amount of movement of the focus lens relative to the amount of zoom movement becomes relatively large.

Normally, the motor driving the lens uses a stepping motor, which has to determine the zooming speed in consideration of the starting / through characteristics of the stepping motor. If the zoom and focus lens are started without considering this characteristic, accurate zoom tracking cannot be guaranteed due to the motor's stepping out.

In the conventional zoom camera zooming, the zooming speed calculation method in the autofocus control apparatus is selected to execute the zooming operation as shown in FIG. 3 (step 100), and the microprocessor 8 reads the current zoom position. (Step 101), the stored zoom speed is read from the memory according to the zoom position (step 102).

The microprocessor 8 calculates the moving distances of the zoom lens and the focus lens at the read zooming speed (step 103), and then moves the zoom / focus motor driver 10 and 12 to move the zoom and focus lens to the designated positions. The zoom / focus motors 11 and 13 are driven (104).

It is determined whether the zoom and focus lenses are moved to the designated position, and when the movement is completed, the driving of the zoom / focus motors 11 and 13 is stopped through the zoom / focus motor units 10 and 12 (step 105). ).

In the conventional zoom camera, the zooming method of the automatic focus control device does not change the zooming speed even when the subject moves or the angle of view of the camera moves during zooming. There is a disadvantage in that it does not fit.

That is, since the zooming speed is not recognized by being recognized as a moving object during zooming, accurate zoom tracking is disadvantageous for the moving object.

Accordingly, the present invention has been made to solve the problems described above, to improve the zoom tracking performance to the fixed focus track for fixed and moving subjects in zoom cameras to set the optimal zooming speed It is an object of the present invention to provide a zooming speed control method for a camera.

Zooming speed control method of the zoom camera according to the present invention for achieving the above object, that is to set the optimal zooming speed during zooming to improve the performance of zoom tracking to the focusing track for fixed and moving subjects,

When zooming, it is determined whether the subject is moving, and the zoom tracking performance is improved by increasing or decreasing the zooming speed according to the moving amount of the subject.

With the minimum trace trajectory curve data for zoom tracking stored in the internal memory of the zoom camera, the zoom lens is used to determine the moving position of the focus lens according to the movement of the zoom lens.

When zooming, it is necessary to move the focus lens and zoom lens to the focal point trajectory by comparing and analyzing the auto focus data (AFD) .However, even if the subject is fixed during zooming, the angle of view may change, which may make it difficult to accurately zoom. In addition, even if the zooming speed is too fast, the in-focus zoom tracking becomes difficult, and if the zooming speed is too slow, the screen zooming time to the desired magnification becomes long, so it is desirable to specify an appropriate zooming speed.

The present invention is characterized in that it comprises a method of increasing the zooming speed at the start of zooming and a method of determining the movement of the subject using the tracking trajectory moved by the focus lens, and controlling the zooming speed accordingly.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

The present invention is configured in the same configuration as the automatic focus control device when zooming in the conventional zoom camera of Figure 1, characterized in that the operation of the microprocessor to perform the speed control and information stored in the memory,

A lens group 1 including a zoom / focus lens for receiving an image having a magnification adjusted according to information for enlarging or reducing the subject;

An imaging unit 2 for converting an image signal input from the lens group 1 into an electrical signal;

A sampling / gain control unit 3 for sampling and gain controlling the image captured by the imaging unit 2,

An analog / digital converter 4 for digitizing the gain-controlled video signal in field units;

A digital signal processor (5) for processing the image converted into the digital signal to calculate the auto focus data;

A digital / analog converter 6 for converting a digital video signal from the digital signal processor 5 back into an analog video signal;

An image output unit 7 receiving the converted analog image signal and outputting the same to the monitor 14;

A zoom motor driver 10 for driving the zoom motor 11 under the control of the microprocessor 8,

A focus motor driver 12 driving the focus motor 13 while being controlled by the microprocessor 8,

A zoom motor 11 for moving the zoom lens 1a of the lens group 1;

The configuration of the focus motors 13 for moving the focus lens 1b of the lens group 1 is the same as that of the automatic focus control apparatus during zooming of the conventional zoom camera.

However, under the control of the microprocessor 8, the upper and lower trajectory curves of the current focus position and the fixed subject are stored in the memory 9 that stores and outputs data according to the operation including various image signals and focus data. Saves the speed information on the acceleration section up to the application speed of the zooming speed and the deceleration coefficient for.

In addition, the microprocessor 8 which receives the focus data from the digital signal processor 5 is configured to perform an operation while reading various data including an image signal stored in the memory 9 so as to control an autofocus operation during zooming. will be.

The zooming speed control method of the zoom camera of the present invention configured as described above,

The lens group 1 including the zoom / focus lens with respect to the front subject receives an image of a magnification adjusted at a ratio of enlargement or reduction selected by the user.

The image signal input from the lens group 1 is converted into an electrical signal by the imaging unit 2 and transferred to the sampling / gain control unit 3 so as to sample and gain control the captured image.

The gain-controlled video signal is digitized by the analog / digital converter 4 on a field basis, and the digital signal processor 5 receiving the digital signal processes the digital video to calculate autofocus data. do.

The digital video signal from the digital signal processor 5 is converted into an analog video signal while being passed through the digital / analog converter 6 and outputted through the video output unit 7 so as to display an image on the monitor 14. Is displayed.

In addition, the zoom motor driver 10 and the focus motor driver 12 controlled by the microprocessor 8 respectively drive the zoom motor 11 and the focus motor 13 to zoom lens 1a of the lens group 1. ) And / or the focus lens 1b.

The microprocessor 8 stores various image signals and focus data according to the operation in the memory 9 and outputs the information on the upper and lower trajectory curves of the current focus position and the fixed subject. The zoom motor driver 10 and the focus motor driver 12 are appropriately controlled by the speed information in the acceleration section up to the zooming speed information and the deceleration coefficient application speed.

The microprocessor 8 is to focus the zoom camera by the zoom trace trajectory curve as shown in FIG.

The area in which the microprocessor 8 can focus the zoom camera depends on the current zoom position. In the wide end, focusing is possible on a subject that is usually in the position of 1 cm to infinity, and in the tele stage, focusing is possible for a subject which is usually in the position of 1 m to infinity.

Areas that can be focused on the entire movable area of the zoom are areas A3 and A4, and areas A1 and A2 become areas that can be focused only at the wide end.

In addition, the memory 9 stores information about a trajectory curve.

As shown in FIG. 5, the trajectory curve C _N and the trajectory curve C _F are designated as the upper trajectory curve C _N and the lower trajectory curve C _F based on the current focus position F _P. Can be.

There may be several such trajectory curves in the memory 9 above, but in order to calculate the zooming speed, two of the upper trajectory curve C _N and the lower trajectory curve C _F are calculated according to the current focus position F _P. You must specify the trajectory curve.

In FIG. 5, the trajectory curves C _TN , C _TM , and C _TF are all tracking trace curves for a subject, and the tracking trace curve C _TM positioned at the center is a fixed subject. The trajectory curve (C _TM ), and the zooming speed at this time is the largest.

On the other hand, the tracking trajectory curve which is located at the top (C _TN) is a tracking locus curve (C _TN) in the case where the object moves in the local area (Near) direction, the tracking trajectory curve which is located at the bottom (C _TF) is a distance (Far The tracking trajectory curve (C _TF ) when moving to

In other words, if the subject moves during zooming, the focused trajectory is biased in one direction so that the zooming speed can be controlled by using this principle.

As shown in Fig. 7, since the zooming speed for the fixed subject is already stored in the memory 9, the maximum driving speed of the zoom motor with respect to the current zoom position is the zooming speed V _M in the case of this fixed subject. Can't go over

As can be seen in the graph of FIG. 7, when the subject moves during zooming, the zooming speed is reduced compared to the fixed subject.

That is, when the subject is moved, the zooming speed should be reduced to a certain ratio to enable the in-focus zoom tracking. The value used to decelerate the zooming speed in this manner is called a deceleration coefficient α.

In the graph shown in FIG. 8, the acceleration section T _s can be checked, which corresponds to the zooming speed corresponding to the deceleration coefficient application ratio P which is a constant ratio of the maximum zooming speed V _M for a predetermined time after the start of zooming. The speed increasing section is referred to, and the zooming speed is referred to as a deceleration coefficient application speed (V _P ).

That is, the interval from the start of zooming until the zooming speed V _Z reaches the deceleration coefficient application speed V _P for the first time is called an acceleration section T _s . In this section, the deceleration coefficient is set to 0 (α = 0) and the deceleration coefficient is not reflected in the zooming speed calculation.

The deceleration coefficient application ratio (P) should be greater than 0 and not greater than 1. (0 <P≤1)

The deceleration coefficient application rate (P) and the deceleration coefficient application speed (V _P ) are values used only in the acceleration section (T _s ) after the first zooming starts. In this acceleration section T _s , the zooming speed is gradually increased. The reason for gradually increasing the zooming speed is to prevent the outage phenomenon caused by the sudden speed increase in consideration of the starting and through characteristics of the stepping motor driving the lens.

The zooming speed increase in the acceleration section T _s of FIG. 8 uses the acceleration coefficient β and the acceleration constant r. The acceleration coefficient β must be greater than 1, and the acceleration coefficient r must be greater than zero.

As such, the zooming speed to which the acceleration coefficient β is applied is expressed by the following equation (1).

V _Z [x] = β * V _Z [x-1] + r (β≥1, r> 0) ..... Equation (1)

Further, the zooming speed V _P [x] obtained by applying the deceleration coefficient application ratio P to the maximum zooming speed V _M [x] in the memory is expressed by the following equation (2).

V _P [x] = P * V _M [x] (0 <P≤1) ..... Equation (2)

Thus, the acceleration period (T _s) when the zooming speed (V _Z [x]) in reaches the zooming speed (V _P [x]), acceleration section (T _s) is ended is applied deceleration coefficient of applying the reduction coefficient interval Is converted to (T _C ).

In FIG. 8, the entire sections T _C1 , T _C2 , and T _C3 from the end of the acceleration section T _s to the point where the zoom stops are referred to as the deceleration coefficient application section T _C. The moving section T _{C2 in} which the zooming speed is reduced due to the movement of the subject during zooming can be set in the applied section, and is distinguished from the stop sections T _C1 and T _C3 where the subject is still.

If the subject continues to move, the moving section T _C2 may be in a state including the stop sections T _C1 and T _C3 .

And the zooming speed is gradually in the turned away from the maximum zooming speed (V _M) on the memory start position of the back section (T _C3) up to the zooming speed in the memory (V _M) of a mobile segment (T _C2) In the above 8 This is the same when the subject stops moving again after the subject moves in the movement section T _C2 .

As such, when the subject moves, the zooming speed is reduced, and when the subject is locked again, the zooming speed is gradually increased to the maximum zooming speed (V _M [x]) in memory.

Next, a method of obtaining the deceleration coefficient α will be described with reference to FIG. 6.

Before calculating the deceleration coefficient, the relative focus position value should be calculated first.

The focus relative position FD [x] is the distance D _C between the upper trajectory curve C _N [x] and the lower trajectory curve C _F [x] at the current focus position F _P [x]. [x]), the ratio of the distance D [x] between the lower trajectory curve C _N [x] and the current focus position F _P [x]. In other words, if the focus relative position values do not change during zooming, the current subject may be a stationary subject which hardly moves. On the other hand, if the change in focus relative position values during zooming is large, it means that the subject is closer or farther away from the camera. .

In order to check the movement of the subject, it is necessary to compare the focus relative position value FD [x-n] before the predetermined time n with the current focus relative position value FD [x]. The focus relative position value is stored in the memory 9 for every field.

In FIG. 6, if the subject is fixed, the focus lens trace is formed as a constant ratio with respect to the upper / lower trajectory curves C _N [x] and (C _F [x]). Will move to position. The deceleration coefficient α at this time will be zero.

On the other hand, if the subject moves in the near direction, the focus will move from the position of ⓐ to the position of ⓑ. The deceleration coefficient α at this time will be greater than zero.

In Figure 6, the focus relative position at point ⓐ is FD [xn] = D [xn] / DC [xn], and the focus relative position at position ⓑ is FD [x] = D [x] / DC [x]. . A focus relative position value of 1 means that the focus position is on the upper trajectory curve, and a 0 means that the focus position is on the lower trajectory curve (C _F [x]). Using these two values, the deceleration coefficient α is obtained by the following equation (3).

α = | FD [x-n]-FD [x] | = | D [x-n] / DC [x-n]-D [x] / DC [x] | (0 ≤α <1)

                                               ..... Formula (3)

Condition 1) α = 0, when α <min (α)

If the deceleration coefficient is less than min (α), min (α) is the minimum threshold of the deceleration coefficient α.

Condition 2) α = max (α), when α> max (α)

If deceleration coefficient α is greater than max (α)

Condition 3) 0≤min (α) ≤max (α) <1

Using the above equation (3) in Figure 8 the zooming speed in the deceleration coefficient application period (T _C1 ) (T _C2 ) (T _C3 ) is the same as the following equation (4).

V _Z [x] = (1-α) * V _M [x] (0≤α <1) ..... Equation (4)

The deceleration coefficient obtained in Equation (3) above is converted into an absolute value for the difference of each relative position value so that it always has a positive number. If the obtained deceleration coefficient has a small value within a certain range (min (α)), the deceleration coefficient is replaced with zero. Although the subject is fixed, some zoom tracking errors occur, and the deviation of the zoom and focus lenses must be taken into account. Therefore, if the change in the deceleration coefficient is below a certain value, the deceleration coefficient is replaced with 0 to reduce unnecessary deceleration. Remove it.

If the maximum value is larger than the specified maximum value max (?), The maximum value is replaced. The maximum value of the deceleration coefficient (max (α)) must be smaller than one.

The larger the deceleration coefficient, the smaller the zoom speed. The smaller the deceleration coefficient, the closer the zooming speed (V _M [x]) approaches.

In FIG. 6, if the subject is fixed, the point ⓑ will move to the position ⓒ. In this case, the two positions of the focus relative positions are almost the same.

D [x-n] / DC [x-n] ≒ D [x] / DC [x]

In this case, the deceleration coefficient α = 0.

However, if the subject gets closer, the focus lens will move from position ⓐ to ⓑ, and in this case, the relative positions of the two points show a big difference.

D [x-n] / DC [x-n] ≪ D [x] / DC [x]

In this case, the deceleration coefficient α> 0, and the subject is moving in the near direction.

If D [x-n] / DC [x-n] '' D [x] / DC [x], the deceleration coefficient α> 0 is obtained, but the subject is moving in the far direction.

By using the change of the focus relative position values in this way, the moving direction of the subject can be known.

Hereinafter, a process of controlling the zooming speed of the present invention will be described in detail with reference to FIG. 9.

When the user first selects the control of the zooming speed, the microprocessor 8 reads initial values stored in the internal memory 8 (step 21).

The information read by the microprocessor 8 reads max (α) and min (α), which are boundary values of the deceleration coefficient α, and reads the deceleration coefficient application ratio P and the acceleration coefficient β. It is. The initial speed V _Z [0] is set to zero.

After reading the initial value, the microprocessor 8 checks the zooming motion execution command or the zooming motion stop command factor (step 22), and if the zooming motion command, the position of the current zoom (Zp) and focus (F _P ) lenses first. Check (step 23).

The upper trajectory curve C _N and the lower trajectory curve C _F are searched for the focus position F _P read in step 23 above (step 24), and the image / image of the current zoom position Zp [x] is After reading the focus position values CN [x] and CF [x] on the lower locus curve, the focusing distance D _C [x] is obtained (step 25).

Further, the distance D [x] between the focus position value C _F [x] on the lower locus curve and the current focus position F _P [x] is obtained (step 26).

The focus relative position value FD [x] is calculated using the respective distances obtained in the above steps 25 and 26 (step 27), and the value is stored in the memory 9 (step 28).

The values stored in the internal memory 9 are the focus relative positions FD [x], (FD [x-1]) ... (FD [xn]), and the corresponding zooming after the start of zooming. Store the velocity V _Z [x], V _Z [x-1] ... V _Z [xn] ..

The maximum zooming speed V _M [x] for the current zoom position Zp [x] is read from the memory 9 (step 29).

If the zooming speed (V _Z [x]) has reached the deceleration factor application speed (V _P [x]) for the first time after the start of zooming, If so, it is determined that the acceleration section T _s is finished (step 30).

Check if the acceleration section (T _s ) is over (step 31). If the acceleration section is not over, apply the acceleration factor (β) to increase the zooming speed at a constant rate and transfer the new zooming speed (V _Z [x]). The zooming speed V _Z [x−1] is multiplied by the acceleration coefficient β and calculated by adding the acceleration constant r (step 32).

Once the acceleration period has passed in step 31, the deceleration coefficient application periods T _C1 , T _C2 , and T _C3 are regarded as regardless of the subsequent zooming speed. The focus relative position FD [xn] before the field n is read (step 33), and the deceleration coefficient α is calculated by the difference from the current focus relative position FD [x] obtained in the above step 27. (Step 34).

The final zooming speed V _Z [x] is calculated using the obtained deceleration coefficient α (step 35).

The zooming speed (V _Z [x]) calculated by the above steps 32 and 35 is greater than or equal to the maximum zooming speed (V _M [x]) in memory (step 36) to be equal if not smaller. (Step 37).

The zooming speed V _Z [x] obtained by the above process is stored in the memory 9 (step 38), and the next moving position of the zoom lens and the focus lens is set and moved (step 39).

The movement is performed until the movement is performed to the desired position so that zooming is possible when the subject is used by the zoom camera (step 40).

Therefore, if the focus state position value before a certain time is greater than the current focus relative position value by using the change of the focus relative position values, the subject moves away from the camera. On the contrary, the subject becomes closer to the camera when the focus position position value decreases. The moving direction of the subject can be confirmed by using the same, and as the magnitude of the deceleration coefficient increases, the moving speed of the subject becomes relatively large.

As described above, according to the zooming speed control method of the zoom camera of the present invention, an optimal zooming speed is set during zooming to improve the performance of zoom tracking to a focusing track for fixed and moving subjects.

When zooming, it is determined whether the subject is moving, and the zoom tracking performance is improved by increasing or decreasing the zooming speed according to the moving amount of the subject.

With the minimum trace trajectory curve data for zoom tracking stored in the internal memory of the zoom camera, the zoom lens is used to determine the moving position of the focus lens according to the movement of the zoom lens.

In addition, the method of increasing the zooming speed at the start of zooming and determining the movement of the subject by using the tracking trajectory of the focus lens, and controlling the zooming speed accordingly.

1 is a block diagram showing a configuration for controlling a zooming speed of a zoom camera;

2 is a graph showing a zooming speed for each conventional zoom position;

3 is a flowchart illustrating a process for controlling a zooming speed of a conventional zoom camera;

4 is a graph showing a zoom trace trajectory curve of the zoom camera of the present invention;

5 is a graph showing an upper trajectory curve and a lower trajectory curve of a current focus position of a zoom camera of the present invention;

6 is a graph showing a state of forming a trace of a focus lens at a constant ratio with respect to the upper / lower trajectory curve of the zoom camera of the present invention;

7 is a graph showing the zooming speed for a fixed subject of the present invention zoom camera;

8 is a graph showing the zooming speed according to the acceleration section of the present invention.

9A and 9B are flowcharts illustrating an operation process of controlling the zooming speed of the present invention.

Explanation of symbols on main parts of drawing

1 Lens group 2 Imaging unit

3: Sampling / gain control unit 5: Digital signal processing unit

8: microprocessor 9: memory

10: zoom motor drive unit 11: zoom motor

12: focus motor driver 13: focus motor

Claims (5)

In the zooming speed control method of the zoom camera, Reading the maximum zooming speed which is the zooming speed stored in the memory 9 and checking the current zoom position and the focus position; After setting the upper / lower trajectory curve for the identified focus position and reading the focus position data on the upper / lower trajectory curve for the current zoom position, the focus relative position value using the focus position data on the trajectory curve and the actual focus position Calculating and storing the result in the memory 9; Determining whether the acceleration or deceleration coefficient is applied by checking whether the zooming speed reaches the deceleration coefficient application speed once once after the start of zooming; In the case of the acceleration section in the above step to increase the zooming speed by applying the acceleration coefficient and the acceleration constant to the previous zooming speed, In the step of applying the deceleration coefficient in the above step, among the focus relative position values stored in the memory 9, the focus relative position value before a predetermined time that can determine the movement of the subject is read and the current position determined in the above process is obtained. Obtaining a deceleration coefficient by obtaining a difference from the relative focus position of Calculating the final zooming speed by applying the deceleration coefficient to the maximum zooming speed read from the memory (9); The final zooming speed calculated in the deceleration coefficient application section and the acceleration section does not exceed the maximum zooming speed compared to the maximum zooming speed read from the memory 9, and the zooming is performed using the final zooming speed thus obtained. A zooming speed control method of a zoom camera, characterized in that performed by the step of driving the motor (11) and the focus motor (13) to move the zoom lens and / or focus lens. The method of claim 1, The focus relative position value may be calculated as a ratio of the difference between the current position of focus and the position of focus data on the lower trajectory curve with respect to the difference between the focus position data on the upper trajectory curve and the focus position data on the lower trajectory curve. How to control the zooming speed of the zoom camera. The method of claim 1, Obtaining a deceleration coefficient application speed by multiplying a predetermined ratio with respect to the maximum zooming speed stored in the memory 9 at the start of zooming; Multiply the acceleration factor by the previous zooming speed and add the result as the acceleration factor to determine the new zooming speed, and the acceleration section is the interval until the calculated zooming speed reaches the first application of the reduction factor. Zooming speed control method of the zoom camera, characterized in that to control the zooming speed by using the process of dividing the remaining section from the first time to apply the deceleration coefficient application speed until the zooming stops by the deceleration coefficient application interval. The method of claim 1, Extracting a value before a certain time from which the movement of the subject can be checked among the focus relative position values stored in the memory 9; Obtaining a deceleration coefficient as an absolute value of the difference between the extracted focus relative position value and the focus relative position value at the current zoom position obtained by the above process; Zooming speed of the zoom camera, characterized by subtracting the obtained deceleration coefficient by a constant 1 and multiplying the result by the maximum zooming speed at the current zooming position read from the memory 9 to obtain the final zooming speed. Control method. The method according to claim 1 or 4, If the focus state position value before a certain time is greater than the current focus relative position value by using the change of the focus relative position values above, the subject moves away from the camera. The zooming speed control method of the zoom camera, characterized in that to determine the relative moving speed of the subject by referring to the size of the deceleration coefficient while determining the moving direction of the subject.