JP2007033735A - Automatic focus adjusting device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve focusing performance for an object to be imaged which has high luminance like a point light source. <P>SOLUTION: An automatic focus adjusting device which obtains a relative focus evaluation value based upon an imaging signal corresponding to the position of a focus lens (S1202) and performs focus adjustment control so that the focus evaluation value becomes large, performs the focus adjustment control (S1207) so that the focus evaluation values becomes small when the ratio of a high luminance part in the acquired focus evaluation value is larger than a specified value (S1203). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an automatic focusing technique using an imaging signal and an imaging technique such as a video camera equipped with the automatic focusing technique.

  As an automatic focus adjustment (AF) device provided in a video camera or the like, a high-frequency component is extracted from an image pickup signal obtained from an image pickup device such as a CCD, and a focusing lens is driven so that the high-frequency component becomes large. A so-called TV-AF system that performs adjustment is known.

  As an evaluation value of the conventionally proposed TV-AF method, a technique for calculating a line peak integration evaluation value by integrating the peak value of the evaluation value for each horizontal line in the vertical direction has been proposed (Patent Document 1). This line peak integration evaluation value is a stable value with less noise due to the integration effect. Therefore, it is not easily affected by instantaneous noise, and the signal changes sensitively with a slight focus shift, which is optimal for direction determination. However, the TV-AF method has a problem that it is difficult to focus on a high-luminance subject. That is, in the line peak integral evaluation value disclosed in Patent Document 1, there is a case where a lens position having a large value is not necessarily the focal point. Specifically, in a normal subject, the point at which the line peak integral evaluation value is maximized as shown in FIG. On the other hand, when a subject such as a point light source whose length varies with focus adjustment is photographed as shown in FIG. 3, when the subject is in focus (the state in FIG. 3A), the peak of each line is obtained. Although the value is large, the number of lines on which the subject image is applied is small. On the other hand, in the case of out-of-focus (state of FIG. 3B), the peak value of each line is small, but the number of lines on which the subject image is applied increases, so the line peak integral evaluation value increases. Therefore, as shown in FIG. 4, since the maximum point of the line peak integral evaluation value does not become the in-focus point, there arises a problem that focusing cannot be performed if the focus adjustment is performed so that the line peak integral evaluation value becomes large.

Further, as a proposal for improving the problem that it is difficult to focus on the high-brightness subject, as in Patent Document 2, the high-brightness portion and the low-brightness portion in the screen are detected, and the high-brightness subject or the normal subject is determined. A technique for switching the focus control signal after discrimination is also proposed.
JP 07-298120 A JP 05-260361 A

  However, the technique disclosed in Patent Document 2 has a problem that the method of determining whether the subject is a high-intensity subject or a normal subject is not related to the method of generating the evaluation value, and thus the case where the evaluation value does not become the maximum at the focal point cannot be correctly determined. is doing. Furthermore, since the low luminance part is detected, there is a problem that it cannot be determined that the screen is bright to some extent.

  An object of the present invention is to provide an automatic focusing apparatus and an imaging apparatus that can improve focusing performance for a high-luminance imaging target such as a point light source.

  In order to achieve the above object, the present invention obtains a relative focus evaluation value based on an imaging signal corresponding to the position of the focus lens, and performs automatic focus adjustment to perform focus adjustment control so that the focus evaluation value becomes large. In the apparatus, when the ratio of the high-luminance portion in the acquired focus evaluation value is larger than a predetermined value, the automatic focus adjustment apparatus performs focus adjustment control so that the focus evaluation value becomes small.

  Similarly, in order to achieve the above object, the present invention provides an image pickup apparatus including the automatic focusing apparatus according to any one of claims 1 to 5.

  According to the present invention, it is possible to provide an automatic focus adjustment apparatus or an imaging apparatus capable of improving the focusing performance for a high-luminance imaging target.

  The best mode for carrying out the present invention is as shown in the following examples.

  FIG. 1 is a block diagram showing a circuit configuration of a video camera according to an embodiment of the present invention. In FIG. 1, a focus adjustment focus lens 101 is moved in the optical axis direction by a lens driving motor 128 driven by a motor driver 127. The light that has passed through the focus lens 101 forms an image on the imaging surface of the CCD 102 that is an imaging element. A signal photoelectrically converted by the image sensor 102 is sampled and held by the CDS / AGC 103 and amplified with an optimum gain. An analog signal from the CDS / AGC 103 is converted into a digital signal by the A / D converter 104.

"Generation of Y integral evaluation value"
The signal from the A / D converter 104 is signal-processed in the TV signal format by the camera signal processing circuit 105, and the luminance signal Y is output for generating an AF evaluation value (focus evaluation value). The luminance signal Y from the camera signal processing circuit 105 is gamma-converted by a gamma curve by the gamma circuit 106, and the low luminance component is emphasized and the high luminance component is suppressed. The luminance signal Y that has been gamma-converted by the gamma circuit 106 is input to the horizontal integration circuit 107, where an integrated value for each horizontal line is detected and the horizontal in the AF frame set by the frame generation circuit 125 described later. The Y integral value for each line is obtained. The signals from the horizontal integration circuit 107 are added in the vertical direction within the AF frame by the vertical integration circuit 108 to generate a Y integration evaluation value.

"Generation of Y peak evaluation value"
The luminance signal Y gamma-converted by the gamma circuit 106 detects the peak value for each horizontal line by the line peak hold circuit 109, and obtains the Y peak value for each horizontal line within the AF frame. The output from the line peak hold circuit 109 is peak-held in the vertical direction within the AF frame by the vertical peak hold circuit 110, and a Y peak hold evaluation value is generated.

"Generation of Max-Min evaluation value"
The luminance signal Y gamma-converted by the gamma circuit 106 holds the maximum value (Max) and the minimum value (Min) for each line in the AF frame by the line maximum value hold circuit 111 and the line minimum value hold circuit 112. Is done. These held Max and Min are input to the subtractor 113 line by line, are subtracted (Max-Min), and are input to the vertical peak hold circuit 114. The vertical peak hold circuit 114 holds the peak in the vertical direction within the AF frame to generate a Max-Min evaluation value.

"Generation of TE peak evaluation value and TE line peak integration evaluation value"
A predetermined frequency component is extracted from the luminance signal Y that has been gamma-converted by the gamma circuit 106 by a BPF (band pass filter) 115. A TE (Top Evaluate) signal from the BPF 115 is input to a line peak hold circuit 116 for detecting a peak value for each horizontal line. The line peak hold circuit 116 calculates the TE peak value for each horizontal line within the AF frame. The TE peak value is peak-held in the vertical direction within the AF frame by the vertical peak hold circuit 117, and a TE peak evaluation value is generated. Further, the TE peak value is added in the vertical direction within the AF frame by the vertical integration circuit 121, and a TE line peak integration evaluation value is generated.

"Generation of TE line peak integral evaluation value Hi"
The Y peak value for each horizontal line from the line peak hold circuit 109 is input to the comparator 118 in which a predetermined threshold value (th) is set by the control microcomputer 126. Further, (Max-Min) is input to the comparator 118. The comparator 118 compares the Y peak value and the (Max-Min) level with a predetermined threshold value. Only the TE peak value of the line where the Y peak value and the level of (Max-Min) are larger than the predetermined threshold value are switched by the selector switch 119 so as to be input to the vertical integration circuit 120. Then, the vertical integration circuit 120 adds in the vertical direction within the AF frame to generate the TE line peak integration evaluation value Hi.

Generate high line count
Similarly, the Y peak value and (Max−Min) for each horizontal line are input to the comparator 118 in which a predetermined threshold value is set by the control microcomputer 126, where the Y peak value and (Max−Min) The level is compared with a predetermined threshold value. Then, a line whose Y peak value and (Max-Min) level are larger than a predetermined threshold value is input to the counter 122 and counted here, and a high line count (meaning a line count of high brightness and high contrast) is obtained. Generated.

“Generating Low Line Count”
(Max-Min) for each horizontal line is input to a comparator 123 in which a predetermined threshold value is set by a control microcomputer 126 described later. Then, the level of (Max-Min) is compared with a predetermined threshold value, and lines smaller than the predetermined threshold value are counted by the counter 124 to generate a low line count (meaning a low contrast line count). The

  As shown in FIG. 3, when a subject such as a point light source whose length fluctuates due to focus adjustment is photographed, when the subject is out of focus as shown in FIG. 3B, the peak value of each line is small. There are many lines on which the image is applied. On the other hand, when focusing is performed as shown in FIG. 3A, the peak value of each line increases, but the number of lines on which the subject image is applied decreases, so the line peak integral evaluation value decreases. Thus, as shown in FIG. 4, the maximum point of the line peak integral evaluation value does not become the focal point. For this reason, when focus adjustment is performed so as to increase the line peak integral evaluation value, focusing cannot be performed.

  However, as shown in FIG. 5, when there is a subject other than the point light source, even if the number of lines on which the subject image of the point light source is reduced, the TE peak value of that line can be obtained by the subject other than the point light source instead. . For this reason, the influence of fluctuations in the number of lines on which the subject image of the point light source is applied is small, and the TE line peak integral evaluation value is maximized at the focal point.

  Here, by comparing the TE line peak integration evaluation value with the TE line peak integration evaluation value Hi, it is determined whether the TE line peak integration evaluation value is only a component due to a high-luminance line (only a point light source subject) or not. Whether a component is included (whether there is a subject other than a point light source) can be predicted.

  FIG. 6A shows a state of the TE line peak integral evaluation value Hi of the point light source subject. According to FIG. 6 (a), since the Y peak level also decreases during out-of-focus, the TE line peak integrated evaluation value Hi is almost zero at, for example, the nearest or infinity, and increases as it approaches the in-focus point. The percentage of peak integrated evaluation value also increases. Therefore, by this ratio, it is possible to determine whether or not the subject is in focus by reducing the ratio of the TE line peak integral evaluation value at the focal point, with a large component due to the high-luminance line (only the point light source subject).

  Further, by the TE line peak integration evaluation value, the TE line peak integration evaluation value Hi, the high line count, and the low line count, it is determined whether the subject is only a point light source subject with high brightness and no other subjects as follows. To do.

1) The ratio of the TE line peak integral evaluation value Hi to the TE line peak integral evaluation value is large (= the influence of the high luminance and high contrast portions on the evaluation value is large)
For all line numbers
2) The ratio of the high line count and the low line count is large (= no subject other than the point light source that is not easily affected by the area variation of the high brightness subject)
3) The low line count is equal to or greater than a predetermined value (= there are many lines that are easily affected by the area variation of the high-luminance subject).

  Further, as shown in FIG. 6B, since the point light source subject has high luminance and high contrast particularly near the in-focus point, it is determined whether the Y peak evaluation value and the Max-Min evaluation value are larger than predetermined values. Thereby, it is possible to determine whether or not the line peak integral evaluation value is in the vicinity of the in-focus point (concave portion) of the subject that is concave (minimum).

  The frame generation circuit 125 generates a gate signal for the AF frame (focus detection area) at a predetermined position in the screen set by the control microcomputer 126. The gate signal is input to the horizontal integration circuit 107, the vertical integration circuits 108, 120, and 121 and the line peak hold circuits 109 and 116. Further, it is inputted to the line maximum value hold circuit 111, the line minimum value hold circuit 112, the vertical peak hold 110, 114, 117 and the counters 122, 124. Then, a timing signal is input so that each AF evaluation value is generated by a Y signal in the AF frame.

  The control microcomputer 126 designates a predetermined position in the screen to the frame generation circuit 125, fetches AF evaluation values from each of the circuits and counters, and uses the motor driver 127 via the motor driver 127 based on these AF evaluation values. Drive. Thereby, the focus lens 101 moves in the optical axis direction, and AF control is performed.

  Next, the AF control performed by the control microcomputer 126 will be described in detail with reference to FIGS.

  FIG. 7 is a flowchart showing the main operation of AF control, which will be described below. The control microcomputer 126 starts AF control from step S701. First, in step S702, a fine driving operation is performed to determine whether or not the focus is in focus, and in which direction the focus is in focus if not in focus. . Details will be described later with reference to FIG. In the next step S703, it is determined whether or not the in-focus state has been determined in step S702. If the in-focus state has been determined, the process proceeds to step S709 and later. On the other hand, if the in-focus state cannot be determined, the process proceeds from step S703 to step S704. In step S704, it is checked whether or not the in-focus direction can be determined in step S702. If the in-focus direction cannot be determined, the process returns to step S702 to continue the minute driving operation. If the in-focus direction can be determined, the process proceeds from step S704 to step S705.

  In step S705, since the in-focus direction can be determined, the control microcomputer 126 drives the focus lens 101 so-called hill-climbing at a high speed in a direction in which the TE line peak integral evaluation value increases. Detailed operation will be described later with reference to FIG. In the next step S706, it is determined whether or not the TE line peak integration evaluation value has exceeded the peak in step S705. If it is determined that the TE line peak integration evaluation value has exceeded the peak, the process proceeds to step S707. If it is not possible to determine that the peak of the TE line peak integration evaluation value has been exceeded, the process returns from step S706 to step S705, and hill-climbing driving is continued until it is determined in step S706 that the peak has been exceeded.

  In step S707, the control microcomputer 126 returns the focus lens 101 to the lens position at which the TE line peak integration evaluation value during the hill-climbing drive becomes a peak (vertex). Then, in the next step S708, it is determined whether or not the focus lens 101 has returned to the peak lens position in step S707. If the focus lens 101 has returned to the peak lens position, the process returns to step S702, and the minute driving operation is performed again. . If the focus lens 101 has not returned to the peak lens position, the process returns to step S707, and the operation to return to the peak is continued until it can be determined in step S708 that the focus lens 101 has returned to the peak lens position.

  Next, the focusing operation after the step S703 can be determined to be in-focus and the process proceeds to step S709.

  In step S709, the control microcomputer 126 holds an AF evaluation value (TE peak evaluation value). In the next step S710, the latest various AF evaluation values are acquired. In subsequent step S711, the TE peak evaluation value held in step S709 is compared with the TE peak evaluation value newly acquired in step S710. As a result, if there is a difference of a predetermined level or more (if the AF evaluation value fluctuation is large), it is determined that the system is restarted, and the process returns to step S702 to restart the minute driving operation. On the other hand, if it is not determined to be restarted in step S711, the process proceeds to step S712, the focus lens 101 is stopped, the process returns to step S710, and the restart determination is continued.

  Next, the fine driving operation executed in step S702 of FIG. 7 will be described with reference to the flowchart of FIG.

  In step S801, minute driving is started. First, in step S802, the latest various AF evaluation values are acquired. Then, in the next step S803, it is determined whether or not the TE line peak integral evaluation value taken in step S802 is larger than the previous TE line peak integral evaluation value. As a result, if the TE line peak integral evaluation value is larger than the previous TE line peak integral evaluation value, the process proceeds to step S804, and the focus lens 101 is driven by a predetermined amount in the previous forward direction. On the other hand, if the TE line peak integration evaluation value is smaller than the previous TE line peak integration evaluation value, the process proceeds to step S805, and the focus lens 101 is driven by a predetermined amount in the direction opposite to the previous time.

  In the next step S806, it is determined whether or not the direction that can be discriminated as the in-focus direction is the same for a predetermined number of times, and the process proceeds to step S807 if the direction has continued in the same direction for a predetermined number of times. Here, it is assumed that the direction can be discriminated, and in the next step S810, the micro-driving operation is terminated, and the process returns to the main routine.

  If the process does not proceed in the same direction for a predetermined number of times in step S860, the process proceeds to step S808. In step S808, it is determined whether the focus lens 101 repeats reciprocation within a predetermined range. If the reciprocation is repeated within a predetermined range, the process proceeds to step S809. Here, it is determined that the in-focus state has been determined, and in the next step S810, the operation of the minute driving is terminated and the process returns to the main routine.

  If it is determined in step S808 that the focus lens 101 has not reciprocated within a predetermined range a predetermined number of times, the process proceeds to step S810, the operation of this minute driving is terminated, and the process returns to the main routine.

  FIG. 9 shows the lens position and time passage when the focus lens 101 is driven. In FIG. 9, the evaluation value A for the electric charge accumulated in the CCD 102 during A is taken in by TA, and the evaluation value B for the electric charge accumulated in the CCD 102 during B is taken in by TB. In TB, the evaluation values A and B are compared. If A <B, the evaluation value is moved in the forward direction, while if A> B, the reverse direction is set. Here, the driving amount of the focus lens 101 is determined on the basis of the depth of focus so that the movement of the focus is not recognized by looking at the imaging signal on the TV screen or the like by one movement.

  Next, the hill-climbing drive operation executed in step S705 of FIG. 7 will be described with reference to the flowchart of FIG.

  In step S1001, the mountain climbing operation is started. First, in step S1002, the latest various AF evaluation values are acquired. In the next step S1003, it is determined whether or not the TE line peak integral evaluation value taken in step S1002 is larger than the previous TE line peak integral evaluation value. As a result, if larger, the process proceeds to step S1004. Here, the focus lens 101 is driven at a predetermined speed in the previous forward direction, and in the next step S1008, the hill-climbing driving operation is terminated, and the process returns to the main routine.

  If it is determined that the TE line peak integral evaluation value taken in step S1002 is smaller than the previous TE line peak integral evaluation value, the process proceeds from step S1003 to step S1005. In step S1005, it is determined whether the TE line peak integral evaluation value decreases beyond the peak. As a result, if it has decreased, the process proceeds to step S1006. Here, it is assumed that the peak has been exceeded, and in this next step S1008, this hill-climbing drive is terminated, and the process returns to the main routine.

  If it is determined in step S1005 that the TE line peak integral evaluation value has not decreased beyond the peak, the process proceeds to step S1007, and the focus lens 101 is driven at a predetermined speed in the direction opposite to the previous time. In step S1008, the hill-climbing drive is terminated, and the process returns to the main routine.

  FIG. 11 shows the lens position and time passage when the focus lens 101 is driven. Here, since the solid line A has decreased beyond the peak, the hill-climbing driving operation is terminated assuming that there is a focal point, and the operation shifts to the minute driving operation. On the other hand, the dotted line B has no peak, and thus has a wrong direction. Inverted and continued to climb the mountain. Note that the amount of movement per fixed time is larger than the amount of movement described above.

  As described above, the control microcomputer 126 moves the focus lens 101 while repeating the restart determination → micro drive → mountain climbing drive → micro drive → restart determination so as to increase the TE line peak integral evaluation value. ing.

  Next, details of the AF evaluation value acquisition operation in step S710 in FIG. 7, step S802 in FIG. 8, and step S1002 in FIG. 10 will be described using the flowchart in FIG.

  In step S1201, AF evaluation value acquisition is started. First, in step S1202, various AF evaluation values are captured. This AF evaluation value is used to determine whether or not the point light source subject is in the vicinity of the focal point.

  In the next step S1203, the TE line peak integral evaluation value and the TE line peak integral evaluation value Hi are compared, and whether or not the component due to the TE line peak integral evaluation value Hi (a high brightness line of the TE line peak integral evaluation value) is large. Is determined. As a result, if the ratio of the TE line peak integral evaluation value Hi to the TE line peak integral evaluation value is large (the influence of the high luminance and high contrast portion on the evaluation value is large), the process proceeds to step S1204. On the other hand, if not, the process proceeds to step S1208, the AF evaluation value acquisition operation is terminated, and the process returns to the main routine.

  In step S1204, it is determined whether or not the ratio of the high line count and the low line count is large, that is, whether or not there is no subject other than the point light source that is not easily affected by the area variation of the high brightness subject. . As a result, if there is no subject other than the point light source, the process proceeds to step S1204. On the other hand, if there is a subject other than the point light source, the process advances to step S1208 to end the AF evaluation value acquisition operation and return to the main routine.

  In step S1205, it is determined whether the low line count is equal to or greater than the predetermined threshold value (th) and there are many lines that are susceptible to the area variation of the high brightness subject, and as a result, the area is affected by the area variation of the high brightness subject. If there are many easy lines, the process advances to step S1205. On the other hand, if there are not many lines that are susceptible to the area variation of the high-luminance subject, the process proceeds to step S1208, the AF evaluation value acquisition operation is terminated, and the process returns to the main routine.

  In step S1206, since the point light source subject has high brightness and high contrast particularly near the in-focus point, it is determined whether or not the Y peak evaluation value and the Max-Min evaluation value are larger than a predetermined threshold value. As a result, if the Y peak evaluation value and the Max-Min evaluation value are larger than the predetermined threshold value, that is, if it is determined that only the point light source is present, the process proceeds to step S1207. On the other hand, if it is determined that it is not only the point light source, the process proceeds to step S1208, the AF evaluation value acquisition operation is terminated, and the process returns to the main routine.

  By each determination in the above steps S1203 to S1206, it is determined whether or not the TE line peak integral evaluation value is near the in-focus point (concave portion) of the subject having a concave shape.

  When it is determined that only the point light source is determined in step S1206 and the process proceeds to step S1207, the maximum data size of the TE line peak integral evaluation value (eg, 111111111111 (binary) = 4095 (decimal) if 12 bits) is obtained here. A value obtained by subtracting the actual TE line peak integration evaluation value is newly set as the TE line peak integration evaluation value.

TE line peak integral evaluation value
= Maximum value of TE line peak integral evaluation value data size
-TE line peak integral evaluation value If the TE line peak integral evaluation value after replacement in step S127 is input to a program that performs AF control so that the evaluation value becomes large, the TE line peak integral evaluation value before replacement is The AF control is performed so as to decrease. As a result, program changes can be minimized and ROM can be saved. Of course, the operation of the present invention can also be realized by independently inputting a program for AF control so that the evaluation value becomes small and switching the programs.

  As described above, when the ratio of the TE line peak integral evaluation value Hi to the TE line peak integral evaluation value is large, the vicinity of the focal point of the point light source subject is detected by obtaining the ratio of the high line count and the low line count. be able to.

  Further, by determining whether the low line count is larger than a predetermined threshold value, and whether the Y peak evaluation value and the Max-Min evaluation value are larger than a predetermined threshold value, the vicinity of the focal point of the point light source subject is determined. It is possible to improve the detection accuracy.

  When it can be determined that the point light source is in the vicinity of the focal point as described above, the TE line peak integral evaluation value at the focal point is driven by driving the focus lens 101 so that the TE line peak integral evaluation value becomes small (minimum). For example, an automatic focus adjustment device capable of focusing even a subject having only a point light source, such as a point light source, and an imaging device such as a video camera including the automatic focus adjustment device can be provided.

It is a block diagram which shows the schematic circuit structure of the video camera concerning the Example of this invention. It is a figure for demonstrating AF evaluation value in the Example of this invention. It is a figure for demonstrating the AF evaluation value of a point light source photographic subject in the Example of this invention. It is a figure for demonstrating the AF evaluation value of a point light source photographic object similarly in the Example of this invention. It is a figure for demonstrating AF evaluation value when including subjects other than a point light source subject in the Example of this invention. It is a figure for demonstrating AF evaluation value at the time of the point light source photographic subject in the Example of this invention. It is a main flowchart which shows the operation | movement of AF control in the Example of this invention. It is a flowchart which shows the detail of the micro drive of the focus lens performed in step S702 of FIG. It is a figure for demonstrating the moving direction of the focus lens in the micro drive process of FIG. It is a flowchart which shows the mountain climbing drive performed in step S705 of FIG. It is a figure for demonstrating the moving direction of a focus lens at the time of the hill-climbing drive of FIG. It is a flowchart which shows the operation | movement at the time of AF evaluation value acquisition performed by step S710 etc. of FIG.

Explanation of symbols

101 Focus lens 102 CCD
103 CDS / AGC
105 Camera Signal Processing Circuit 106 Gamma Circuit 107 Horizontal Integration Circuit 108 Vertical Integration Circuit 109 Line Peak Hold Circuit 110 Vertical Peak Hold Circuit 111 Line Maximum Value Hold Circuit 112 Line Minimum Value Hold Circuit 113 Subtractor 114 Vertical Peak Hold Circuit 115 BPF
116 Line Peak Hold Circuit 117 Vertical Peak Hold Circuit 118 Comparator 119 Changeover Switch 120 Vertical Integration Circuit 121 Vertical Integration Circuit 122 Counter 123 Comparator 124 Counter 125 Frame Generation Circuit 126 Control Microcomputer 127 Motor Driver 128 Motor

Claims (6)

In an automatic focus adjustment device that obtains a relative focus evaluation value based on an imaging signal corresponding to the position of the focus lens and performs focus adjustment control so that the focus evaluation value becomes large.
An automatic focus adjustment apparatus that performs focus adjustment control so that the focus evaluation value becomes smaller when a ratio of a high luminance portion in the acquired focus evaluation value is larger than a predetermined value.   The automatic focus adjustment apparatus according to claim 1, wherein when the ratio of the high luminance part in the focus evaluation value is larger than a predetermined value, the imaging target is determined to be a high luminance target.   3. The focus adjustment control is performed according to a ratio of a high-luminance and high-contrast part and a ratio of a low-contrast part in the imaging signal in addition to the ratio of the high-luminance part in the focus evaluation value. The automatic focusing apparatus according to any one of the above.   4. The automatic focus adjustment apparatus according to claim 1, wherein the maximum value of the luminance signal acquired from the imaging signal is used as one requirement when performing focus adjustment control.   5. The automatic focus adjustment apparatus according to claim 1, wherein a difference between a maximum value and a minimum value of a luminance signal acquired from an imaging signal is used as one requirement when focus adjustment control is performed. An imaging apparatus comprising the automatic focus adjustment apparatus according to claim 1.

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