JP2012150236A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an imaging performance with attention focused on an eye part.SOLUTION: An imager 16 includes an imaging surface for capturing an image of a field via a focus lens 12 and repetitively outputs raw image data. Search image data based on the outputted raw image data is written in a search image area 32c of an SDRAM 32. CPU 26 sets the depth of field to "D1", and then searches an image representing the eye part of a person from the search image data on the search image area 32c. When the eye-part image is searched, the CPU 26 sets the depth of field to "D2" that is shallower than the "D1" and executes an AF process, with the attention focused on the searched eye-part image. After that, the CPU 26 sets the depth of field to "D3" that is shallower than "D1" and deeper than the "D2".

Description

  The present invention relates to an electronic camera, and more particularly to an electronic camera that adjusts focus by paying attention to a specific object such as a human eye.

  An example of this type of camera is disclosed in Patent Document 1. According to this background art, the imaging unit converts incident light into an electrical signal corresponding to the amount of light, and outputs image data. The face detection processing unit detects a human eye included in the image data from the imaging unit, and outputs information indicating the position and size of the detected eye. The AF control unit sets a focus frame at a position covering the eye detected by the face detection processing unit, detects a focal point position for each focus frame, and selects a focal point position for shooting from the detected focal point position To decide. This makes it possible to easily obtain a photographed image focused on the eyes when photographing a person.

JP 2005-128156 A

  However, when a plurality of eyes are detected, the aperture amount is adjusted so that a plurality of in-focus positions respectively corresponding to the detected plurality of eyes are included in the depth of field. Therefore, the imaging performance is limited in the background art.

  Therefore, a main object of the present invention is to provide an electronic camera that can improve imaging performance with attention paid to a specific object.

  An electronic camera according to the present invention (10: reference numeral corresponding to the embodiment; the same applies hereinafter) has an imaging surface that captures the scene through the focus lens (12), and imaging means (16) that repeatedly outputs the scene image. ), Search means (S55, S1 to S45, S93 to S95, S109 to S111, S117) for searching for a specific object image from the object scene image output from the imaging means, depth of field prior to the processing of the search means The first setting means (S51) for setting the first depth to the first depth, the second setting means (S127) for setting the depth of field to the second depth shallower than the first depth in response to detection by the search means, and the focus lens First adjustment means (S129) for adjusting the distance from the imaging surface to the imaging surface based on the high frequency component of the specific object image detected by the search means, and the depth of field from the first depth after the processing of the first adjustment means 3rd setting means (S131 ~ S137, S141 ~ S145) to set the third depth which is shallower and deeper than the second depth .

  Preferably, a diaphragm mechanism (14) for defining a depth of field is further provided, and the second depth corresponds to a depth obtained by opening the diaphragm mechanism.

  Preferably, the specific object image corresponds to the closest eye part of the two eye parts forming the face, and the search means searches for the face image from the object scene image (S1 to S45), Face orientation specifying means (S95) for specifying the orientation of the face image detected by the face image searching means, and eye detection means for detecting the closest eye portion with reference to the orientation specified by the face orientation specifying means ( S109 to S111, S117).

  In one aspect, a determination unit (S119) for determining whether or not the direction specified by the face direction specifying unit is a direction in which the infinite eye part is hidden, the nose when the determination result of the determination unit is affirmative The first designation means (S121 to S123) for designating the area corresponding to the area of interest, and the second designation for designating the area corresponding to the infinite eye area as the attention area when the discrimination result of the discrimination means is negative Means (S125) is further provided, and the third depth corresponds to a depth at which a high-frequency component of a partial image belonging to the region of interest among the object scene image output from the imaging means satisfies a predetermined condition.

  Preferably, the area specified by the first specifying means is a base area of the nose.

  In another aspect, fourth setting means (S73) is further provided for setting the depth of field to a fourth depth that is shallower than the first depth and deeper than the second depth in response to detection by the face image search means. .

  In another aspect, second adjustment means (S115) for adjusting the distance from the focus lens to the imaging surface in a predetermined manner, and activation means (S113) for starting the second adjustment means in response to non-detection of the eye part detection means. ) Is further provided.

  An imaging control program according to the present invention includes a processor (26) for an electronic camera (10) having an imaging surface for capturing an object scene through a focus lens (12) and including an imaging means (16) for repeatedly outputting the object scene image. In addition, a search step (S55, S1 to S45, S93 to S95, S109 to S111, S117) for searching for a specific object image from the object scene image output from the imaging means, the depth of field prior to the processing of the search step A first setting step (S51) for setting the first depth to the first depth, a second setting step (S127) for setting the depth of field to a second depth shallower than the first depth in response to detection of the search step, a focus lens An adjustment step (S129) for adjusting the distance from the image pickup surface to the imaging surface based on the high-frequency component of the specific object image detected by the search step, and a depth of field that is shallower than the first depth and processed after the adjustment step processing Set the third depth deeper than the second depth To execute the setting step (S131 ~ S137, S141 ~ S145), an imaging control program.

  An imaging control method according to the present invention includes an imaging surface that captures an object scene through a focus lens (12), and imaging performed by an electronic camera (10) that includes an imaging means (16) that repeatedly outputs the object scene image. A control method for searching for a specific object image from a scene image output from an imaging means (S55, S1 to S45, S93 to S95, S109 to S111, S117), prior to the processing of the search step A first setting step (S51) for setting the depth of field to the first depth, and a second setting step (S127) for setting the depth of field to a second depth shallower than the first depth in response to detection in the search step. ), An adjustment step (S129) for adjusting the distance from the focus lens to the imaging surface based on the high-frequency component of the specific object image detected by the search step, and the depth of field from the first depth after the processing of the adjustment step 3rd shallower and deeper than 2nd depth A third setting step for setting the time (S131 ~ S137, S141 ~ S145).

  An external control program according to the present invention has an imaging surface for capturing an object scene through a focus lens (12), an image pickup means (16) for repeatedly outputting the object scene image, and an internal control stored in a memory (44). An external control program supplied to an electronic camera (10) having a processor (26) for executing processing according to a program, and a search step for searching for a specific object image from a scene image output from an imaging means (S55, S1 to S45, S93 to S95, S109 to S111, S117), a first setting step (S51) for setting the depth of field to the first depth prior to the processing of the search step, and a response in response to detection of the search step. Second setting step (S127) for setting the depth of field to a second depth shallower than the first depth, and adjusting the distance from the focus lens to the imaging surface based on the high frequency component of the specific object image detected by the searching step Adjustment step (S129), And a third setting step (S131 to S137, S141 to S145) for setting the depth of field to a third depth that is shallower than the first depth and deeper than the second depth after the adjustment step processing. This is an external control program for causing a processor to execute.

  An electronic camera (10) according to the present invention has an imaging surface for capturing an object scene through a focus lens (12), an image pickup means (16) for repeatedly outputting the object scene image, and an input means (48) for taking in an external control program. ), And an external control program captured by the capturing means and a processor (26) that executes processing according to the internal control program stored in the memory (44), the external control program being output from the imaging means Search step (S55, S1 to S45, S93 to S95, S109 to S111, S117) for searching for a specific object image from the captured object field image, and setting the depth of field to the first depth prior to the processing of the search step A first setting step (S51), a second setting step (S127) for setting the depth of field to a second depth shallower than the first depth in response to detection in the search step, and a distance from the focus lens to the imaging surface Explore An adjustment step (S129) for adjusting based on the high-frequency component of the specific object image detected by the step, and a third depth that is shallower than the first depth and deeper than the second depth after the processing of the adjustment step. This corresponds to a program that executes the third setting step (S131 to S137, S141 to S145) to be set in cooperation with the internal control program.

  According to this invention, the depth of field decreases in the order of the first depth, the third depth, and the second depth. By searching for the specific object image corresponding to the first depth, the detection accuracy of the specific object image is improved. Further, by performing the distance adjustment based on the high-frequency component of the specific object image corresponding to the second depth, the focusing accuracy with respect to the specific object is improved. Furthermore, the sharpness of the image in the vicinity of the specific object is improved by setting the depth of field to the third depth after the distance adjustment. Thereby, it is possible to improve imaging performance with attention paid to a specific object.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

It is a block diagram which shows the basic composition of one Example of this invention. It is a block diagram which shows the structure of one Example of this invention. It is an illustration figure which shows an example of the allocation state of the evaluation area in an imaging surface. It is an illustration figure which shows an example of the face frame used in a face detection process. It is an illustration figure which shows an example of a structure of the face dictionary referred in a face detection process. It is an illustration figure which shows a part of face detection process. FIG. 3 is an illustrative view showing one example of a configuration of a register applied to the embodiment in FIG. 2; (A) is an illustration figure which shows an example of a scene image, (B) is an illustration figure which shows an example of the allocation state of a face frame or a face frame character. (A) is an illustrative view showing an example of a setting state of an eye part search area, (B) is an illustrative view showing another example of a setting state of an eye part search area, and (C) is an eye part search area. FIG. 6D is an illustrative view showing another example of the setting state of the eye, (D) is an illustrative view showing still another example of the setting state of the eye part search area, and (E) is another setting state of the eye part search area. (F) is an illustrative view showing another example of the setting state of the eye part search area, and (G) is an illustrative view showing still another example of the setting state of the eye part search area. FIG. It is an illustration figure which shows an example of a structure of the eye part dictionary referred in an eye part detection process. FIG. 10 is an illustrative view showing one example of a configuration of another register applied to the embodiment in FIG. 2; (A) is an illustration which shows an example of the setting state of a nose part search area, (B) is an illustration figure which shows another example of the setting state of a nose part search area, (C) is a nose part search area. FIG. 4D is an illustrative view showing another example of the setting state of FIG. 2D, FIG. 4D is an illustrative view showing still another example of the setting state of the nose search area, and FIG. (F) is an illustrative view showing another example of the setting state of the nose portion search area, and (G) is an illustrative view showing still another example of the setting state of the nose portion search area. FIG. It is an illustration figure which shows an example of a structure of the nose part dictionary referred in a nose part detection process. FIG. 10 is an illustrative view showing one example of a configuration of another register applied to the embodiment in FIG. 2; It is an illustration figure which shows an example of the operation | movement which adjusts the depth of field. It is an illustration figure which shows another example of the operation | movement which adjusts the depth of field. It is a flowchart which shows a part of operation | movement of CPU applied to the FIG. 2 Example. It is a flowchart which shows a part of other operation | movement of CPU applied to the FIG. 2 Example. FIG. 11 is a flowchart showing still another portion of behavior of the CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing yet another portion of behavior of the CPU applied to the embodiment in FIG. 2; It is a flowchart which shows a part of other operation | movement of CPU applied to the FIG. 2 Example. FIG. 11 is a flowchart showing still another portion of behavior of the CPU applied to the embodiment in FIG. 2; FIG. 10 is a flowchart showing yet another portion of behavior of the CPU applied to the embodiment in FIG. 2; It is a flowchart which shows a part of other operation | movement of CPU applied to the FIG. 2 Example. It is a flowchart which shows a part of operation | movement of CPU applied to the other Example of this invention. It is an illustration figure which shows an example of the operation | movement which adjusts the depth of field in the other Example of this invention. It is a block diagram which shows the structure of the further another Example of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[Basic configuration]

  Referring to FIG. 1, the electronic camera of this embodiment is basically configured as follows. The imaging means 1 has an imaging surface for capturing the scene through the focus lens 7 and repeatedly outputs the scene image. The search means 2 searches for a specific object image from the object scene image output from the imaging means 1. The first setting unit 3 sets the depth of field to the first depth prior to the processing of the search unit 2. The second setting means 4 sets the depth of field to a second depth shallower than the first depth in response to the detection by the searching means 2. The first adjusting unit 5 adjusts the distance from the focus lens 7 to the imaging surface based on the high frequency component of the specific object image detected by the searching unit 2. The third setting means 6 sets the depth of field to a third depth that is shallower than the first depth and deeper than the second depth after the processing of the first adjusting means 5.

The depth of field decreases in the order of the first depth, the third depth, and the second depth. By searching for the specific object image corresponding to the first depth, the detection accuracy of the specific object image is improved. Further, by performing the distance adjustment based on the high-frequency component of the specific object image corresponding to the second depth, the focusing accuracy with respect to the specific object is improved. Furthermore, the sharpness of the image in the vicinity of the specific object is improved by setting the depth of field to the third depth after the distance adjustment. Thereby, it is possible to improve imaging performance with attention paid to a specific object.
[Example]

  Referring to FIG. 2, the digital camera 10 of this embodiment includes a focus lens 12 and an aperture mechanism 14 driven by drivers 18a and 18b, respectively. The optical image of the object scene that has passed through these members is irradiated onto the imaging surface of the imager 16 and subjected to photoelectric conversion. As a result, a charge representing the object scene image is generated.

  When the power is turned on, the CPU 26 gives corresponding commands to the drivers 18a and 18b to validate the pan focus setting under the imaging task. Thus, the position of the focus lens 12 and the aperture amount of the aperture mechanism 14 are adjusted so that the depth of field indicates “D1”.

  Subsequently, the CPU 26 instructs the driver 18c to repeat the exposure operation and the charge reading operation under the imaging task in order to start the moving image capturing process. In response to a vertical synchronization signal Vsync periodically generated from an SG (Signal Generator) (not shown), the driver 18c exposes the imaging surface and reads out the charges generated on the imaging surface in a raster scanning manner. From the imager 16, raw image data based on the read charges is periodically output.

  The preprocessing circuit 20 performs processing such as digital clamping, pixel defect correction, and gain control on the raw image data output from the imager 16. The raw image data subjected to these processes is written into the raw image area 32 a of the SDRAM 32 through the memory control circuit 30.

  The post-processing circuit 34 reads the raw image data stored in the raw image area 32a through the memory control circuit 30, and performs color separation processing, white balance adjustment processing, and YUV conversion processing on the read raw image data. The post-processing circuit 34 further performs display zoom processing and search zoom processing in parallel on the image data in the YUV format. As a result, display image data and search image data conforming to the YUV format are individually created.

  The display image data is written into the display image area 32 b of the SDRAM 32 by the memory control circuit 30. The search image data is written into the search image area 32 c of the SDRAM 32 by the memory control circuit 30.

  The LCD driver 36 repeatedly reads the display image data stored in the display image area 32b through the memory control circuit 30, and drives the LCD monitor 38 based on the read image data. As a result, a real-time moving image (through image) of the object scene is displayed on the monitor screen.

  Referring to FIG. 3, an evaluation area EVA is allocated at the center of the imaging surface. The evaluation area EVA is divided into 64 parts in each of the horizontal direction and the vertical direction, and the evaluation area EVA is formed by a total of 4096 divided areas. In addition to the above-described processing, the preprocessing circuit 20 shown in FIG. 2 executes simple RGB conversion processing that simply converts raw image data into RGB data.

  The AE evaluation circuit 22 integrates RGB data belonging to the evaluation area EVA among the RGB data generated by the preprocessing circuit 20 for each divided area. This integration process is executed every time the vertical synchronization signal Vsync is generated. As a result, 4096 integral values, that is, 4096 AE evaluation values, are output from the AE evaluation circuit 22 in response to the vertical synchronization signal Vsync.

  Further, the AF evaluation circuit 24 integrates the high-frequency components of the RGB data belonging to the evaluation area EVA among the RGB data generated by the preprocessing circuit 20 for each divided area. This integration process is also executed each time the vertical synchronization signal Vsync is generated. As a result, 4096 integral values, that is, 4096 AF evaluation values, are output from the AF evaluation circuit 24 in response to the vertical synchronization signal Vsync.

  The processing based on the AE evaluation value output from the AE evaluation circuit 22 and the AF evaluation value output from the AF evaluation circuit 24 will be described later.

  The CPU 26 also repeatedly searches for a human face image from the search image data stored in the search image area 32c under a face detection task executed in parallel with the imaging task. At this time, a face frame FD whose size is adjusted in the manner shown in FIG. 4 and a face dictionary DC_F containing seven dictionary images shown in FIG. 5 are used.

  Here, the face dictionary DC_F is stored in the flash memory 44. In the face dictionary DC_F, a dictionary image assigned to FC = 1 corresponds to a face image facing front, a dictionary image assigned to FC = 2 corresponds to a face image facing 30 ° to the left, and FC The dictionary image assigned to = 3 corresponds to a face image facing 60 ° to the left, and the dictionary image assigned to FC = 4 corresponds to a face image facing 90 ° to the left. Also, the dictionary image assigned to FC = 5 corresponds to a face image that faces 30 ° to the right, and the dictionary image assigned to FC = 6 corresponds to a face image that faces 60 ° to the right. The dictionary image assigned to FC = 7 corresponds to a face image that faces 90 ° to the right.

  In the face detection task, first, the entire evaluation area EVA is set as a face search area. Further, in order to define a variable range of the size of the face frame FD, the maximum size FSZmax is set to “200”, and the minimum size FSZmin is set to “20”.

  The face frame FD is moved by a predetermined amount in a raster scanning manner from the start position (upper left position) to the end position (lower right position) of the face search area (see FIG. 6). The size of the face frame FD is reduced by “5” from “FSZmax” to “FSZmin” every time the face frame FD reaches the end position.

  Some search image data belonging to the face frame FD is read from the search image area 32 c through the memory control circuit 30. The feature amount of the read search image data is collated with the feature amount of each of the seven dictionary images stored in the face dictionary DC_F. When a matching degree equal to or higher than the threshold TH_F is obtained, it is considered that a face image has been detected. The current position and size of the face frame FD are registered in the register RGSTtmp shown in FIG. 7 together with the value of the face dictionary number FC that identifies the collation destination dictionary image. Further, the number of faces described in the register RGSTtmp is incremented along with such registration processing.

  Therefore, when the object scene shown in FIG. 8A is captured by the imaging surface, the position and size of the face frame registered in the register RGSTtmp indicate the position and size of the frame indicated by the bold line in FIG. The face dictionary number registered in the register RGSTtmp indicates “5”, and the number of faces described in the register RGSTtmp indicates “1”.

  When the face frame FD having the minimum size FSZmin reaches the end position of the face search area, the CPU 26 copies the description of the register RGSTtmp to the register RGSTout, and then clears the register RGSTtmp. The flag FLG_F referred to by the imaging task is set to “0” when the number of faces described in the register RGSTout is “0”, and is set to “1” when the number of faces described in the register RGSTout is “1” or more. Is set.

  When the flag FLG_F indicates “1”, the CPU 26 gives a face frame character display command to the character generator 46 under the imaging task in order to display one or more face frame characters on the LCD monitor 38. The face frame character is displayed on the LCD monitor 38 in a manner that matches the size and position of the face frame registered in the register RGSTout. When the object scene shown in FIG. 8A is captured, the face frame character is multiplexed on the through image in the manner shown in FIG.

  Subsequently, the CPU 26 detects the maximum size face frame character, and sets an area surrounded by the detected face frame character as an AE / AF area. In the example of FIG. 8B, since only one face frame character is displayed, the area surrounded by this face frame character is the AE / AF area.

  If the flag FLG_F is “0”, the face frame character is not displayed and the AE / AF area is set at the center of the evaluation area EVA.

  When the setting of the AE / AF area is completed, the CPU 26 executes a simple AE process. In the simple AE process, the appropriate EV value is calculated based on some AE evaluation values belonging to the AE / AF area among the 4096 AE evaluation values output from the AE evaluation circuit 22. The aperture amount and the exposure time that define the calculated appropriate EV value are set in the drivers 18b and 18c, respectively, and thereby the brightness of the through image is appropriately adjusted.

  When the shutter button 28sh is pressed halfway with the flag FLG_F indicating “1”, the CPU 26 sets the aperture amount of the aperture mechanism 14 so that the depth of field is set to “D4”, which is shallower than “D1”. The strict AE process is executed in such a manner that the adjusted aperture amount is prioritized. On the other hand, when the shutter button 28sh is half-pressed in a state where the flag FLG_F indicates “0”, the strict AE process is executed in a default manner.

  Any of the strict AE processes is executed with reference to a part of the AE evaluation values belonging to the AE / AF area, thereby calculating the optimum EV value. The aperture amount and the exposure time that define the calculated optimal EV value are set in the drivers 18b and 18c, respectively, as described above. The brightness of the live view image is adjusted strictly.

  When the strict AE process is completed, the CPU 26 executes an AF process with reference to 4096 AF evaluation values output from the AF evaluation circuit 24. The focus lens 12 is disposed at the focal point discovered by the AF process, and thereby the sharpness of the through image is improved. The AF process will be described in detail later.

  When the shutter button 28sh is fully pressed, the CPU 26 executes still image capture & recording processing. As a result of the still image capturing process, one frame of image data representing the scene at the time when the shutter button 28 sh is fully pressed is saved from the YUV image area 32 b to the still image area 32 d. As a result of the recording process, the memory I / F 40 is activated. The memory I / F 40 reads the image data saved in the still image area 32d through the memory control circuit 30, and records the read image data on the recording medium 42 in a file format.

  The AF process is executed as follows. First, it is determined whether the current AF mode selected by the mode switch 28md of the key input device 28 is the normal AF mode or the eye priority AF mode. Further, it is determined whether or not the logical product condition that the flag FLG_F is “1” and the maximum size of the face frame is equal to or larger than the threshold value TH_SZ is satisfied.

  When the current AF mode is the normal AF mode, or when the logical product condition is not satisfied, the normal AF process is executed. The normal AF process is executed with reference to some AF evaluation values belonging to the AE / AF area among the 4096 AF evaluation values output from the AE evaluation circuit 24. The focus lens 12 is disposed at a position where the sum of the referred AF evaluation values is maximized, thereby improving the sharpness of an image belonging to the AE / AF area.

  When the current AF mode is the eye priority AF mode and the above AND condition is satisfied, the face frame having the maximum size is specified from one or more face frames registered in the register RGSTout. Furthermore, the orientation of the face belonging to the specified face frame is detected based on the face dictionary number described in the register RGSTout accompanying the specified face frame.

  If the face dictionary number assigned to the face frame of the maximum size is “1”, the direction of the face belonging to the face frame of the maximum size is considered to be the front face toward the imaging surface. At this time, both eyes are searched from the face image belonging to the face frame of the maximum size. In the search, an eye search area is set on the face image in the manner shown in FIG. 9A, and four dictionary images assigned EY = 1 in the eye dictionary DC_EY shown in FIG. 10 are referred to. The size and position of the eye part detected in this way are set in the register RGSTey shown in FIG.

  Note that according to FIG. 10, characters indicating the shape of the eye and the left / right distinction are described, but an image corresponding to this is actually stored in the eye dictionary DC_EY. The dictionary image assigned to EY = 1 corresponds to the eye image facing the front, the dictionary image assigned to EY = 2 corresponds to the eye image directed to the left by 30 °, and EY = The dictionary image assigned to 3 corresponds to an eye image that faces 60 ° to the left, and the dictionary image assigned to EY = 4 corresponds to an eye image that turns 90 ° to the left.

  Further, the dictionary image assigned to EY = 5 corresponds to an eye image oriented in a direction inclined 30 ° to the right, and the dictionary image assigned to EY = 6 is an eye image directed in a direction inclined 60 ° to the right. The dictionary image assigned to EY = 7 corresponds to an eye image that faces 90 ° to the right.

  If neither the left eye nor the right eye is detected, it is considered that both eyes are closed, and the normal AF process described above is executed. This improves the sharpness of images belonging to the AE / AF area.

  On the other hand, when at least one of the left eye and the right eye is detected, the detected eye is designated as a main focus target. When both eyes are detected, the eye with the larger size is designated preferentially. When the designation of the main focus target is completed, the other eye is designated as the secondary focus target. When only one eye is detected, the other eye is estimated based on the position of the eye search area set on the face image and the detected position of the eye.

  If the face dictionary number assigned to the maximum size face frame is not “1”, the face belonging to the maximum size face frame is considered to be tilted to the right or left. At this time, the closest eye part is searched for among the left eye and the right eye. That is, the right eye is searched if the face direction is left toward the imaging surface, and the left eye is searched if the face direction is right toward the imaging surface.

  When searching for the right eye, the eye search area is set on the face image in the manner shown in FIG. 9B, FIG. 9C, or FIG. 9D, and EY in the eye dictionary DC_EY shown in FIG. Two dictionary images assigned to = 2, 3 or 4 are referred to. When searching for the left eye, the eye search area is set on the face image in the manner shown in FIG. 9 (E), FIG. 9 (F), or FIG. 9 (G), and in the eye dictionary DC_EY shown in FIG. Two dictionary images assigned to = 5, 6 or 7 are referenced.

  When searching for either the right eye or the left eye, the setting procedure of the eye part search area and the dictionary image to be referred to follow the face orientation. Further, the detected size and position of the eye are set in the register RGSTey shown in FIG.

  If the desired eye is not detected, it is considered that the eye is closed, and the above-described normal AF process is executed. This improves the sharpness of images belonging to the AE / AF area. On the other hand, when a desired eye is detected, the detected eye is designated as a main focus target. The secondary focusing target is specified as follows.

  If the orientation of the face belonging to the maximum size face frame is right side or substantially right side (≈ left 90 ° or right 90 °), the nose is searched from the face image belonging to the maximum size face frame. In the search, a nose search area is set on the face image in the manner shown in any one of FIGS. 12A to 12G, and NS = 1 to 7 in the nose dictionary DC_NS shown in FIG. A dictionary image assigned to any one of these is referred to. As described above, the setting procedure of the nose portion search area and the dictionary image to be referenced follow the face orientation. The detected size and position of the nose are set in the register RGSTns shown in FIG. When the setting process is completed, the detected root of the nose is designated as a secondary focusing target.

  Note that, according to FIG. 13, characters indicating the shape of the nose are described, but an image corresponding to this is actually stored in the nose dictionary DC_NS. Further, the dictionary image assigned to NS = 1 corresponds to the nose portion image facing front, the dictionary image assigned to NS = 2 corresponds to the nose portion image facing 30 ° to the left, and NS = The dictionary image assigned to 3 corresponds to a nose image that faces 60 ° to the left, and the dictionary image assigned to NS = 4 corresponds to a nose image that faces 90 ° to the left.

  Furthermore, the dictionary image assigned to NS = 5 corresponds to a nose image that faces 30 ° to the right, and the dictionary image assigned to NS = 6 corresponds to a nose image that faces 60 ° to the right. The dictionary image assigned to NS = 7 corresponds to a nose image that faces 90 ° to the right.

  If the orientation of the face belonging to the face frame of the maximum size is different from the front and right side (≈ left 30 °, left 60 °, right 30 ° or right 60 °), the eye part that is not selected as the search target, that is, infinite The side eye is designated as the secondary focusing target. In detecting the infinite eye part, the detected position of the near eye part and the face orientation are referred to.

  When the main focusing mode and the secondary focusing target are designated in this way, the aperture mechanism 14 is opened, and AF processing focusing on the main focusing target is executed. By opening the aperture mechanism 14, the depth of field is changed to the shallowest “D2”. In addition, the sharpness of the image representing the close eye side is improved by the AF processing focusing on the main focus target.

  Subsequently, some AF evaluation values corresponding to the secondary focus target are extracted from 4096 AF evaluation values output from the AF evaluation circuit 24, and the sum of the extracted AF evaluation values is calculated. In a state where the depth of field is set to “D2”, the calculated sum is less than the threshold value TH_SM. The process of calculating the sum of the AF evaluation values corresponding to the secondary focus target is repeatedly executed, and the aperture mechanism 14 is reduced by a predetermined amount in parallel with the sum calculation process. When the calculated sum reaches the threshold value TH_SM, the aperture amount is fixed, and thereby the depth of field is fixed to “D3”.

  If the secondary focusing target is an infinite eye part, the depth D3 is determined as shown in FIG. On the other hand, if the secondary focus target is the root of the nose, the depth D3 is determined as shown in FIG. 15 and 16, the depth of field changes in the order of “D1” → “D4” → “D2” → “D3”. Further, the magnitude relationship between the depths D1 to D4 is common between FIGS. 15 and 16. However, the limit of the depth of field is adjusted to the infinite eye part in FIG. 15 and to the root of the nose part in FIG.

  The CPU 26 executes a plurality of tasks including a face detection task shown in FIGS. 17 to 19 and an imaging task shown in FIGS. 20 to 24 in parallel under the control of the multitask OS. Note that control programs corresponding to these tasks are stored in the flash memory 44.

  Referring to FIG. 17, in step S1, flag FLG_F is set to “0”, in steps S3, registers RGSTtmp and RGSTout are cleared, and in step S5, the entire evaluation area EVA is set as a face search area. In step S7, the maximum size FSZmax is set to “200” and the minimum size FSZmin is set to “20” in order to define a variable range of the size of the face frame FD. When the definition of the variable range is completed, the process proceeds to step S9, and the size of the face frame FD is set to “SZmax”.

  In step S11, the face frame FD is arranged at the start position (upper left position) of the face search area. In step S13, a part of the search image data belonging to the face frame FD is read from the search image area 32c, and the feature amount of the read search image data is calculated. In step S15, the face dictionary number FC is set to “1”.

  In step S17, the feature amount calculated in step S13 is collated with the feature amount of the dictionary image corresponding to the face dictionary number FC among the seven dictionary images stored in the face dictionary DC_F. In step S19, it is determined whether or not the matching degree is greater than or equal to a threshold value TH_F. In step S21, it is determined whether or not the face dictionary number FC is “7”.

  If the decision result in the step S19 is YES, the process advances to a step S23 so as to register the current position and size of the face frame FD and the value of the face dictionary number FC in the register RGSTtmp. In step S23, the number of faces described in the register RGSTtmp is incremented. When the process of step S23 is completed, the process proceeds to step S27.

  If the decision result in the step S21 is YES, the face dictionary number FC is incremented in a step S25, and thereafter, the process returns to the step S17. If both the determination result in step S19 and the determination result in step S21 are NO, the process proceeds to step S27 as it is.

  In step S27, it is determined whether or not the face frame FD has reached the end position (lower right position) of the search area. If the determination result is NO, the face frame FD is moved in the raster direction by a predetermined amount in step S29, and then the process returns to step S13. If the determination result is YES, it is determined in a step S31 whether or not the size of the face frame FD is equal to or less than “FSZmin”. If the determination result is NO, the size of the face frame FD is reduced by “5” in step S33, the face frame FD is placed at the start position of the face search area in step S35, and then the process returns to step S13.

  If the determination result of step S31 is YES, it will progress to step S37 and will copy the description of register | resistor RGSTtmp to register | resistor RGSTout. In step S39, the register RGSTtmp is cleared. In step S41, it is determined whether or not the number of faces described in the register RGSTout is “1” or more. If the determination result is YES, a flag FLG_F is set to “1” in step S43 in order to assert that a face has been detected. If the determination result is NO, a flag FLG_F is set to “0” in step S45 in order to assert that no face has been detected. When the process of step S43 or S45 is completed, the process returns to step S9.

  Referring to FIG. 20, in step S51, the pan focus setting is validated, and in step S53, the moving image capturing process is started. As a result of the processing in step S51, the position of the focus lens 12 and the aperture amount of the aperture mechanism 14 are adjusted so that the depth of field indicates “D1”. Further, as a result of the processing in step S53, a through image representing the object scene is displayed on the LCD monitor 38.

  In step S55, the above-described face detection task is activated. In step S57, it is determined whether or not the flag FLG_F indicates “1”. If FLG_F = 1, the process proceeds to steps S67 through steps S59 to S61, and if FLG_F = 0, the process proceeds to steps S67 through steps S63 to S65.

  In step S59, a face frame display command is given to the character generator 46 in order to display one or more face frame characters on the LCD monitor 38. The face frame character is displayed on the LCD monitor 38 in a manner that matches the size and position of the face frame registered in the register RGSTout. In step S61, a face frame character having the maximum size is detected, and an area surrounded by the detected face frame character is set as an AE / AF area. In step S63, a face frame non-display command is given to the character generator 46. As a result, the display of the face frame character is stopped. In step S65, an AE / AF area is set at the center of the evaluation area EVA.

  In step S67, a simple AE process is executed. The simple AE process is executed with reference to some AE evaluation values belonging to the AE / AF area set in the above manner among the 4096 AE evaluation values output from the AE evaluation circuit 22. As a result, the brightness of the through image is appropriately adjusted.

  In step S69, it is determined whether or not the shutter button 28sh has been half-pressed. If the determination result is NO, the process returns to step S57, whereas if the determination result is YES, the process proceeds to step S71. In step S71, it is determined whether or not the flag FLG_F is “1”. If the determination result is YES, the process proceeds to step S79 through steps S73 to S75. If the determination result is NO, the process of step S77 is performed. Then, the process proceeds to step S79.

  In step S73, the aperture amount of the aperture mechanism 14 is adjusted so that the depth of field is set to “D4”. In step S75, the strict AE process is executed in such a manner that the adjusted aperture amount is prioritized. On the other hand, in step S77, the strict AE process is executed in a default mode. Any strict AE process is executed with reference to some AE evaluation values belonging to the AE / AF area, and thereby the brightness of the through image is strictly adjusted.

  In step S79, AF processing is executed (details will be described later). When the AF process is completed, it is determined in step S81 whether or not the shutter button 28sh has been fully pressed, and it is determined in step S83 whether or not the operation of the shutter button 28sh has been released.

  If the determination result of step S83 is YES, it will return to step S57 as it is, and if the determination result of step S81 is YES, it will perform a still image taking & recording process in step S85, and then will return to step S57. As a result of the processing in step S85, one frame of image data representing the scene at the time when the shutter button 28sh is fully pressed is captured in the still image area 32d, and the captured image data is stored in the recording medium 42 by the memory I / F 40. To be recorded.

  The AF process in step S79 is executed according to a subroutine shown in FIGS. In step S91, it is determined whether the current AF mode is the normal AF mode or the eye priority AF mode. In step S93, it is determined whether or not a logical product condition that the flag FLG_F is “1” and the maximum size of the face frame is equal to or larger than the threshold value TH_SZ is satisfied.

  If at least one of the determination result in step S91 and the determination result in step S93 is NO, the normal AF process is executed in step S103. The normal AF process is executed with reference to some AF evaluation values belonging to the AE / AF area among the 4096 AF evaluation values output from the AF evaluation circuit 24. The focus lens 12 is disposed at a position where the sum of the referred AF evaluation values is maximized, thereby improving the sharpness of an image belonging to the AE / AF area. When the process of step S103 is completed, the process returns to the upper layer routine.

  If both the determination result in step S91 and the determination result in step S93 are YES, the process proceeds to step S95. In step S95, the face frame having the maximum size is identified from one or more face frames registered in the register RGSTout, and the face frame number of the maximum size is determined based on the face dictionary number attached to the identified face frame. The direction of the face to which it belongs is detected. In step S97, it is determined whether or not the direction of the face thus detected is the front side toward the imaging surface. If the determination result is YES, the process proceeds to step S99. If the determination result is NO, the process proceeds to step S109. move on.

  In step S99, both eyes are searched from the face image belonging to the face frame of the maximum size. In the search, an eye search area is set on the face image in the manner shown in FIG. 9A, and four dictionary images assigned EY = 1 in the eye dictionary DC_EY shown in FIG. 10 are referred to. The size and position of the eye part detected in this way are set in the register RGSTey shown in FIG.

  In step S101, whether or not at least one of the left eye and the right eye has been detected is determined with reference to the register RGSKey. If the determination result is NO, the process returns to the upper hierarchy routine through the normal AF process in step S103, and if the determination result is YES, the process proceeds to step S105.

  In step S105, one of the left eye and the right eye is designated as the main focusing target based on the detection result. When both eye parts are detected, the eye part with the larger size is designated as the main focusing object. When only one eye is detected, the detected eye is designated as a main focus target. In step S107, the other eye is designated as a secondary focusing target. When only one eye is detected, the other eye is estimated based on the position of the eye search area set on the face image and the detected position of the eye. When the process of step S107 is completed, the process proceeds to step S127 shown in FIG.

  In step S109, which is shifted when the determination result in step S97 is NO, the closest eye part is selected with reference to the face orientation detected in step S95. The right eye is selected if the face direction is left toward the imaging plane, and the left eye is selected if the face direction is right toward the imaging plane. In step S111, the eye part thus selected is searched.

  When searching for the right eye, the eye search area is set on the face image in the manner shown in FIG. 9B, FIG. 9C, or FIG. 9D, and EY in the eye dictionary DC_EY shown in FIG. Two dictionary images assigned to = 2, 3 or 4 are referred to. When searching for the left eye, the eye search area is set on the face image in the manner shown in FIG. 9 (E), FIG. 9 (F), or FIG. 9 (G), and in the eye dictionary DC_EY shown in FIG. Two dictionary images assigned to = 5, 6 or 7 are referenced.

  When searching for either the right eye or the left eye, the setting procedure of the eye part search area and the dictionary image to be referred to follow the face orientation. Further, the detected size and position of the eye are set in the register RGSTey shown in FIG.

  In step S113, it is determined whether or not the selected eye part has been detected by referring to the register RGSTey. If the determination result is NO, the routine returns to the upper-level routine through the normal AF process in step S115, while the determination is made. If a result is YES, it will progress to step S117. In step S117, the selected eye is designated as the main focus target. In step S119, it is determined whether or not the face orientation detected in step S95 is right side (or substantially right side). If the determination result is YES, the process proceeds to step S127 through steps S121 to S123, If a determination result is NO, it will progress to Step S127 through processing of Step S125.

  In step S121, the nose part is searched from the face image belonging to the face frame of the maximum size. In the search, the nose search area is shown in FIG. 12 (A), FIG. 12 (B), FIG. 12 (C), FIG. 12 (D), FIG. 12 (E), FIG. The dictionary image set on the face image in the manner shown in FIG. 13 and assigned to NS = 1, 2, 3, 4, 5, 6 or 7 in the nose dictionary DC_NS shown in FIG. As described above, the setting procedure of the nose portion search area and the dictionary image to be referenced follow the face orientation. The detected size and position of the nose are set in the register RGSTns shown in FIG. In step S123, the detected root of the nose is designated as a secondary focusing target with reference to the register RGSTns.

  On the other hand, in step S125, the eye part that is not selected in step S109, that is, the non-selected eye part among the left eye and the right eye is detected from the face image, and the detected non-selected eye part is designated as a secondary focusing target. . In detecting the non-selected eye part, the position of the selected eye part and the orientation of the face are referred to.

  In step S127, the aperture mechanism 14 is opened, and in step S129, AF processing focusing on the main focus target is executed. By opening the aperture mechanism 14, the depth of field is changed to "D2". In addition, the sharpness of the image representing the close eye side is improved by the AF processing focusing on the main focus target. In step S131, a part of AF evaluation values corresponding to the secondary focusing target is extracted from 4096 AF evaluation values output from the AF evaluation circuit 24, and the sum of the extracted AF evaluation values is calculated.

  In step S133, it is determined whether or not the calculated sum is equal to or greater than a threshold value TH_SM. In step S135, it is determined whether or not the aperture amount of the aperture mechanism 14 is minimum. If both the determination result in step S133 and the determination result in step S135 are NO, the diaphragm mechanism 14 is throttled by a predetermined amount in step S137, and then the process returns to step S131. If either the determination result in step S133 or the determination result in step S135 is YES, the process returns to the upper-level routine. At the time of returning to the upper layer routine, the depth of field is fixed to “D3”.

  As can be understood from the above description, the imager 16 has an imaging surface for capturing the object scene through the focus lens 12 and repeatedly outputs raw image data. Search image data based on the output raw image data is written in the search image area 32 c of the SDRAM 32. The CPU 26 sets the depth of field to “D1” (S51), and then searches for an image representing the human eye from the search image data on the search image area 32c (S55, S1 to S45, S93 to S95). , S109 ~ S111, S117). When the eye image is detected, the CPU 26 sets the depth of field to “D2”, which is shallower than “D1” (S127), and executes AF processing focusing on the detected eye image (S129). . Thereafter, the CPU 26 sets the depth of field to “D3” which is shallower than “D1” and deeper than “D2” (S131 to S137).

  Thus, the depth of field decreases in the order of “D1” → “D3” → “D2”. By searching for the eye image corresponding to “D1”, the detection accuracy of the eye image is improved. In addition, by performing AF processing based on the high-frequency component of the eye part image corresponding to “D2”, the focusing accuracy for the eye part is improved. Furthermore, by setting the depth of field to “D3” after the AF processing, the sharpness of the image in the vicinity of the eye part is improved. As a result, it is possible to improve imaging performance with attention paid to the eye.

  In this embodiment, when changing the depth of field from “D2” to “D3”, the diaphragm mechanism is compared with the threshold value TH_SM while comparing the sum of some AF evaluation values corresponding to the secondary focus target. 14 is reduced by a predetermined amount (see steps S131 to S137 in FIG. 24). However, the distance from the main focus target to the secondary focus target in the depth direction is calculated based on the focus distance, the face image size, and the face orientation at the time when the AF processing focusing on the main focus target is completed. Then, the depth of field may be adjusted to “D3” based on the calculated distance. In this case, instead of the processes in steps S131 to S137 shown in FIG. 24, the processes shown in steps S141 to S145 shown in FIG. 25 are executed.

  Referring to FIG. 25, in step S141, the in-focus distance is calculated based on the current position of the focus lens 12. The calculated focus distance corresponds to the distance from the digital camera 10 to the main focus target. In step S143, the distance from the main focus target to the secondary focus target in the depth direction based on the face frame size and face orientation specified or detected in step S95 and the focus distance calculated in step S141. Is calculated. In step S145, the depth of field is adjusted to “D3” with reference to the calculated distance.

  The secondary focusing target noticed in step S143 is the infinite eye part if the face direction is diagonally forward, while it is the root of the nose part if the face direction is just beside or almost beside. For this reason, “D3” is adjusted in the manner shown in FIG. 15 when the face orientation is diagonally forward, and is adjusted in the manner shown in FIG. 16 when the face orientation is right side or substantially right side.

  However, the position of the infinite eye part is estimated based on the distance from the digital camera 10 to the close eye part and the size of the face image when the face direction is right side or substantially right side, and the depth limit is limited. The depth of field may be adjusted to coincide with the estimated position. In this case, “D3” is set as shown in FIG.

  In this embodiment, the multitask OS and control programs corresponding to a plurality of tasks executed thereby are stored in the flash memory 42 in advance. However, as shown in FIG. 27, a communication I / F 48 is provided in the digital camera 10, and some control programs are prepared in the flash memory 42 from the beginning as internal control programs, while other control programs are prepared as external control programs. May be acquired from an external server. In this case, the above-described operation is realized by cooperation of the internal control program and the external control program.

  Furthermore, in this embodiment, the processing executed by the CPU 26 is divided into a plurality of tasks as described above. However, each task may be further divided into a plurality of small tasks, and a part of the divided plurality of small tasks may be integrated with other tasks. Further, when each task is divided into a plurality of small tasks, all or part of the tasks may be acquired from an external server.

DESCRIPTION OF SYMBOLS 10 ... Digital camera 12 ... Focus lens 14 ... Aperture mechanism 16 ... Imager 22 ... AE evaluation circuit 24 ... AF evaluation circuit 26 ... CPU
32 ... SDRAM
44 ... Flash memory

Claims (11)

An imaging means having an imaging surface for capturing the object scene through the focus lens and repeatedly outputting the object scene image;
Search means for searching for a specific object image from the object scene image output from the imaging means;
A first setting means for setting a depth of field to a first depth prior to the processing of the search means;
Second setting means for setting the depth of field to a second depth shallower than the first depth in response to detection by the search means;
First adjusting means for adjusting a distance from the focus lens to the imaging surface based on a high-frequency component of the specific object image detected by the searching means; and the depth of field after the processing of the first adjusting means An electronic camera comprising third setting means for setting a third depth that is shallower than the first depth and deeper than the second depth. A diaphragm mechanism for defining the depth of field;
The electronic camera according to claim 1, wherein the second depth corresponds to a depth obtained by opening the aperture mechanism. The specific object image corresponds to a close eye part of two eye parts forming a face,
The search means is specified by a face image search means for searching for a face image from the object scene image, a face orientation specifying means for specifying the orientation of the face image detected by the face image search means, and the face orientation specifying means. The electronic camera according to claim 1, further comprising an eye part detection unit that detects the close eye part with reference to the orientation of the eye. A discriminating unit for discriminating whether or not the direction specified by the face direction specifying unit is a direction in which the infinite eye part is hidden;
When the discrimination result of the discrimination means is affirmative, first designation means for designating a region corresponding to the nose as a region of interest, and when the discrimination result of the discrimination means is negative, it corresponds to the infinite eye portion A second designating unit for designating a region to be designated as the region of interest;
The electronic camera according to claim 3, wherein the third depth corresponds to a depth at which a high-frequency component of a partial image belonging to the region of interest among the object scene image output from the imaging unit satisfies a predetermined condition.   The electronic camera according to claim 4, wherein the area specified by the first specifying means is a base area of the nose.   4. The apparatus further comprises fourth setting means for setting the depth of field to a fourth depth that is shallower than the first depth and deeper than the second depth in response to detection by the face image search means. The electronic camera according to any one of 5. The apparatus further comprises: a second adjustment unit that adjusts a distance from the focus lens to the imaging surface in a predetermined manner; and an activation unit that activates the second adjustment unit in response to non-detection of the eye part detection unit. The electronic camera according to any one of 3 to 6. To the processor of an electronic camera that has an imaging surface that captures the scene through the focus lens and that has imaging means for repeatedly outputting the scene image,
A search step for searching for a specific object image from the object scene image output from the imaging means;
A first setting step for setting a depth of field to a first depth prior to the processing of the searching step;
A second setting step for setting the depth of field to a second depth shallower than the first depth in response to detection in the searching step;
An adjusting step of adjusting a distance from the focus lens to the imaging surface based on a high frequency component of the specific object image detected by the searching step; and the depth of field after the processing of the adjusting step An imaging control program for executing a third setting step for setting a third depth that is shallower than the second depth and deeper than the second depth. An imaging control method executed by an electronic camera having an imaging surface that captures an object scene through a focus lens and having an imaging unit that repeatedly outputs an object scene image,
A search step for searching for a specific object image from the object scene image output from the imaging means;
A first setting step for setting a depth of field to a first depth prior to the processing of the searching step;
A second setting step for setting the depth of field to a second depth shallower than the first depth in response to detection in the searching step;
An adjusting step of adjusting a distance from the focus lens to the imaging surface based on a high frequency component of the specific object image detected by the searching step; and the depth of field after the processing of the adjusting step An imaging control method comprising a third setting step of setting a third depth that is shallower than the second depth and deeper than the second depth. External control supplied to an electronic camera having an imaging surface that captures an object scene through a focus lens and that repeatedly outputs an image of the object scene and a processor that executes a process according to an internal control program stored in a memory A program,
A search step for searching for a specific object image from the object scene image output from the imaging means;
A first setting step for setting a depth of field to a first depth prior to the processing of the searching step;
A second setting step for setting the depth of field to a second depth shallower than the first depth in response to detection in the searching step;
An adjusting step of adjusting a distance from the focus lens to the imaging surface based on a high frequency component of the specific object image detected by the searching step; and the depth of field after the processing of the adjusting step An external control program for causing the processor to execute a third setting step for setting a third depth that is shallower than the second depth and deeper than the second depth in cooperation with the internal control program. An imaging means having an imaging surface for capturing the object scene through the focus lens and repeatedly outputting the object scene image;
An electronic camera comprising a capturing unit that captures an external control program, and a processor that executes processing according to the external control program captured by the capturing unit and an internal control program stored in a memory,
The external control program is
A search step for searching for a specific object image from the object scene image output from the imaging means;
A first setting step for setting a depth of field to a first depth prior to the processing of the searching step;
A second setting step for setting the depth of field to a second depth shallower than the first depth in response to detection in the searching step;
An adjusting step of adjusting a distance from the focus lens to the imaging surface based on a high frequency component of the specific object image detected by the searching step; and the depth of field after the processing of the adjusting step An electronic camera corresponding to a program that executes a third setting step for setting a third depth that is shallower and deeper than the second depth in cooperation with the internal control program.

Images