JP4585921B2 - Image processing apparatus and method - Google Patents

Description

  The present invention relates to an image processing apparatus and method having a focus adjustment function.

  Conventionally, focusing on a subject in a television camera of a broadcasting station has been performed by a manual focus (hereinafter referred to as MF) operation in which focus adjustment is manually performed by a cameraman. In addition, consumer digital video cameras (hereinafter referred to as DVC (Digital Video Camcorder)) can be switched to MF as well as auto focus (hereinafter referred to as AF) that automatically adjusts the focus on some models. There is something that is possible. Here, in general, in the case of consumer products, the size of EVF (Electrical View Finder) and the liquid crystal panel is also small, and it is difficult to say that the visibility is high and proper focus adjustment is difficult.

  Recently, high-definition format consumer digital camcorders have also begun to appear on the market. When high-definition video (hereinafter referred to as HD video) is viewed on a large screen, conventional SD video (NTSC, PAL, etc.) As described above, since the out-of-focus is known, there is a demand for an image processing apparatus that can realize more accurate focus adjustment. Therefore, in order to improve the visibility of focus confirmation with EVF for both business models and consumer models, contour signals are extracted from captured images, which are called “contour correction, peaking, enhancer”, etc. There is a technology that performs processing for emphasizing the outline in a form that is added to the lens to assist in focusing during manual focus.

    Further, the high frequency component of the spatial frequency is extracted from the given image data, the differential image data is generated, and a predetermined color is assigned to be colored according to the pixel value indicating the high frequency component of the differential image data. An in-focus state display device has been proposed that generates a differentiated image signal and displays colored differential image data to notify a focus state from a difference in color. (For example, Reference 1)

JP 2002-196225 A

  However, in the above-described in-focus state display device, the appearance of the display device varies depending on characteristics such as the display size and the number of pixels of the EVF in each video device, and the photographing subject. There are cases where it is difficult to understand and annoying an operator who needs more precise focus adjustment.

  An object of the present invention is to improve the operability of an operator by properly displaying the focused state of an image.

The image processing apparatus of the present invention includes an operation unit for instructing adjustment of a focus of an imaging optical system, an imaging unit that receives an object light that has passed through the imaging optical system, and captures an image, and the captured image Filter means for performing signal processing for adjusting a frequency band for an image, operation amount detection means for detecting an operation amount of a focus adjustment operation based on an input from the operation means, and the operation amount according to the operation amount And changing means for changing the frequency characteristic of the filter means.

  According to the present invention, the visibility of focus confirmation can be improved.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as necessary.
(First embodiment)
An image recording (processing) apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. The number of claims corresponding to the description in the present embodiment is not limited to one. Also, this description does not limit the elements of each claim.

  2 is a schematic block diagram of a digital video camera as an image recording apparatus according to the first embodiment of the present invention, FIG. 3 is an external view of the digital video camera, and FIG. 1 is an FIR digital horizontal filter unit (Finite Impulse). FIG. 4 shows a control procedure (flowchart) for realizing the present embodiment as a circuit example of (Response Filter).

First, a configuration example of a digital video camera will be described with reference to FIG.
Reference numeral 201 denotes a lens unit (optical system) of the video camera, which is a lens group and a lens mechanism with a zoom function and a focus adjustment function for imaging a subject (not shown).

  Reference numeral 202 denotes a CCD (Charge Coupled Device), which is an image pickup device that picks up an image coming from an optical system constituted by the lens unit 201.

  An image sensor driving unit 203 drives the CCD 202 according to the timing signal from the camera signal processing unit 206.

  Reference numeral 204 denotes a CDS (Correlated Double Sampling) and AGC (Auto Gain Controller) section that samples an analog signal from the CCD 202 and controls the signal level gain under the control of the system control section 209.

  Reference numeral 205 denotes an A / D (Analog to Digital) converter that converts an analog signal from the previous stage into a digital signal.

  A camera signal processing unit 206 controls the camera imaging system in cooperation with the system control unit 209 such as timing generation, AE (Auto Exposure) control, and AF (Auto Focus) control.

  A lens driving unit 207 drives the lens unit 201 to perform zoom magnification and focus adjustment. During autofocus, the camera signal processing unit 206 detects focus adjustment information, and the system control unit 209 outputs a control signal to the lens driving unit 207 based on the detected information. The lens driving unit 207 performs focus adjustment by controlling the driving of the lens unit 201 based on the control signal. During manual focusing, the operator adjusts the focus ring 307 of FIG. 3 that belongs to the input operation unit 214 and is generally provided on the outer periphery of the lens. In an electronic mechanism, the system control unit 209 rotates the focus ring 307. Detect direction and amount of rotation. The system control unit 209 drives the lens driving unit 207 according to the detection information and controls the lens unit 201 to perform focus adjustment. In the mechanical mechanism, the focus ring 307 is mechanically connected to the lens unit 201. When the operator rotates the focus ring 307, the lens unit 201 is mechanically moved to perform focus adjustment.

  The camera imaging system has a manual focus mode (function) and an autofocus mode (function), and can capture a video (image). Switching between the manual focus mode and the autofocus mode can be performed by a changeover switch or menu setting.

  Reference numeral 208 denotes a microphone, which collects sound for recording ambient sounds together with video that has entered through the imaging system.

  Reference numeral 209 denotes a system control unit for executing each control procedure of the present embodiment, and executes various control procedures such as a flowchart shown in FIG.

A memory control unit 210 controls access to the general-purpose storage unit 211.
A general-purpose storage unit (memory) 211 is a buffer for video signal processing, stores programs and data for realizing various control means of the present embodiment, and a work area as necessary for control execution. As a general term, ROMs and RAMs used are also collectively referred to.

  Reference numeral 212 denotes an external recording medium connection interface, which is a memory card slot here.

  Reference numeral 213 denotes an external storage medium, which is a memory card here. Normally, a jpeg file is stored in this memory card 213 when shooting a still image.

  An input operation unit 214 includes a shooting start / stop button, a selection button, a determination button, a shutter button for shooting a still image, a manual focus ring, and the like.

  A time counter 215 includes a real time clock (RTC) and a backup battery, counts the date and time, and returns date information in response to a request from the system control unit 209.

  A video control unit 216 includes the horizontal filter function unit of FIG. 1 according to the present embodiment, and controls output to the first display unit 218, the second display unit 219, and the line output unit 220, and a tape recording / reproducing unit. Control 217 is performed.

  Reference numeral 217 denotes a tape recording / reproducing unit which records or reproduces a video signal encoded in a tape recording format such as a DV format in the SD mode and an HDV format in the HD mode by the video control unit 216.

  Reference numeral 218 denotes a first display unit, which is an EVF (Electrical View Finder), which displays the input video from the imaging system when recording with the tape recording / reproducing unit 217 and is recorded on the tape when reproducing. Display the current video. Further, the first display unit 218 displays input operation information by an operator from the input operation unit 214, arbitrary image information in the external recording medium, and the like.

  Reference numeral 219 denotes a second display unit, which is a liquid crystal display panel. When recording is performed by the tape recording / reproducing unit 217, an input image from the imaging system is displayed, and when reproducing, an image recorded on the tape is displayed. Is displayed. The second display unit 219 displays input operation information by the operator from the input operation unit 214, arbitrary image information in the external recording medium, and the like.

  Reference numeral 120 denotes an interface for analog component video output, S terminal output, composite video output, and the like, which is connected to an external TV monitor or the like, and displays video output from the digital video camera on a TV screen.

Next, the external appearance of the digital video camera will be described with reference to FIG.
Reference numeral 301 denotes a main body, a lens optical system 306, a video recording / reproducing unit (not shown) in which a recording / reproducing tape cassette can be attached and detached, an EVF (Electrical View Finder) 302, various function switches 303, 304, 305, 310, 311 and the like. The liquid crystal display panel 308 is attached to the main body 301 by a rotating hinge 309. The power source battery is assumed to be built in the main body.

  Reference numeral 302 denotes an EVF (Electrical View Finder), which displays the same contents as when the liquid crystal display panel 308 is used when the liquid crystal display panel 308 is not used.

  Reference numeral 303 denotes a diopter adjustment slider for adjusting the focal length of the EVF by moving the eyepiece back and forth so that the operator can easily see when looking through the EVF 302.

  Reference numeral 304 denotes a start / stop button. The outer periphery of the button is a mode dial, which can be switched by rotating camera operation modes such as OFF, camera shooting mode, and tape playback mode. In normal use, after turning the mode dial to camera mode, the start / stop button is pressed once to start shooting, press again to start shooting standby, and press again to start shooting again. .

  A zoom switch 305 can be adjusted to the telephoto side or the wide side by pressing it back and forth.

  A lens optical system 306 performs zoom adjustment and focus adjustment, and forms an image from a subject on a CCD (Charge-Coupled Device not shown) in the main body 301.

  Reference numeral 307 denotes a manual focus ring. When the manual focus mode is switched by a changeover switch (not shown), the operator can manually adjust the focus by turning the ring 307 in the circumferential direction.

  A liquid crystal display panel 308 displays an image input from the lens optical system 306, displays an image reproduced from an image recording / reproducing unit on a tape (not shown), 304, 305, 310, 311. Display related to control by various function switches. Further, the liquid crystal display panel 308 has a structure that can be rotated in multiple directions with respect to the main body 301 by a hinge 309.

  A hinge 309 connects the liquid crystal display panel 308 and the main body 301, and the liquid crystal display panel 308 can rotate about the X axis and the orthogonal Y axis in FIG. For example, when the photographer lifts the main body 301 to a high position, the photographer (not shown) is easy to see by, for example, turning the display screen downward when shooting with the display screen held downward and holding the display screen at a low position. The liquid crystal display panel 308 can be adjusted to an angle. Functionally, even when the liquid crystal display panel 308 is moved by the rotating hinge 309, the electrical signal wiring (not shown) that connects the inside of the main body 301 and the liquid crystal display panel 308 is not entangled or pulled. It has become.

  When a shutter button 310 is pressed in a shooting standby state, a still image is recorded on the tape for several seconds in the same manner as a moving image, or during moving image shooting, a memory card (not shown) as an external recording medium 213 is recorded. It is often recorded as a jpeg file.

  Reference numeral 311 denotes an operation button, which is often used for various mode settings and a playback button in the tape playback mode.

  Reference numeral 312 denotes an IEEE 1394 interface, which is a digital interface capable of exchanging video information and various control information by connecting to digital video cameras and editing equipment such as an external computer via a cable.

  FIG. 1 shows an example of a FIR (Finite Impulse Response) type horizontal filter circuit used in the digital video camera shown in FIGS. 2 and 3, which is a feature of this embodiment. Note that an FIR filter (Finite Impulse Response Filter), which is a linear phase filter, is a general term for filters in which an output signal when an impulse is input converges to 0 in a finite time. The FIR filter can be efficiently implemented by hardware because the design method is linear.

  The horizontal filter circuit in FIG. 1 is configured in the video control unit 216. Here, it is assumed that the signal for applying the horizontal filter is applied only to the luminance signal. Of course, the same configuration may be applied not only to the luminance signal but also to the color difference signal at the same time. Conversely, considering the application to only the color difference signal, various system configurations, shooting scenes, and operator preferences It is possible to configure a system according to the above.

  The horizontal filter circuit can perform filtering independently on the luminance signal, the color difference signal, or the red (R) signal / green (G) signal / blue (B) signal.

  Reference numeral 101 denotes an input video signal which is not output to the tape recording / reproducing unit 217 but is output to the first display unit (EVF) 218 and the second display unit (liquid crystal display panel) 219. Here, for the sake of convenience, the signals going to the first display unit (EVF) 218 and the second display unit (liquid crystal display panel) 219 are described as the same signal. However, each display system has a horizontal filter circuit independently. It can also be configured to be independently controllable.

  The display units 218 and 219 display the video filtered by the horizontal filter circuit. When a plurality of horizontal filter circuits are provided, the plurality of horizontal filter circuits are controlled independently. The plurality of display units 218 and 219 can display video signals independently filtered by a plurality of horizontal filter circuits.

  Reference numeral 102 denotes a D-FF (Delay type Flip Flop), which latches the input video signal 101 by the pixel clock of the video signal and passes it to the D-FF 103 at the next stage. As a result, the output signal of the D-FF 102 is delayed by one pixel clock with respect to the input signal. The pixel clock here is 13.5 MHz assuming that the input video signal is SD video (NTSC or PAL).

103 to 109 are D-FFs like 102, and the data from the previous stage is latched by the pixel clock of the video signal to delay the video signal data in order to form an FIR type horizontal filter. It is. Here, let us consider a configuration in which 3 taps to be combined are selected from among the 9 taps Y (−4) to Y (4) depending on the frequency to be emphasized. Specifically, the center tap Y (0) is the same, changing the combination of the front and rear taps,
Y (-1), Y (0), Y (1)
Y (-2), Y (0), Y (2)
Y (-3), Y (0), Y (3)
Y (-4), Y (0), Y (4)
Think of a combination like this.

Further, the coefficient of the tap portion that is not selected in each combination is substantially equivalent to the tap coefficient being made zero.
By controlling the combination of tap coefficients as described above, the emphasized frequency band is made variable.

Here, the breakdown of the three tap coefficients combined to make the emphasized frequency band variable is as follows.
Center tap tap coefficient: n + 2α (n is a natural number)
Tap coefficient of front and rear taps: -α

The DC gain is as follows.
(N + 2α−α−α) × (1 / n) = 1

Reference numeral 110 denotes a gain adjustment signal which is controlled by the system control unit 209 and adjusts the level of the emphasized frequency band in the horizontal filter. Here, the gain adjustment signal 110 is a 4-bit signal, and the gain level to be emphasized can be switched to 16 levels.
α = 15: Gain maximum to α = 0: OFF (Gain minimum)
Here, α = 0 is not shown in FIG. 1, but is assumed to pass through the horizontal filter for convenience.

  A frequency adjustment signal 111 is controlled by the system control unit 209 and adjusts the center frequency of the frequency emphasized by the horizontal filter. Here, the frequency adjustment signal 111 is a 2-bit signal, and the center frequency point to be emphasized can be switched between four types.

  A signal selector 112 is controlled by the frequency adjustment signal 111 to switch the center frequency at which this horizontal filter works. The emphasis center frequency point setting for the luminance signal by the horizontal filter is as follows.

Sampling frequency: 13.5 MHz
Frequency adjustment signal: Enhanced center frequency (fc)
00: fc = f = 6.75 MHz
(Use of center tap and front and rear taps adjacent to the center tap)
01: fc = f / 2 = 6.75 / 4 = 3.375 MHz
(Use the center tap and the tap that has been skipped forward and backward from the center tap)
10: fc = f / 3 = 6.75 / 4 = 2.25 MHz
(Using the center tap and two taps skipped forward and backward from the center tap)
11: fc = f / 4 = 6.75 / 4 = 1.875 MHz
(Use of the center tap and three taps skipped back and forth from the center tap)

  Reference numeral 113 denotes a horizontal filter selection signal which is controlled by the system control unit 209 and outputs a video signal (luminance signal) that passes through a gain adjustment function having an arbitrary frequency characteristic by the horizontal filter or is simply a tap (in FIG. 1). , Y (0)) to select whether to output a video signal (luminance signal).

A signal selector 114 is a video signal (luminance signal) obtained by applying a horizontal filter to the input video signal 101 according to the horizontal filter selection signal 113, or simply passes through the horizontal filter circuit without being affected by the frequency characteristics. Select the video signal (luminance signal) that is sufficient to do.
Reference numeral 115 denotes an output video signal which is an output signal selected by the signal selector 114.

  The horizontal filter circuit performs filtering on the horizontal direction of the imaged video signal 101. The gain adjustment signal 110 can control the gain characteristic of the horizontal filter circuit. The frequency adjustment signal 111 can control the frequency characteristics of the horizontal filter circuit. The horizontal filter selection signal 113 can control a signal selector (selection means) 114 that selects whether the function of the horizontal filter is valid or invalid.

  According to the example of the control procedure shown in FIG. 4, the control method of the video recording / reproducing apparatus of the present embodiment is realized. Hereinafter, the control procedure will be described with reference to FIG.

  It is assumed that at the start of step S401, the mode dial on the outer periphery of the start / stop button 304 is changed from “OFF” to “camera shooting mode” to enter a shooting standby state.

  In step S402, the system control unit 209 determines whether the previous mode dial has been changed to other than “camera shooting mode” such as “camera shooting mode” → “OFF”. If changed, the process proceeds to step S411, where the control mode ends. If it is as it is, it will progress to step S403.

  In step S403, the system control unit 209 detects whether the start / stop button 304 has been pressed. If the start / stop button 304 is pressed by the operator and the system control unit 209 detects the start of shooting, the process proceeds to step S404. Otherwise, the process proceeds to step S402 and control is continued.

  In step S404, the system control unit 209 determines whether the manual focus mode is set. If the manual focus mode is not selected, the process proceeds to step S405, and shooting is performed in the auto focus mode. If it is in the manual focus mode, the process proceeds to step S408, and shooting is performed in the manual focus mode. If the manual focus mode is switched separately even during shooting in the autofocus mode, the process proceeds to step S408, and shooting in the manual focus mode is performed. Note that the switching setting between the auto focus mode and the manual focus mode can be performed by a physical switch (not shown) or menu setting.

  In step S405, shooting is performed in the autofocus mode, and the process proceeds to step S406.

  In step S406, the system control unit 209 determines whether the previous mode dial has been changed to other than “camera shooting mode” such as “camera shooting mode” → “OFF”. If changed, the process proceeds to step S411, where the control mode ends. If it is as it is, it will progress to step S407.

  In step S407, the system control unit 209 detects whether the start / stop button 304 has been pressed. If the start / stop button is pressed by the operator and photographing interruption is detected, the process proceeds to step S403. Otherwise, the process proceeds to step S404 and control is continued.

  In step S408, shooting is performed in the manual focus mode, and the process proceeds to step S409.

  In step S409, the system control unit 209 determines whether the previous mode dial has been changed to something other than “camera shooting mode”, such as “camera shooting mode” → “OFF”. If changed, the process proceeds to step S411, where the control mode ends. If it is as it is, it will progress to step S410.

In step S410, the system control unit 209 detects whether the start / stop button 304 has been pressed. If the start / stop button 304 is pressed by the operator and the photographing interruption is detected, the process proceeds to step S403. Otherwise, the process proceeds to step S404 and control is continued.
In step S411, the control mode here ends.

  FIG. 5 to FIG. 8 show images when the center frequency to be emphasized is changed by changing the frequency adjustment signal 111 while the control by the gain adjustment signal 110 is fixed in FIG.

FIG. 5 shows an image of fc = f = 6.75 MHz when the frequency adjustment signal 111 = 00, and reference numeral 501 denotes a horizontal edge.
FIG. 6 shows an image of fc = f / 2 = 6.75 / 4 = 3.375 MHz when the frequency adjustment signal 111 = 01, and reference numeral 601 denotes a horizontal edge.
FIG. 7 shows an image of fc = f / 3 = 6.75 / 4 = 2.25 MHz when the frequency adjustment signal 111 = 10, and reference numeral 701 denotes a horizontal edge.
FIG. 8 shows an image of fc = f / 4 = 6.75 / 4 = 1.875 MHz when the frequency adjustment signal 111 = 11, and 801 indicates a horizontal edge.

  5 to 8 are image diagrams (images) showing display screens of the EVF 218 or the liquid crystal display panel 219. The edge component emphasized in FIGS. 5 to 8 changes from a high frequency to a low frequency. As a result, the edge 501 (high enhancement center frequency) of the horizontal boundary portion of the subject is emphasized thinly, and the edge 801 (low enhancement center frequency) of the horizontal boundary portion of the subject appears to be emphasized thickly. In addition, when the focus is adjusted by the focus lens focusing operation by the operator at the edge emphasized for each frequency, the feeling of glare at the edge of the horizontal boundary portion of the subject becomes strong, so that the focus is close to the focal point. This is visible to the operator.

  Therefore, when the operator manually adjusts the focus, the image displayed on the display screen can be visually inspected in detail when the emphasized edge component has a high frequency, but the focus is greatly increased. If it is out of focus, it is difficult to focus even if a high frequency component is extracted. If the emphasized edge component is at a low frequency, the focus state cannot be seen more finely as the emphasized edge component is at a high frequency. However, even if the focus is greatly deviated, it is easy to grasp the operation direction for focusing.

  However, this visibility has individual differences for each operator. Accordingly, as in the present embodiment, an image recording (processing) device with improved operability is provided by making it possible to adjust the frequency characteristics and gain level for enhancing the edge of an image (or video). Is possible.

FIG. 9 shows an image diagram of the frequency characteristics of the horizontal filter of FIG. 1 at this time.
FIG. 9A shows frequency characteristics of fc = f = 6.75 MHz when the frequency adjustment signal 111 = 00.
FIG. 9B shows frequency characteristics of fc = f / 2 = 6.75 / 4 = 3.375 MHz when the frequency adjustment signal 111 = 01.
FIG. 9C shows frequency characteristics of fc = f / 3 = 6.75 / 4 = 2.25 MHz when the frequency adjustment signal 111 = 10.
FIG. 9D shows frequency characteristics of fc = f / 4 = 6.75 / 4 = 1.6875 MHz when the frequency adjustment signal 111 = 11.

  Since SD video is considered here, the upper limit of the video frequency is about 5 to 6 MHz or less, and the frequency characteristics in the band beyond that in FIG. 9 are pre-filtered in advance so as not to turn up. And so on.

  On the other hand, here, the control by the gain adjustment signal 110 is fixed, and the effect when the center frequency to be emphasized is changed by changing the frequency adjustment signal 111 has been described. By adjusting the gain adjustment signal 110, Conversely, even when the frequency adjustment signal 111 is fixed, the appearance of the edge of the horizontal boundary portion of the subject changes. As the gain is increased, the glare at the edge of the horizontal boundary of the subject becomes stronger. The horizontal filter is applied to the brightness, so the tendency can be recognized more clearly when black and white is displayed.

  As described above, according to the digital video camera which is an example of the image recording apparatus of the present embodiment, a simple FIR digital filter can be used when an operator manually focuses while watching an EVF, a liquid crystal display panel, a television monitor, or the like. The circuit makes it possible to adjust the frequency characteristics and gain level for emphasizing the edge of the video in real time according to the shooting system and the preference of the operator.

(Second Embodiment)
Hereinafter, a video photographing apparatus and a video editing apparatus according to a second embodiment of the present invention will be described with reference to the drawings. The second embodiment differs from the first embodiment in the control method of emphasis control for the edge of the horizontal boundary portion of the subject with respect to the digital video camera as the image recording apparatus in the first embodiment. is there.

  In the present embodiment, in addition to the case of the first embodiment, when the horizontal filter of the present embodiment is applied to the luminance, the display is set to display in black and white during manual focus operation, If the amount of rotation of the focus ring is large by the user, it is determined that the focus adjustment has started, and the focus is not in focus by lowering the edge emphasis frequency or increasing the emphasis amount (increasing gain). Control to increase the visibility at the time. Also, if the focus is gradually adjusted and the amount of rotation of the focus ring is decreased, the emphasis frequency is increased and the emphasized edge of the horizontal boundary portion of the subject is adjusted in order to focus with higher accuracy. Control is performed such as making the image thinner or reducing the gain so that the amount of emphasis is not too large.

  10, FIG. 11, and FIG. 12 show examples of control flows performed in step S408 in FIG. In any place of control in step S408, control flows from the processing terminal A and exits to the processing terminal B in FIGS.

  FIG. 10 shows a dynamic control of the center frequency of the horizontal filter of FIG. 1 according to the amount of movement of the focus ring (the amount here may be an absolute amount or a rate moved in unit time, that is, a speed). This is an example.

  In step S1001, the system control unit 209 displays the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to black and white during manual focus operation according to a set value (a menu set by the operator) that is separately set in advance. Judge whether to change to. If the color display remains, the process proceeds to step S1003, and if the display is changed to the monochrome display, the process proceeds to step S1002.

  When the manual focus mode is set in advance, the EVF 218 or the liquid crystal display panel 219 can be set as a setting value by selecting color display or monochrome display. When the manual focus mode is entered, the EVF 218 or the liquid crystal display panel 219 can be switched to color display or monochrome display according to the set value.

  In step S1002, the system control unit 209 changes the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to monochrome display. In this way, when the black and white display is performed, a horizontal filter is applied to the imaged signal, so that the in-focus state can be recognized more clearly.

  In step S1003, the system control unit 209 detects the amount of movement of the focus ring, and proceeds to step S1004. The operation amount of the focus ring is the operation amount of the operation for adjusting the focus by the manual focus operation.

  In step S1004, the system control unit 209 compares the amount of movement of the focus ring with an arbitrary threshold value. If it is larger, the process proceeds to step S1005, and if smaller, the process proceeds to step S1006.

  In step S1005, since the amount of rotation of the focus ring is large, it is determined that focusing is started, and the center frequency of the horizontal filter in FIG. 1 is controlled to be one step lower than the current center frequency. In that case, leave it as it is.

  In step S1006, since the amount of turning the focus ring is small and the focus needs to be adjusted with higher accuracy, the center frequency of the horizontal filter in FIG. 1 is controlled to be selected one step higher than the current center frequency, If it is the highest, leave it as it is.

  FIG. 11 also shows the dynamic control of the gain of the horizontal filter of FIG. 1 in accordance with the amount of movement of the focus ring (the amount here may be an absolute amount or the rate of movement per unit time, that is, the speed). This is an example.

  In step S1101, the system control unit 209 changes the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to black and white display during manual focus operation according to a set value (value set by the operator) that is separately set in advance. Determine whether to change. If the color display remains, the process proceeds to step S1103. If the display is changed to the monochrome display, the process proceeds to step S1102.

  In step S1102, the system control unit 209 changes the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to monochrome display.

  In step S1103, the system control unit 209 detects the amount of movement of the focus ring, and proceeds to step S1104.

  In step S1104, the system control unit 209 compares the amount of movement of the focus ring with an arbitrary threshold value. If it is larger, the process proceeds to step S1105, and if smaller, the process proceeds to step S1106.

  In step S1105, the gain of the horizontal filter shown in FIG. 1 is controlled to be one step lower than the current gain.

  In step S1106, control is performed so that the gain of the horizontal filter in FIG. 1 is selected to be one step higher than the current gain.

  Here, the horizontal edge enhancement method using the horizontal filter has been changed dynamically according to the amount of adjustment of the focus ring during manual focus, but AF information (information indicating the focus condition) of the autofocus mechanism (function) is manually focused. The above-described control shown in FIGS. 10 and 11 can be realized by utilizing the mode. Specifically, if it is determined from the AF information of the autofocus mechanism (function) that the focus adjustment is started and the focus is significantly shifted, the edge emphasis frequency is lowered or the emphasis amount is increased ( If it is determined that the focus is gradually increased from the AF information of the autofocus mechanism (function) by increasing the visibility at the time when the focus is not achieved. This can be realized by increasing the frequency to be emphasized to make the edge to be emphasized in the horizontal boundary portion of the subject thinner, or by reducing the gain so that the amount of enhancement is not too large.

  As described above, when the amount of movement of the focus ring is larger than the predetermined threshold (when the amount of turning the focus ring is large), it is determined that focus adjustment is started, and the frequency for edge enhancement is lowered or the amount of enhancement By increasing the number (increasing the gain), the visibility at the time when the focus is not achieved can be increased. In addition, when the amount of movement of the focus ring is smaller than the predetermined threshold (when the focus is gradually adjusted and the amount of rotation of the focus ring is reduced), the frequency to be emphasized is increased and the horizontal boundary portion of the subject is Focusing can be performed with high accuracy by making the edge to be emphasized thinner or by reducing the gain so that the amount of enhancement is not too large.

  FIG. 12 shows the focus ring when the movement amount (the amount here may be an absolute amount or the rate of movement per unit time, that is, the speed) becomes zero, that is, the focus is adjusted by the operator. This is an example in which when the ring is not turned, the edge emphasis is stopped and the display is returned from the monochrome display to the color display when the stopped time becomes a certain time or more.

  In step S1201, the system control unit 209 determines whether to change the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to black and white display at the time of manual focus operation according to a set value set separately in advance. If the color display remains, the process proceeds to step S1203, and if the display is changed to the monochrome display, the process proceeds to step S1202.

  In step S1202, the system control unit 209 changes the display screen of the EVF 218 or the liquid crystal display panel 219 from color display to monochrome display.

  In step S1203, the system control unit 209 detects the amount of movement of the focus ring, and proceeds to step S1204.

  In step S1204, the system control unit 209 proceeds to step S1205 if the state where the amount of movement of the focus ring is zero compared to an arbitrary threshold, and proceeds to the processing terminal “B” if it is shorter.

  In step S1205, the system control unit 209 sets the horizontal edge enhancement control by the horizontal filter of FIG. That is, the horizontal filter function is disabled.

  In step S1206, the system control unit 209 changes the display screen of the EVF 218 or the liquid crystal display panel 219 that has been displayed in black and white in step S1202 from monochrome display to color display.

  As described above, according to the digital video camera which is an example of the image recording apparatus of the present embodiment, when focusing manually while watching an EVF, a liquid crystal display panel, a TV monitor, etc., a simple FIR digital filter circuit The frequency characteristics and gain level for emphasizing the edge of the video in real time can be adjusted according to the shooting system and the preference of the operator. Further, by switching the display color, or by linking the assist display with the adjustment amount of the focus adjustment or the passage of time, further convenience can be created in the manual focus operation during video camera shooting.

  As described above, in the first and second embodiments, in order to improve the visibility of the video captured in the EVF at the time of MF, the contour signal is extracted, and then the contour enhancement is not performed on the video signal. An FIR digital filter circuit is applied to a horizontal video line, and an edge enhancement is performed on a video signal displayed on an EVF or a liquid crystal display panel by adjusting frequency characteristics and gain of an arbitrary band. By making the frequency and level to be emphasized variable, various subjects with different edges (definition) and the characteristics of the display device displaying the subject (physical resolution, systemable display frequency, etc.) ), The operator can arbitrarily adjust the edge enhancement.

  Since it is possible to change not only the edge emphasis level but also the frequency characteristics, the way in which the edge portion is emphasized (how it looks) can be changed, and the MF assist function according to the system specifications, shooting target, and operator preference Can be provided.

  Further, it is determined whether the focus adjustment is performed from the out-of-focus state or the focus is adjusted from the adjustment function for MF (for example, the operating state of the focus ring, that is, the amount of control). Control of the assist function, such as adjusting the frequency characteristics and gain characteristics of edge emphasis by judging the focus condition from AF information, and switching the color / monochrome display on the display screen. realizable.

  It can be applied to various video devices. In particular, in a video recording device with a camera, an assist function for manually adjusting the focus while watching an EVF, a liquid crystal display panel, a TV monitor, etc. is realized with a simple circuit. be able to. In addition, the frequency characteristics and gain level for emphasizing the edges of the video can be adjusted in real time according to the shooting system and the preferences of the operator. And the assist display are linked, creating further convenience in manual focus operation during camera shooting.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is a circuit image figure of a FIR digital horizontal filter part in one embodiment (first embodiment) of the present invention. It is a block diagram of a digital video camera in one embodiment (first embodiment) of the present invention. 1 is an external view of a digital video camera according to an embodiment (first embodiment) of the present invention. It is a control flowchart of a digital video camera in one embodiment (first embodiment) of the present invention. It is an image figure when the center frequency emphasized in one Embodiment (1st Embodiment) of this invention is fc = f = 6.75MHz. It is an image figure when the center frequency emphasized in one Embodiment (1st Embodiment) of this invention is fc = f / 2 = 6.75 / 4 = 3.375MHz. It is an image figure when the emphasized center frequency is fc = f / 3 = 6.75 / 4 = 2.25 MHz in one embodiment (first embodiment) of the present invention. It is an image figure when the center frequency emphasized in one Embodiment (1st Embodiment) of this invention is fc = f / 4 = 6.75 / 4 = 1.875MHz. It is an image figure of the frequency characteristic of the FIR digital horizontal filter in one Embodiment (1st Embodiment) of this invention. It is a control flowchart of a digital video camera in one embodiment (second embodiment) of the present invention. It is a control flowchart of a digital video camera in one embodiment (second embodiment) of the present invention. It is a control flowchart of a digital video camera in one embodiment (second embodiment) of the present invention.

Explanation of symbols

101 Input video signal 102 D-FF (flip-flop)
103-109 D-FF (flip-flop)
110 gain adjustment signal 111 frequency adjustment signal 112 signal selector 113 horizontal filter selection signal 114 signal selector 115 output video signal

Claims (10)

Operation means for instructing the adjustment of the focus of the imaging optical system;
Imaging means for receiving an object light passing through the imaging optical system and capturing an image;
Filter means for performing signal processing for adjusting a frequency band for the captured image;
An operation amount detection means for detecting an operation amount of a focus adjustment operation based on an input from the operation means;
The image processing apparatus characterized by comprising a changing means for changing the frequency characteristic of the filter means in response to the operation amount. The image processing apparatus according to claim 1, further comprising display means for displaying an image signal-processed by the filter means. The changing means, the image processing apparatus according to claim 1 or 2, further comprising a selection means for selecting whether or not to perform processing by the filter means. The image according to any one of claims 1 to 3 , wherein the filter unit performs signal processing on at least one of a luminance signal, a color difference signal, a red signal, a green signal, and a blue signal. Processing equipment. Manual focus detection means for detecting whether or not it is a manual focus mode for performing focus adjustment based on an input from the operation means;
The image processing apparatus according to claim 2, wherein the display unit performs black and white display when a detection result by the detection unit is in a manual focus mode. Motion detection means for detecting a focus adjustment operation by the operation means;
6. The image processing apparatus according to claim 5, wherein the display unit changes the monochrome display to a color display when the focus adjustment operation is not performed for a predetermined time or more. The image processing apparatus according to any one of claims 1 to 6, further comprising a recording control means for recording in the recording means the image captured by the imaging means. An image processing method for an image processing apparatus, comprising: an operation unit for instructing adjustment of a focus of an imaging optical system; and an imaging unit that receives an object light that has passed through the imaging optical system and captures an image.
A filter step for performing signal processing for adjusting a frequency band for the captured image;
An operation amount detection step of detecting an operation amount of a focus adjustment operation based on an input from the operation means;
Image processing method characterized by in response to the operation amount, and a changing step of changing the frequency characteristic of the filter step. Operation means for instructing the adjustment of the focus of the imaging optical system;
Imaging means for receiving an object light passing through the imaging optical system and capturing an image;
Filter means for performing signal processing for adjusting a frequency band for the captured image;
An operation amount detection means for detecting an operation amount of a focus adjustment operation based on an input from the operation means;
An image processing apparatus comprising: a changing unit that changes a gain of the filter unit according to the operation amount. An image processing method for an image processing apparatus, comprising: an operation unit for instructing adjustment of a focus of an imaging optical system; and an imaging unit that receives an object light that has passed through the imaging optical system and captures an image.
A filter step for performing signal processing for adjusting a frequency band for the captured image;
An operation amount detection step of detecting an operation amount of a focus adjustment operation based on an input from the operation means;
An image processing method comprising: a change step of changing a gain of the filter step according to the operation amount.

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