JP2002271673A - Electronic camera and static image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera and a static image recording method that enable record of an image at the instant a photographer desires taking photograph. SOLUTION: The digital camera is provided with a time lag measurement mode and measures in advance a time (time lag) T1 , starting from the visual recognition of a photographer until the shutter switch is depressed. When preparation of photographing, such as AE/AF processing, is ready, the capturing of an image is started without waiting for depression of the shutter switch. The captured image is stored sequentially in a temporary storage memory, which stores image data for at least a period of T1 or longer. When the photographer depresses the shutter switch, the image traced back by the time T1 from the depressing point of time is selected for recording data an the selected image is written in a recording medium. The time lag is a time, e.g. by lighting an LED provided in the camera, until the shutter switch is depressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera for converting an optical image into electronic image data for recording, and a still image recording method applied to the electronic camera.

[0002]

2. Description of the Related Art An electronic camera disclosed in Japanese Patent Application Laid-Open No. H11-136557 temporarily stores in a memory a plurality of pieces of image data continuously imaged by an imaging means, and evaluates the plurality of image data. And choose the best one,
The selected image data is recorded and stored. It is disclosed that a shutter time lag is detected as an evaluation item, and an image having a small time lag (one close to a shutter timing intended by a photographer) can be selected as image data for storage.

[0003]

However, according to the above-mentioned conventional technique, an image at the moment when the shutter switch is actually pressed can be captured, but an image at the moment when the photographer sees it cannot be recorded. If the photographer recognizes the moment he wants to shoot and presses the shutter switch, there will be a time lag between recognition of the object visually and actual depression of the shutter switch, and the processing time until the camera captures the image. A minute shutter time lag occurs. There were individual differences in the time between when the person visually recognized and when the shutter switch was pressed, and the photographer could not record the image at that moment when he wanted to take a picture.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electronic camera and a still image recording method capable of recording an image at a moment when a photographer desires to photograph.

[0005]

In order to achieve the above object, the present invention provides an electronic camera capable of recording an image obtained via an image sensor on a recording medium.
A time difference measuring means for measuring a time T ₁ from when the photographer visually recognizes the target to when the recording instruction switch is operated, and when the image capturing is started before the recording instruction switch is operated, and the image is captured. A storage unit for temporarily storing a plurality of image data, and a plurality of image data stored in the storage unit, which are taken in at a time when the recording instruction switch is operated and the time T ₁ is up, and Recording means for recording image data on a recording medium.

According to the present invention, the photographer measures the time lag T ₁ of his / her shutter operation in advance by the time difference measuring means. When preparation for photographing is completed, image capture is started without waiting for a recording start instruction input (shutter switch ON), and the captured images are sequentially stored in the storage unit. When recording instruction switch by the photographer is operated to select the image that has been captured at the timing of up reverse only the time lag T ₁ from the operation point as an image for recording, and writes the image data in the recording medium processing I do. Thereby, an image at the moment when the photographer intends to photograph can be recorded.

Further, in the still image recording method according to the present invention, a step of measuring a time T ₁ from when the photographer visually recognizes the target until the photographer operates the recording instruction switch, and the recording instruction switch is operated. before start the image capture from the steps of temporarily storing a plurality of image data imaged, among the plurality of image data to which the are temporary storage, from said recording instruction when the switch is operated by said time T ₁ It is characterized by including a step of specifying the image data taken in at the time of going up, and a step of recording the specified image data on a recording medium.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electronic camera and a still image recording method according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram of a digital camera according to an embodiment of the present invention. The camera 10 is a digital camera that can convert an optical image of a subject into electronic image data and record it as a still image, and a CCD image sensor (hereinafter referred to as a CCD)
That. ) 14 are arranged. Photosensors are arranged on the light receiving surface of the CCD 14 in a plane. Is converted to Note that the CCD 14 has a so-called electronic shutter function of controlling the charge accumulation time (shutter speed) of each photosensor by the timing of a shutter gate pulse.

The signal charges accumulated in each photo sensor are:
The signal is sequentially read out as a voltage signal (image signal) corresponding to the signal charge based on a pulse given from a CCD driver (not shown) and sent to the analog signal processing unit 16. The analog signal processing unit 16 includes signal processing circuits such as a sampling and holding circuit, a color separation circuit, and a gain adjustment circuit. In the analog signal processing unit 16, correlated double sampling (CDS) processing and each of R, G, and B colors are performed. The signals are subjected to color separation processing, and the signal level of each color signal is adjusted (pre-white balance processing).

The signal output from the analog signal processing unit 16 is converted into a digital signal by an A / D converter 18 and then sent to a digital signal processing unit 20. The digital signal processing unit 20 includes a luminance / color difference signal generation circuit, a gamma correction circuit, a sharpness correction circuit, a contrast correction circuit,
It functions as image processing means including a white balance correction circuit and the like. The image data captured via the CCD 14 is converted into a luminance signal (Y signal) and color difference signals (Cr, Cb signals) by a digital signal processing unit 20 and is subjected to predetermined processing such as gamma correction. , A memory as a temporary storage means (hereinafter, referred to as a temporary memory) 2
2 is stored. Note that the temporary memory 22 is constituted by a volatile memory.

The CPU 24 controls the operation of a corresponding circuit based on input signals received from the switches SW1 and SW2 and other operation units, and performs autofocus (AF) control.
It controls photographing operations such as automatic exposure (AE) control and recording process control. In this example, the switch SW1 corresponds to a switch for detecting "half-press" of the release button, and the switch SW2 corresponds to a switch for detecting "full-press" of the release button. Hereinafter, if necessary, switch S
W1 is called a shooting preparation switch, and switch SW2 is called a shutter switch.

The CPU 24 performs various calculations such as a focus evaluation calculation and an AE calculation from the captured image data in response to the "half press" of the release button (SW1 = ON).
Based on the calculation result, a lens driving unit (not shown) is controlled to move the photographing lens 12 to a focusing position, while controlling an aperture mechanism (not shown) and controlling the charge accumulation time of the CCD 14.

After the AE and AF processes, the camera 10 starts capturing an image without waiting for the release button to be fully pressed (SW2 = ON), and stores the image obtained by imaging in the temporary memory 22. I do. Importing images
A plurality of image data are successively repeated at a predetermined cycle programmed in advance, and a plurality of image data are stored in the temporary memory 22 in chronological order.

"Full press" of the release button (SW2 = O
When N) is detected, the image data for recording and preservation is determined from the plurality of image data stored in the temporary memory 22. Although the details of the determination method will be described later, before the photographing, the shutter switch S
Measured in advance time T ₁ of the until you press W2, the image data taken when the shutter switch SW2 is up reverse by time T ₁ from the time of ON and image data for record keeping.

The method of measuring the time T ₁ is, for example, the camera 1
The light emitting diode (LED) 30 provided for 0 is turned on, and in response to the lighting, the photographer presses the shutter switch SW2. Obtaining data time lag T ₁ by measuring the time from LED lighting until the shutter switch ON. In this example, the LED 30 of the finder lamp is also used as a means for giving a stimulus for visual recognition.
ED may be used. Although not shown, the finder lamp is a display means arranged near the finder window, and displays the state of the camera (ready for shooting, charging, etc.) by its lighting color and lighting state (lighting / flashing / lighting out). Things.

The measurement result of the time lag T ₁ is recorded in a non-illustrated non-volatile memory (EEPROM or the like) in the camera 10, and the measurement data is referred to at the time of photographing. Thus, the image data the photographer had been taken at the time of up reverse by time T ₁ from the time of operating the shutter switch SW2 is intended to record the image is selected as the data for recording. The image data according to this selection is subjected to predetermined signal processing such as compression processing,
2 is recorded on the recording medium 34.

The recording medium 34 includes electronic media, magnetic media, optical media such as smart media (Solid-State Floppy Disk Card), PC card, compact flash, magnetic disk, optical disk, magneto-optical disk, memory stick, or any of these. Various readable and writable media can be used in accordance with a method based on a combination of the above. Signal processing means and interfaces corresponding to the medium used are applied. The means for storing the image is not limited to the removable medium, but may be a recording medium (internal memory) built in the camera 10. In the case of storing images in the internal memory, a communication interface for transferring data to an external device such as a personal computer is provided.

Next, the operation of the camera 10 configured as described above will be described. FIG. 2 is a flowchart showing the procedure for measuring the time difference (time lag) from the visual recognition of the photographer to the shutter operation. The camera 10 has a “time lag measurement mode”, and when the user selects the “time lag measurement mode” by a mode selection means (not shown) provided in the camera 10, the time lag measurement process shown in FIG. 2 starts (step S100). ). In this example, a finder lamp (LED 30) is used as a means for giving a visual recognition stimulus, and the LED 30 is turned on at an appropriate timing such as after half-pressing the release button (switch SW1 = ON) (step S110). .

Next, the shutter switch SW2 is turned on.
Is determined (step S112). N in this judgment
When the determination is O, the process of step S112 is repeated. When the shutter switch SW2 = ON is detected in step S114 (when the determination is YES), the process proceeds to step S114.

[0021] At step S114, measuring the time T ₁ of the the LED lit until the shutter switch SW2 = ON. Thus, the data of the measured time lag T ₁ is set in the non-volatile memory (step S116), and the present sequence ends (step S120).

FIG. 3 is a flowchart showing a control procedure of the photographing operation. When the process is started by turning on the photographing preparation switch SW1 (step S200), first, A
The E / AF operation is started, and it is determined whether the AE and the AF processing have been completed (step S210). When a "NO determination" is obtained in this determination, the process of step S210 is repeated. When the end of the AE / AF process is detected in step S210 (when YES is determined), the process proceeds to step S212, and image capture is started.

The captured images are sequentially stored in the temporary memory 22. Although at least the time period T ₁ or more data is held, the image data has elapsed time T ₁ so becomes unnecessary, overwrite the deleted or a new image data at that time.

While continuing the image taking process, it is determined whether or not the shutter switch SW2 has been pressed (step S214). If the shutter switch SW2 has not been pressed, step S214 is repeated, and the image capture and the update of the held data are repeated until the shutter switch SW2 is pressed. If it is detected in step S214 that the shutter switch SW2 has been pressed, the flow advances to step S2.
Proceed to 16. In step S216, performs processing for selecting an image at the time of up reverse only the time lag T ₁ from the time of accepting the shutter switch SW2 = ON from the temporary memory 22 (step S216), then writes the image to the recording medium 34 Execute processing (step S
218).

FIG. 4 shows a timing chart of the image recording operation. FIG. 4A shows a conventional recording method for comparison, and FIG. 4B shows a recording method of the present embodiment. Conventionally, the photographer is there is a time delay of T ₁ from to recognize the object until you press the shutter switch. Furthermore, due to the camera in the mechanical and electrical operation of the properties as well as signal processing on the need, the time difference T ₂ also to actually image after receiving a shutter switch is captured is generated. That is, in the conventional camera, photographing is performed with a time delay of T ₁ + T ₂ from the moment when the photographer desires to photograph.

On the other hand, in the camera 10 of the present embodiment, the capture of an image is started simultaneously with the completion of the AE / AF processing, and the captured image (,,.
2 is sequentially stored. Then the shutter switch is ON, the stored inverse upstream from that point by the time T _1, the corresponding image (image captured at the timing of the drawing) in the recording medium 34. Uptake interval is preferably as short image to a temporary memory 22, but equivalent to the camera device-specific shutter time lag T ₂ are in this example.

If there is no image corresponding to the point in time that has gone up by the time T ₁ , the image captured at the timing closest to that point is recorded on the recording medium 34. If the time interval from the "half-press" of the release button until the "full-press" is shorter than the time lag T ₁ is,
Image before only T ₁ from the time of "full-press" is the temporary memory 2
In this case, the first captured image is written to the recording medium 34 because it is not stored in the storage medium 34.

According to the present embodiment, the shutter switch pressing time difference is measured in advance for each photographer, and an image which is reversed by the time difference from the time when the shutter switch is received is recorded on the recording medium 34. Therefore, the image at the moment when the photographer wants to photograph can be recorded.

Further, according to the camera 10 of the present embodiment, since the capture of the recording image has been completed before the shutter release operation that induces camera shake, there is also an effect that camera shake does not occur.

In the above description, the switch SW1 has been described as means for detecting half-pressing of the release button, and the switch SW2 has been described as means for detecting full-pressing of the release button.
Instead of this mode, switch SW1 is set to power (power supply).
An embodiment in which the switch and the switch SW2 are shutter switches is also possible. In this case, the photographing preparation such as the AE and the AF processing is started by turning on the power switch, and after the photographing preparation is completed, the capture of the image is started. Thus,
The shutter switch SW2 is monitored while the image is constantly captured and the image data in the temporary memory 22 is updated, and the recorded image is selected in response to the depression of the shutter switch SW2. 3 is changed to a control procedure that returns to step S210 when a NO determination is obtained in step S214.

In implementing the present invention, the method of measuring the time lag T ₁ is not limited to the above example. For example, when the camera 10 is provided with an image display device such as a liquid crystal monitor, the LED 30 is used as a means for providing visual recognition stimulus.
Alternatively, or in combination with this, a mode using a liquid crystal monitor is also possible.

[0032]

According to the present invention as described above, according to the present invention, measured in advance the time (time lag) T ₁ from recognition by visual photographer to press the shutter switch, after completion of the photographic preparation, recording instruction an image capture starts without waiting for the operation of the switch, as well as sequentially stored in the storage means for temporarily storing the image captured, recorded when the indication switch is operated, amok by time T ₁ from the operation point Since the captured image is stored in the recording medium, it is possible to record the image at the moment when the photographer just wants to photograph.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital camera according to an embodiment.

FIG. 2 is a flowchart showing a procedure for measuring a time lag (T ₁ ) of a shutter operation.

FIG. 3 is a flowchart illustrating a control procedure relating to a shooting operation of the digital camera according to the embodiment;

FIG. 4 is a timing chart showing a comparison between a conventional image recording operation and an image recording operation according to the present embodiment.

[Explanation of symbols]

10: camera (electronic camera), 12: photographing lens, 14
... CCD (image sensor), 20 ... Digital signal processor, 2
2 temporary memory (storage means), 24 CPU (time difference measurement means), 30 LED (time difference measurement means), 32 media interface (recording means), 34 recording medium (recording medium), SW1 ... switch, SW2 … Switch (recording instruction switch)

Claims (3)

[Claims] 1. An electronic camera capable of recording an image acquired via an image sensor on a recording medium, the electronic camera comprising: a time period from when a photographer visually recognizes an object to when a recording instruction switch is operated; Time difference measuring means for measuring T ₁ , storage means for starting capture of an image before the recording instruction switch is operated, and temporarily storing a plurality of captured image data, and a plurality of data stored in the storage means Of the image data, the time T ₁ from the point in time when the recording instruction switch is operated.
Recording means for recording the image data captured at the time when the image data is moved up on the recording medium. 2. The method according to claim 1, wherein the storing means stores at least the time T
_2. The electronic camera according to claim 1, wherein the electronic camera holds image data for at least _one period. 3. A step of measuring a time T ₁ from when the photographer visually recognizes the target to when the recording instruction switch is operated, and starts capturing an image before the recording instruction switch is operated. a step of temporarily storing a plurality of image data, among the plurality of image data to which the are temporarily stored, the recording instruction switch has been captured at the time of up reverse only the time T ₁ from the time when the operation image A still image recording method, comprising: a step of specifying data; and a step of recording the specified image data on a recording medium.