JP2002190980A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital camera in which the image is not subjected to shake of the hands even if a low shutter speed is selected. SOLUTION: The digital camera comprises a photometric means for measuring the light from an object, means for operating the shutter speed based on the photometric results from the photometric means, means for reading out images focused on an image sensor continuously at a specified time interval and storing two consecutive images sequentially, means for deciding occurrence of the shake of the hands by comparing two images stored in the storage means, and a control means for starting imaging operation if a decision is made that the shake of the hands has not occurred substantially after release operation when a shutter speed having a risk of the shake of the hands is set by the shutter speed operating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera capable of determining whether or not camera shake has occurred.

[0002]

2. Description of the Related Art Similar to a camera using a film, in a digital camera, camera shake is a major factor that degrades the performance of an image and is a problem that is difficult to take measures against. Therefore, even if the focus and exposure are appropriate at the time of shooting, an image that cannot be saved is obtained if camera shake occurs.

[0003] Camera shake is likely to occur when the shutter speed is low.
The shutter speed is converted into a focal length of five formats, and a shutter speed lower than a shutter speed corresponding to the reciprocal of the focal length is set as a shutter speed at which there is a risk of camera shake.

Since the diagonal dimension of a 135 format screen is 43.3 mm and the diagonal dimension of a 1/3 inch CCD is 8 mm, for example, the focal length of the lens is 6 m.
When converted to a 135 format focal length as m, the focal length is equivalent to 43.3 × (6/8) ≒ 32 mm.

In such a conventional digital camera, when such a shutter speed is selected, a warning display of camera shake is displayed on an image monitor based only on information on the shutter speed.

[0006]

When a camera shake warning is given using a conventional digital camera, the user fixes the digital camera on a tripod and shoots. However, when there is no tripod, the user brings the body into close contact with a fixed object such as a building or a standing tree, and shoots in a posture in which camera shake hardly occurs. However, this is still insufficient in many cases, and photographing may be performed while camera shake occurs. Also, even if camera shake occurs during shooting, the user does not immediately know
I can't tell until I play the image taken later on a large monitor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-described problems. An object is to propose a digital camera that displays blur.

[0008]

The above object is achieved by any of the following means.

Photometric means for measuring the subject light; shutter speed calculating means for calculating a shutter speed based on the photometric result of the photometric means; and an image formed on the image pickup device is continuously read at predetermined time intervals. Storage means for sequentially storing two images; camera shake determination means for comparing the two images stored in the storage means to determine whether or not camera shake has occurred; and camera shake by the shutter speed calculation means. Control means for controlling to start a photographing operation after the camera shake determining means determines that almost no camera shake has occurred after the release operation when a shutter speed having a risk of being set is set. A digital camera.

[0010] A camera shake determining means for comparing the image before shooting with the image after shooting to determine whether or not camera shake has occurred, a storage means for storing the shot image, and the camera shake determining means after shooting. A digital camera characterized in that when it is determined that camera shake has hardly occurred, the captured image is stored in the storage unit, and when it is determined that camera shake has occurred, at least a warning of camera shake is issued.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment relating to a digital camera according to the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of a digital camera, FIGS. 2 and 3 are flowcharts of the digital camera, and FIG. 4 is a timing chart of the digital camera.

First, the basic configuration of a digital camera will be described with reference to the block diagram of FIG.

Reference numeral 11 denotes a photographing lens. An optical image of a subject is formed on the image pickup device 12 by the photographing lens 11. The imaging element 12 may be a CCD or a CMOS,
It is desirable that the number of pixels is not less than one million. The optical image is photoelectrically converted by the imaging device 12 into image data.
Is stored. As will be described later, the DRAM 13 stores only the two image data before and after read out for camera shake determination. Then, only the image data that is finally desired to be stored by shooting is stored in the flash memory 14.

The image data is transferred to the CPU 17 by USB.
(General-purpose serial bus) is converted to a standard and output to an external personal computer connected by a connector 16 via an interface 15. The CPU 17 controls each circuit of the digital camera.

Numeral 18 denotes a display unit composed of a liquid crystal plate, which displays the remaining number of images that can be photographed and, when it is detected that camera shake has occurred after photographing, displays the camera shake. Reference numeral 19 denotes a first LE including an orange LED or the like in a finder.
If the shutter speed is at D, and there is a risk of camera shake, it will light up to warn the user. Reference numeral 20 denotes a second LED, such as a red LED, in the viewfinder. When a camera shake occurs, the second LED 20 blinks to give a warning.

When the digital camera is started, the main switch M-SW is turned on, when taking a picture, the release switch R-SW is turned on, and when the taken image is deleted from the memory 13, the erasing switch E-SW is used. Turn on.

Next, the present invention will be described with reference to the flowcharts of FIGS. 2 and 3 and the timing chart of FIG.

First, in FIG. 2, the main switch M-
When the SW is turned on (101), the capture of image data from the image sensor 12 is started (102), and is continuously performed at 1/60 second intervals. For example, the nth image data _Bn is fetched (103), and the image data _Bn is written to the DRAM 13 (104). Then, the CPU 17 measures the subject luminance based on the image data _Bn and calculates the shutter speed (105).

The DRAM 13 sequentially stores only the two image data before and after the readout. Thus, in FIG. 4, following the state in which the image data B ₂ read at the time of image data B ₁ and T ₂ read at time T ₁ to DRAM13 is stored, the image data B at of T _{3 Three}
Reading the image data B ₁ is image data B ₂ is overwritten in an area that is stored, the image data B ₂ is image data B ₃ are stored by overwriting in the area are stored.

The focal length converted to 135 film is defined as f, and the shutter speed corresponding to 1 / f is compared with the calculated shutter speed K. When the shutter speed K is larger than 1 / f, that is, when the shutter speed is low (Y in 106), for example, the first LED 19 in the finder is turned on to issue a camera shake warning (107).

Next, a release button (not shown) is pressed to turn on the release switch R-SW (108).
Y). As a result, as shown in FIG. 4, an image captured at an interval of 1/60 second is compared with the previous and next images (109). For example, images and T ₂ acquired at the time of T ₁
Comparing with the image captured at the time of (1), the image becomes different because camera shake has occurred (Y in 109).
Reference numeral 17 detects the presence of camera shake, and turns on camera shake detection. Be compared with the captured image at the time of the image and the T ₃ taken at time T _2, likewise shake detection is turned on. However, comparing the captured image at the time of the captured image and the T ₄ at time T _3, since the equivalent of the image (109 N), CPU 17, it is determined that there is no camera shake, camera shake detection Is turned off.

By comparing the images before and after, if the images are not completely the same but are substantially the same, the CPU 17 determines that there is no camera shake.

When the camera shake detection is on, the second LED 20 in the finder blinks to warn that camera shake is occurring (110). When the CPU 17 detects that the camera shake has stopped, the second LED 2 in the finder
The warning is released by turning off 0 (111).

Proceeding to FIG. 3, when the camera shake detection is turned off,
Photographing is automatically performed based on the shutter speed obtained in step 105 (121). Then, the captured image data B _{n + 1} is fetched (122) and overwritten on the DRAM 13 (123). At this time, the image data B _n of T _n at the start of shooting and written in the DRAM 13 are compared with the image data B _{n + 1} of T _{n + 1} at the end of shooting. In FIG.
And image data of the photographing start T ₄ compares the image data of the photographing end time T _5. Then, the image data B _n and the image data B
_{If n + 1} is substantially equal (Y of 124), there is no camera shake during shooting, and the display without camera shake is displayed on the display unit 18 for t.
It is displayed for a second (for example, 2 seconds) (125). If the image data B _n is not equal to the image data B _{n + 1} (1
24N), since the camera shake occurred during shooting,
Is displayed for t seconds (for example, 2 seconds) (126).

Then, the image data B _{n + 1} is written into the flash memory 14 (127) and stored.

Thereafter, n becomes n + 1 (12
8) As long as the main switch M-SW is ON (12
9) N), the above flow is repeated, and the main switch M
When the switch is turned off (Y in 129), the process ends.

When the shutter speed K is smaller than 1 / f, that is, when the shutter speed is high (N in 106), the first LED 19
Is not lit, and no camera shake warning is issued (112). Of course, at this time, the photographing can be performed by turning on the release switch R-SW, but is omitted in this flowchart.

If camera shake occurs during shooting, (1
24, Y), the camera shake may be displayed (126), and the image data B _{n + 1} may not be written to the flash memory 14 and may go below (127).

When camera shake is detected as described above,
The warning may be given by an LED different from the above, or by a sound.

Further, in the above example, the image data before and after the camera shake detection was compared. However, a sensor for camera shake detection was provided. May be started. By providing such a sensor, even if camera shake occurs during long-time shooting, this can be detected and a warning can be issued. In this example, two sensors for detecting that the optical axis of the photographing lens is shifted in the vertical direction and the horizontal direction are provided.

Finally, the correspondence between the terms described in the "claims" and the terms described in the "embodiment of the invention" will be described.

The light measuring means includes the image pickup device 12 and the CPU 17
Is equivalent to Shutter speed calculation means, camera shake determination means,
And control means correspond to the CPU 17.

According to the first aspect, the storage means is a DRAM 1
Equivalent to 3. The storage unit according to claims 3 to 5 corresponds to the flash memory 14.

[0035]

According to the digital camera of the first and second aspects, the photographing is started after the camera shake has been settled.
Even if a low shutter speed is selected, a camera shake image is not generated.

According to the digital camera of the third to fifth aspects, if camera shake occurs at the time of shooting, a camera shake warning is issued after shooting, and this can be known.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital camera.

FIG. 2 is a flowchart of the digital camera.

FIG. 3 is a flowchart of the digital camera.

FIG. 4 is a timing chart of the digital camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Image sensor 13 DRAM 14 Flash memory 17 CPU 18 Display part 19 1st LED 20 2nd LED

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G03B 17/20 G03B 17/20 19/02 19/02 H04N 5/225 H04N 5/225 A F-term (Reference) 2H002 CC09 DB02 FB23 FB69 FB71 FB73 GA42 HA07 2H054 AA01 BB11 2H102 AB11 BB05 BB08 CA01 CA11 5C022 AA13 AB55 AC01 AC18 AC52 AC69 CA00

Claims (5)

[Claims] 1. A photometer for measuring light of a subject, a shutter speed calculator for calculating a shutter speed based on a photometric result of the photometer, and an image formed on an image sensor is continuously read at predetermined time intervals. A storage unit for sequentially storing two images before and after, a camera shake determination unit for comparing the two images stored in the storage unit to determine whether or not a camera shake has occurred, and a shutter speed calculation unit. When a shutter speed at which there is a risk of camera shake is set, control means for controlling to start a photographing operation after the camera shake determination means has determined that camera shake hardly occurs after the release operation. A digital camera, comprising: 2. A shutter speed at which there is a risk of camera shake is a shutter speed lower than a shutter speed corresponding to a reciprocal of a focal length obtained by converting a focal length of a used photographic lens into a 135 format. The digital camera according to claim 1. 3. A camera shake determining means for comparing an image before shooting with an image after shooting to determine whether or not camera shake has occurred, a storage means for storing a shot image, and the camera shake determining means after shooting. When it is determined that camera shake has hardly occurred, the captured image is stored in the storage unit, and when it is determined that camera shake has occurred, at least a warning of camera shake is issued. camera. 4. The digital camera according to claim 3, wherein even when it is determined by the camera shake determining means that camera shake has occurred after shooting, the captured image is stored in the storage means. 5. The digital camera according to claim 3, wherein when the camera shake determination unit determines that camera shake has occurred after shooting, the captured image is not stored in the storage unit.