JPH10164412A - Digital still camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital still camera by which a video image without a camera-shake can be recorded as much as possible, even when a main body is shaken due to a camera-shake or the like. SOLUTION: A video signal of 6 consecutive fields is stored in a memory 18. On the other hand, a motion of a video image of two adjacent fields is detected, and the result of detection is stored in an internal memory 20a of a microcomputer 20. The microcomputer 20 selects a video signal, whose motion is least according to the result of detection. The selected video signal is read from the memory 18 by the microcomputer 20 and given to a signal-processing circuit 22, where a prescribed processing is conducted and the resulting signal is stored in an image memory 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital still camera, and more particularly, to a digital still camera for recording, for example, a video signal of one field or one frame.

[0002]

2. Description of the Related Art An example of a conventional digital still camera of this type is disclosed in Japanese Patent Application Laid-Open No. 2-111171 [H04N 5/225, H0] filed on Apr. 24, 1990.
4N5 / 232]. According to this conventional technique, if the camera moves due to camera shake when the shutter is turned on, the photographer is warned of the camera shake by a sound or a lamp. At this time, the system controller waits for an instruction from the photographer for a certain period of time. Even if the camera is moving, if there is an instruction to record a video, the system controller directly shoots the image.

[0003]

However, in such a conventional technique, the photographer is warned by sound or a lamp, but a blurred image is recorded as a result of the photographer's instruction. there were. Therefore, a main object of the present invention is to provide a digital still camera capable of recording an image with as little blurring as possible even when the main body is moved due to camera shake or the like.

[0004]

According to the present invention, there are provided a generating means for generating a video signal of a plurality of fields or a plurality of frames corresponding to a subject, a detecting means for detecting a movement of a main body, and a plurality of fields based on a detection result by the detecting means. Alternatively, there is provided a digital still camera including a selection unit that selects a video signal of one field or one frame having the least motion among video signals of a plurality of frames, and recording the video signal selected by the selection unit.

[0005]

According to the present invention, the selection means selects one of the plurality of video signals of a plurality of fields or a plurality of frames corresponding to the subject, based on the detection result of the detection means for detecting the movement of the main body.
Select a field or one frame video signal. The detecting means detects the movement of the main body based on video signals of two adjacent fields or two frames.

The detecting means detects the movement of the main body based on the angular velocity detected by the angular velocity detecting means for detecting the angular velocity of the main body for each field or frame.

[0007]

According to the present invention, the video signal with the least movement is selected, so that even if the main body moves due to camera shake or the like, it is possible to record a video as little as possible. The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments.

[0008]

Referring to FIG. 1, a digital still camera 10 according to this embodiment includes a CCD (Charge Coupled Device) 1.
2 inclusive. When a shutter (not shown) is pressed, images of six consecutive fields (subject images) are captured by the CCD 12. The camera signal output from the CCD 12 is processed by a signal processing circuit 14 in a CDS (Correlated Double Sampling).
g), an AGC (Automatic Gain Control), an analog clamp, an A / D conversion, a digital clamp, and other processing are performed to produce a video signal including a luminance signal component and a chrominance signal component. The memory 18 is provided.

A video signal of six consecutive fields is stored by a microcomputer 20 in a memory 18 having a memory capacity of six fields. Further, the motion detection circuit 16
Motion detection is performed by a representative point matching method based on a luminance signal component included in the video signal. More specifically, referring to FIG. 2, the motion detection circuit 16 detects the motion of the video between two adjacent fields among the video of the continuous six fields, and supplies the detection result to the microcomputer 20. The microcomputer 20 detects the minimum value from the detection results (1) and (2) and selects the latter image from the two-field image corresponding to the minimum value. Therefore, for example, if the detection result is the minimum value, the video signal of the fourth field stored in the memory 18 is read. If the minimum value is 2 or more, the microcomputer 20 gives priority to the detection result obtained earlier. Therefore, for example, if the detection result and the minimum value are obtained, the detection result is prioritized, and the video signal of the third field stored in the memory 18 is read.

The video signal read from the memory 18 is
The data is compressed in the signal processing circuit 22 according to the JPEG format, and the compressed data is stored in the image memory 24.
When the shutter is pressed, the microcomputer 20 starts the processing of the flowchart shown in FIG. 3 and selects the video signal with the least movement. That is, first, in step S1, the field number counter 20b is initialized (fc = 0), and in step S3, it is determined whether or not the count value fc of the field number counter 20b is smaller than "6". If "YES" is determined here, it is determined whether or not the count value fc is "0" in a step S5. If "YES" is determined in the step S5, it is determined that the currently input video signal is the first field, and the process directly proceeds to the step S11 to write the video signal into the memory 18. Then, step 13
Increments the field number counter 20b, and returns to step S3.

If "NO" is determined in the step S5,
In step S7, the motion detection circuit 16 is controlled to perform motion detection between the first field and the second field. When the detection result is obtained, it is written into the internal memory 20a of the microcomputer 20 in step S9. Then, step S11
To write the video signal of the second field to the memory 18,
In step S13, the field number counter 20b is incremented, and the process returns to step S3. This operation is repeated until the count value fc becomes "6", thereby detecting the motion of the video of two adjacent fields and storing the video signals of the first to sixth fields in the memory 18. .

When the count value fc becomes "6", "NO" is determined in a step S3, a minimum value is detected from among the detection results written in the internal memory 20a in a step S15, and the minimum value is detected. , One of the two-field images corresponding to is selected. Then, the process ends. According to this embodiment, motion is detected for each of two adjacent video fields from the video signal of six consecutive fields, and the video with the least motion is selected according to the detection result. A video signal having no image can be written to the image memory.

In this embodiment, the video of the next field is selected from the video of the two adjacent fields, but the video of the previous field may be selected. If two or more minimum values are detected, any minimum value may be selected. Further, although the motion detection is performed for each field, the motion detection may be performed for each frame. Referring to FIG. 4, a digital still camera 10 according to another embodiment includes a CCD 12. When the shutter is pressed, images of five consecutive fields are captured by the CCD 12. The camera signal output from the CCD 12 is processed by the signal processing circuit 14 in the same manner as in the above-described embodiment, and is supplied to the memory 18.

On the other hand, the motion detection circuit 40 includes the angular velocity sensor 30, and detects the motion of the camera body by a voltage value. That is, the output of the angular velocity sensor 30 is almost 0 level as shown in FIG. 5A if there is no movement of the main body, but if there is movement of the main body, it is proportional to the movement of FIG. The amplitude increases as shown in FIG. The output of the angular velocity sensor 30 is converted into an absolute value by an absolute value conversion circuit 32, and the absolute value is represented by A
The signal is supplied to an integration circuit 36 via a / D conversion circuit 34.
The integration circuit 36 calculates an integrated value of the movement of the main body for each field and supplies the calculated value to the microcomputer 38. The microcomputer 38
The minimum value is detected from the given integrated values of the five fields, and the image of the corresponding field is selected. That is, the microcomputer 38 reads the video signal corresponding to the minimum integrated value from the memory 18 and supplies the video signal to the signal processing device 22. Therefore, this video signal is compressed as in the above-described embodiment, and the compressed data is written to the image memory 24. If the minimum value is 2 or more, the microcomputer 38 gives priority to the calculation result obtained earlier.

When the shutter is pressed, the microcomputer 38 starts the processing of the flowchart shown in FIG. That is, first, in step S21, the field number counter 38b is initialized (fc = 0), and in step S23, it is determined whether or not the count value fc of the field number counter 38b is smaller than "5". If "YES" is determined in the step S23, the motion detection circuit 40 is controlled in a step S25 to detect the motion of the main body when capturing the video of the first field. When the detection result is obtained, it is written to the internal memory 38a of the microcomputer 38 in step S27. After that, the video signal of the first field is written to the memory 18 in step S29, the field number counter 38 is incremented in step S31, and the process returns to step S23. This operation is repeated while the count value fc becomes "5", whereby the motion of the main body is detected for each field from the first field to the fifth field, and at the same time, from the first field to the fifth field. Are stored in the memory 18.

When the count value fc becomes "5", "NO" is determined in a step S23, and a video signal corresponding to the minimum detection result written in the internal memory 38a is selected in a step S33. According to this embodiment, the video of one field with the least movement of the camera body is selected from the video signals of five consecutive fields, so that the video with the least blur can be written in the image memory.

When two or more minimum values are detected in the detection result of the motion detection of the camera body, any minimum value may be selected. In addition, although the movement of the camera body during the shooting of one field is detected, the movement of the camera body during the shooting of one frame may be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an illustrative view showing motion detection between fields;

FIG. 3 is a flowchart showing the operation of the microcomputer in the embodiment in FIG. 1;

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a graph showing an output of an angular velocity sensor.

FIG. 6 is a flowchart showing the operation of the microcomputer in the embodiment in FIG. 4;

[Explanation of symbols]

 10 Digital still camera 16, 40 Motion detection circuit 18 Memory 20, 38 Microcomputer 20a, 38a Internal memory 20b, 38b Field counter

Claims (4)

[Claims] 1. A generating means for generating a video signal of a plurality of fields or a plurality of frames corresponding to a subject, a detecting means for detecting a movement of a main body, an image of the plurality of fields or the plurality of frames based on a detection result by the detecting means A digital still camera, comprising: selection means for selecting a video signal of one field or one frame having the least movement among signals, and recording the video signal selected by the selection means. 2. The digital still camera according to claim 1, wherein said detecting means detects the movement of said main body based on video signals of two adjacent fields or two frames. 3. The apparatus according to claim 2, wherein said detecting means includes an angular velocity detecting means for detecting an angular velocity of the main body for each field or frame, and detecting a movement of said main body based on the angular velocity detected by said angular velocity detecting means. 2. The digital still camera according to 1. 4. The image processing apparatus according to claim 1, wherein said selecting means includes a video signal selecting means for selecting a video signal of one field or one frame corresponding to a detection result having the least movement among a plurality of detection results obtained by said detecting means. Item 4. A digital still camera according to any one of Items 1 to 3.