Imaging apparatus

Abstract

An LCD driver starts reading a digital image signal of one frame from a VRAM in response to a reproduction timing signal. A driving timing signal generator generates a driving timing signal in response to a synchronizing signal, whose phase is shifted by a delay time from the reproduction timing signal. So a phase difference corresponding to the delay time is provided between the driving timing signal and the reproduction timing signal. Synchronously with the driving timing signal, an image sensor is driven to shoot a subject and output an analog image signal of one frame. After being converted into a digital form, the image signal is written in the VRAM sequentially from the first line of one frame. The phase difference is determined so that the LCD driver starts reading the image signal sequentially from the first line, immediately after the first line is written in the VRAM.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention will be more apparent from the following detailed description of the preferred embodiments when read in connection with the accompanied drawings, wherein like reference numerals designate like or corresponding parts throughout the several views, and wherein:

FIG. 1 is a front view of a digital camera according to an embodiment of the present invention;

FIG. 2 is a rear view of the digital camera shown in FIG. 1;

FIG. 3 is a block diagram illustrating the circuitry of the digital camera of FIG. 1;

FIG. 4 is an explanatory diagram illustrating a condition of image data written in a VRAM in a normal shooting mode;

FIG. 5 is an explanatory diagram illustrating a condition of image data written in a VRAM in an electronic zooming mode;

FIG. 6 is an explanatory diagram illustrating a condition of image data written in a VRAM in an assist thumbnail mode;

FIG. 7 is a functional block diagram illustrating how a drive timing signal and a reproduction timing signal are generated;

FIG. 8 is a timing chart illustrating signals outputted for displaying a camera-through image in the normal shooting mode;

FIG. 9 is a timing chart illustrating signals outputted for displaying a camera-through image in the electronic zooming mode; and

FIG. 10 is a timing chart illustrating signals outputted for displaying a camera-through image in the assist thumbnail mode.

Claims

1. An imaging apparatus comprising: an image sensor that is driven to shoot a subject to output an image signal of one frame;an image memory for storing the image signal of one frame, wherein the image signal is written in said image memory synchronously with the output of the image signal from said image sensor, and is read out of said image memory for displaying an image reproduced from said image signal; anda synchronizing device for synchronizing driving timing of said image sensor with reproduction timing to start reading the image signal of one frame out of said image memory, while providing such a phase difference between the driving timing and the reproduction timing that the reading of the image signal of one frame starts before the image signal of said one frame is completely written in said image memory.

2. An imaging apparatus comprising: a driving timing signal generator for generating a driving timing signal;an image sensor that is driven to shoot a subject to output an image signal of one frame synchronously with the driving timing signal;an image memory for storing the image signal of one frame;a writing device for writing the image signal of one frame in said image memory synchronously with the output of the image signal from said image sensor;a reproduction timing signal generator for generating a reproduction timing signal;a reading device that starts reading the image signal of one frame out of said image memory synchronously with the reproduction timing signal, to display an image of the subject shot by said image sensor; anda synchronizing device for synchronizing the driving timing signal with the reproduction timing signal, while providing such a phase difference between the driving timing signal and the reproduction timing signal that said reading device starts reading the image signal of one frame before said writing device completes writing the image signal of said one frame in said image memory.

3. An imaging device as claimed in claim 2, wherein said writing device writes the image signal of one frame sequentially from a first line, and said synchronizing device decides the phase difference so that said reading device starts reading the image signal of one frame sequentially from the first line, immediately after said writing device completes writing the first line.

4. An imaging device as claimed in claim 2, further comprising a first resolution converting device that crops a designated image cropping area out of the image signal of one frame before being written in said image memory, and converts an absolute resolution of said image cropping area so as to coincide with an absolute resolution of a display screen for displaying the image of the subject, wherein said writing device writes the image signal obtained from said first resolution converting device in said image memory, and said synchronizing device decides the phase difference between the driving timing signal and the reproduction timing signal, taking account of a time necessary for the process in said first resolution converting device.

5. An imaging device as claimed in claim 4, wherein said image cropping area is designated according to an electronic zoom ratio of said imaging device.

6. An imaging device as claimed in claim 2, further comprising a second resolution converting device that converts the image signal of one frame to a smaller absolute resolution to display an image of the subject in a reduced size on a display screen, wherein said writing device writes an image signal obtained from said second resolution converting device in a memory location of said image memory, corresponding to a display zone for displaying the reduced image on said display screen, whereas said reading device reads the image signal of one frame sequentially out of said image memory, including the image signal written in said memory location, and wherein said synchronizing device decides the phase difference between the driving timing signal and the reproduction timing signal, so that said reading device starts reading a last line of the image signal written in said memory location after the last line is written in said memory location.

7. An imaging device as claimed in claim 2, wherein said synchronizing device controls said driving timing signal generator so as to synchronize the driving timing signal on the basis of the reproduction timing signal.

8. An imaging device as claimed in claim 7, wherein said driving timing signal generator generates the driving timing signal in a longer period than a generation period of the reproduction timing signal, and is reset to generate the driving timing signal immediately after the reset in response to a reset signal given from said synchronizing device, wherein said synchronizing device produces the reset signal by shifting the reproduction timing signal by a predetermined delay time.

9. An imaging device as claim 8, wherein said synchronizing device controls the delay time corresponding to the phase difference to be provided between the driving timing signal and the reproduction timing signal.