Converting a multi-pixel image to a reduced-pixel image to provide an output image with improved image quality

• US 6,801,250 B1
• Filed: 09/08/2000
• Issued: 10/05/2004
• Est. Priority Date: 09/10/1999
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Miyashita, Satoshi
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): Hannett, James M.
• Application Number:
  US09/657,932
• Time in Patent Office: 1,488 Days
• Field of Search: 348/240.2, 348/220.1, 348/208.6, 348/208.13, 348/208.99
• US Class Current: 348/220.1
• CPC Class Codes: G06T 2200/28 involving image processing hardware
• CPC Class Codes: G06T 3/4015 Image demosaicing, e.g. colour filter arrays [CFA] or Bayer patterns
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/683 performed by a processor, e.g. controlling the readout of an image memory
• CPC Class Codes: H04N 23/684 performed by controlling the image sensor readout, e.g. by controlling the integration time
• CPC Class Codes: H04N 23/6842 by controlling the scanning position, e.g. windowing
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation
• CPC Class Codes: H04N 7/0135 involving interpolation processes interpolation-based image scaling G06T3/4007; interpolation for video coding H04N19/587, H04N19/59

Abstract

A CCD image sensor 14 uses sufficiently more pixels than those in an output image. A pixel number conversion block applies pixel number reduction conversion to an image pickup signal from the CCD image sensor 14. This signal is output as a monitor output or motion-picture recording signal via a terminal 43. Converting the multi-pixel image signal to a reduced image can provide an output image with improved sharpness.

Claims

1. An image pickup apparatus for receiving an input image and producing an output image, the image pickup apparatus comprising:

an image pickup element having more pixels than those in the output image, said image pickup element configured to receive the input image and produce an intermediate image having a first number of pixels; and

a pixel number conversion means configured to receive the intermediate image, said pixel number conversion means operating to reduce the first number of pixels in the intermediate image to produce the output image, said pixel number conversion means including;

a horizontal pixel interpolating filter configured to interpolate signals between horizontal pixels,

a plurality of line delay devices configured to store interpolated signals from said horizontal pixel interpolating filter,

a vertical pixel interpolating filter, and

a memory controller configured to selectively transmit stored interpolated signals from said plurality of line delay devices to said vertical pixel interpolating filter to interpolate signals between vertical pixels.

2. An image pickup apparatus according to claim 1 having motion-picture mode and still-picture mode,

wherein the motion-picture mode is used for extracting a signal for said intermediate image containing fewer pixels than those in said image pickup element and more pixels than those in said output image from an image pickup area of said image pickup element and

wherein the still-picture mode is used for reading the entire image pickup area in said image pickup element for generating a signal for said intermediate image.

3. An image pickup apparatus according to claim 2, wherein said motion-picture mode is used for extracting said intermediate image from the image pickup area of said image pickup element with camera-shake correction.

4. An image pickup apparatus according to claim 2, wherein said still-picture mode has a still-picture monitoring mode and a still-picture recording mode, wherein said still-picture monitoring mode is used for generating a signal for said intermediate image by reading two mixed lines from the image pickup area of said image pickup element, and wherein said still-picture recording mode is used for generating a signal for said intermediate image by independently reading all pixels from the image pickup area of said image pickup element.

5. An image pickup apparatus according to claim 1, wherein said image pickup element uses a CCD image sensor whose pixel forms a tetragonal lattice.

6. An image pickup apparatus according to claim 1, wherein said pixel number conversion means converts said intermediate image to output images based on different systems by changing reduction rates of signals.

7. An image pickup apparatus according to claim 1, wherein said pixel number conversion means provides zooming by changing conversion ratios of signals for said intermediate image.

8. An image pickup method for receiving an input image and producing an output image, the method comprising:

providing an image pickup element having more pixels than those in the output image;

configuring the image pickup element to receive the input image and to produce an intermediate image having a first number of pixels; and

reducing the first number of pixels in said intermediate image to produce said output image by;

interpolating signals between horizontal pixels,

storing interpolated signals, and

selectively transmitting stored interpolated signals to interpolate signals between vertical pixels.

9. An image pickup method according to claim 8, wherein said image pickup apparatus has a motion-picture mode and a still-picture mode comprising the steps of:

using the motion-picture mode to extract a signal for said intermediate image containing fewer pixels than those for said image pickup element and more pixels than those for said output image from an image pickup area in said image pickup element; and

using the still-picture mode to read the entire image pickup area in said image pickup element for generating a signal for said intermediate image.

10. An image pickup method according to claim 9, comprising the step of:

using said motion-picture mode to extract said intermediate image from the image pickup area of said image pickup element with camera-shake correction.

11. An image pickup method according to claim 9, wherein said still-picture mode has a still-picture monitoring mode and a still-picture recording mode, comprising the steps of:

using said still-picture mode to generate a signal for said intermediate image by reading two mixed lines from the image pickup area of said image pickup element, and

using said still-picture recording mode to generate a signal for said intermediate image by independently reading all pixels from the image pickup area of said image pickup element.

12. An image pickup method according to claim 8, wherein said image pickup element uses a CCD image sensor whose pixel forms a tetragonal lattice.

13. An image pickup method according to claim 8, wherein reducing the first number of pixels in the intermediate image to produce the output image includes converting said intermediate image to output images based on different systems by changing reduction rates.

14. An image pickup method according to claim 8, wherein reducing the first number pixels in the intermediate image to produce the output image includes providing zooming by changing conversion ratios of signals from said intermediate image.