System And Method For An Image Sensor Operable In Multiple Video Standards

• US 20120194735A1
• Filed: 06/11/2010
• Published: 08/02/2012
• Est. Priority Date: 06/22/2009
• Status: Active Grant

• Current Assignee: Ominivision Technologies Incorporated
• Original Assignee: Ominivision Technologies Incorporated
• Inventors: Luo, Xiaodong
• Granted Patent: US 9,215,385 B2
• Time in Patent Office: Days
• US Class Current: 348/441
• 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 25/42 by switching between different modes of operation using different resolutions or aspect ratios, e.g. switching between interlaced and non-interlaced mode
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array

Abstract

An image sensor system and associated method supporting multiple video output standards, such as NTSC and PAL, including a pixel array corresponding in size to the frame size having a smaller line number of the video standards, is described. System and method for resolving discrepancies between standards includes multiple crystal oscillators or frequency synthesis to derive a dot clock, and a standard-specific pixel read-out scheme that provides additional lines when outputting according to the frame size having a larger line number of the video standards. In an embodiment, additional line video data is derived by duplicating a line of image data, and in an alternative embodiment additional line video data is derived by digital vertical interpolation.

Claims

1. A system for providing image data in a first mode according to a first video specification having a first number of lines of image data and in a second mode according to a second video specification having a second number of lines of image data, the second number greater than the first number, and for an integer N, the system comprising:

a video sensor having a pixel array having a third number of lines of pixels;

a video encoder for receiving digital video information and providing a video output;

a line buffer capable of storing information corresponding to at least one line of pixels from the video sensor; and

a controller capable of controlling operation of the system, the controller interspersing an additional line after every N'"'"'th normal line in the second mode to increase a number of lines of image data provided to the video encoder to comply with the second video specification.

2. The system of claim 1 wherein the third number is equal to the first number.

3. The system of claim 1 wherein the third number is equal to one half the first number.

4. The system of claim 1 wherein N is 5, the first video specification is the National Television Standards Committee (NTSC) video specification, and the second video specification is a video specification selected from the group consisting of Phase Alternate Line (PAL) and SECAM.

5. The system of claim 1 wherein the digital video information provided to the video encoder during each additional line duplicates a previous line.

6. The system of claim 1 wherein the digital video information provided to the video encoder during each additional line is derived by interpolating between pixel data of a previous line and a following line.

7. A system for providing color image data in a first mode according to a first video specification having a first number of lines of image data and in a second mode according to a second video specification having a second number of lines of image data, the second number greater than the first number, comprising:

a video sensor having a pixel array having a third number of lines of pixels;

a video encoder for receiving color digital video information and providing a video output;

a line buffer capable of storing information corresponding to at least a first and a second line of pixels from the video sensor; and

a controller capable of controlling operation of the system, the controller interspersing an additional line after every N'"'"'th normal line in the second mode to increase a number of lines of image data provided to the video encoder to comply with the second video specification,

wherein digital video information having intensity information derived from at least one line of pixels and chroma information derived from at least two lines of pixels is provided to the video encoder in normal lines, and digital video information derived from at least two lines of pixels of the video sensor is received from the line buffer and provided to the video encoder during each additional line.

8. The system of claim 7 wherein the digital video information provided to the video encoder during each additional line is stored video information.

9. The system of claim 7 wherein the digital video information provided to the video encoder during each additional line is interpolated from at least two lines of pixels of stored video information.

10. A method for providing video image data to an output in a first mode according to a first video specification having a first number of lines of image data and in a second mode according to a second video specification having a second number of lines of image data, the second number greater than the first number comprising:

In the first mode, reading image data from a pixel array having the first number of lines, and providing derivative image data to the output; and

In the second mode, repeatedly;

reading an integer number of lines of image data from the pixel array and providing that image data to the output; and

duplicating a line of image data to the output.

11. A method for providing video image data to an output in a first mode according to a first video specification having a first number of lines of image data and in a second mode according to a second video specification having a second number of lines of image data, the second number greater than the first number comprising:

In the first mode, reading image data from a pixel array having the first number of lines, and providing derivative image data to the output; and

In the second mode, repeatedly;

reading an integer number of lines of image data from the pixel array and providing that image data to the output;

interpolating between at least two lines of image data to derive a line of interpolated image data; and

providing the interpolated image data to the output.