Preview mode low resolution output system and method

• US 7,304,679 B1
• Filed: 12/19/2003
• Issued: 12/04/2007
• Est. Priority Date: 03/31/1999
• Status: Expired due to Term

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Itani, Nadi R., Johnson, Sandra M., Holberg, Douglas R.
• Primary Examiner(s): Villecco, John M.
• Application Number:
  US10/742,170
• Time in Patent Office: 1,446 Days
• Field of Search: 348/220.1, 348/222.1, 348/221.1, 348/229.1, 348/230.1, 348/254, 348/255, 348/372, 348/333.11, 348/333.13, 348/333.01, 341/139, 341/161, 341/162, 341/155
• US Class Current: 348/333.11
• CPC Class Codes: H03M 1/002 Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed
• CPC Class Codes: H03M 1/007 among different resolutions
• CPC Class Codes: H03M 1/12 Analogue/digital converters H03M1/001 – H03M1/10 take precedence
• 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 23/84 for processing colour signals
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters

Abstract

A processing system for a charge coupled device (CCD) or CMOS imaging system includes a correlated double sample (CDS) circuit for receiving data from an imager, a variable gain amplifier (VGA) having amplifiers of selectable current level to enable reduced data resolution in a preview display, a low power mode analog-to-digital converter (ADC) having a selectable narrow bit-width output and coupled to said VGA circuit, and a gain circuit coupled to said ADC. The single chip low-power analog front end produces digitized CCD data in either 13-bit, 12-bit or 10-bit formats at a first current level and 9-bit, 8-bit, or 6-bit formats at a second current level. The VGA amplifier includes symmetrical subcircuits which are independently actuable to enable full or reduced data resolution levels respectively for still image capture operation and video previewing on a separate preview screen.

Claims

1. A method of previewing an image, comprising:

receiving, by an image processor system, an image signal for an image;

amplifying, by the image processor system, said image signal at a higher current level or a lower current level;

converting, by the image processor system, said image signal into a digital signal correspondingly having a higher data resolution level or a lower data resolution level;

determining, by the image processor system, whether the image signal is to be previewed; and

in response to the determination that the image signal is to be previewed, selecting, by the image processor system, the lower current level to produce a preview digital image at the lower data resolution level.

2. The method according to claim 1, wherein amplifying, by the image processor system, said image signal further comprises:

amplifying, by a variable gain amplifier of the image processor system, said image signal at the higher current level or the lower current level.

3. The method according to claim 1, wherein converting, by the image processor system, said image signal further comprises:

converting, by an analog-to-digital converter of the image processor system, said image signal into the digital signal correspondingly having the higher data resolution level or the lower data resolution level.

4. The method according to claim 1 wherein selecting, by the image processor system, the lower current level to produce a preview digital image at the lower data resolution level further comprises:

configuring a gain adjust circuit to produce the preview digital image at the lower data resolution level.

5. The method according to claim 1, further comprising:

in response to the determination that the image signal is not to be previewed, selecting, by the image processor system, the higher current level to produce an enhanced digital image at the higher data resolution level.

6. The method according to claim 5, wherein the enhanced digital image is a still image.

7. The method according to claim 1, wherein the preview digital image is a video image.

8. A system for previewing an image, comprising:

an image processor system that;

receives an image signal for an image;

amplifies said image signal at a higher current level or a lower current level;

converts said image signal into a digital signal correspondingly having a higher data resolution level or a lower data resolution level;

determines whether the image signal is to be previewed; and

in response to the determination that the image signal is to be previewed, selects the lower current level to produce a preview digital image at the lower data resolution level.

9. The system according to claim 8, wherein the image processor system further comprises:

a variable gain amplifier for amplifying said image signal at the higher current level or the lower current level.

10. The system according to claim 8, wherein the image processor system further comprises:

an analog-to-digital converter for converting said image signal into the digital signal correspondingly having the higher data resolution level or the lower data resolution level.

11. The system according to claim 8, wherein the image processor system further comprises:

a gain adjust circuit configured to produce the preview digital image at the lower data resolution level.

12. The system according to claim 8, wherein the image processor system further:

in response to the determination that the image signal is not to be previewed, selects the higher current level to produce an enhanced digital image at the higher data resolution level.

13. The system according to claim 12, wherein the enhanced digital image is a still image.

14. The system according to claim 8, wherein the preview digital image is a video image.