Video camera with major functions implemented in host software

• US 6,995,794 B2
• Filed: 05/18/2001
• Issued: 02/07/2006
• Est. Priority Date: 06/30/1999
• Status: Expired due to Fees

• Current Assignee: Logitech Europe S A (Logitech International SA)
• Original Assignee: Logitech Europe S A (Logitech International SA)
• Inventors: Li, Wei, Zimmermann, Remy, Billerbeck, Bryed, Maggi, Sergio, Labrousse, Jean-Michel Junien, Hsu, Mark, Norcross, Mitchell, Sanchez, George, Auberger, Georges
• Primary Examiner(s): Moe, Aung
• Application Number:
  US09/861,279
• Publication Number:
  US 20020039139A1
• Time in Patent Office: 1,726 Days
• Field of Search: 348241-248, 382/254, 382/275
• US Class Current: 348/241
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 2201/001 Sharing resources, e.g. processing power or memory, with a connected apparatus or enhancing the capability of the still picture apparatus
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof
• CPC Class Codes: H04N 25/61 the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4"
• CPC Class Codes: H04N 25/68 applied to defects

Abstract

A low cost camera by implementing the major functions in host software is provided. This is accomplished by sending raw, digitized data from the camera directly to the host. The increased volume of raw data is handled by either an improved compression/decompression scheme using lossless compression, using lossy compression or using a shared bus with higher bandwidth. By moving such functions as color processing and scaling to the host, the pixel correction can also be moved to the host. This in turn allows the elimination of the frame buffer memory from the camera. Finally, the camera can use a low cost lens by implementing vignetting, distortion, gamma or aliasing correction with a correction value stored in a register of the camera for later access by the host to perform corrections.

Claims

1. A video camera system comprising:

(a) a video camera having

an image sensor, and

a processing element for performing data compression;

(b) an interface coupled to said video camera; and

(c) a processing unit for receiving compressed data from said interface, said processing unit being configured to perform

decompression of said compressed data, at least a portion of the operations of said decompression being performed in parallel,

anomalous pixel correction, and

color processing;

such that anomalous pixel correction and color processing circuitry is not needed in said video camera, and said anomalous pixel correction is performed prior to said color processing.

2. The video camera of claim 1 wherein said video camera includes a lens, and said processing unit is further configured to perform vignetting correction for said lens.

3. The video camera of claim 1 further comprising a memory element in said video camera for storing a constant value corresponding to an amount of vignetting of said lens.

4. The video camera of claim 1 wherein said anomalous pixel correction is designed to minimize its impact on video frame rate by including video sub sampling to determine defective pixels and statistical recording of only pixel position and data related to the frequency of detected defective pixels.

5. The system of claim 1 wherein said processing unit comprises a processor having instructions for operating on multiple pixels in a register in parallel, said processor being programmed for decompression a data stream of variable size compression codes, wherein at least a portion of the operations of the decompression are performed in parallel on multiple fields in said register.

6. The system of claim 5 wherein said data stream is compressed using Huffman encoding, and said operations include:

duplicating a group of bits from said data stream to provide duplicates in multiple positions in a first register; and

performing an operation between values in a second register and said duplicates in parallel, with a different value being used for each duplicate.