Methods and apparatus for the measurement of video quality

• US 6,734,898 B2
• Filed: 04/17/2001
• Issued: 05/11/2004
• Est. Priority Date: 04/17/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Zeidler, David E.
• Primary Examiner(s): Lee, Michael H.
• Assistant Examiner(s): DESIR, JEAN WICEL
• Application Number:
  US09/836,728
• Publication Number:
  US 20030086001A1
• Time in Patent Office: 1,120 Days
• Field of Search: 348/183, 348/180, 348/181, 348/188, 348/192, 348/193, 348/194, 348/189, 348/177, 348/182, 348/191, 348/184, 375/226, 375/227, 725/107, 725/109, 725/110, 725/114, 725/115
• US Class Current: 348/183
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details
• CPC Class Codes: H04N 17/004 for digital television systems

Abstract

The present invention relates to methods and apparatus for measuring the quality of video (e.g., television) signals. In particular, the methods and apparatus of the present invention allow for the measurement of various quality parameters of analog or digital video signals at a set-top terminal 10 or similar device, without the need for external test equipment. A video signal 14, which contains a test signal, is received at a decoder 20. The video signal 14 is decoded and temporarily stored in memory 40. A processor 30 associated with the decoder 20 and the memory 40 analyzes the test signal and calculates a quality parameter for the received video signal 14 based on the test signal. The quality measurements can also be accessed remotely and downloaded, for example, by a cable television provider at a cable television headend. The video quality measurement may include various indicators of end-to-end system performance, including the performance of the set-top terminal 10 or similar device.

Claims

1. A method for the measurement of video quality, comprising the steps of:

receiving via a network a video signal at a decoder, said video signal containing a test signal;

decoding said video signal;

temporarily storing at least the test signal portion of the video signal in memory;

analyzing the test signal at a processor associated with the decoder to determine a type of the test signal;

calculating a quality parameter associated with the type of the test signal for the received video signal based on the test signal at the processor;

storing the quality parameter in memory; and

accessing the stored quality parameter from a remote location.

2. A method in accordance with claim 1, wherein the video signal is an analog signal, comprising the further steps of:

converting the analog signal to a digital signal;

separating the digital signal into digital component samples; and

the storing step temporarily stores the digital component samples in the memory.

3. A method in accordance with claim 1, wherein the quality parameter relates to at least one of signal to noise ratio of the received video signal, differential phase, differential gain, chrominance/luminance gain, chrominance/luminance delay, chrominance/luminance intermodulation, short time distortion, line time distortion, frequency response, luminance nonlinearity, chrominance nonlinear phase, and chrominance nonlinear gain.

4. A method in accordance with claim 1, wherein:

the video signal is a digital signal; and

the test signal is embedded in the compressed video syntax of the digital signal.

5. A method in accordance with claim 1, wherein:

the video signal is a National Television Systems Committee (NTSC) video signal; and

the test signal is a vertical interval test signal (VITS) carried in the vertical interval of the video signal.

6. A method in accordance with claim 1, comprising the further step of:

displaying the quality parameter as an on-screen diagnostic display.

7. A method in accordance with claim 1, comprising the further step of:

downloading said stored quality parameter at said remote location from the memory.

8. Apparatus for providing a measurement of video quality, comprising:

a receiver for receiving via a network a video signal containing a test signal;

a decoder for decoding said received video signal;

memory for temporarily storing at least the test signal portion of the decoded video signal; and

a processor associated with the memory for;

analyzing the test signal to determine a type of the test signal, and

calculating a quality parameter associated with the type of the test signal for the received video signal based on the test signal;

wherein;

the quality parameter is stored in said memory; and

the stored quality parameter is accessed from a remote location.

9. Apparatus in accordance with claim 8, wherein:

the video signal is an analog signal;

the analog video signal is converted to a digital signal;

the digital signal is separated into digital component samples; and

the digital component samples are temporarily stored in the memory.

10. Apparatus in accordance with claim 8, wherein the quality parameter relates to at least one of the signal to noise ratio of the received video signal, differential phase, differential gain, chrominance/luminance gain, chrominance/luminance delay, chrominance/luminance intermodulation, short time distortion, line time distortion, frequency response, luminance nonlinearity, chrominance nonlinear phase, and chrominance nonlinear gain.

11. Apparatus in accordance with claim 8, wherein:

the video signal is a digital signal; and

the test signal is embedded in the compressed video syntax of the digital signal.

12. Apparatus in accordance with claim 8, wherein:

the video signal is a National Television Systems Committee (NTSC) video signal; and

the test signal is a video interval test signal (VITS) carried in the vertical interval of the video signal.

13. Apparatus in accordance with claim 8, wherein:

the quality parameter is displayed as an on-screen diagnostic display.

14. Apparatus in accordance with claim 8, wherein:

said stored quality parameter is downloaded at said remote location from said memory.