Automatic video signal identification

• US 5,661,527 A
• Filed: 07/07/1995
• Issued: 08/26/1997
• Est. Priority Date: 07/07/1995
• Status: Expired due to Term

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Ferguson, Kevin M.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Murrell, Jeffrey S.
• Application Number:
  US08/499,539
• Time in Patent Office: 781 Days
• Field of Search: 348/179, 348/180, 348/189, 348/129, 348/130, 348/177, 348/554, 348/555, 348/556, 348/557, 348/558
• US Class Current: 348/558
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details

Abstract

An automatic video signal identification system uses zero-mean normalized reference signals that are cross-correlated with an input video signal. The input video signal is stored in an acquisition memory and then cross-correlated with a plurality of reference signal templates, each template representing a particular video signal to be identified. The cross-correlation process provides a corresponding plurality of maximum correlation outputs. The largest maximum correlation output is determined, and the corresponding template identified. If not already normalized, the largest maximum correlation .output is normalized to produce a correlation coefficient. Based upon the identified template the correlation coefficient is tested to determine the validity of the match, i.e., whether the video signal is identified or whether the video signal is unknown. The resulting match ID is then converted into a code which is used to steer video signal measurements for the identified video signal and/or into a text label for display. The reference signal templates may be preloaded or captured from the input signal, making the system adaptable for identifying additional video signals.

Claims

1. A method of identifying video signals within an input video signal comprising the steps of:

cross-correlating the input video signal with each of a plurality of zero-mean reference signal templates to produce a set of maximum correlation outputs, each template representing an individual one of the video signals to be identified;

selecting the largest of the maximum correlation outputs from the set as an optimum correlation output, identifying a location within the set corresponding to the optimum correlation output; and

qualifying the optimum correlation output in the form of a correlation coefficient as a function of the location to produce an output identification code indicating the zero-mean reference signal template corresponding to the qualified optimum correlation output.

2. The method as recited in claim 1 further comprising the step of aligning the input video signal with the plurality of zero-mean reference signal templates prior to the cross-correlating step to improve processing speed.

3. The method as recited in claim 1 further comprising the step of steering a video signal measurement based upon the output identification code.

4. The method as recited in claim 1 further comprising the step of displaying a text message identifying the zero-mean reference signal template based upon the output identification code.

5. The method as recited in claim 1 further comprising the step of normalizing the input video signal prior to the cross-correlating step so that the maximum correlation outputs are respective template correlation coefficients and the optimum correlation output is the correlation coefficient.

6. The method as recited in claim 1 further comprising the step of normalizing the optimum correlation output using the input video signal to produce the correlation coefficient.

7. An apparatus for identifying video signals within an input video signal comprising:

means for cross-correlating the input video signal with each of a plurality of zero-mean reference signal templates to produce a set of maximum correlation outputs, each template representing an individual one of the video signals to be identified;

means for selecting the largest of the maximum correlation outputs from the set as an optimum correlation output, identifying a location within the set corresponding to the optimum correlation output; and

means for qualifying the optimum correlation output in the form of a correlation coefficient as a function of the location to produce an output identification code indicating the zero-mean reference signal template corresponding to the qualified optimum correlation output.

8. The apparatus as recited in claim 7 further comprising means for aligning the input video signal with the plurality of zero-mean reference signal templates.

9. The apparatus as recited in claim 7 further comprising means for steering a video signal measurement based upon the output identification code.

10. The apparatus as recited in claim 7 further comprising means for displaying a text message identifying the zero-mean reference signal template based upon the output identification code.

11. The apparatus as recited in claim 7 further comprising means for normalizing the input video signal prior to the cross-correlating means so that the maximum correlation outputs are respective template correlation coefficients and the optimum correlation output is the correlation coefficient.

12. The apparatus as recited in claim 7 further comprising means for normalizing the optimum correlation output using the input video signal to produce the correlation coefficient.

13. An apparatus for automatic video signal identification comprising:

means for storing an acquired input video signal and a plurality of zero-mean reference signal templates;

means for cross-correlating the acquired input video signal with each of the templates to generate a set of maximum correlation outputs;

means for selecting the largest of the maximum correlation outputs from the set as an optimum correlation output, identifying a location within the set corresponding to the optimum correlation output; and

means for qualifying the optimum correlation output as a function of the location to produce an identification code indicating the zero-mean reference signal template corresponding to the qualified optimum correlation output.

14. The apparatus as recited in claim 13 further comprising means for steering a video signal measurement as a function of the identification code.

15. The apparatus as recited in claim 13 further comprising means for displaying a text message as a function of the identification code.

16. The apparatus as recited in claim 13 further comprising means for normalizing the acquired input video signal prior to input to the cross-correlating means so that the maximum correlation outputs are respective template correlation coefficients and the optimum correlation output is the correlation coefficient.

17. The apparatus as recited in claim 13 further comprising:

means for normalizing the acquired input video signal to produce a normalized input video signal; and

means for converting the optimum correlation output to the correlation coefficient as a function of the normalized input video signal.