public double ContrastFractionThreshold { get; set; }

public double ContrastFractionThreshold { get; set; }

Public Property ContrastFractionThreshold As Double 
	Get 
	Set

Public Property ContrastFractionThreshold As Double 
	Get 
	Set

public:
property double ContrastFractionThreshold {
	double get ();
	void set (double value);
}

public:
property double ContrastFractionThreshold {
	double get ();
	void set (double value);
}

Property Value

The contrast fraction is a number between zero and one. It is computed by dividing the average contrast of the matching image features by the average contrast of the trained pattern features. If this ratio exceeds one it is reported as exactly one.

You can discard results with very low contrast (relative to the pattern) by setting the ContrastFractionThreshold. You should supply a non-zero value that is lower than the lowest contrast fraction you ever expect to receive from a true instance of your pattern.

There are several parameters that affect how PMRedLine reports results. If the ReturnAllResults property of CogPMRedLineRunParams is "false", every returned result will have its Accepted property set to "true", and a result will be returned only if all of the following conditions are met:

• Its Score is greater than or equal to AcceptThreshold.
• Its ContrastFraction is greater than or equal to ContrastFractionThreshold.
• Its angle (as reported by the Rotation property of the CogTransform2DLinear returned by GetPose ) was either:
  • obtained using an angle zone whose Configuration was set to Nominal, or
  • obtained using an angle zone whose Configuration was set to LowHigh, and has a value between the Low and High angles that you specified.
• Its scale (as reported by the Scaling property of the CogTransform2DLinear returned by GetPose ) was either:
  • obtained using a scale zone whose Configuration was set to Nominal, or
  • obtained using a scale zone whose Configuration was set to LowHigh, and has a value between the Low and High scales that you specified.
• Its Score makes it one of the top-scoring results. Only the NumberToFind top-scoring results (that meet all of the other conditions) will be returned.

If, however, ReturnAllResults is "true", additional pattern instances may be reported as results. You can use the value of Accepted to determine why the additional result was excluded initially.

If Accepted is "true" the additional result was excluded solely because the NumberToFind was set too low. This could happen, for example, if your input image contains five instances of the pattern but you set NumberToFind to only find three. In this case you might get two additional results that meet all of the acceptance conditions listed above, but were excluded from the results solely because they were not among the three highest-scoring instances.

If Accepted is "false" the additional result was excluded because it has one or more of the following:

• A Score less than AcceptThreshold.
• A ContrastFraction less than ContrastFractionThreshold.
• An angle that is outside of the angle range you specified using Low and High (if Configuration is set to LowHigh).
• A scale that is outside of the scale range you specified using Low and High (if Configuration is set to LowHigh).