Machine vision apparatus and method for sorting objects

A method of sorting an object into one of at least a first class and a second class, said method comprising steps of:

• producing a video image of an object in which the video image comprises a series of pixels each having an intensity;
• determining signal gradients for a plurality of pixels in the video image;
• counting how many pixels have both a signal gradient that is less than a first signal gradient value and an intensity less than a first intensity value to produce a first parameter value;
• defining a plurality of regions in the video image wherein each region has a given plurality of pixels;
• and counting how many regions exist in which all the pixels in the region have both a signal gradient that is greater than a second signal gradient value and an intensity greater than a second intensity value;
• determining, from the first parameter count, a probability that the object should be classified within a first class;
• selecting a path along which to direct the object in response to the probability;
• and
• directing the object along the selected path.

A method of sorting an object into one of at least a first class and a second class, said method comprising steps of:

• producing a video image of an object in which the video image comprises a series of pixels each having an intensity;
• determining signal gradients for a plurality of pixels in the video image;
• counting how many pixels have both a signal gradient that is less than a first signal gradient value and an intensity less than a first intensity value to produce the first parameter count designated LFR;
• and further comprising:
• defining a plurality of regions in the video image in which each region has a given plurality of pixels;
• counting how many regions exist wherein all the pixels in the region have both a signal gradient that is greater than a second signal gradient value and an intensity greater than a second intensity value to produce a second parameter count designated HGR;
• and
• counting how many pixels have a signal gradient that is greater than a third signal gradient value and less than a fourth signal gradient value to produce a third parameter count designated MG;
• determining, from the first parameter count, a probability that the object should be classified within a first class;
• selecting a path along which to direct the object in response to the probability;
• and
• directing the object along the selected path.

A method of sorting an object into one of at least a first class and a second class, said method comprising steps of:

• producing a plurality of video images of the object with each video image formed by a series of pixels each having an intensity;
• determining signal gradients for a plurality of pixels in each video image;
• for each video image counting how many pixels have both a signal gradient less than a first gradient value and an intensity less than a first intensity value to produce the first parameter count designated LFR;
• and further comprising:
• defining a plurality of regions in the video image in which each region has a given plurality of pixels;
• counting how many regions exists in which all the pixels in the region have both a signal gradient that is greater than a second gradient value and an intensity greater than a second intensity value to produce a second parameter count designated HGR;
• and
• counting how many pixels have a signal gradient that is greater than a third gradient value and less than a fourth gradient value to produce a third parameter count designated MG;
• determining, from the parameter count, a probability that the object should be classified within the first class;
• and
• selecting a path along which to direct the object in response to the probability.

An apparatus for classifying objects, which apparatus comprises:

• an input at which to receive a video image of an object in which the video image comprises a series of pixels each having an intensity;
• a processor connected to said input and producing signal level gradients for a plurality of pixels in the video image;
• an image evaluator coupled to said processor which comprises:
• a first counter which determines how many pixels have both a signal gradient that is less than a first signal gradient value and an intensity less than a first intensity value to produce a first parameter value;
• a second counter which determines how many regions exist wherein all the pixels in the region have both a signal gradient that is greater than a second signal gradient value and an intensity greater than a second intensity value to produce a second parameter value;
• and
• a third counter which determines how many pixels have a signal gradient that is greater than a third signal gradient value and less than a fourth signal gradient value to produce a third parameter value;
• and
• an output circuit which in response to the first, second and third parameter values transmits a command to a sorting device which command designates a path along which to direct the object.