Analog waveform decoder utilizing histogram of edge sizes

In a symbol scanning system, an analog waveform decoder that operates directly upon an analog waveform representative of a high density symbol for decoding information contained in said high density symbol, said analog waveform decoder comprising:

• means for identifying boundaries of said analog waveform to identify a decodable portion of said waveform;
• means responsive to said decodable portion of said waveform for obtaining a plurality of waveform descriptors defining said decodable portion of said waveform;
• high density decoder means responsive to one or more of said plurality of waveform descriptors for decoding information contained in said high density symbol;
• and
• means for outputting a signal representative of information contained in said symbol,
• wherein said means for obtaining said plurality of waveform descriptors includes:
• a) means for obtaining extrema locations representative of peaks and valleys of said analog waveform;
• b) means for determining edge sizes that connect adjacent extrema locations;
• and
• c) means for determining inflection point triplets of said analog waveform.

A method for decoding an analog waveform representative of information contained in a symbol comprising the steps of:

• determining boundaries of said analog waveform to identify a decodable portion of said waveform;
• processing said decodable portion of said analog waveform to obtain a plurality of waveform descriptors defining said decodable portion of said waveform;
• performing a first decoding process on one or more of said plurality of waveform descriptors for producing a first decode signal representative of information contained in a high density symbol or producing a non-decode signal;
• performing a second decoding process on one or more of said plurality of waveform descriptors in response to said non-decode signal for producing a second decode signal representative of information contained in a low density symbol;
• and
• outputting said first decode signal when said symbol is a high density symbol and outputting said second decode signal when said symbol is a low density symbol,
• wherein the processing step includes the steps of:
• obtaining extrema locations representative of peaks and valleys of said analog waveform;
• determining edge sizes that connect adjacent extrema locations;
• and
• determining inflection point triplets of said analog waveform.

A method for decoding an analog waveform representative of information contained in a high density symbol comprising the steps of:

• determining boundaries of said analog waveform to identify a decodable portion of said waveform;
• processing said decodable portion of said analog waveform to obtain a plurality of waveform descriptors defining said decodable portion of said waveform;
• performing a high density decoding process on one or more of said plurality of waveform descriptors for producing a decode signal representative of information contained in said high density symbol;
• and
• outputting said signal representative of information contained in said symbol,
• wherein said processing step includes the steps of:
• obtaining extrema locations representative of peaks and valleys of said analog waveform;
• determining edge sizes that connect adjacent extrema locations;
• and
• determining inflection point triplets of said analog waveform.

In a symbol scanning system, an analog waveform decoder that operates directly upon an analog waveform representative of a symbol for decoding information contained in said symbol, said analog waveform decoder comprising:

• means for identifying a decodable portion of said waveform;
• means responsive to said decodable portion of said waveform for obtaining a plurality of waveform descriptors defining said decodable portion of said waveform;
• first decoding means responsive to one or more of said plurality of waveform descriptors for producing a first decode signal representative of information contained in a high density symbol or producing a non-decode signal;
• second decoding means responsive to one or more of said plurality of waveform descriptors for producing a second decode signal representative of information contained in a low density symbol in response to said non-decode signal;
• means for outputting said first decode signal when said symbol is a high density symbol;
• and
• means for outputting said second decode signal when said symbol is a low density symbol,
• wherein said symbol is a bar code symbol, and said decoder further includes a means responsive to said plurality of waveform descriptors for deblurring said decodable portion of said waveform and for obtaining an additional set of descriptors that define successive edges of said bar code.

A decoder comprising:

• means receptive of an analog signal having a waveform representative of a decodable symbology and including a decodable portion;
• means for locating the decodable portion of the waveform;
• means for producing a plurality of waveform descriptors relating to edge sizes of the decodable portion of the waveform;
• and means for decoding information contained in the decodable symbology in response to the descriptors.

A method of decoding comprising the steps of:

• receiving an analog signal having a waveform representative of a decodable symbology and including a decodable portion;
• locating the decodable portion of the waveform;
• producing a plurality of waveform descriptors relating to edge sizes of the decodable portion of the waveform;
• and decoding information contained in the decodable symbology in response to the descriptors.

A system for reading and decoding symbology comprising:

• a light source;
• means for directing light from the light source on a decodable symbology;
• means receptive of reflected light from the symbology for producing an analog signal having a waveform representative of the decodable symbology and including a decodable portion;
• and decoding means receptive of the analog signal for decoding the symbology and comprising means for locating the decodable portion of the waveform, means for producing a plurality of waveform descriptors relating to edge sizes of the decodable portion of the waveform and means for producing a decode signal representative of information contained in the decodable symbology in response to the descriptors.