Method and apparatus for determining a cell density of a honeycomb body, in particular for an exhaust gas catalytic converter

A method of automatically determining an area-related cell density of a cell structure of a honeycomb body including a multiplicity of passages having open ends at an end of the honeycomb body at which the cell structure is visible, the method which comprises:

• recording an image of at least a portion of the cell structure, with an optical instrument, the image having a known image scale;
• processing the image by establishing a number of cells by counting cells and calculating the cell density by relating the number of cells to a reference area established with the aid of the image scale;
• and
• immovably mounting a scale object of known dimensions to the end of the honeycomb body, and at least also partially recording the scale object in the image for establishing a scale with which the image scale is formed.

A method of automatically determining an area-related cell density of a cell structure of a honeycomb body including a multiplicity of passages having open ends at an end of the honeycomb body at which the cell structure is visible, the method which comprises:

• recording an image of at least a portion of the cell structure, with an optical instrument, the image having a known image scale;
• processing the image by establishing a number of cells by counting cells and calculating the cell density by relating the number of cells to a reference area established with the aid of the image scale;
• illuminating the end of the honeycomb body for reflecting light from cell edges in the direction of the optical instrument;
• and
• forming a brightness average value over at least a part of the image, establishing a brightness threshold value above the brightness average value, and inferring a position of the cell edges from a position of image regions having a brightness above the brightness threshold value.

An apparatus for automatically determining an area-related cell density of a cell structure of a honeycomb body, the apparatus comprising:

• a scale object having known dimensions for establishing a reference area, said scale object framing a region of cells at an end of the honeycomb body;
• an optical instrument having a matrix camera for recording an image of the honeycomb body and at least partially of the image object, including:
• a peripherally closed external light shielding device having an object opening;
• and
• an internal lamp for illuminating the end of the honeycomb body, said internal lamp emitting light passing outwardly from said external light shielding device through said object opening upon said internal lamp being turned on;
• and
• a data processing installation connected to said optical instrument for ascertaining a number of cells by counting cells and for calculating a cell density by relating the number of cells to said reference area.