Foreign matter detecting device

In general, used beer, alcoholic drink, soft drink or medical bottles are collected to be used again. Such used returnable bottles often have foreign matters or contaminants such as dust and leavings or cracks, and they must be removed from the bottling line before or after the bottle cleaning process. This invention positively satisfies such a requirement. The foreign matter detecting device comprises: a photoelectric conversion device having a number of light receiving elements; and a video signal processing device for successively subjecting to comparison and discrimination the detection signals of variable two adjacent points which are detected by the photoelectric conversion device, to determine whether or not the bottle has a foreign matter.

What is claimed is:

1. A device for detecting a foreign matter on an object such as a bottle to be inspected which comprises a light source from which light is applied to said object; a photoelectric conversion device having a number of light receiving elements to which light passed through said object is applied; and a video signal processing device for successively subjecting to comparison and discrimination of detection signals each of which is detected at variable two adjacent points of said object thereby, said video signal processing device discriminating the variations in magnitude of said detection signals at said variable two adjacent points to detect the presence or absence of a foreign matter on said object.

2. A device as claimed in claim 1, wherein said video signal processing device comprises:

an analog-to-digital converter for converting an output signal of said photoelectric conversion device into a digital signal;

a register means inputting said digital signal and outputting a delay signal variously delayed by selecting a comparison distance of two adjacent points which are subjected to comparison and discrimination;

a subtracting means for obtaining an absolute value of a difference between said delay signal and said digital signal;

an adding means for successively adding said digital signal during a predetermined gate time and for outputting a transmitted light signal;

a first memory for outputting a permissive value which is stored in advance, corresponding to the magnitude of said transmitted light signal; and

a decision circuit for deciding presence or absence of foreign matter in said object according to comparison between the absolute value and the permissive value.

3. A device as claimed in claim 1, wherein a plurality of photoelectric conversion devices are arranged so as to form a predetermined angle with respect to said object to detect said object in its entirety.

4. A device as claimed in claim 1, wherein said object is conveyed with rotation and is inspected while said object makes at least a half revolution.

5. A device as claimed in claim 2, wherein said video signal processing device further includes a second memory for outputting a minimum transmitted light value which is stored in advance, and a comparator for comparing said transmitted light signal with the minimum transmitted light value and for outputting a discharge signal when said transmitted light signal is lower than the minimum transmitted light value.

6. A device as claimed in claim 1, 2, 3, 4 or 5, wherein said photoelectric conversion device comprises a charge coupled device.

7. A device for detecting a foreign matter on an object such as a bottle to be inspected through a polarization filter which comprises a light source from which light is applied to said object; a photoelectric conversion device having a number of light receiving elements to each of which light having passed through said object is applied through another polarization filter which is orthogonal with said polarization filter; and a video signal processing device for successively subjecting to comparison and discrimination detection signals of said photoelectric conversion device which correspond to variable two adjacent points detected thereby, said video signal processing device discriminating the variations in magnitude of said detection signals corresponding to said variable two adjacent points to detect the presence or absence of a foreign matter such as a cellophane sheet on said object, which is optically anisotropic and transparent.

8. A device as claimed in claim 7, wherein said photoelectric conversion device comprises a charge coupled device.

9. A foreign matter detecting device comprising:

a photoelectric conversion device having a number of photoelectric conversion elements on which an optical image of an object such as a bottle to be inspected is formed, and converting said optical image into an electrical signal;

a level detecting circuit for detecting an output level of a video signal which is provided by said photoelectric conversion device according to the presence or absence of said object;

an inspection region determining circuit for determining from said video signal provided by said photoelectric conversion device an inspection region in parallel with the axis of said object; and

a selection circuit for picking up an output signal of said level detecting circuit which corresponds to an inspection region signal provided by said inspection region determining circuit, to provide a selection signal which is utilized to discriminate whether or not said object has a foreign matter.

10. A device as claimed in claim 9, wherein said photoelectric conversion device comprises a charge coupled device.

11. A device as claimed in claim 9 or 10, wherein a plurality of photoelectric conversion devices are arranged so as to form a predetermined angle with respect to said object to detect said object without rotation in its entirety.

12. A device as claimed in claim 9 or 10, wherein said object is conveyed with rotation and is inspected while said object makes at least a half revolution.

13. A foreign matter detecting device comprising:

a photoelectric conversion device having a number of photoelectric conversion elements on which an optical image of an object such as a bottle to be inspected is formed, and converting said optical image into an electrical signal;

a level detecting circuit for detecting an output level of a video signal which is provided by said photoelectric conversion device according to the presence or absence of said object;

an inspection region determining circuit for determining from said video signal provided by said photoelectric conversion device an inspection region in a direction perpendicular to the axis of said object; and

a selection circuit for picking up an output signal of said level detecting circuit which corresponds to an inspection region signal provided by said inspection region determining circuit, to provide a selection signal which is utilized to discriminate whether or not said object has a foreign matter.

14. A device as claimed in claim 13, wherein said photoelectric conversion device comprises a charge coupled device.

15. A device for detecting a foreign matter on a bottom of an object such as a bottle to be inspected, which comprises:

a light source from which light is applied to said object;

a photoelectric conversion device having a number of light receiving elements to which light passed through said bottom is applied;

an analog-to-digital converter for converting an output signal of said photoelectric conversion device into a digital signal;

a register means inputting said digital signal and outputting a delay signal variously delayed by selecting a comparison distance of two adjacent points are subjected to comparison and discrimination;

a subtracting means for absolutely subtracting said delay signal from said digital signal;

an adding means for successively adding said digital signal during a predetermined gate time and for outputting a transmitted light signal;

a first memory outputting a first permissive value which is stored in advance and represents a central portion of the bottom, corresponding to the magnitude of said transmitted light signal therein;

a second memory outputting a second permissive value which is stored in advance and represents a peripheral portion of the bottom, corresponding to the magnitude of said transmitted light signal therein;

a first decision circuit for deciding presence or absence of foreign matter in said central portion of the bottom according to comparison between the absolute value and the first permissive value;

a second decision circuit for deciding presence or absence of foreign matter in said peripheral portion of the bottom according to comparison between the absolute value and the second permissive value;

an inspection region signal generating circuit for generating a central inspection region signal corresponding to said central portion of the bottom and a peripheral inspection region signal corresponding to said peripheral portion of the bottom;

a first gate for outputting a first discharge signal according to the central inspection region signal and an output of the first decision circuit;

a second gate for outputting a second discharge signal according to the peripheral inspection region signal and an output of the second decision circuit;

a third memory outputting a minimum transmitted light value which is stored in advance; and

a comparator for comparing said transmitted light signal with the minimum transmitted light value and for outputting a third discharge signal when said transmitted light signal is lower than the minimum transmitted light value.

16. A device as claimed in claim 15, wherein said photoelectric conversion device comprises a charge coupled device.