Passive type moving object detection system

• US 5,461,231 A
• Filed: 05/10/1994
• Issued: 10/24/1995
• Est. Priority Date: 05/11/1993
• Status: Expired due to Term

• Current Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Original Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Inventors: Amano, Hiroyuki, Ohkawa, Shingo, Sugimoto, Tadashi, Murata, Norikazu, Kawabuchi, Shinya, Iwasawa, Masashi
• Primary Examiner(s): FIELDS, CAROLYN
• Application Number:
  US08/241,309
• Time in Patent Office: 532 Days
• Field of Search: 250/342, 250/349, 250/DIG. 1, 250/338.3, 340/567
• US Class Current: 250/342
• CPC Class Codes: G08B 13/191 using pyroelectric sensor means
• CPC Class Codes: Y10S 250/01 Passive intrusion detectors

Abstract

A passive-type moving object detection system is disclosed. The system includes an infrared detector, infrared sensors mounted on the infrared detector, a detection field including two columns of detection regions for monitoring a human intruder and two rows of detection regions for detecting a non-human intruder. The columns have a height corresponding to a human height, and an optical system is located between the infrared detector and the detection field. The infrared sensors have infrared accepting areas that include first and second sections. The first section optically corresponds to the columns and the second section optically corresponds to the rows. Each sensor receives infrared radiation from a moving object passing through the detection regions. The detector includes an arithmetic circuit that subtracts the peak values of signals generated by the detector and a decision circuit to compare the result with a reference level.

Claims

1. A passive type moving object detection system comprising:

an infrared detector;

infrared sensors mounted on the infrared detector;

a detection field including two columns of detection regions for monitoring a human intruder and two rows of detection regions for detecting a non-human intruder, wherein the columns of detection regions have a height covering a human height;

an optical system located between the infrared detector and the detection field;

the infrared sensors having infrared accepting areas comprising a first section and a second section wherein the first section optically corresponds to the columns of detection regions and the second section optically corresponds to the rows of detection regions, so as to receive infrared rays radiating from a moving object passing through the detection regions, the sensors including two columns of sensors and two rows of sensors, the columns of sensors optically corresponding to the columns of detection regions, and the rows of sensors optically corresponding to the rows of detection regions, wherein the columns of sensors are connected to each other with opposite polarity, and the rows of sensors are connected to each other with opposite polarity; and

the detector including an arithmetic circuit which makes subtraction between the peak values of signals generated by the detector, and a decision circuit whereby the balance of subtraction is compared with a reference level.

2. The passive type moving object detection system according to claim 1, wherein the detection regions in columns and in rows partly overlap one another.

3. The passive type moving object detection system according to claim 1, wherein the sensors in the first section and the second section are mounted on a single detector in such a manner that they partly overlap each other.

4. A passive type moving object detection system comprising:

an infrared detector including groups of infrared sensors;

a detection field including two columns of detection regions having a human height and two rows of detection regions;

an optical system located between the infrared detector and the detection field;

the infrared sensors having infrared accepting areas comprising a first section and a second section wherein the first section optically corresponds to the columns of detection regions and the second section optically corresponds to the rows of detection regions, the infrared accepting areas receiving infrared rays radiating from a moving object within the detection regions;

a first circuit for totalling the outputs from the detection regions in the same column under same polarity, and totalling the outputs from the detection regions in different columns under opposite polarity;

a second circuit for totalling the outputs from the detection regions in the same row under same polarity, and negating the outputs from the detection regions in different columns under opposite polarity; and

an arithmetic circuit for making subtraction between the peak values of signals from the first circuit and second circuit circuit whereby the balance of subtraction is compared with a reference level.

5. The passive type moving object detection system according to claim 4, wherein the detection regions in column and row partly overlap each other.

6. A passive type moving object detection system comprising:

an infrared detector including groups of infrared sensors;

a detection field including two columns of detection regions having a human height and two rows of detection regions;

an optical system located between the infrared detector and the detection field;

the infrared sensors having infrared accepting areas comprising a first section and a second section wherein the first section optically corresponds to the columns of detection regions and the second section optically corresponds to the rows of detection regions, the infrared accepting areas receiving infrared rays radiating from a moving object within the detection regions;

a first circuit for totalling the outputs from the detection regions in the same column under same polarity, and totalling the outputs from the detection regions in different columns under opposite polarity;

a second circuit for totalling the outputs from the detection regions in the same row under opposite polarity, and negating the outputs from the detection regions in different columns under opposite polarity; and

an arithmetic circuit for making subtraction between the peak values of signals from the first circuit and second circuit circuit whereby the balance of subtraction is compared with a reference level.

7. The passive type moving object detection system according to claim 6, wherein the detection regions in column and row partly overlap each other.