Imaging fire detector

• US 7,286,704 B2
• Filed: 02/15/2001
• Issued: 10/23/2007
• Est. Priority Date: 03/09/2000
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Oppelt, Ulrich, Pfefferseder, Anton
• Primary Examiner(s): Mehta; Bhavesh M
• Assistant Examiner(s): KIM, CHONG R
• Application Number:
  US10/221,081
• Publication Number:
  US 20030038877A1
• Time in Patent Office: 2,441 Days
• Field of Search: None
• US Class Current: 382/181
• CPC Class Codes: G06F 18/256 of results relating to different input data, e.g. multimodal recognition
• CPC Class Codes: G08B 17/125 by using a video camera to detect fire or smoke
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q

Abstract

An imaging fire detector is used to detect a fire from a recorded image sequence. Either a video camera or an infrared camera is used as an imaging device. Characterizing parameters of a fire are either analyzed individually or in combination. In order to detect changes, an object analysis, a pattern analysis or a spatial-frequency analysis of the recorded image sequences is conducted. Using a threshold value for the duration of the changes, short-term changes are detected and discarded. In a further embodiment, the fire detector may also be used as a burglar alarm. With the aid of communication means, the fire detector transmits a fire alert to a master station.

Claims

1. An image-producing fire detector, comprising:

at least one imaging device configured to generate image sequences;

a communication device;

a processor configured to analyze the image sequences generated by the at least one imaging device, detect a change in pattern resolution over time from the image sequences, generate a fire alert based on an outcome of detection, and output the fire alert, the process configured to transmit the fire alert via the communication device; and

a memory device coupled to the processor.

2. The image-producing fire detector of claim 1, wherein the processor transmits one of an image and an image sequence with the fire alert via the communication device.

3. The image-producing fire detector of claim 1 further comprising:

a housing accommodating the at least one imaging device, the processor, the memory device and the communication device.

4. The image-producing fire detector of claim 3, wherein the at least one imaging device includes a video camera.

5. The image-producing fire detector of claim 3, wherein the at least one imaging device includes an infrared camera.

6. The image-producing fire detector of claim 5, wherein the infrared camera includes one of a heat-imaging camera and a thermopile array.

7. The image-producing fire detector of claim 5, further comprising:

an optical system for use with the at least one imaging device.

8. The image-producing fire detector of claim 7, further comprising:

a light source for use with the at least one imaging device.

9. The image-producing fire detector of claim 8, wherein the processor is configured to detect at least one of smoke-related opacity and scattering in the image sequences using the light source.

10. The image-producing fire detector of claim 1, wherein the at least one imaging device is detachably coupled to the processor, the memory device, and the communication device, and is usable while detached therefrom.

11. The image-producing fire detector of claim 1, wherein the processor is configured to detect at least one of heat streaks and smoke clouds in the image sequences using data stored in the memory device.

12. The image-producing fire detector of claim 1, wherein the processor is configured to classify a flame based on the image sequences, and transmits the classification with the fire alert via the communications device.

13. The image-producing fire detector of claim 1, wherein the processor is configured to detect changes in the image sequences by a comparison to a reference image, and identifies short-term changes based on a duration of the change, using a threshold value.

14. The image-producing fire detector of claim 13, wherein the processor is configured to resolve images of the image sequences into spatial frequencies and to detect a change in the image sequence on the basis of a change in the spatial frequencies.

15. The image-producing fire detector of claim 14, wherein bar code patterns having encoded information are applied for a measurement of the spatial frequencies.

16. The image-producing fire detector of claim 1, wherein the fire detector is adapted to detect a presence of burglars and function as a burglar alarm.

17. The image-producing fire detector of claim 1, wherein the processor is configured to output a fire alert via the communication device, as a function of at least one of:

a voter-basis decision of characterizing parameters of a fire; and

results of analyses of the image sequences.

18. The image-producing fire detector of claim 1, wherein the detection of a change in pattern resolution over time includes ascertaining a change in sharpness of structures in the image sequences by ascertaining at least one of a gradient of brightness values and chromaticity in the horizontal and the vertical directions of images in the image sequences.

19. The image-producing fire detector of claim 1, wherein the detection of a change in pattern resolution over time includes ascertaining a change in sharpness of structures in the image sequences by ascertaining a change in a spectrum of spatial frequencies.