ES2221580B1 - AUTONOMOUS SYSTEM FOR ACQUISITION AND PROCESSING OF THERMOMETRIC IMAGES. - Google Patents

Abstract

Autonomous system for acquiring and processing thermometric images. The system has its fundamental application as part of complex systems for the detection, location and classification of uncontrolled temperature sources, in the field of detection of fire sources in large areas of land, both forest and inhabited or other applications where thermal control be critical Basically, it comprises a stage of acquisition of thermometric images (2) and a series of processing stages (3), so that in the acquisition stage (2) the thermometric images captured by means of a thermal sensor (1) are acquired, converting them to digital format and commands are sent to these thermal sensors for control, while in the processing stages (3) the captured images are processed and it is decided if there are significant temperature changes and how is their behavior over time, being able to generate different decisions, such as types of alarms (4), depending on the intensity of the thermal change detected.

Description

Autonomous system of acquisition and processing of thermometric images

Object of the invention

The present invention relates to a system of acquisition and processing of thermometric images, planned preferably for application in detection, location and classification of uncontrolled temperature sources, in the field of fire detection in large areas of land, both forest and inhabited. This preferred application does not limits its use in other applications where the temperature is a fundamental factor to watch.

The object of the invention is therefore provide an autonomous surveillance system with a minimum probability of false alarm and with maximum probability of detection, that is able to detect possible changes of real-time temperature as well as classify them and Decide if there is a risk of uncontrolled fire and at what level.

Background of the invention

The systems currently used for the forest fire detection, use simple detectors temperature threshold that perform a minimum processing of signals captured by thermal cameras, so the results They are generally unreliable. The limitations presented by systems based on such media can provide large Probabilities of false alarms if the threshold chosen is low, for what are systems that in practice will not be useful; yes on the contrary, higher thresholds are chosen to decrease this probability of false alarm, are systems with a Detection probability very low and therefore unreliable.

Description of the invention

The system that is recommended has been conceived to solve the problem described above, constituting a new and technically advanced system to get it give a minimal probability of false alarm, and yet get a maximum probability of detection, being able to detect possible temperature changes in real time, classify them and know whether or not there is a real fire risk.

More specifically, the system of the invention is based on the acquisition, processing, detection and classification of temperature increases through the use of images thermometers, these being captured by thermometric sensors and later converted into digital, to finally be processed in real time, with the consequent detection of temperature increases likely to be generators of uncontrolled heat sources.

Therefore, the system comprises two stages clearly differentiated, the first one consisting of the acquisition of thermometric images in the frequency range infrared and convert them to digital format for storage and subsequent treatment. The second stage consists precisely in the processing of the referred images, establishing if they exist significant temperature changes and how is their behavior over time, being able to generate different decisions in function of the intensity of the thermal change detected, all minimizing false alarms that could be caused by others external and external causes to those originating from heat sources out of control

Logically, the system will be supported by a specific acquisition and processing software, developed in high level language that allows you to capture images thermometers in real time, digitize them using a system digitizer and process them in real time, providing data relating to:

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Yes there is detection;

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That type of detection is, and

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Which It is the level of risk.

Based on that data, it will be generated subsequently alarms with higher or lower priority level, of so that if you reach the maximum possible alarm level you can conclude that there is an uncontrolled fire in a given coverage area.

Therefore, the processing stage can be summarize by saying that based on it the system is able to go taking acquired images in the acquisition stage and go processing them pixel by pixel, considering not only the image of the current moment but images from earlier times and later.

Moreover, the system of the invention and specifically its processing stage, it is able to decide which is the type of alarm originated, that is, if it corresponds to a focus of uncontrolled heat, or if it corresponds to thermal variations produced by thermal noise, wind, etc., for which it is included a prediction stage and a detection stage, the first of they planned to reduce background noise and increase the detection probability, while the second is planned to generate different levels of risk.

Description of the figures

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization of it, is accompanied as part member of this description, a set of designs where with illustrative and non-limiting nature, what has been represented next:

Figure 1.- Shows the general scheme corresponding to the block diagram of the autonomous system of acquisition and processing of thermometric images made of according to the object of the invention.

Figure 2.- Shows a schematic view of the succession of images in different sweeps and noise prediction, according to pixel to pixel processing.

Figure 3.- Shows a block diagram corresponding to the general scheme of image processing thermometers, performed according to the purpose of the invention.

Preferred Embodiment of the Invention

Referring specifically to Figure 1, it can be seen how the system of the invention includes a block initial (1) corresponding to a camera thermo-graphic as a means of collecting sensor thermometric images in the infrared frequency range, to continuation of whose block (1) there is a second block (2) of data acquisition, based on which it is possible to capture images analog and converting them to digital format for storage and subsequent treatment. Also communication between the second block and the first one is bidirectional since they have of transmitting and receiving control commands between the camera and the Acquisition and processing system.

Then there is a third block (3) corresponding to the processing stage, in which a prediction and several detections, so that at this stage or block (3) the thermometric images captured above are processed and it is decided if there are temperature changes significant and how is their behavior over time, being able to generate different decisions depending on the intensity of thermal change detected for, by means of a last block (4), generate alarms with higher or lower priority level, so that if the maximum possible alarm level is reached, it can be concluded that there is an uncontrolled fire in a certain area of coverage.

The processing stage (3) is essential for the validity of the system, since its objective is to detect automatically the possible existence of temperature sources uncontrolled, but minimizing false alarms, whether due to infrared background noise, or occasional effects such as vehicles, people or movements of branches or other phenomena that may cause sudden temperature changes.

Also noteworthy is the fact that the system has been designed in a way that is reliable, that is, may not be continuously generating false alarms, but also sensitive, that is, you should detect the minimum changes of temperatures due to possible uncontrolled heat sources, and although these two aspects seem contradictory, they demand a Advanced processing of thermometric signals.

To this end, a system of processed and specific acquisition and processing software that allows you to capture thermometric images in real time, digitize them and process them also in real time, deciding if there is detection, what type of detection and what level of risk is getting

Also noteworthy is the fact that the system It has been robustly designed against power outages and system crashes, developing specific protocols for communication with thermal sensors and data generation of alarms so that their subsequent transmission can be made of efficient way regarding both the data time to transmit as at the time of transmission.

The processing can be basically summarized in a system that is able to take the images acquired in the acquisition stage and process them pixel by pixel, considering not only the image of the current moment but images of moments of previous time, as shown in figure 2, taking into note that the thermometric image is formed by a matrix of pixels, and that each pixel can be associated with a cell of resolution with their corresponding and range or distances.

In this way the processing system is capable to decide automatically, sweep by sweep for each and every one of the pixels, if there is an alarm and what type it is; is say, if the system is to consider that it can go beyond the simple detection and indicate what risk exists in the area of surveillance with a series of possible alarm levels, depending on of whether the measured level simply exceeds a threshold, or if they give other more restrictive conditions.

The above, leads to the system of Figure 3, to be applied to each of the resolution cells, with two stages or parts clearly differentiated, and corresponding to blocks (5) and (6), the first as the prediction stage and the second as a detection stage. In this scheme of Figure 3, the block (7) corresponds to the environment statistics, block (8) to calibration and block (9) to knowledge about evolution thermal, with the particularity that the stage or part relative to the  prediction, represented in block (5), basically consists of an element that allows the system to reduce the noise background and increase the probability of detection while the part corresponding to the detection block (6) consists of the use of statistical techniques of signal processing for generation of the different possible alarms. These two parts or blocks are nurtured in parallel to a knowledge deduced from the calibration corresponding to block (8) on the statistics of infrared block of the environment under surveillance. Additionally, it take advantage of all possible knowledge about evolution of the temperature change, to maximize the probability of detection of uncontrolled foci and minimize the detection of occasional effects not corresponding to thermal increases out of control, maintaining a certain probability of false alarms due to background noise from the environment.

Claims (3)

1. Autonomous system for the acquisition and processing of thermometric images, which is applicable in the field of fire detection in large areas of land, both forest and inhabited, and intended as a means of autonomous surveillance to detect and locate potential sources of Fire is characterized in that it comprises a stage (2) for the acquisition of thermometric images and a processing stage (3) of the images captured in the previous stage; having anticipated that in the acquisition stage (2) a thermal sensor (1) intervenes in the thermal infrared band, as well as means of converting the analog images to digital format, for storage and subsequent treatment, while in the stage processing (3) a pixel-by-pixel treatment of the digital images is performed to determine if there are significant temperature changes, as well as their behavior over time, generating different alarm decisions (4) depending on the intensity of the thermal change detected . 2. Autonomous system of acquisition and processing of thermometric images, according to claim 1, characterized in that in the processing stage (3) the thermometric images captured in the acquisition stage (2), are digitized to provide in the corresponding processing thereof If there is detection, what type of detection it is and what its level of risk is, so that depending on this data alarms are generated with a higher or lower level of priority. 3. Autonomous system for the acquisition and processing of thermometric images, according to claims 1 and 2, characterized in that in the processing stage a prediction (5) is made that allows the system to reduce background noise and increase the probability of detection, also having place a phase or stage of detection (6) for the generation of the different possible alarms.