Co2 detection camera

Abstract

The invention provides a CO2 detection system comprising a camera suitable to be used with a platform that moves relative to the ground surface. The camera comprises at least one detector (D) sensitive to light, at least one lens arranged to focus light from the SWIR region of the electromagnetic spectrum onto the detector (D), a background filter (F0) coated on the surface of the detector (D) on which the light from the lens falls, and four absorption region (S) filters (F1, F2, F3, F4).

Description

[0001] C02 DETECTION CAMERA

[0002] Relevant Technical Field

[0003] The present invention relates to a camera that enables monitoring the amount of carbon dioxide gas and a detection system comprising the camera, developed for use with low earth orbit (LEO) satellites, unmanned aerial vehicles or similar platforms.

[0004] Prior Art

[0005] Global warming can be defined as the decrease in the Earth's ability to reflect the sun's rays and the gradual warming of the Earth as a result of the increase in the amount of greenhouse gases (e.g. carbon dioxide, methane, etc.) in the atmosphere. In order to control or prevent global warming, the factors that produce these greenhouse gases must be identified and prevented. One of the most important greenhouse gases is carbon dioxide (CO2), and identifying and monitoring the areas where this gas is produced intensively is very important in preventing global warming. 002 gas accounts for approximately 80% of total greenhouse gas emissions. To better understand the carbon cycle, there is a need to measure atmospheric 002 concentration in space. In this context, applications for the detection and monitoring of greenhouse gases are gaining importance. The world's leading space agencies (NASA, ESA, JAXA) have been conducting missions for many years to monitor the source and amount of 002 and other greenhouse gases. The most prominent of these missions is NASA's OCO-2 (Orbiting Carbon Observatory) mission, which monitors the distribution of greenhouse gases in the atmosphere using a spectrometer-based camera as part of ESA's Copernicus program. The camera used in OCO-2 is a high-cost spectrometer short-wave infrared (SWIR) camera that separates light into wavelengths, is designed by combining many different disciplines, has complex design processes and a very long project duration. Due to its high weight of 131 kg and its size, it is considered unsuitable for use in satellites operating in low earth orbit (LEO) or unmanned aerial vehicles such as drones. On the other hand, although there are (SWIR) camera manufacturers in the industry that do not use spectrometers, the SWIR cameras in question are mostly used for imaging purposes such as imaging in low light conditions (sunrise and sunset), behind-the-cloud imaging, smart agriculture, mine and mineral monitoring, and disaster monitoring.

[0006] Therefore, considering the lack of camera solutions for satellites operating in LEO; C02 imaging with cameras operating in LEO provides an innovative and low-cost answer to an important need. Object of the invention

[0007] The object of the present invention is to develop a camera and detection system suitable for use with LEO satellites, drones and similar platforms and that enables the detection and monitoring of CO2 gas.

[0008] Another object of the present invention is to develop a low-cost and small-sized CO2 detection camera and system.

[0009] Definition of the figures

[0010] Exemplary applications of the camera and system developed with the present invention are shown in the attached figures and from these figures;

[0011] Figure 1 is a graphical representation of the infrared absorption bands of CO2 gas.

[0012] Figure 2 is a representation of the filters located on the light sensitive detector plane of the satellite camera according to the present invention.

[0013] Figure 3 is an exemplary demonstration of the process of capturing images from the ground surface, which takes place with the movement of a platform on which the satellite camera, which is the subject of the invention, is located.

[0014] The elements in the figures are referenced one by one and the correspondences of these elements are given below:

[0015] Absorption region (S)

[0016] Detector plane (D)

[0017] Background filter (FO)

[0018] First filter (F1)

[0019] Second filter (F2)

[0020] Third filter (F3)

[0021] Fourth filter (F4)

[0022] Filter covered section (1)

[0023] Platform movement direction (2)

[0024] Field of view (3)

[0025] Detailed description of the invention

[0026] With the present invention, a camera that enables the detection of CO2 gas and which is suitable for use with LEO satellites or drones and similar aircraft and is being developed in order to provide a solution to the technical problems mentioned above. In addition, a CO2 detection system comprising the said camera is being developed with the invention to enable the detection of places where CO2 gas is concentrated.

[0027] The camera according to the invention is sensitive to light in the short-wave infrared (SWIR) wavelength range (900nm - 2500nm). The most important feature of cameras operating in this band is that they can photograph details that the human eye and standard cameras cannot see. For example, while the human eye and standard cameras cannot capture images due to lack of light at sunset before the weather becomes completely dark, SWIR cameras can capture images in this environment.

[0028] Gas molecules absorb some wavelengths of light rather than reflecting them. The band gaps where CO2, one of the greenhouse gases, absorbs incoming infrared light and prevents its passage are shown in Figure 1. In Figure 1 , the horizontal axis shows the wavelength (pm), and the four absorption regions (S) where CO2 gas absorbs light are shown in dark rectangular frames on the graph. The camera in question takes the images in these bands and compares them with the images in other bands to obtain relative information about the CO2 density. Each of the absorption regions (S) is used to determine the band gap of the filters applied to the photosensitive detector plane contained in the camera. Figure 2 shows an exemplary view of the detector plane (D) of the camera according to the invention. The detector plane preferably comprises five thin film optical filters (FO, F1, F2, F3, F4) of equal size and positioned adjacent to each other to cover the entire detector plane (D). In the embodiment shown in Figure 2, there is a background filter (FO) passing the 950nm - 2400nm band range, a first filter (F1) passing the 1410nm - 1470nm band range, a second filter (F2) passing the 1550nm - 1630nm band range, a third filter (F3) passing the 1930nm - 2000nm band range and a fourth filter (F4) passing the 2050nm - 2100nm band range on the detector plane (D). The background filter (FO) is arranged to pass the entire short-wave infrared wavelength range and provides information about the total amount of light for an imaged area. Each of the first to fourth filters (F1 , F2, F3, F4) is configured to pass the wavelength range related to one of the absorption regions (S) shown in Figure 1. When the amount of light coming from these bands is compared with the total amount of light coming from the background filter (FO), the relative density of CO2 gas in the imaged area can be determined. The filters on the detector plane (D) are positioned perpendicular to the flight direction of the platform on which the camera will be placed (preferably the LEO satellite) and preferably in the order indicated in Figure 2. In this way, the imaged area on the ground will be captured first with the background filter (FO) then each of the following filters (F1, F2, F3, F4) will capture the same area. The imaging method specified here is a method used in satellite cameras, and an exemplary representation of the method is shown in Figure 3. In order to facilitate the explanation in Figure 3, a section (1) of the detector plane (D) covered with only one filter is shown. The direction of movement of the platform (2) and the direction of the field of view (3) as a result of the platform movement are shown by arrows. With the movement of the platform, the relevant filter covered section of the detector plane (1) captures the image of the surface in rows and the same process is repeated for each filter covered section with the movement of the platform. Photographic data is obtained by combining the images obtained.

[0029] In this direction the camera developed with the present invention; which is suitable for use with a platform that moves according to the surface of the earth, preferably a LEO satellite; comprises a photosensitive detector (D), at least one lens arranged to focus light from the SWIR region of the electromagnetic spectrum onto the detector (D) in question, at least one background filter (FO) that passes the 950nm - 2400nm band, at least a first filter (F1) passing the 1410nm - 1470nm band range, at least a second filter (F2) passing the 1550nm - 1630nm band range, at least a third filter (F3) passing the 1930nm - 2000nm band range and at least a fourth filter (F4) passing the 2050nm - 2100nm band range coated on the surface of the detector (D) where the light coming from the lens falls, wherein the said filters (FO, F1 , F2, F3, F4) are positioned adjacent to each other and perpendicular to the direction of movement of said platform, such that the field of view of each filter (FO, F1 , F2, F3, F4) on the ground surface is scanned by all filters in sequence with the movement of the platform, and preferably each of said filters has equal surface areas. The filters mentioned here preferably have at least a substantially rectangular form, with the long side of the rectangle positioned perpendicular to the direction of movement of the platform.

[0030] In an exemplary application of the invention, the image data obtained by the camera on a LEO satellite is transmitted to a ground station by the satellite, and the CO2 density is determined on a regional basis with the image data gathered at the ground station.

[0031] With the present invention, a CO2 detection system comprising the above-mentioned camera is also developed; which includes at least one processing unit to which the image captured by the camera is transmitted. The processing unit in question is arranged to evaluate the received image data, create separate image data for each filter-covered section of the detector plane, and compare the image data of the filters (F1 , F2, F3, F4) that pass the band gap of each specific absorption region (S) with the image data of the background filter (FO) that passes the entire SWIR band, thus determining the CO2 density on a regional basis. The said processing unit is preferably positioned on the platform together with the camera and ensures that the detection process is carried out on the platform.

[0032] With the camera and detection system developed with the present invention, CO2 density can be displayed by taking photographs of the desired regions of the world in the appropriate spectral band. In this way, it is possible to detect regions with high CO2 density. The camera in question, weighing up to 750 gr, approximately 10x10x10 cm in size and being less costly than the current state of the art CO2 imaging applications, can be used in LEO satellites and has features that can provide solutions to the CO2 SWIR imaging needs of unmanned aerial vehicles.

Claims

CLAIMS1. A camera suitable for use with a platform that moves relative to the ground surface in determining the amount of CO2 comprising; at least one detector (D) that is sensitive to light, at least one lens arranged to focus the light coming from the SWIR region of the electromagnetic spectrum on the said detector (D),• at least one background filter (F0) that passes the 950nm - 2400nm band,• at least one first filter (F1) that passes the 1410nm - 1470nm band,• at least one second filter (F2) that passes the 1550nm - 1630nm band,• at least one third filter (F3) that passes the 1930nm - 2000nm band and• at least one fourth filter (F4) that passes the 2050nm - 2100nm band coated on the surface of the detector (D) where the light coming from the lens falls, wherein said filters (FO, F1, F2, F3, F4) are positioned adjacent to each other and perpendicular to the direction of movement of the platform in question, such that the field of view of each filter (FO, F1, F2, F3, F4) on the ground surface is scanned by all filters sequentially along with the movement of the platform.

2. A camera according to Claim 1 , comprising said filters (FO, F1 , F2, F3, F4), each having equal surface areas.

3. A camera according to any one of Claims 1 or 2, comprising said filters (FO, F1 , F2, F3, F4) having at least a substantially rectangular form and the long side of said rectangle being positioned perpendicular to the direction of movement of the platform.

4. A CO2 detection system comprising at least one camera according to any of the preceding claims and at least one processing unit to which the image received by the camera is transmitted and which is arranged to evaluate the received image data and to create separate image data for each filter-covered section of the detector plane and to determine the CO2 density on a regional basis by comparing the image data of the filters (F1, F2, F3, F4) passing the band gap, each of which is related to a specific absorption region (S), with the image data of the background filter (FO) passing the entire SWIR band.

Images