Portable Lambert scanning light source and method

Abstract

The invention discloses a portable Lambert scanning light source and a method, the portable Lambert scanning light source comprises a controller, a main frame, a two-dimensional translation mechanism and a light source assembly, the controller drives the two-dimensional translation mechanism to respectively drive the light source to translate in two mutually perpendicular directions; the light source is a linear light source, the length direction of the light source is parallel to any translation direction of the two-dimensional translation mechanism, the light source performs two-dimensional scanning on the full aperture and the full view field of the large-view-field remote sensor, fused images are obtained through pixel splicing, and whether the response state of the large-view-field remote sensor changes or not can be judged by comparing the fused images at different moments. The device is small in size and light in weight, full-aperture and full-view-field time-sharing illumination can be conveniently and efficiently carried out on the large-view-field remote sensor, and the view field of the remote sensor is not shielded in a non-test stage, so that high-precision satellite loading test and on-satellite calibration of the large-view-field remote sensor are realized on the premise that the normal detection function of the large-view-field remote sensor is not influenced.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to a portable Lambertian scanning light source and method for large-field-of-view remote sensor installation test and on-star calibration. Background Art

[0002] Large-field-of-view remote sensors need to undergo radiation response testing after being installed and launched into orbit, so as to detect in real time whether the status of the remote sensor has changed. The requirements for the test light source are: 1) portability and high efficiency; 2) the test range covers the full aperture and full field of view of the remote sensor; 3) the remote sensor field of view cannot be blocked during the non-test phase; 4) good Lambertian properties, stability, repeatability, and radiation resistance.

[0003] At present, the light sources commonly used in remote sensor radiation response testing are mainly traditional surface light sources such as integrating sphere light sources. This type of surface light source has the advantages of high Lambertian, stability, repeatability, and high efficiency. However, the diameter of the integrating sphere is usually at least 3 times the diameter of its light outlet. As a star-mounted light source, it has the following problems: 1) It is large in size and weight, not convenient for carrying, and difficult to disassemble and assemble; 2) For on-board calibration applications, the power consumption, weight, space and other resources occupied by the supporting equipment for moving the integrating sphere into and out of the field of view of a large-field-of-view remote sensor are greatly increased.

[0004] Mature copiers and scanners on the market use linear light sources, beam deflection and collection components, and array detectors to perform one-dimensional scanning imaging perpendicular to the length direction, which can realize the collection of information on the content of paper. Some products use cold cathode fluorescent lamps (CCFL) combined with other light sources at both ends to form a linear light source, but the CCFL has a slightly longer preheating time, which affects the user experience of copiers and scanners. More and more copiers and scanner products are beginning to use LED point light sources in combination with uniform light devices to form linear light sources. The scanning technology of line light sources of copiers and scanners can ensure that the field of view of the remote sensor is not blocked during the non-test phase with a smaller volume and weight. The use of linear light sources can also greatly improve the scanning efficiency. However, there are the following problems with the application of such scanning technology in the satellite installation test and on-board calibration of large-field-of-view remote sensors: 1) Due to the application scenario, linear light sources do not need to consider radiation resistance and data accuracy. When used as on-board calibration light sources, they will face aging, radiation, high-energy particles and other factors in space, which will affect the performance and attenuation of the light source, affecting the reliability, stability, and repeatability of the light source; 2) There is only one-dimensional adjustment. When the length of the line light source is not enough, it is difficult to completely cover the full aperture and full field of view of the large-field-of-view remote sensor; 3) The image size and position of the image of the line light source of the copier and scanner on the array detector are fixed. The fixed pixel array on the same array detector is used to collect the content of different positions of the paper one by one, and the images at different times are spliced ​​to form an image of the complete paper content. There is no need to use the image to quantitatively evaluate the status of the equipment. The position of the image of the line light source on the image plane of the wide field of view remote sensor will change continuously as the scanning progresses. The images at different times correspond to different pixel arrays. Therefore, the image processing methods of copiers and scanners are not suitable for the installation test and on-board calibration of the wide field of view remote sensor. 4) The technical purpose of the beam deflection and collection components is to adjust the optical path so that the content of the scanned or copied paper can be received by the array detector. For the wide field of view remote sensor, the functions of these components are redundant, which increases the volume and weight cost. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a portable Lambertian scanning light source and method, so that a large field of view remote sensor can be conveniently and efficiently illuminated in a full-aperture, full-field-of-view time-sharing manner with a relatively small volume and weight, and the field of view of the remote sensor is not blocked during the non-testing stage, thereby realizing high-precision satellite installation testing and on-board calibration of the large field of view remote sensor without affecting the normal detection function of the large field of view remote sensor.

[0006] The solution adopted by the present invention to solve the technical problem is:

[0007] The portable Lambertian scanning light source of the present invention is characterized in that it comprises: a controller, a main frame, a two-dimensional translation mechanism, and a light source assembly;

[0008] The two-dimensional translation mechanism is arranged on the main frame, and a loading slider is arranged on the two-dimensional translation mechanism. Under the instruction of the controller, the two-dimensional translation mechanism drives the loading slider to translate in two mutually perpendicular directions according to the set translation speed, and forms a virtual translation interface;

[0009] The light source assembly is fixed on the object-carrying slider and comprises: a light source and a light source base;

[0010] The length direction of the light source is parallel to any translation direction of the two-dimensional translation mechanism, and the light emission direction of the light source is toward the normal direction of the virtual translation interface.

[0011] The testing method of a portable Lambertian scanning light source of the present invention is characterized in that it is applied to the portable Lambertian scanning light source and comprises the following steps:

[0012] 1) Test preparation:

[0013] 1.1) Fix the portable Lambertian scanning light source in front of the remote sensor with a large field of view, and make the center of the remote sensor's field of view face the center point of the virtual translation interface of the portable Lambertian scanning light source. At the same time, adjust the portable Lambertian scanning light source so that the two translation directions of the two-dimensional translation mechanism are respectively consistent with the row and column directions of the image of the remote sensor with a large field of view;

[0014] The light source and the large field of view remote sensor are both preheated to be stable;

[0015] 2) Match the acquisition interval t of the large field of view remote sensor with the scanning speed v of the Lambertian scanning light source:

[0016] 2.1) Adjust the position of the object-carrying slider so that the light source is displayed as a long strip image on the image of the wide-field remote sensor and is located at the edge of the image; the width of the long strip image is recorded as B, the length is recorded as L, and the center point is recorded as C;

[0017] Setting the brightness of the light source or the parameters of the remote sensor with a large field of view so that the maximum signal of the long strip image is within the dynamic range of the remote sensor with a large field of view;

[0018] Define the current scan group number as , and initialize ;

[0019] Define the image number in the current scan group as n;

[0020] 2.2) The controller controls the light source to translate along a direction perpendicular to its length direction and translate at a scanning speed v at a uniform speed until the full stroke. During the movement, the large field of view remote sensor continuously images N times at an acquisition interval t, thereby obtaining the xth group of images captured at the acquisition interval t. ,in, The nth image in the xth image set is captured at the acquisition interval t;

[0021] 2.3) Selection Take any adjacent nth and n+1th images in the image and analyze the position difference between the center points of the nth and n+1th images. ,like , then after changing the values ​​of t and v, return to step 2.2 and execute sequentially, otherwise, execute step 2.4; where, Represents the mean value between the widths of the long strips of the nth and n+1th images;

[0022] 2.4) If Minimum length corresponding to the medium-long strip image is less than the length of the image row or column parallel to the length direction of the light source, the controller controls the light source to move less than / 2, and assign x+1 to x, and then return to step 2.2 and execute sequentially until the scanning path of the long strip image completely covers the image, thereby obtaining the remote sensing image set of the image under the acquisition interval t , X represents the number of groups;

[0023] 2.5) After the scanning is completed, the controller controls the light source to return to the outside of the field of view of the large field of view remote sensor;

[0024] 3) Remote sensing image collection All images in the collection are preprocessed, and the preprocessed remote sensing image set under the collection interval t is obtained. ,right After the images are spliced ​​in the pixel dimension, the fused image at the acquisition interval t is obtained. ;

[0025] 4) Determine whether the state of the wide field of view remote sensor has changed;

[0026] 4.1) At different first test times A and second test times B, obtain first fused images according to the process of step 1) to step 3) respectively. and the second fused image ;

[0027] 4.2) Calculation of the response variation coefficient of a large field of view remote sensor ;

[0028] 4.3) Yes and After normalization, the first normalized fusion image is obtained. And the normalized second fusion image ,

[0029] 4.4) Calculation of uniformity variation coefficient of large field of view remote sensor ;

[0030] 4.5) If the response variation coefficient Does not exceed the set threshold , and the uniformity variation coefficient Does not exceed the set threshold , it means that the radiation response state of the wide field of view remote sensor has not changed, otherwise it means that the absolute responsivity of the wide field of view remote sensor has changed or the absolute responsivity has changed.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] 1. The present invention sets a line light source on a two-dimensional translation mechanism, and uses a two-dimensional scanning time-sharing illumination method to cover the full aperture and full field of view of the remote sensor during the installation test and on-board calibration phase of the large field of view remote sensor, and is outside the field of view of the remote sensor during the non-test phase to avoid blocking the field of view of the remote sensor. The two-dimensional scanning method has the advantages of small size, light weight and portability. The present invention effectively eliminates the problems of traditional uniform surface light sources, such as large size, heavy weight, inconvenience in carrying, high difficulty in assembly and disassembly, and large amount of resources occupied by supporting mobile devices. At the same time, it effectively eliminates the problem that the one-dimensional scanning light source of copiers and scanners on the market may be difficult to fully cover the full aperture and full field of view of the large field of view remote sensor, as well as the problem of beam turning and collection component redundancy;

[0033] 3. The linear light source of the present invention has been screened for Lambertian property, stability, repeatability, radiation resistance, etc., which ensures the long-term reliability of the light source while improving the accuracy of the satellite installation test and on-satellite calibration, effectively eliminating the problem that the scanning light source of the copiers and scanners on the market has not been strictly screened and cannot guarantee the reliability, stability, repeatability and further test accuracy of the light source;

[0034] 4. The test method proposed by the present invention for the remote sensor with a large field of view ensures sufficient coverage between different scanned images by matching the acquisition interval with the scanning speed, makes full use of the Lambertian illumination area of ​​the linear light source to improve the uniformity of the fused image, and thus improves the test accuracy of the response performance of the remote sensor with a large field of view, and effectively eliminates the defects that the test method and data processing method of the traditional scanning light source are not suitable for the satellite installation test and on-board calibration of the remote sensor with a large field of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the composition of the portable Lambertian scanning light source and the placement of the large field of view remote sensor of the present invention;

[0036] Figure 2 It is a schematic diagram of a long strip image of the portable Lambertian scanning light source of the present invention;

[0037] Numbers in the figure: 1 controller, 2 main frame, 3 two-dimensional translation mechanism, 4 light source assembly, 5 large field of view remote sensor, 2.1 fixed structure, 3.1 loading slider, 3.2 virtual translation interface, 4.1 light source, 4.1a strip image, 4.2 light source base, B width of the strip image, L length of the strip image, C center point of the strip image. DETAILED DESCRIPTION

[0038] In this embodiment, Figure 1 As shown, a portable Lambertian scanning light source comprises: a controller 1, a main frame 2, a two-dimensional translation mechanism 3, and a light source assembly 4; the two-dimensional translation mechanism 3 is arranged on the main frame 2, and a carrier slider 3.1 is arranged on the two-dimensional translation mechanism 3. Under the instruction of the controller 1, the two-dimensional translation mechanism 3 drives the carrier slider 3.1 to translate in two mutually perpendicular directions according to the set translation speed, and forms a virtual translation interface 3.2; a fixed structure 2.1 is arranged on the periphery of the main frame 2 for fixing the entire Lambertian scanning light source.

[0039] The light source assembly 4 comprises: a light source 4.1 and a light source base 4.2. The light source assembly 4 is fixed on the object-carrying slider 3.1. The light source (4.1) is a linear light source that has been screened for Lambertian property, stability, repeatability, radiation resistance, etc. The length direction of the light source 4.1 is parallel to any translation direction of the two-dimensional translation mechanism 3, and the light emission direction of the light source 4.1 is toward the normal direction of the virtual translation interface 3.2.

[0040] Light source 4.1 is a linear light source, preferably a slender cold cathode fluorescent lamp. This slender cold cathode fluorescent lamp has good Lambertian properties, so there is no need to further use a uniform light device, avoiding the aging problem faced by the additional uniform light device in the space environment, and at the same time reducing the volume and weight of the portable Lambertian scanning light source. Before use, the linear light source needs to be strictly screened for Lambertian properties, stability, repeatability, and radiation resistance. Among them, the Lambertian screening of the light source is to analyze the discrete degree of the spectral radiance of the linear light source at different positions and different observation angles in the length direction. The stability screening of the light source is to obtain the energy of the linear light source at a certain time interval within a period of at least 2 times the longest actual possible test time and evaluate its discrete degree. The repeatability of the light source is to obtain the energy of the linear light source after sufficient cooling and restarting to stability, and evaluate its discrete degree after repeated multiple times. The radiation resistance of the light source is to simulate the space radiation environment to irradiate the linear light source and compare the consistency of the radiation energy of the linear light source before and after irradiation.

[0041] In this embodiment, a method for testing a portable Lambertian scanning light source includes the following steps:

[0042] 1) Test preparation:

[0043] 1.1) The portable Lambertian scanning light source is fixed in front of the remote sensor (5) with a large field of view, and the center of the remote sensor field of view (5) is aligned with the center point of the virtual translation interface (3.2) of the portable Lambertian scanning light source. At the same time, the portable Lambertian scanning light source is adjusted so that the two translation directions of the two-dimensional translation mechanism (3) are respectively consistent with the row and column directions of the image (5.1) of the remote sensor (5) with a large field of view;

[0044] The light source 4.1 and the large field of view remote sensor 5 are both preheated to be stable.

[0045] 2) If Figure 2 As shown, the acquisition interval t of the large field of view remote sensor 5 is matched with the scanning speed v of the Lambertian scanning light source:

[0046] 2.1) Adjust the position of the object-carrying slider 3.1 so that the light source 4.1 is displayed as a long strip image 4.1a on the image 5.1 of the wide-field remote sensor 5 and is located at the edge of the image 5.1; the width of the long strip image 4.1a is recorded as B, the length is recorded as L, and the center point is recorded as C;

[0047] The brightness of the light source 4.1 or the parameters of the large-field-of-view remote sensor 5 are set so that the maximum signal of the long strip image 4.1a is within the dynamic range of the large-field-of-view remote sensor 5;

[0048] Define the current scan group number as , and initialize ;

[0049] Define the image number in the current scan group as n.

[0050] 2.2) The controller 1 controls the light source 4.1 to translate along a direction perpendicular to its length direction and translate at a constant speed v until the full stroke. During the movement, the large field of view remote sensor 5 continuously images N times at a collection interval t, thereby obtaining the xth group of images captured at the collection interval t. ,in, The nth image in the xth group of images is taken at the acquisition interval t.

[0051] 2.3) Selection Take any adjacent nth and n+1th images in the image and analyze the position difference between the center points of the nth and n+1th images. ,like , then after changing the values ​​of t and v, return to step 2.2 and execute sequentially, otherwise, execute step 2.4; where, It represents the mean value between the widths of the strips of the nth image and the n+1th image.

[0052] 2.4) If Minimum length corresponding to the medium-long strip image is less than the length of the row or column of the image 5.1 parallel to the length direction of the light source 4.1, the controller 1 controls the light source 4.1 to move along another translation direction less than / 2, and assign x+1 to x, and then return to step 2.2 and execute sequentially until the scanning path of the long strip image 4.1a completely covers the image 5.1, thereby obtaining the remote sensing image set of image 5.1 at the acquisition interval t. , X represents the number of groups;

[0053] 2.5) After the scanning is finished, the controller 1 controls the light source 4.1 to return to the outside of the field of view of the large field of view remote sensor 5.

[0054] 3) Remote sensing image collection After preprocessing all images in the image set, such as background subtraction and bad pixel processing, the remote sensing image set after preprocessing under the acquisition interval t is obtained. , image set The total number of images is X*N, that is, each pixel of image 5.1 will have X*N data. After the images in the middle are spliced ​​in the pixel dimension, the fused image at the acquisition interval t is obtained. The data stitching algorithm is not specifically limited, and the surface uniformity of the actual fused image is used as the judgment criterion. This embodiment provides a simple data stitching algorithm based on the image characteristics, that is, the X*N data of each pixel are counted separately to obtain the maximum value collected by each pixel, and the value is assigned to the corresponding pixel position in the fused image to obtain the fused image under the collection interval t. .

[0055] 4) Determine whether the state of the large field of view remote sensor (5) has changed;

[0056] 4.1) At different first test times A and second test times B, obtain first fused images according to the process of step 1) to step 3) respectively. and the second fused image ;

[0057] 4.2) Calculation of the response variation coefficient of the wide field of view remote sensor (5) ;

[0058] 4.3) Yes and After normalization, the first normalized fusion image is obtained. And the normalized second fusion image ;

[0059] 4.4) Calculation of uniformity variation coefficient of large field of view remote sensor (5) ;

[0060] 4.5) If the response variation coefficient Exceeding the set threshold , it indicates that the absolute responsivity of the large field of view remote sensor (5) has changed, otherwise, it indicates that the absolute responsivity of the large field of view remote sensor (5) has not changed;

[0061] If the uniformity variation coefficient Exceeding the set threshold , it indicates that the relative responsivity of the large field of view remote sensor (5) has changed, otherwise, it indicates that the relative responsivity of the large field of view remote sensor (5) has not changed, and the responsivity of the large field of view remote sensor (5) is not updated.

Claims

1. A portable Lambertian scanning light source, characterized in that: include: Controller (1), main frame (2), two-dimensional translation mechanism (3), light source assembly (4); The two-dimensional translation mechanism (3) is arranged on the main frame (2), and an object-carrying slider (3.1) is arranged on the two-dimensional translation mechanism (3). Under the instruction of the controller (1), the two-dimensional translation mechanism (3) drives the object-carrying slider (3.1) to translate in two mutually perpendicular directions at a set translation speed, and forms a virtual translation interface (3.2); The light source assembly (4) is fixed on the object-carrying slider (3.1), and comprises: a light source (4.1) and a light source base (4.2); The length direction of the light source (4.1) is parallel to any one translation direction of the two-dimensional translation mechanism (3), and the light emission direction of the light source (4.1) is toward the normal direction of the virtual translation interface (3.2).

2. A method for testing a portable Lambertian scanning light source, characterized in that: It is applied to the portable Lambertian scanning light source as claimed in claim 1, and comprises the following steps; Step 1) Test preparation: Step 1.1) The portable Lambertian scanning light source is fixed in front of the large field of view remote sensor (5), and the center of the remote sensor field of view (5) is aligned with the center point of the virtual translation interface (3.2) of the portable Lambertian scanning light source. At the same time, the portable Lambertian scanning light source is adjusted so that the two translation directions of the two-dimensional translation mechanism (3) are respectively consistent with the row and column directions of the image (5.1) of the large field of view remote sensor (5); The light source (4.1) and the large field of view remote sensor (5) are both preheated to be stable; Step 2) Match the acquisition interval t of the large field of view remote sensor (5) with the scanning speed v of the Lambertian scanning light source: Step 2.1) Adjust the position of the object-carrying slider (3.1) so that the light source (4.1) is displayed as a long strip image (4.1a) on the image (5.1) of the large-field-of-view remote sensor (5) and is located at the edge of the image (5.1); the width of the long strip image (4.1a) is recorded as B, the length is recorded as L, and the center point is recorded as C; Setting the brightness of the light source (4.1) or the parameters of the large-field-of-view remote sensor (5) so that the maximum signal of the long strip image (4.1a) is within the dynamic range of the large-field-of-view remote sensor (5); Define the current scan group number as , and initialize ; Define the image number in the current scan group as n; Step 2.2) The controller (1) controls the light source (4.1) to translate along a direction perpendicular to its length direction and translate at a scanning speed v at a uniform speed until the full stroke, and during the movement, the large field of view remote sensor (5) continuously images N times at a collection interval t, thereby obtaining the xth group of images captured at the collection interval t. ,in, The nth image in the xth image set is captured at the acquisition interval t; Step 2.3) Select Take any adjacent nth and n+1th images in the image and analyze the position difference between the center points of the nth and n+1th images. ,like , then after changing the values ​​of t and v, return to step 2.2 and execute sequentially, otherwise, execute step 2.4; where, Represents the mean value between the widths of the long strips of the nth and n+1th images; Step 2.4) If Minimum length corresponding to the medium-long strip image If the length of the image (5.1) is less than the length of the row or column of the image (5.1) parallel to the length direction of the light source (4.1), the controller (1) controls the light source (4.1) to move along another translation direction less than / 2, and assign x+1 to x, and then return to step 2.2 and execute sequentially until the scanning path of the long strip image (4.1a) completely covers the image (5.1), thereby obtaining the remote sensing image set of the image (5.1) at the acquisition interval t. , X represents the number of groups; Step 2.5) After the scanning is completed, the controller (1) controls the light source (4.1) to return to the outside of the field of view of the large field of view remote sensor (5); Step 3) Remote sensing image set All images in the collection are preprocessed, and the preprocessed remote sensing image set under the collection interval t is obtained. ,right After the images are spliced ​​in the pixel dimension, the fused image at the acquisition interval t is obtained. ; Step 4) determining whether the state of the large field of view remote sensor (5) has changed; Step 4.1) At different first test times A and second test times B, obtain first fused images according to the process of step 1) to step 3). and the second fused image ; Step 4.2) Calculate the response variation coefficient of the wide field of view remote sensor (5) ; Step 4.3) and After normalization, the first normalized fusion image is obtained. And the normalized second fusion image , Step 4.4) Calculate the uniformity variation coefficient of the large field of view remote sensor (5) ; Step 4.5) If the response variation coefficient Does not exceed the set threshold , and the uniformity variation coefficient Does not exceed the set threshold , it indicates that the radiation response state of the large field of view remote sensor (5) has not changed, otherwise it indicates that the absolute responsivity of the large field of view remote sensor (5) has changed or the absolute responsivity has changed.

Images