Device and method for estimating integral time of remote sensing detector

Abstract

The invention discloses an integral time estimation device and method for a remote sensing detector, and relates to the field of remote sensing detection.The narrow-band optical filters in a narrow-band optical filter set in the device are correspondingly fixed to the light receiving faces of photoresistors in a photoresistor array; spectral passbands of narrow-band filters in the narrow-band filter group are uniformly distributed in a remote sensing observation spectral range; a combination body of the narrow-band optical filter group and the photoresistor array is fixed at the edge of an optical path of the remote sensing instrument; the photoresistor array is connected with the resistance measuring circuit; the resistance value measuring circuit is used for measuring the resistance value of the photoresistor array; the remote sensing detector drive circuit is connected with the resistance measuring circuit and the remote sensing detector. The remote-sensing detector driving circuit is used for adjusting the integral time of the remote-sensing detector in real time according to the resistance value. According to the invention, the efficiency of detector integration time adjustment can be improved, available remote sensing data can be rapidly obtained, and the accuracy of the remote sensing detector is improved.

Description

Technical Field

[0001] The present application relates to the field of remote sensing detection, and in particular to a remote sensing detector integration time estimation device and method. Background Art

[0002] With the development of research fields such as climate change monitoring and land resource management, higher requirements are placed on the quality of remote sensing measurement data. Fine observation means high discrimination of remote sensing observation information. For example, the difference in digital values ​​between two adjacent pixels is 10. The light intensity difference of the remote sensing observation target corresponding to these two pixels can be calculated based on parameters such as the detector integration time, the gain setting of the detector output signal, and the uniformity of the detector pixel, thereby inverting the characteristics of the observed target in the remote sensing image. When the remote sensing image data is oversaturated or undersaturated, even if the characteristics of the observed target are quite different, the difference in the digital values ​​of the remote sensing image output by the detector is extremely small, and the difference in the characteristics of the observed target cannot be distinguished. Therefore, the oversaturation and undersaturation of the remote sensing image data are unacceptable, which indicates the loss of remote sensing observation information. In order to avoid this situation, the integration time of the remote sensing detector is often adjusted in real time as the observed target changes.

[0003] Existing methods often use the detector integration time adaptive algorithm to achieve adaptive adjustment of remote sensing images by obtaining the current output data of the detector and using a predetermined integration time adjustment algorithm. However, if the light intensity of the observed target is extremely strong or weak, the detector integration time adaptive algorithm of the existing method is difficult to extract effective adjustment information from the oversaturated or undersaturated image data, and it will take a longer time to adjust the integration time. Even after the observed target changes, the process is not completed, making it difficult to obtain usable data.

[0004] Therefore, based on the above problems, there is an urgent need to provide a new adjustment structure or method that can provide effective information for the adjustment of the detector integration time when the light intensity of the observed target is extremely strong or extremely weak, so that the detector integration time can be adjusted quickly to obtain usable remote sensing data, thereby improving the accuracy of remote sensing detector observations. Summary of the invention

[0005] The purpose of this application is to provide a remote sensing detector integration time estimation device and method, which can improve the efficiency of detector integration time adjustment, quickly obtain available remote sensing data, and thus improve the accuracy of the remote sensing detector.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a remote sensing detector integration time estimation device, the remote sensing detector integration time estimation device comprising: a narrow band filter group, a photoresistor array, a resistance measurement circuit and a remote sensing detector driving circuit;

[0008] The narrowband filters in the narrowband filter group correspond to the light-receiving surfaces of the photoresistors fixed in the photoresistor array; the spectral passbands of the narrowband filters in the narrowband filter group are evenly distributed in the remote sensing observation spectral range;

[0009] The combination of the narrow-band filter group and the photoresistor array is fixed to the edge of the optical path of the remote sensing instrument;

[0010] The photoresistor array is connected to the resistance measurement circuit; the resistance measurement circuit is used to measure the resistance value of the photoresistor array;

[0011] The remote sensing detector driving circuit is connected to the resistance value measuring circuit and the remote sensing detector respectively; the remote sensing detector driving circuit is used to adjust the integration time of the remote sensing detector in real time according to the resistance value.

[0012] Optionally, the number of narrow-band filters in the narrow-band filter group is equal to the number of photoresistors in the photoresistor array.

[0013] Optionally, the number of the narrow-band filters and the number of the photoresistors are both greater than 2.

[0014] In a second aspect, the present application provides a remote sensing detector integration time estimation method, which is applied to the remote sensing detector integration time estimation device, and the remote sensing detector integration time estimation method comprises:

[0015] Set the initial integration time of the remote sensing detector;

[0016] The remote sensing instrument of the combination of the fixed narrow-band filter group and the photoresistor array is pre-set to obtain the corresponding relationship between the actual light intensity and the output value of the remote sensing detector; the actual light intensity is determined according to the spectral passband and the resistance value of the narrow-band filter group at the photoresistor array;

[0017] When a remote sensing instrument combining a fixed narrow-band filter set and the photoresistor array is used for remote sensing observation, the actual light intensity at the current moment is determined according to the remote sensing detector integration time at the current moment and the resistance value of the photoresistor array;

[0018] The updated integration time of the remote sensing detector is determined according to the initial integration time, the corresponding relationship and the actual light intensity at the current moment.

[0019] Optionally, the remote sensing instrument of the combination of the fixed narrow-band filter set and the photoresistor array is pre-set to obtain a corresponding relationship between the actual light intensity and the output value of the remote sensing detector, specifically including:

[0020] The remote sensing instrument with the combination of the fixed narrow-band filter group and the photoresistor array is placed in front of the calibration lamp, so that the incident light emitted by the calibration lamp is incident on the light-receiving surface of the corresponding photoresistor through the narrow-band filter; the calibration lamp has a total of m light intensity energy levels;

[0021] Starting from the lowest light intensity of the calibration lamp, record the resistance value of the photoresistor array and the output value of the remote sensing detector at each level of light intensity;

[0022] Determine the actual light intensity at the photoresistor array at the current energy level light intensity according to the spectral passband of the narrowband filter group and the resistance value of the corresponding photoresistor;

[0023] The corresponding relationship is determined according to the actual light intensity at the photoresistor array at the current energy level light intensity and the output value of the remote sensing detector at the corresponding energy level light intensity.

[0024] Optionally, determining the actual light intensity at the photoresistor array at the current energy level light intensity according to the spectral passband of the narrowband filter group and the resistance value of the corresponding photoresistor specifically includes:

[0025] Using the formula Determine the photoresistor R at the jth energy level of the calibration lamp i The actual light intensity P j ;

[0026] Where n is the number of photoresistors, k is i is the light response coefficient of the ith photoresistor, R i，j is the photoresistor R i The resistance value at the j-th energy level of light.

[0027] Optionally, determining the corresponding relationship according to the actual light intensity at the photoresistor array at the current energy level light intensity and the output value of the remote sensing detector at the corresponding energy level light intensity specifically includes:

[0028] Using the formula Determine the corresponding relationship between the actual light intensity P at the photoresistor array at the current energy level light intensity and the output value DN of the remote sensing detector at the corresponding energy level light intensity;

[0029] Among them, DN max DN min They represent the output values ​​of the remote sensing detector under overexposure and underexposure respectively, P1 and P2 represent the actual light intensity at the photoresistor array under overexposure and underexposure respectively, a0, a1, a2..a rare the constant coefficients obtained by fitting the actual light intensity with the output value of the remote sensing detector, r is the number of constant coefficients, and r≥1.

[0030] Optionally, determining the updated integration time of the remote sensing detector according to the initial integration time, the corresponding relationship and the actual light intensity at the current moment specifically includes:

[0031] If the remote sensing detector outputs an image that is overexposed or underexposed, the formula Determine the updated remote sensing detector integration time t next ;

[0032] Among them, t0 is the initial integration time, P now is the actual light intensity at the current moment.

[0033] 9. The remote sensing detector integration time estimation method according to claim 8, characterized in that the formula Determine the actual light intensity P at the current moment now ;

[0034] Among them, R i，now is the resistance value of the i-th photoresistor in the photoresistor array at the current moment.

[0035] According to the specific embodiments provided in this application, this application has the following technical effects:

[0036] The present application provides a remote sensing detector integration time estimation device and method, by fixing the narrow-band filters in a narrow-band filter group to the light-receiving surface of the photoresistor in the photoresistor array, and then establishing a light intensity response structure for the scene where the remote sensing observation target changes rapidly according to the characteristics of the photoresistor and the narrow-band filter; the photoresistor array is connected to a resistance measurement circuit, and the resistance measurement result is input into the remote sensing detector drive circuit to adjust the remote sensing detector integration time in real time; thereby compensating for the problem of information loss in the detector output image data under oversaturation and undersaturation conditions, making the detector integration time adjustment faster, thereby quickly acquiring available remote sensing data, and can be widely used in the field of remote sensing detection where the observation target changes rapidly. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 This is a schematic diagram of the structure of a remote sensing detector integration time estimation device in one embodiment of the present application;

[0039] Figure 2 This is a schematic flow chart of a remote sensing detector integration time estimation method in one embodiment of the present application. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0042] In an exemplary embodiment, Figure 1 As shown, a remote sensing detector integration time estimation device is provided, and the remote sensing detector integration time estimation device comprises: narrow band filter groups A1, A2...A n , photoresistor array R1, R2...R n , resistance measurement circuit and remote sensing detector drive circuit;

[0043] The narrowband filters in the narrowband filter group correspond to the light-receiving surfaces of the photoresistors fixed in the photoresistor array; the number of narrowband filters in the narrowband filter group is equal to the number of photoresistors in the photoresistor array. The number of narrowband filters and the number of photoresistors are both greater than 2. For example, narrowband filter A1 is fixed to the light-receiving surface of photoresistor R1, narrowband filter A2 is fixed to the light-receiving surface of photoresistor R2, and so on until narrowband filter A n Fixed to the photoresistor R n The light-receiving surface;

[0044] The spectral passbands of the narrowband filters in the narrowband filter set are λ1, λ2, ... λ n The narrowband filters in the narrowband filter group correspond to the light-receiving surfaces of the photoresistors fixed in the photoresistor array; the spectral passbands of the narrowband filters in the narrowband filter group are evenly distributed in the remote sensing observation spectral range; the i-th photoresistor represents the i-th spectral passband; the resistance change of different photoresistors indicates the light intensity change of the input light in the spectral passband;

[0045] The combination of the narrow-band filter set and the photoresistor array is fixed to the edge of the optical path of the remote sensing instrument, so that there is no non-light-transmitting object blocking the photoresistor array and the observation target of the remote sensing instrument;

[0046] The photoresistor array is connected to the resistance measurement circuit; the resistance measurement circuit is used to measure the resistance value of the photoresistor array;

[0047] The remote sensing detector driving circuit is connected to the resistance value measuring circuit and the remote sensing detector respectively; the remote sensing detector driving circuit is used to adjust the integration time of the remote sensing detector in real time according to the resistance value.

[0048] Based on the same inventive concept, the embodiment of the present application also provides a remote sensing detector integration time estimation method. The implementation scheme for solving the problem provided by the method is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more remote sensing detector integration time estimation method embodiments provided below can refer to the limitations of the remote sensing detector integration time estimation device above, and will not be repeated here.

[0049] In an exemplary embodiment, Figure 2 As shown, a remote sensing detector integration time estimation method is provided, including:

[0050] S101, setting the initial integration time t0 of the remote sensing detector;

[0051] S102, presetting the remote sensing instrument of the combination of the fixed narrow-band filter group and the photoresistor array to obtain the corresponding relationship between the actual light intensity and the output value of the remote sensing detector; the actual light intensity is determined according to the spectral passband and the resistance value of the narrow-band filter group at the photoresistor array;

[0052] S102 specifically includes:

[0053] S201, placing a remote sensing instrument having a fixed narrow-band filter set and the photoresistor array in front of a calibration lamp, so that the incident light emitted by the calibration lamp passes through the narrow-band filter and enters the light-receiving surface of the corresponding photoresistor; the calibration lamp has a total of m light intensity energy levels;

[0054] S202, starting from the lowest light intensity of the calibration lamp, recording the resistance value of the photoresistor array and the output value of the remote sensing detector at each light intensity level;

[0055] Let the photoresistor R i The resistance measurement result at the jth energy level is R i，j , the output value of the remote sensing detector at the jth calibration light intensity level is DN j , where 1≤i≤n, 1≤j≤m;

[0056] S203, according to the spectral passbands λ1, λ2, ...λ of the narrowband filter group, nand the resistance value of the corresponding photoresistor to determine the actual light intensity at the photoresistor array at the current energy level light intensity;

[0057] Using the formula Determine the photoresistor R at the jth energy level of the calibration lamp i The actual light intensity P j ;

[0058] Where n is the number of photoresistors, k is i is the light response coefficient of the ith photoresistor, R i，j is the photoresistor R i The resistance value at the j-th energy level of light.

[0059] S204, determining a corresponding relationship according to the actual light intensity at the photoresistor array at the current energy level light intensity and the output value of the remote sensing detector at the corresponding energy level light intensity.

[0060] Using the formula Determine the corresponding relationship between the actual light intensity P at the photoresistor array at the current energy level light intensity and the output value DN of the remote sensing detector at the corresponding energy level light intensity;

[0061] Among them, DN max DN min They represent the output values ​​of the remote sensing detector under overexposure and underexposure respectively, P1 and P2 represent the actual light intensity at the photoresistor array under overexposure and underexposure respectively, a0, a1, a2..a r are the constant coefficients obtained by fitting the actual light intensity with the output value of the remote sensing detector, r is the number of constant coefficients, and r≥1.

[0062] S103, when a remote sensing instrument combining a fixed narrow-band filter set and the photoresistor array is used for remote sensing observation, the actual light intensity at the current moment is determined according to the remote sensing detector integration time at the current moment and the resistance value of the photoresistor array;

[0063] S104, determining the updated integration time of the remote sensing detector according to the initial integration time, the corresponding relationship and the actual light intensity at the current moment.

[0064] If the remote sensing detector outputs an image that is overexposed or underexposed, the formula Determine the updated remote sensing detector integration time t next ;

[0065] Among them, t0 is the initial integration time, P now is the actual light intensity at the current moment.

[0066] Using the formula Determine the actual light intensity P at the current moment now ;

[0067] Among them, R i，now is the resistance value of the i-th photoresistor in the photoresistor array at the current moment.

[0068] The following is explained through a specific embodiment, wherein a photoresistor array R1, R2, R3, R4 and a narrowband filter group A1, A2, A3, A4 are composed; the photoresistor response spectrum in the photoresistor array covers the spectral range of 1.3μm to 3μm of remote sensing observation; the narrowband filter spectral passband in the narrowband filter group is uniformly distributed in the remote sensing observation spectral range, and the spectral passbands of the narrowband filter groups A1, A2, A3, A4 are 1.3μm to 1.7μm, 1.8μm to 2.2μm, 2.3μm to 2.7μm, and 2.6μm to 3μm, respectively;

[0069] First, the initial integration time of the remote sensing detector is set to 300ms, and the remote sensing instrument assembled with the combination of the narrow-band filter set and the photoresistor array is placed in front of a calibration lamp with adjustable light intensity, and the calibration lamp has 10 light intensity levels;

[0070] Next, starting from the lowest light intensity of the calibration lamp, record the resistance measurement results of the photoresistor array R1, R2, R3, and R4 and the digital value output by the remote sensing detector at each light intensity level, and let the photoresistor R i The resistance measurement result at the jth calibration light intensity level is R i，j , the output value of the remote sensing detector at the jth energy level is DN j , where 1≤i≤4, 1≤j≤10;

[0071] According to the spectral passbands λ1, λ2, ... λ4 of the narrowband filter group, the actual light intensity P at the remote sensing detector integral estimation structure under the j-th energy level of the calibration lamp is calculated. j , the calculation formula is as follows:

[0072] P j =1.85R1+6.71R2+2.84R3+3.95R4;

[0073] Among them, the light response coefficient of the photoresistor is obtained by calibration test;

[0074] Afterwards, a 14-bit analog-to-digital converter was used for remote sensing data acquisition. The maximum digital value output of the analog-to-digital converter is 2 14-1=16383, the minimum digital value output is 0, and the actual light intensity at the remote sensing detector integral estimation structure under overexposure and underexposure are P1 and P2 respectively. According to the actual light intensity at the remote sensing detector integral estimation structure and the digital value output by the remote sensing detector, the value of the constant coefficient a is obtained, and the corresponding relationship between the actual light intensity P at the remote sensing detector integral estimation structure and the digital value DN output by the remote sensing detector is established:

[0075]

[0076] Finally, remote sensing instruments are used for remote sensing observation. The current remote sensing detector integration time is 400ms. At this time, the remote sensing detector output image is overexposed, that is, the measured digital output value is 16383. At this time, the resistance values ​​of the resistor array are measured as R1=9, R2=31, R3=5, and R4=8, and the actual light intensity P at its position is calculated. now :

[0077] P now =270.46;

[0078] Calculate the new remote sensing detector integration time t next :

[0079] t next =110.37ms;

[0080] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0081] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0082] In this application, all actions to obtain signals, information or data are carried out in compliance with the relevant data protection laws and policies of the country where they are located and with the authorization given by the owner of the corresponding device.

[0083] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A remote sensing detector integration time estimation device, characterized in that: The remote sensing detector integration time estimation device comprises: a narrow-band filter group, a photoresistor array, a resistance measurement circuit and a remote sensing detector driving circuit; The narrowband filters in the narrowband filter group correspond to the light-receiving surfaces of the photoresistors fixed in the photoresistor array; the spectral passbands of the narrowband filters in the narrowband filter group are evenly distributed in the remote sensing observation spectral range; The combination of the narrow-band filter group and the photoresistor array is fixed to the edge of the optical path of the remote sensing instrument; The photoresistor array is connected to the resistance measurement circuit; the resistance measurement circuit is used to measure the resistance value of the photoresistor array; The remote sensing detector driving circuit is connected to the resistance value measuring circuit and the remote sensing detector respectively; the remote sensing detector driving circuit is used to adjust the integration time of the remote sensing detector in real time according to the resistance value.

2. The remote sensing detector integration time estimation device according to claim 1, characterized in that: The number of narrow-band filters in the narrow-band filter group is equal to the number of photoresistors in the photoresistor array.

3. The remote sensing detector integration time estimation device according to claim 2, characterized in that: The number of the narrowband filters and the number of the photoresistors are both greater than 2.

4. A remote sensing detector integration time estimation method, applied to the remote sensing detector integration time estimation device according to any one of claims 1 to 3, characterized in that: The remote sensing detector integration time estimation method comprises: Set the initial integration time of the remote sensing detector; The remote sensing instrument of the combination of the fixed narrow-band filter group and the photoresistor array is pre-set to obtain the corresponding relationship between the actual light intensity and the output value of the remote sensing detector; the actual light intensity is determined according to the spectral passband and the resistance value of the narrow-band filter group at the photoresistor array; When a remote sensing instrument combining a fixed narrow-band filter set and the photoresistor array is used for remote sensing observation, the actual light intensity at the current moment is determined according to the remote sensing detector integration time at the current moment and the resistance value of the photoresistor array; The updated integration time of the remote sensing detector is determined according to the initial integration time, the corresponding relationship and the actual light intensity at the current moment.

5. The remote sensing detector integration time estimation method according to claim 4, characterized in that: The remote sensing instrument combining the fixed narrow-band filter set and the photoresistor array is pre-set to obtain a corresponding relationship between the actual light intensity and the output value of the remote sensing detector, specifically including: The remote sensing instrument with the combination of the fixed narrow-band filter group and the photoresistor array is placed in front of the calibration lamp, so that the incident light emitted by the calibration lamp is incident on the light-receiving surface of the corresponding photoresistor through the narrow-band filter; the calibration lamp has a total of m light intensity energy levels; Starting from the lowest light intensity of the calibration lamp, record the resistance value of the photoresistor array and the output value of the remote sensing detector at each level of light intensity; Determine the actual light intensity at the photoresistor array at the current energy level light intensity according to the spectral passband of the narrowband filter group and the resistance value of the corresponding photoresistor; The corresponding relationship is determined according to the actual light intensity at the photoresistor array at the current energy level light intensity and the output value of the remote sensing detector at the corresponding energy level light intensity.

6. The remote sensing detector integration time estimation method according to claim 5, characterized in that: The method of determining the actual light intensity at the photoresistor array at the current energy level light intensity according to the spectral passband of the narrowband filter group and the resistance value of the corresponding photoresistor specifically includes: Using the formula Determine the photoresistor R at the jth energy level of the calibration lamp i The actual light intensity P j ; Where n is the number of photoresistors, k is i is the light response coefficient of the ith photoresistor, R i，j is the photoresistor R i The resistance value at the j-th energy level of light.

7. The remote sensing detector integration time estimation method according to claim 6, characterized in that: The determining of the corresponding relationship according to the actual light intensity at the photoresistor array at the current light intensity level and the output value of the remote sensing detector at the corresponding light intensity level specifically includes: Using the formula Determine the corresponding relationship between the actual light intensity P at the photoresistor array at the current energy level light intensity and the output value DN of the remote sensing detector at the corresponding energy level light intensity; Among them, DN max DN min They represent the output values ​​of the remote sensing detector under overexposure and underexposure respectively, P1 and P2 represent the actual light intensity at the photoresistor array under overexposure and underexposure respectively, a0, a1, a2..a r are the constant coefficients obtained by fitting the actual light intensity with the output value of the remote sensing detector, r is the number of constant coefficients, and r≥1.

8. The remote sensing detector integration time estimation method according to claim 7, characterized in that: Determining the updated integration time of the remote sensing detector according to the initial integration time, the corresponding relationship and the actual light intensity at the current moment specifically includes: If the remote sensing detector outputs an image that is overexposed or underexposed, the formula Determine the updated remote sensing detector integration time t next ; Among them, t0 is the initial integration time, P now is the actual light intensity at the current moment.

9. The remote sensing detector integration time estimation method according to claim 8, characterized in that: Using the formula Determine the actual light intensity P at the current moment now ; Among them, R i，now is the resistance value of the i-th photoresistor in the photoresistor array at the current moment.

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