CN-121994362-A - Method for testing nonlinearity of detector output voltage

CN121994362ACN 121994362 ACN121994362 ACN 121994362ACN-121994362-A

Abstract

The invention relates to the technical field of infrared focal plane detection, in particular to a detector output voltage nonlinearity testing method, which comprises the steps of setting a detector to image a preset blackbody, respectively obtaining an output voltage value and an area array output voltage average value of each pixel of the detector under a first preset effective integration time and a second preset effective integration time, calculating a first correction coefficient and a second correction coefficient of each pixel through a two-point correction formula, obtaining an output voltage value of each pixel of the detector under a third preset effective integration time, calculating a correction voltage value and an area array correction voltage average value, carrying out plane fitting according to the correction voltage values of all pixels of the detector, calculating the residual root mean square of the correction voltage values of all pixels of the detector and fitting voltage values corresponding to the correction voltage values in a fitting plane, and calculating the nonlinearity of an area array voltage value curved surface.

Inventors

LI KEJUN
TAN BISONG
QIU WEIQIANG
LIU ZHIYONG
MAO JIANHONG

Assignees

浙江珏芯微电子有限公司

Dates

Publication Date: 20260508
Application Date: 20260212

Claims (10)

1. A method for testing the nonlinearity of a detector output voltage, the method comprising: Placing the detector in front of a surface source black body, setting the working temperature of the surface source black body to be a preset temperature, and setting the distance between the detector and the surface source black body to be smaller than or equal to a preset distance; Respectively acquiring an output voltage value of each pixel of the detector under a first preset effective integration time and a second preset effective integration time, and an area array output voltage average value of the detector under the first preset effective integration time and the second preset effective integration time; for each pixel of the detector, calculating a first correction coefficient and a second correction coefficient of the pixel according to the output voltage value of the pixel under the first preset effective integration time and the second preset effective integration time and the area array output voltage average value of the detector under the first preset effective integration time and the second preset effective integration time through a two-point correction formula; Acquiring an output voltage value of each pixel of the detector under a third preset effective integration time, correcting the output voltage value of the pixel under the third preset effective integration time according to the first correction coefficient and the second correction coefficient of the pixel for each pixel to obtain a correction voltage value of the pixel, and obtaining an area array correction voltage average value of the detector according to the average value of the correction voltage values of all the pixels of the detector; Performing plane fitting according to the correction voltage values of all the pixels of the detector, and obtaining a fitting voltage value corresponding to each pixel of the detector according to a plane fitting result; And calculating residual root mean square according to the corrected voltage values and fitting voltage values of all pixels of the detector, and acquiring the nonlinearity value of the output voltage of the detector according to the ratio of the residual root mean square to the area array corrected voltage average of the detector.
2. The method for testing nonlinearity of detector output voltage according to claim 1, wherein the respectively obtaining the output voltage value of each pixel of the detector at a first preset effective integration time and a second preset effective integration time and the area array output voltage average value of the detector at the first preset effective integration time and the second preset effective integration time comprises: The detector is controlled to continuously acquire first detection data with multi-frame integration time being the first preset integration time under the condition of optimal bias voltage, so that a plurality of first output voltage values corresponding to each pixel of the detector are obtained for the pixel; Controlling the detector to continuously acquire second detection data with multi-frame integration time being the second preset integration time under the optimal bias voltage condition, so as to obtain a plurality of second output voltage values corresponding to each pixel of the detector; For each pixel of the detector, acquiring an output voltage value of the pixel under the first preset effective integration time according to the average value of a plurality of first output voltage values corresponding to the pixel, and acquiring an output voltage value of the pixel under the second preset effective integration time according to the average value of a plurality of second output voltage values corresponding to the pixel; Acquiring an area array output voltage average value of the detector under the first preset effective integration time according to the average value of the output voltage values of all pixels of the detector under the first preset effective integration time; and acquiring the area array output voltage average value of the detector under the second preset effective integration time according to the average value of the output voltage values of all the pixels of the detector under the second preset effective integration time.
3. The method for testing the nonlinearity of the output voltage of a detector according to claim 1, wherein said obtaining the output voltage value of each pixel of the detector at the third predetermined effective integration time comprises: The detector is controlled to continuously acquire third detection data with multi-frame integration time being the third preset integration time under the condition of the optimal bias voltage, so that a plurality of third output voltage values corresponding to each pixel of the detector are obtained for the pixel; and aiming at each pixel of the detector, acquiring the output voltage value of the pixel under the third preset effective integration time according to the average value of a plurality of third output voltage values corresponding to the pixel.
4. The method of claim 1, wherein the third predetermined effective integration time is greater than the second predetermined effective integration time, and wherein the second predetermined effective integration time is greater than the first predetermined effective integration time.
5. The method for testing the nonlinearity of the output voltage of a detector according to claim 1, wherein the first preset effective integration time, the second preset effective integration time and the third preset effective integration time are set according to a preset calibrated output voltage swing and an area array bare voltage average value of the detector.
6. The detector output voltage nonlinearity test method of claim 5, wherein the detector output voltage swing and area array bare voltage mean value are calibrated by: Placing the detector in front of a surface source black body, setting the working temperature of the surface source black body to be the preset temperature, and setting the distance between the detector and the surface source black body to be smaller than or equal to the preset distance; The detector is controlled to continuously acquire fourth detection data with multi-frame integration time being minimum integration time under the condition of minimum bias voltage, so that a plurality of fourth output voltage values corresponding to each pixel of the detector are obtained for the pixel; under the condition of the optimal bias voltage, adjusting the integration time until the area array of the detector reaches a saturated state so as to obtain the saturated integration time corresponding to the detector; The detector is controlled to continuously acquire fifth detection data with multi-frame integration time being the saturation integration time under the condition of the optimal bias voltage, so that a plurality of fifth output voltage values corresponding to each pixel of the detector are obtained for the pixel; For each pixel of the detector, acquiring a minimum output voltage value corresponding to the pixel according to the average value of a plurality of fourth output voltage values corresponding to the pixel, and acquiring a maximum output voltage value corresponding to the pixel according to the average value of a plurality of fifth output voltage values corresponding to the pixel; Acquiring an area array bare voltage average value of the detector according to an average value of minimum output voltage values corresponding to all pixels of the detector, and acquiring an area array saturated voltage average value of the detector according to an average value of maximum output voltage values corresponding to all pixels of the detector; and acquiring the output voltage swing of the detector according to the difference value between the area array saturation voltage average value and the area array bare voltage average value of the detector.
7. The detector output voltage nonlinearity test method of claim 1, wherein the first correction coefficient and the second correction coefficient for each pixel are calculated by the following two-point correction formula: Wherein i e [1,2,3 ], M is the total number of rows of the detector's area array, j e [1,2,3 ], N is the total number of columns of the detector's area array, An average value of the area array output voltage of the detector under the first preset effective integration time is obtained, For the output voltage value of the pixel of the ith row and jth column in the detector's planar array at the first preset effective integration time, For the area array output voltage average value of the detector under the second preset effective integration time, For the output voltage value of the pixel of the ith row and jth column in the detector's planar array at the second preset effective integration time, For a first correction factor for a picture element of an i-th row and j-th column in an area array of the detector, A second correction coefficient for the pixel of the ith row and jth column in the planar array of the detector.
8. The method of claim 7, wherein the corrected voltage value for each pixel is calculated by the following equation: in the formula, For the correction voltage value of the pixel of the ith row and jth column in the detector's planar array at the third preset effective integration time, And outputting voltage values of pixels of the ith row and the jth column in the area array of the detector under the third preset effective integration time.
9. The detector output voltage nonlinearity test method of claim 1, further comprising, prior to performing a plane fit from corrected voltage values for all pixels of the detector: for each pixel of the detector, if the difference value between the correction voltage value of the pixel and the average value of the correction voltage values of a plurality of adjacent pixels around the pixel is within a preset range, judging the pixel as a normal pixel, otherwise, judging the pixel as a bad pixel; And taking the average value of correction voltage values of normal pixels in a plurality of neighborhood pixels around each bad pixel as a new correction voltage value of the bad pixel for each bad pixel in the detector.
10. The method for testing the nonlinearity of the output voltage of a detector according to claim 1, wherein the performing plane fitting based on the corrected voltage values of all pixels of the detector comprises: And performing plane fitting on correction voltage values of all pixels of the detector based on a least square method.

Description

Method for testing nonlinearity of detector output voltage Technical Field The invention relates to the technical field of infrared focal plane detection, in particular to a detector output voltage nonlinearity testing method. Background The nonlinearity of the detector is an important factor influencing the imaging quality of the infrared focal plane, the existing nonlinearity test method usually adopts a single-point calibration or multi-point piecewise fitting mode to evaluate the linearity of each pixel by measuring the voltage response curve of each pixel under different irradiance, however, the method can only acquire the nonlinearity data of discrete pixels or local sampling areas, cannot intuitively display the nonlinearity spatial distribution characteristics of the whole focal plane array, is difficult to comprehensively evaluate the integral nonlinearity level of the area array, and has the limitations of non-intuitive test results and lacking global evaluation capability. Disclosure of Invention The invention aims to provide a detector output voltage nonlinearity testing method, which can solve the problem that the existing nonlinearity testing method cannot evaluate the overall nonlinearity of an area array. In order to solve the technical problems, the invention provides a detector output voltage nonlinearity testing method, which comprises the steps of placing a detector in front of a surface source black body, setting the working temperature of the surface source black body to be a preset temperature, setting the distance between the detector and the surface source black body to be smaller than or equal to a preset distance, respectively acquiring an output voltage value of each pixel of the detector under a first preset effective integration time and a second preset effective integration time and an area array output voltage average value of the detector under the first preset effective integration time and the second preset effective integration time, respectively acquiring a first correction coefficient and a second correction coefficient of each pixel through a two-point correction formula, respectively acquiring an output voltage average value of the detector under the first preset effective integration time and the second preset effective integration time, respectively correcting an output voltage value of each pixel under the first preset effective integration time and the second preset effective integration time and an area array output voltage average value of the pixel according to the pixel, respectively correcting the first correction coefficient and the second correction coefficient of each pixel under the second correction coefficient, respectively fitting the first correction coefficient and the second correction coefficient to the second correction coefficient, and calculating residual root mean square according to the corrected voltage values and the fitted voltage values of all the pixels of the detector, and obtaining the output voltage nonlinearity value of the detector according to the ratio of the residual root mean square to the area array corrected voltage average of the detector. The method comprises the steps of controlling the detector to continuously acquire first detection data of which the multi-frame integration time is the first preset integration time under the optimal bias voltage condition, so as to acquire a plurality of first output voltage values corresponding to the pixels for each pixel of the detector, controlling the detector to continuously acquire second detection data of which the multi-frame integration time is the second preset integration time under the optimal bias voltage condition, aiming at each pixel of the detector, so as to acquire a plurality of second output voltage values corresponding to the pixel, aiming at each pixel of the detector, according to the average value of the plurality of first output voltage values corresponding to the pixel, acquiring the output voltage values of the pixel under the first preset integration time, aiming at the pixel, and acquiring the second detection data of which the pixel is the second output voltage value corresponding to the second preset integration time under the average value, and acquiring the second output voltage values corresponding to the pixel under the average value according to the average value of the second output voltage values corresponding to the pixel, and acquiring the second output voltage values corresponding to the pixel under the average value of the pixel. Optionally, the obtaining the output voltage value of each pixel of the detector under the third preset effective integration time includes controlling the detector to continuously collect third detection data with multi-frame integration time being the third preset integration time under the optimal bias voltage condition, so as to obtain a plurality of third output voltage values corresponding to each pixel of the detec