CN205305021U - Test system based on equivalence illumination and minimum distinguishable contrast - Google Patents

Abstract

The utility model relates to a test system based on equivalence illumination and minimum distinguishable contrast, including total mark ball (1), PC display (2), the camera that awaits measuring (3) and resolution ratio target (6), resolution ratio target (6) are fixed on the department is placed to the resolution ratio target. The utility model discloses a capability test is differentiated to the principle of equivalence illumination, the imaging system limit, and the test system based on equivalence illumination and minimum distinguishable contrast who combines johnson's criterion or MRC range forecasting model to provide can carry out scientific test to photoelectricity imaging system's performance, obtains the overall evaluation of its performance.

Description

Test system based on equivalent illumination and Minimum resolvable contrast

Technical field

This utility model relate to a kind of adopt active illumination but under poor light condition the system of the active near infrared imaging system performance testing of imaging, particularly relate to a kind of test system based on equivalent illumination and Minimum resolvable contrast, belong to the field tests of active IR imaging.

Background technology

Since the sixties in last century five, night vision technology is just always up one of domestic and international study hotspot for a long time. Actively near-infrared imaging technology is as night vision technology pattern the earliest, has advantage of lower cost, the features such as operating distance is remote, picture quality is good. In recent years, development along with laser/semiconductor illumination technique technology and CCD/CMOS imaging technique, relative to imaging and passive imaging, utilize the solid state image technology of near-infrared light source floor light strong with its identification ability, can all weather operations, under night " completely black " condition, the feature such as monitoring round the clock can obtain successful application in land and sea border defense supervision at night, region security monitoring, vehicle assistant drive etc. field.

In the process of imaging technique development, all the time along with the application of imaging system Performance Evaluation technology. From the scheme Design of early stage to research and development to the application in later stage, System Performance Analysis can provide various analytical data, the direction instructed the positioning problems in system development, use procedure, solution to formulate and improve further. The introducing of any new technology, new construction and new technique simultaneously and employing, while promoting imaging system performance, also require that Performance Evaluation technology must continuously improve, to be suitable for new demand. The active near infrared imaging system adopting new device and new lighting engineering is no exception.

The field performance that imaging system Performance Evaluation includes in the proper property assessment of imaging system and complex environment predicts the content of two aspects. In general, the performance evaluating imaging system has three kinds of methods: test method(s), simulation method and performance theory pattern law. The intuitive measurement results of test method(s), accurately, reliable, but, field test measurement is subject to the restriction of all many condition such as weather, place, result in Performance Evaluation process and is inconvenient for, especially for needing often, the market of mass detection actively near infrared imaging system. Simulation method needs the analogue system possessing costliness. Therefore, current research both domestic and external is substantially all the predictability aspect concentrating on performance model.

No matter being passive low-light level imaging or active illumination imaging, limit of utilization resolution theory or Minimum resolvable contrast theory carry out the performance evaluation of photo electric imaging system at home and abroad very big progress and certain application. But continuing to bring out of new image device, it is desirable to method of testing and system also want development and perfect, adopt active illumination but under poor light condition the active near infrared imaging system performance testing of imaging, domestic just ununified method and technical specification. For the operating distance evaluation under some concrete application scenarios of the active near-infrared video camera, need also exist for doing substantial amounts of real work, this photo electric imaging system unified measurement method to adopting novel image device, new image device and the demonstration of new system, design and development all have certain practice significance.

Utility model content

In order to overcome the deficiencies in the prior art, resolve problem of the prior art, make up the deficiency of existing existing product in the market.

This utility model provides a kind of test system based on equivalent illumination and Minimum resolvable contrast, and including integrating sphere, PC display, video camera to be measured and resolution target, described resolution target is fixed on resolution target lay down location; Above-mentioned PC display is connected to PC case; Above-mentioned PC display and video camera to be measured connect, and are placed on test platform; Above-mentioned PC case is arranged on below test platform. ; Above-mentioned integrating sphere and resolution target lay down location are separately positioned on corresponding handbarrow.

Preferably, the basic target line chart of the above-mentioned each unit of resolution target is by 3 target line compositions of horizontal and vertical, and the length of target line is 5 times of width, and live width and interval are equal, 2 times that are spaced apart target line width of horizontal target line and vertical target line, the recursion common ratio of resolution target target line isNamely every 6 unit, target line width successively decreases half.

This utility model is by the principle of equivalent illumination, the test of imaging system limit resolution performance, the performance of photo electric imaging system can be carried out the test of science by the test system based on equivalent illumination and Minimum resolvable contrast provided in conjunction with Johnson criteria or MRC operating distance forecast model, obtains the overall evaluation of its performance.

Accompanying drawing explanation

Fig. 1 is this utility model structural representation;

Fig. 2 is the measuring principle figure of MRC.

Accompanying drawing labelling: 1-integrating sphere; 2-PC display; 3-video camera to be measured; 4-PC cabinet; 5-test platform; 6-resolution target.

Detailed description of the invention

Understand for the ease of those of ordinary skill in the art and implement this utility model, below in conjunction with the drawings and the specific embodiments, this utility model being described in further detail.

If Fig. 1 is the test system based on equivalent illumination and Minimum resolvable contrast of the present utility model, test system is mainly made up of resolution card two parts of equivalent light source part and different contrast. When system starts, equivalent light source is placed on handbarrow, and the resolution card of different contrast adopts Magnet on the iron shelf of utility cart.

The same with the testing scheme of Johnson criteria with based on equivalent illumination with the testing scheme that MRC (Minimum resolvable contrast) operating distance is predicted based on equivalent illumination, include three steps equally: the evaluation procedure of the equivalence simulation of illumination, the test of video camera limiting performance and operating distance forecast model.

Operating distance for Extended Source Target still adopts target Equivalent strip pattern, it is assumed that bright respectively Lt and the Lb of target and background, and the intrinsic contrast C 0 of target and background is

C=(L_t-L_b)/(L_t+L_b)

To have spatial frequency f, depth-width ratio is 5: 1, the three band target patterns that brightness is Lt are in homogeneous background brightness Lb, observer just can differentiate (50% probability) when going out band target pattern by photo electric imaging system, the contrast C (f) of target and background is called photo electric imaging system Minimum resolvable contrast MRC (f, Lm) under spatial frequency f and scene average luminance Lm=(Lb+Lt)/2

$MRC(f,L_m)=\frac{{\mathrm{SNR}}_{th}\sqrt{2N_{av}+N_{ccd}}\sqrt{N_x\left(x\right)N_y\left(y\right)}}{2N_{av}\sqrt{t_c}{p}_x\left(x\right)p_y\left(y\right)}$

The measuring principle of MRC can be as shown in Figure 2. Fig. 2 controls to provide the band target of different contrast, spatial frequency by contrast. Colimated light system simulated target is in infinite point, projects on photo electric imaging system.

Its manufacturing specification of resolution target target is: the basic target line chart of each unit is by 3 target line compositions of horizontal and vertical, the length of target line is 5 times of width, live width and interval are equal, and 2 times that are spaced apart target line width of horizontal target line and vertical target line, the recursion common ratio of resolution target target line isNamely every 6 unit, target line width successively decreases half.

According to above-mentioned specification, be respectively adopted printing paper, common print paper collocation coloured silk beat, common print paper collocation powdered ink printing, the target obtained is imaging results under near-infrared. Consider from imaging effect, the resolution target that final choice common print paper (more coarse more good) inkjet printing pattern makes, make different contrast 6 altogether.

The detailed description of the invention of the above is better embodiment of the present utility model; not limit with this and of the present utility model be embodied as scope; scope of the present utility model includes being not limited to this detailed description of the invention, and all equivalences made according to the shape of this utility model, structure change all in protection domain of the present utility model.

Claims (2)

1. the test system based on equivalent illumination and Minimum resolvable contrast, it is characterized in that: described test system includes integrating sphere (1), PC display (2), video camera to be measured (3) and resolution target (6), and described resolution target (6) is fixed on resolution target lay down location; Described PC display (2) is connected to PC case (4); Described PC display (2) and video camera to be measured (3) connect, and are placed on test platform (5); Described PC case (4) is arranged on test platform (5) lower section; Described integrating sphere (1) and resolution target lay down location are separately positioned on corresponding handbarrow.

2. the test system based on equivalent illumination and Minimum resolvable contrast according to claim 1, it is characterized in that: the basic target line chart of each unit of described resolution target (6) is by 3 target line compositions of horizontal and vertical, the length of target line is 5 times of width, live width and interval are equal, 2 times that are spaced apart target line width of horizontal target line and vertical target line, the recursion common ratio of resolution target target line isNamely every 6 unit, target line width successively decreases half.