CN202889533U - Color image quality evaluation detection system for space camera - Google Patents

Abstract

The utility model relates to a color image quality evaluation detection system for a space camera, and the system comprises a light source, a target unit, a collimating optical system, a spectrum information acquisition unit and a control unit, wherein the target unit, the collimating optical system and the spectrum information acquisition unit are arranged in sequence in an emergent light path of the light source, and the control unit is connected with the spectrum information unit. The utility model provides a color image quality evaluation detection system for the space camera, which can rebuild evaluation on color accuracy of an image of a space color camera and has high public trust and high stability.

Description

Space camera color image quality evaluation detection system

Technical field

The utility model belongs to the optical detection field, relate to a kind of space camera color image quality evaluation detection system, relate in particular to a kind of space camera image and carry out the colored rear space camera color image quality evaluation detection system that its coloured image color accuracy is estimated of restoring.

Background technology

Colour vision determines that by illumination, body surface form and vision system are common they have conclusive impact to color evaluation.Solve the metric question of color, at first must find the corresponding relation between ambient light stimulation and the colour perception amount, in order to indirectly obtain the colour perception amount by the measurement to the light radiation physical quantity.Therefore used the method for psychophysics, the subjects such as comprehensive optics, vision physiological, visual psychology, by a large amount of scientific experiments, the researcher has set up the colorimetry system, has tentatively solved color is quantitatively described problem with criterion.Technology through Commission Internationale De L'Eclairage (CIE) is coordinated, and makes it standardization, has set up cie color and has learned system, realizes representing color, replacing human eye to carry out the measurement of color with physical apparatus with quantity.

In the moon and survey of deep space activity that the mankind carry out, surveying and make an inspection tour prospecting around detection, soft landing is topmost detection means, the first step that another celestial body carries out scientific exploration is on the spot set foot in soft landing especially, from the substantivity of obtaining detection data and rich angle, soft landing and to make an inspection tour prospecting be that other detection form is irreplaceable, in the moon and survey of deep space technical development in occupation of consequence very.

The space color camera will be more and more general aspect following celestial body soft landing, because it has more colouring information at space black and white camera more traditional aspect the visual information digitlization, also more meets human eye to the needs of image.

Now, weighing aspect colored reconstructed image quality good and bad, but still following traditional mode in the past.Although considering the main body of information is image, yet the final receptor of image is the people, the quality that human eye is experienced the coloured image perceptual quality just can become the important indicator of measurement system.Visual method is main color evaluation means, but this method is subject to the impact of the aspect factors such as lighting condition, background luminance, material gloss, texture, size shape and operating personnel's vision and psychological difference, and accuracy is low, consistency is poor.Even getting a plurality of different personnel's average judgement even same observer repeatedly repeats to judge that its result still sizable discreteness and randomness can occur.And the subjective assessment test is not only loaded down with trivial details, consuming time, carries out also very expensive.This more can't obtain feedback information by test so that the space color camera in the development later stage, can't be tested and be estimated the color accuracy of its reconstructed image by effective means, improves the color rendition algorithm, obtains rebuilding more really coloured image.

Just because of the deficiency of subjective assessment, people come to realise the coloured image quantitative description and measure the importance of estimating.And only have the color accuracy of colored reconstructed image is carried out the quantification test, effective whole colored flow process and the method for rebuilding, the accurate coloured image of obtain more truly, easier quilt masses accepting of instructing of ability.

The utility model content

In order to solve the problems referred to above that exist in the background technology, the utility model provide a kind of can be to the evaluation of space color camera image reconstruction color accuracy, the space camera color image quality evaluation detection system that public trust is high and stability is strong.

Technical solution of the present utility model is: the utility model provides a kind of space camera color image quality evaluation detection system, and its special character is: described space camera color image quality evaluation detection system comprises light source, object element, collimating optical system, spectral information collecting unit and control unit; Described object element, collimating optical system, spectral information collecting unit are successively set on the emitting light path of light source; Described control unit links to each other with the spectral information unit.

Above-mentioned light source is the standard illuminants light source that the CIE recommend adoption of stabilized light source can be provided for detection system; The standard illuminants light source of described CIE recommend adoption comprises D55, D65 and D75 at least; The correlated colour temperature of described D55 is 5503K; The correlated colour temperature of described D65 is 6504K; The correlated colour temperature of described D75 is 7504K.

Above-mentioned object element is Standard colour board.

Above-mentioned collimating optical system is the off axis reflector parallel light tube; Described object element is arranged on the focal plane of off axis reflector parallel light tube; Described light source reflexes to the off axis reflector parallel light tube by object element.

Above-mentioned off axis reflector parallel light tube is that bore is Φ 100mm, and focal length is 1000mm off axis reflector parallel light tube.

Above-mentioned off axis reflector parallel light tube comprises off axis paraboloid mirror primary mirror and iris diaphgram; Described object element is arranged on the focal plane of off axis paraboloid mirror primary mirror; Described light source reflexes on the off axis paraboloid mirror primary mirror by object element; Described iris diaphgram is arranged on the light-emitting window place of off axis reflector parallel light tube; Described iris diaphgram is the stray light diaphragm that disappears.

Above-mentioned spectral information collecting unit comprises electronic control translation stage and spectral radiant emittance meter; Described spectral radiant emittance meter and space camera to be measured are separately positioned on the electronic control translation stage; Described control unit links to each other with spectral radiant emittance meter and space to be measured color camera respectively; Described control unit is controlled respectively spectral radiant emittance meter or space camera to be measured move to collimating optical system at electronic control translation stage light-emitting window place.

Above-mentioned control unit is controllor for step-by-step motor.

Above-mentioned space camera color image quality evaluation detection system also comprises the data processing unit that links to each other with the spectral information collecting unit; Described data processing unit is to be realized by the computer software programs of the algorithm that is packaged with CIE DE2000 colour difference formula.

Above-mentioned space camera color image quality evaluation detection system also comprises the display unit that links to each other with data processing unit.

The utility model has the advantages that:

The utility model provides a kind of space camera coloured image evaluation test system, and this test macro is comprised of light-source system, colimated light system, object element, spectra collection unit, control unit, data processing unit and display unit.When standard sources illuminated object element, control unit moved to the spectral radiant emittance meter first parallel light tube light-emitting window place and carries out the spectral information collection; Then control unit shifts out the spectral radiant emittance meter, the detected space color camera is moved to parallel light tube light-emitting window place gather image.Data processing unit calculates resulting data, obtains rebuilding the aberration of coloured image, and by display output result of calculation and realtime graphic.Particularly, the utlity model has following advantage:

1, the utility model passes through spectral radiant emittance instrumentation amount colimated light system light-emitting window spoke brightness value, and conversion obtains the spectral tristimulus value of light-emitting window.The space color camera to the object element imaging, behind the reconstruction coloured image, directly obtains the image tristimulus values from display unit at light-emitting window.Utilize CIE DE2000 uniform colour space, carry out the calculating of aberration, can be poor from luminosity equation, chroma, the many-side such as hue difference evaluates the color of image accuracy, has very high public trust.Filled up domestic and can't pass through objective data, the blank that coloured image after space camera rebuild is estimated, the space camera field is real at home belongs to pioneering, and the uncertain factor of having avoided Traditional Man to estimate has substituted subjective evaluation with objective data evaluation.

2, the light source selection standard working flare of the utility model employing has improved the stability of test, and object element selection standard colour table ColorCheckDC has very high color saturation, uniformity, can improve the stability of test; High accuracy spectral radiant emittance meter is selected in the spectra collection unit, greatly improves measuring accuracy; The place is equipped with iris diaphgram at colimated light system outgoing window, can adjust according to the clear aperture size of different spaces camera the bore of colimated light system outgoing beam, to satisfy the needs of different cameral test; The place is equipped with iris diaphgram at colimated light system outgoing window, can effectively block stray light, improves measuring accuracy; Select the high precision electric control translation stage, carry tested camera and spectral radiant emittance meter and alternately move to colimated light system light-emitting window place, guaranteed the repeatability of test.

Description of drawings

Fig. 1 is the structural representation of space camera color image quality evaluation detection system provided by the utility model;

Wherein:

The 1-light source; The 2-Standard colour board; 3-off axis paraboloid mirror primary mirror; The 4-iris diaphgram; 5-detected space camera; 6-spectral radiant emittance meter; The 7-electronic control translation stage; The 8-control unit; The 9-data processing unit; The 10-display unit; The 11-collimating optical system.

Embodiment

Referring to Fig. 1, the utility model provides a kind of space camera color image quality evaluation detection system, and this evaluation detection system comprises light source 1, object element, collimating optical system 11, spectral information collecting unit and control unit 8; Object element, collimating optical system 11, spectral information collecting unit are successively set on the emitting light path of light source 1; Control unit 8 links to each other with the spectral information unit.

Light source 1 is the standard illuminants light source that the CIE recommend adoption of stabilized light source can be provided for detection system; The standard illuminants light source of CIE recommend adoption comprises D55, D65 and D75 at least; The correlated colour temperature of D55 is 5503K; The correlated colour temperature of D65 is 6504K; The correlated colour temperature of D75 is 7504K.

Object element is Standard colour board 2.

Collimating optical system 11 is off axis reflector parallel light tubes; Object element is arranged on the focal plane of off axis reflector parallel light tube; Light source 1 reflexes to the off axis reflector parallel light tube by object element.

The off axis reflector parallel light tube is that bore is Φ 100mm, and focal length is 1000mm off axis reflector parallel light tube.

The off axis reflector parallel light tube comprises the parabolic primary mirror 3 of vertical shaft and iris diaphgram 4; Object element is arranged on the focal plane of the parabolic primary mirror 3 of vertical shaft; Light source 1 reflexes on the parabolic primary mirror 3 of vertical shaft by object element; Iris diaphgram 4 is arranged on the light-emitting window place of off axis reflector parallel light tube; Iris diaphgram 4 is the stray light diaphragms that disappear.

The spectral information collecting unit comprises electronic control translation stage 7 and spectral radiant emittance meter 6; Spectral radiant emittance meter 6 and space camera to be measured are separately positioned on the electronic control translation stage 7; Control unit 8 links to each other with spectral radiant emittance meter 6 and space to be measured color camera 5 respectively; Control unit 8 is controlled respectively spectral radiant emittance meter 6 or space camera to be measured move to collimating optical system 11 at electronic control translation stage 7 light-emitting window place.

Control unit 8 is controllor for step-by-step motor.

Space camera color image quality evaluation detection system also comprises the data processing unit 9 that links to each other with the spectral information collecting unit; Data processing unit 9 is to be realized by the computer software programs of the algorithm that is packaged with CIE DE2000 colour difference formula.

Space camera color image quality evaluation detection system also comprises the display unit 10 that links to each other with data processing unit 9.

The course of work of the present utility model is: the irradiation that standard illuminants light source 1 sends is on Standard colour board 2; Standard colour board 2 is diffuse reflector, is positioned on the focal plane of colimated light system 11, beat again on colimated light system primary mirror 3 through the light of Standard colour board reflection, with collimated light beam from the colimated light system outgoing; The place is provided with iris diaphgram 4 at the outgoing window, both has been used for the bore of control collimated light beam, can also suppress stray light; Control unit 8 moves to colimated light system 11 light-emitting window places by control electronic control translation stage 7 and bearing space camera 5, and Standard colour board 2 is carried out memory image after the imaging; Control unit 8 moves electronic control translation stage 7 motions, and spectral radiant emittance meter 6 is moved into colimated light system 11 light-emitting window places, gathers exit spectral radiance value; Image to the space camera collection carries out the colour recovery, and extracts the tristimulus values of restoring rear image; The spoke brightness value that the spectral radiant emittance meter is gathered calculates, and obtains the standard tristimulus values at light-emitting window place; And then carry out computing in the numerical value substitution CIE DE2000 colour difference formula that two equipment are obtained, and obtaining restoring the aberration between coloured image and the actual value, above flow process is all carried out in the data processing unit 9 again; Display unit 10 can display space collected by camera image, also result of calculation can be output into form.

Specific works principle of the present utility model is as follows:

Standard illuminants light illuminating Standard colour board, through forming collimated light beam behind the colimated light system collimation, the spectral radiant emittance meter of signal gathering unit gathers the spoke brightness value at colimated light system light-emitting window place, by calculating working flare relative spectral power distribution function S (λ), and then be calculated as follows the tristimulus values X1 of cie color system, Y1, the Z1 at light-emitting window place.

In the formula:

Be Color Stimulus Function, namely enter the light energy that human eye produces color perception.

Be CIE specified standard colourity observer's spectral tristimulus value, k is normalization coefficient.

When testee is non-self-luminous object:

Wherein ρ (λ) is the spectral reflectance of object, and S (λ) is that the relative spectral power of standard illuminants light source distributes.Spectral reflectance ρ (λ) with the tested colour table of spectrophotometer measurement.

By mobile electronic control translation stage with tested mobile camera moving to colimated light system light-emitting window place, Standard colour board is carried out imaging, restore the coloured image of Standard colour board by the colored composition algorithm of camera self, read Standard colour board R, G, B value from display unit, this numerical value is and restores coloured image tristimulus values X2, Y2, Z2.

The coloured image tristimulus values of obtaining more than the data processing unit basis is calculated, and at last evaluation result is passed through display unit Output rusults form.Below be the Correlation method for data processing algorithm:

Utilize CIE DE2000 uniform colour space, carry out the evaluation of aberration, metric system lightness L ^*, metric system chromaticity a ^*, b ^*:

$\left\{\begin{array}{c}{L}^{*}=\left\{\begin{array}{cc}116{(Y/Y_n)}^{1/3}-16& (Y/Y_n>0.008856)\\ 903.3Y/Y_n& (Y/Y_n\≤0.008856)\end{array}\right.\\ a^{*}=\left\{\begin{array}{cc}500[{(X/X_n)}^{1/3}-{(Y/Y_n)}^{1/3}]& (X/X_n>0.008856)\\ 3893.5[X/X_n-Y/Y_n]& (X/X_n\≤0.008856)\end{array}\right.\\ b^{*}=\left\{\begin{array}{cc}200[{(Y/Y_n)}^{1/3}-{(Z/Z_n)}^{1/3}]& (Z/Z_n>0.008856)\\ 1557.4[Y/Y_n-Z/Z_n]& (Z/Z_n\≤0.008856)\end{array}\right.\end{array}\right.$

(X, Y, Z) is the tristimulus values of sample of colour, (X _n, Y _n, Z _n) be that the CIE standard illuminants is radiated on the perfectly diffusion reflector, reflex to the white tristimulus values in observer's eye.

The chroma of color

$C_{\mathrm{ab}}^{*}={(a^{*2}+b^{*2})}^{1/2}$

Calculate a of a '=(1+G) ^*,

H '=arctan (b ^*/ a ')

Wherein $G=0.5\{1-{\{{\left(\stackrel{\‾}{C_{\mathrm{ab}}^{*}}\right)}^7/[{\left(\stackrel{\‾}{C_{\mathrm{ab}}^{*}}\right)}^7+25\left]\right\}}^{1/2}\},$ It is the arithmetic mean of two tinctorial pattern chroma values.

Calculate $\mathrm{\&Delta;L}={\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA00002289075400011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1^{*}-L_2^{*},$ ΔC′=C′ ₁-C′ ₂，ΔL′=h′ ₁-h′ ₂， ${\mathrm{\&Delta;H}}^{\&prime;}=2\sin \left(\frac{{\mathrm{\&Delta;h}}^{\&prime;}}{2}\right)\sqrt{{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HDA00002289075400011.png"\; state="\{\{state\}\}">C</figure-callout>}}_1^{\&prime;}{C}_2^{\&prime;}}$

Colorimetry formula between two colors is Δ E ₀₀

${\mathrm{\&Delta;E}}_{00}=\sqrt{{\left(\frac{{\mathrm{\&Delta;L}}^{*}}{k_L{S}_L}\right)}^2+{\left(\frac{{\mathrm{\&Delta;C}}^{\&prime;}}{k_C{S}_C}\right)}^2+{\left(\frac{{\mathrm{\&Delta;H}}^{\&prime;}}{k_H{S}_H}\right)}^2+R_T\left(\frac{{\mathrm{\&Delta;C}}^{\&prime;}}{k_C{S}_C}\right)\left(\frac{{\mathrm{\&Delta;H}}^{\&prime;}}{k_H{S}_H}\right)}$

$S_L=1+\frac{0.015{({\stackrel{\&OverBar;}{L}}^{*}-50)}^2}{\sqrt{20+{({\stackrel{\&OverBar;}{L}}^{*}-50)}^2}},S_C=1+0.045{\stackrel{\&OverBar;}{C}}^{\&prime;},S_H=1+0.015{\stackrel{\&OverBar;}{C}}^{\&prime;}T$

R _T=-sin（2Δθ)R _C, $R_C=2\sqrt{\frac{{\left({\stackrel{\&OverBar;}{C}}^{\&prime;}\right)}^7}{{\left({\stackrel{\&OverBar;}{C}}^{\&prime;}\right)}^7+{25}^7}}$

By the value of chromatism Δ E that obtains at last ₀₀Colored restored image to space camera is estimated, and NBS is the aberration unit of colour difference formula, and following table is the visual sensation of NBS aberration unit:

Space camera color image quality evaluation detection system of the present utility model, count benchmark with standard illuminants light source, Standard colour board, spectral radiant emittance, utilize CIE DE2000 uniform color space colour difference formula for instructing, calculate first the trichromatic coordinates value at colimated light system light-emitting window place, obtain again the combined color image trichromatic coordinates value at colimated light system light-emitting window place by the colored composition algorithm of camera, carry out the evaluation of color accuracy by colour difference formula.

When the method is estimated at color composite image, abandoning tradition " visual method " is estimated subjectivity and the uncertainty of coloured image, with chromatism data color composite image is carried out objective, quantitative evaluation, surmount traditional constraint, synthetic with a kind of brand-new pattern guiding space color camera coloured image, worth quilt is learnt and is used for reference.

Space camera color image quality evaluation detection system of the present utility model, the color that is not only applicable to the space color camera restores the evaluation of accuracy, also has very strong applicability in association areas such as civilian, aviations.

Present stage, civilian color digital camera is very universal, and the list of all kinds, each producer is anti-, the card camera emerges in an endless stream.Japan's technology in this respect is particularly outstanding, and the camera of the brands such as Canon, Nikon is flooded with the market in the whole world.The competition of each manufacturer on correlation technique is also unusually fierce, because civil camera just is used for taking, the requirements such as not mapping, measurement, so survey and draw, measure mutually confidential simple in the control aspect the camera aberration, but the color saturation of coloured image, gorgeous degree then are the major criterions of weighing the digital camera quality.Although the adjustment that a lot of manufacturers are artificial parameter in the coloured image composition algorithm so that the truer image of photographic images is more gorgeous, in the hope of winning the satisfaction of user Geng Gao.But in the application of space color camera, judgment criteria that but must strict image color accuracy is verified repeatedly to the image color restoration algorithm so that restored image with truly have between the scenery objective, truly, correspondence accurately.This has just proposed very high requirement to the standard of space camera color image quality evaluation.And the utility model just for above problem provide one objective, rationally, evaluation criterion accurately, replace subjective judgement with data, solved the problem of space camera coloured image evaluation aspect.

Claims (10)

1. space camera color image quality evaluation detection system, it is characterized in that: described space camera color image quality evaluation detection system comprises light source, object element, collimating optical system, spectral information collecting unit and control unit; Described object element, collimating optical system, spectral information collecting unit are successively set on the emitting light path of light source; Described control unit links to each other with the spectral information unit.

2. space camera color image quality evaluation detection system according to claim 1, it is characterized in that: described light source is the standard illuminants light source that the CIE recommend adoption of stabilized light source can be provided for detection system; The standard illuminants light source of described CIE recommend adoption comprises D55, D65 and D75 at least; The correlated colour temperature of described D55 is 5503K; The correlated colour temperature of described D65 is 6504K; The correlated colour temperature of described D75 is 7504K.

3. space camera color image quality evaluation detection system according to claim 2, it is characterized in that: described object element is Standard colour board.

4. according to claim 1 and 2 or 3 described space camera color image quality evaluation detection systems, it is characterized in that: described collimating optical system is the off axis reflector parallel light tube; Described object element is arranged on the focal plane of off axis reflector parallel light tube; Described light source reflexes to the off axis reflector parallel light tube by object element.

5. space camera color image quality evaluation detection system according to claim 4, it is characterized in that: described off axis reflector parallel light tube is that bore is Φ 100mm, and focal length is 1000mm off axis reflector parallel light tube.

6. space camera color image quality evaluation detection system according to claim 5, it is characterized in that: described off axis reflector parallel light tube comprises off axis paraboloid mirror primary mirror and iris diaphgram; Described object element is arranged on the focal plane of off axis paraboloid mirror primary mirror; Described light source reflexes on the off axis paraboloid mirror primary mirror by object element; Described iris diaphgram is arranged on the light-emitting window place of off axis reflector parallel light tube; Described iris diaphgram is the stray light diaphragm that disappears.

7. space camera color image quality evaluation detection system according to claim 6, it is characterized in that: described spectral information collecting unit comprises electronic control translation stage and spectral radiant emittance meter; Described spectral radiant emittance meter and space camera to be measured are separately positioned on the electronic control translation stage; Described control unit links to each other with spectral radiant emittance meter and space to be measured color camera respectively; Described control unit is controlled respectively spectral radiant emittance meter or space camera to be measured move to collimating optical system at electronic control translation stage light-emitting window place.

8. space camera color image quality evaluation detection system according to claim 7, it is characterized in that: described control unit is controllor for step-by-step motor.

9. space camera color image quality evaluation detection system according to claim 8, it is characterized in that: described space camera color image quality evaluation detection system also comprises the data processing unit that links to each other with the spectral information collecting unit; Described data processing unit is to be realized by the computer software programs of the algorithm that is packaged with CIE DE2000 colour difference formula.

10. space camera color image quality evaluation detection system according to claim 9, it is characterized in that: described space camera color image quality evaluation detection system also comprises the display unit that links to each other with data processing unit.

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