CN104792706A - Image-forming light measurement system based on position triangular wave frequency coded excitation of area array CCD (charge coupled device) - Google Patents

Abstract

The invention discloses an image-forming light measurement system based on position triangular wave frequency coded excitation of an area array CCD (charge coupled device). The image-forming light measurement system comprises a set of n*n monochromatic light sources, the area array CCD and a computer externally connected with the area array CCD, wherein the set of n*n monochromatic light sources with preset wavelengths are uniformly distributed on one side of a sample, and the area array CCD is arranged on the opposite side of the sample in a manner of corresponding to the monochromatic light sources. Triangular waves different in frequency and forming a double ratio relationship are adopted for driving each monochromatic light source in the set of monochromatic light sources, each pixel in the area array CCD receives a monochromatic light combination, penetrating through the sample, of each light source in the monochromatic light sources, and the computer is used for performing demodulation and separation on the monochromatic light combination to obtain contribution of each monochromatic light source to the monochromatic light combination Ilm, so that the sample can be subjected to image formation. The image-forming light measurement system realizes high-speed, large-information and high-precision measurement of image-forming light, and has the advantages of simple structure and circuit, low device and process requirements, easiness for debugging, high reliability and the like.

Description

The imaging measuring system that the position triangular wave frequency of area array CCD is code-excited

Technical field

The present invention relates to imaging measuring system field, particularly relate to the imaging measuring system that a kind of position triangular wave frequency of area array CCD is code-excited.

Background technology

By light, imaging is carried out to interior of articles in prior art, particularly imaging is carried out to inside of human body, there is the harmless outstanding advantages radiationless without wound, but not yet there is the imaging measuring system that can enter Clinical practice so far, its reason is that existing imaging measuring system precision is low, quantity of information is less, cannot meet the needs in practical application.

Summary of the invention

The invention provides the imaging measuring system that a kind of position triangular wave frequency of area array CCD is code-excited, present invention achieves the high-acruracy survey of high speed, the greatly imaging of information, meet the needs in practical application, described below:

The imaging measuring system that a kind of position triangular wave frequency of area array CCD is code-excited, described imaging measuring system comprises: one group of n × n monochromatic source, area array CCD, and the computing machine external with area array CCD, uniformly distribute in the side of sample n × n monochromatic source of one group of preset wavelength, and the corresponding monochromatic source of offside arranges area array CCD;

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each monochromatic source in one group of monochromatic source respectively, in area array CCD, each pixel-by-pixel basis receives each light source in monochromatic source and combines through the monochromatic light of sample, and computing machine carries out demodulation to monochromatic light combination and is separated and obtains each monochromatic source and combine I to monochromatic light _lmcontribution, accordingly can to imaging of samples.

Wherein, described monochromatic source is that square is uniformly distributed.Wherein, described monochromatic source is laser diode.

Another embodiment, described monochromatic source is monochrome photodiode.Another embodiment, described monochromatic source is that monochromatic filter plate is to the filtered monochromatic light of white light.

The beneficial effect of technical scheme provided by the invention is: the present invention adopts different frequency triangular wave to drive monochromatic source, the monochromatic light combination detected area array CCD is carried out demodulation and is separated and can obtains the contribution of each monochromatic source to area array CCD, carries out high precision image reconstruction accordingly to sample.Present invention achieves the high-acruracy survey of imaging of high speed, large information, and there is structure and circuit is simple, device and technological requirement is low, debugging easily, high reliability.

Accompanying drawing explanation

Fig. 1 is the structural representation of the code-excited imaging measuring system of the position triangular wave frequency of area array CCD;

Fig. 2 is monochromatic source provided by the invention, sample and area array CCD relative position schematic diagram.

In accompanying drawing, the list of parts representated by each label is as follows:

1: monochromatic source; 2: sample;

3: area array CCD.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below embodiment of the present invention is described further in detail.

Embodiment 1

The imaging measuring system that a kind of position triangular wave frequency of area array CCD is code-excited, see Fig. 1 and Fig. 2, described imaging measuring system comprises: one group of n × n monochromatic source 1 (representing with LD) and an area array CCD 3, n >=3 and (n is odd number for odd number, then middle light source or photosensitive device can be used as center line, are convenient to aim at arrangement, wherein, the concrete value of n is relevant to the cross-sectional area of sample 2, and the embodiment of the present invention does not limit this).Namely uniformly distribute in the side of sample 2 n × n monochromatic source 1 of one group of preset wavelength, and the corresponding monochromatic source 1 of offside arranges area array CCD 3, and monochromatic source 1 and area array CCD 3 are close to sample 2 and are installed.

Wherein, preferred monochromatic source 1 is uniformly distributed in square; This imaging measuring system also comprises the computing machine (not shown) external with area array CCD 3.

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each monochromatic source in one group of monochromatic source 1 respectively, in area array CCD 3, lm pixel-by-pixel basis receives each light source in monochromatic source 1 and combines I through the monochromatic light of sample 2 _lm, computing machine combines I to monochromatic light _lmcarry out demodulation to be separated and can to obtain each monochromatic source and combine I to monochromatic light _lmcontribution, imaging can be carried out to sample 2 accordingly.That is, according to the light intensity that lm pixel-by-pixel basis in area array CCD 3 receives, backprojection reconstruction obtains the transmission image of sample 2, according to the organizational information in graphical analysis sample 2, determines the scattering degree information of sample tissue.These concrete operations are this area proven technique, and the embodiment of the present invention does not repeat this.

Wherein, computing machine combines I to monochromatic light _lmcarry out demodulation separation and can obtain monochromatic light combination I _lmin each monochromatic source LD _jthe step of contribution be specially:

1) the highest frequency f to drive monochromatic source is supposed _max4M speed sampling f is carried out to photosignal _s=4M × f _max, obtain sampled signal x (m), wherein M be more than or equal to 1 positive integer;

$x\left(m\right)=\underset{i=0}{\overset{M-1}{\mathrm{\Σ}}}x(4\mathrm{lm}+i),l=\mathrm{0,1,2},......\left(1\right)$

2) computing machine will add up to the sampled signal in the positive and negative half period in each triangular wave cycle corresponding to each wavelength respectively, and accumulation result carries out asking difference operation;

That is, obtain cumulative sum by cumulative for the sampled value of the positive half period of each triangular wave in certain hour (an integer triangular wave cycle), the sampled value of the negative half period of each triangular wave is cumulative obtains cumulative sum, and these two cumulative sums are subtracted each other.

3) difference of each wavelength above-mentioned is carried out k cycle or an integral multiple k periodic accumulation, wherein:

$k=\frac{a\frac{1}{f_{\min }}}{\frac{1}{f_n}}---\left(2\right)$

In formula: f _minfor the low-limit frequency in excitation triangular wave; A is preset constant, value be more than or equal to 1 positive integer, a/f _minfor the cycle of lower sampling; f _nfor the triangular wave excitation frequency of handled wavelength.

To amplitude be x be sampled value, if uniform sampling N (>>1) puts and is averaged within the regular hour, the mean value obtained is

$\stackrel{\‾}{x}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\left[x_i\right]=\frac{1}{N}N\left(\right[x]+\mathrm{\Δ}{x}_i)=\left[x\right]+\mathrm{\Δ}{x}_i---\left(3\right)$

Wherein, [x] is that analog to digital converter quantizes x, is also the positive integer that round off rounding obtains.X _ithe amplitude of i-th, [x _i] be that analog to digital converter is to x _iquantizing, is also the positive integer that round off rounding obtains.

(3) formula shows, the signal sampling one being compared to " totally " is repeatedly averaged, and can not improve its precision, and the error of the mean value obtained is identical with the error of unitary sampling, is Δ x _i.

If to amplitude be x be sampled sawtooth wave, within the regular hour, uniform sampling N (>>1) puts and is averaged equally, and the mean value obtained is

$\stackrel{\‾}{x}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\left[x_i\right]=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}[m_i+\mathrm{\Δ}{x}_i]---\left(4\right)$

Wherein, x _i=m _i+ Δ x _i, m _i=[x _i].Also be m _ithat rounding obtains positive integer, and Δ x _iit is " at random " error of losing after being rounded.

(4) formula can utilize arithmetic series sum formula to obtain further:

$\begin{array}{c}\stackrel{\‾}{x}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{m}_i+\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{\Δ}{x}_i=\frac{1}{N}\frac{1}{2}(0+[x\left]\right)N+\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{\Δ}{x}_i\\ =\frac{1}{2}\left[x\right]+\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{\Δ}{x}_i\end{array}---\left(5\right)$

(5) the last item in formula is the value after quantizing, although less than the result of (3) formula half, according to theory of errors, the precision of data does not change because being multiplied by a fixing non-zero constant.But be the random number of zero-mean in one next, compare will reduce in (3) formula doubly, therefore, the effect of the precision that can be improved equally after over-sampling is carried out to sawtooth wave or triangular wave pumping signal, and do not need another external high-frequency disturbing signal.

The embodiment of the present invention is to the model of each device except doing specified otherwise, and the model of other devices does not limit, as long as can complete the device of above-mentioned functions.

Embodiment 2

The imaging measuring system that the position triangular wave frequency of area array CCD is code-excited, see Fig. 1 and Fig. 2, this embodiment is described for laser diode as monochromatic source 1.

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each laser diode in one group of monochromatic source 1 respectively, in area array CCD 3, each pixel lm to receive in monochromatic source 1 each laser diode through the monochromatic light combination I of sample 2 _lm, computing machine combines I to monochromatic light _lmcarry out demodulation to be separated and can to obtain each laser diode and combine I to monochromatic light _lmcontribution, imaging can be carried out to sample 2 accordingly.

The embodiment of the present invention is to the model of each device except doing specified otherwise, and the model of other devices does not limit, as long as can complete the device of above-mentioned functions.

Embodiment 3

The imaging measuring system that the position triangular wave frequency of area array CCD is code-excited, see Fig. 1 and Fig. 2, this embodiment is described for monochrome photodiode as monochromatic source 1.

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each monochrome photodiode in one group of monochromatic source 1 respectively, in area array CCD 3, each pixel lm to receive in monochromatic source 1 each monochrome photodiode through the monochromatic light combination I of sample 2 _lm, computing machine combines I to monochromatic light _lmcarry out demodulation to be separated and can to obtain each monochrome photodiode and combine I to monochromatic light _lmcontribution, imaging can be carried out to sample 2 accordingly.

The embodiment of the present invention is to the model of each device except doing specified otherwise, and the model of other devices does not limit, as long as can complete the device of above-mentioned functions.

Embodiment 4

The imaging measuring system that the position triangular wave frequency of area array CCD is code-excited, see Fig. 1 and Fig. 2, this embodiment is described as monochromatic source 1 for monochromatic filter plate the filtered monochromatic light of white light.

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each monochromatic filter plate in one group of monochromatic source 1 to the filtered monochromatic light of white light respectively, in area array CCD 3, each pixel lm to receive in monochromatic source 1 each monochromatic light through the monochromatic light combination I of sample 2 _lm, computing machine combines I to monochromatic light _lmcarry out demodulation to be separated and can to obtain each monochromatic light and combine I to monochromatic light _lmcontribution, imaging can be carried out to sample 2 accordingly.

The embodiment of the present invention is to the model of each device except doing specified otherwise, and the model of other devices does not limit, as long as can complete the device of above-mentioned functions.

It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. the imaging measuring system that the position triangular wave frequency of area array CCD is code-excited, described imaging measuring system comprises: one group of n × n monochromatic source, area array CCD, and the computing machine external with area array CCD, is characterized in that,

Uniformly distribute in the side of sample n × n monochromatic source of one group of preset wavelength, and the corresponding monochromatic source of offside arranges area array CCD;

Adopt different frequency and become the triangular wave of 2 times of ratio to drive each monochromatic source in one group of monochromatic source respectively, in area array CCD, each pixel-by-pixel basis receives each light source in monochromatic source and combines through the monochromatic light of sample, and computing machine carries out demodulation to monochromatic light combination and is separated and obtains each monochromatic source and combine I to monochromatic light _lmcontribution, accordingly can to imaging of samples.

2. the imaging measuring system that the position triangular wave frequency of a kind of area array CCD according to claim 1 is code-excited, is characterized in that, described monochromatic source is that square is uniformly distributed.

3. the imaging measuring system that the position triangular wave frequency of a kind of area array CCD according to claim 1 is code-excited, is characterized in that, described monochromatic source is laser diode.

4. the imaging measuring system that the position triangular wave frequency of a kind of area array CCD according to claim 1 is code-excited, is characterized in that, described monochromatic source is monochrome photodiode.

5. the imaging measuring system that the position triangular wave frequency of a kind of area array CCD according to claim 1 is code-excited, is characterized in that, described monochromatic source is that monochromatic filter plate is to the filtered monochromatic light of white light.