Summary of the invention
Fundamental purpose of the present invention is to provide a kind of can reduce the workload measuring gamma curves of liquid crystal spatial light modulator, writes the method and system that image just can obtain the gamma curve of LCD space light modulator.
In order to achieve the above object, the present invention proposes a kind of method measuring gamma curves of liquid crystal spatial light modulator, and the method comprises the following steps:
In LCD space light modulator, write image, image comprises main viewing area and is positioned at two secondary display area of both sides, main viewing area, and main viewing area comprises the first standard grayscale information, and secondary display area comprises the second standard grayscale information;
LCD space light modulator is filtered the second standard grayscale information and the first standard grayscale information is converted to test half-tone information and outputs to photoelectric sensor;
The test half-tone information that photoelectric sensor obtains is normalized, utilizes normalization result to draw gamma curve
Preferential, described first standard grayscale information and described second standard grayscale information all comprise multiple standard grayscale value, the number of the standard grayscale value that the number of the standard grayscale value that described first standard grayscale information comprises comprises more than described second standard grayscale value information.
Preferential, the standard grayscale value of described image is included in the two-dimensional matrix of a 256*n, and often row gray-scale value increases progressively continuously with 0-255 order, and wherein, n is natural number.
Preferential, be describedly normalized test half-tone information, the step utilizing the result after normalization to draw gamma curve comprises:
Determine the standard grayscale value corresponding with each test gray-scale value in described test half-tone information;
By test gray-scale value divided by the standard grayscale value of correspondence, using its result as ordinate, standard grayscale value is set up coordinate system as horizontal ordinate, draw gamma curve.
Preferential, describedly determine that the concrete steps of the standard grayscale value corresponding with described test gray-scale value are:
Determine the maximal value X of the standard grayscale value writing LCD space light modulator;
Determine the number Y of the test gray-scale value that photoelectric sensor receives, the test gray-scale value that the number Y of described test gray-scale value equals first non-zero that photoelectric sensor receives adds 1 to the number of the test gray-scale value of last non-zero;
The spacing value Z between standard grayscale value is calculated, Z=X/ (Y-1) according to X and Y;
Calculate the standard grayscale value An corresponding to test gray-scale value according to spacing value Z, An=Z*m, m are the integer being more than or equal to 0 and being less than Y.
Present invention also offers a kind of system measuring gamma curves of liquid crystal spatial light modulator, comprise the light source, LCD space light modulator and the photoelectric sensor that sequentially arrange along light path, described light source output beam enters described photoelectric sensor through described LCD space light modulator, the test half-tone information that described photoelectric sensor exports for receiving LCD space light modulator.
Preferential, be provided with the beam expanding lens of expanded light beam diameter between the LCD space light modulator of described system and light source, between described photoelectric sensor and LCD space light modulator, be provided with the convex lens for convergent beam.
Preferential, be provided with front polaroid between described LCD space light modulator and light source, between the photoelectric sensor of described system and LCD space light modulator, be provided with rear polarizer.
Preferential, front half-wave plate is provided with between described LCD space light modulator and described front polaroid, rear half-wave plate is provided with between described LCD space light modulator and described rear polarizer, be provided with attenuator and outer half-wave plate between described light source and described front polaroid, outer half-wave plate is between attenuator and front polaroid.
Preferential, described photoelectric sensor is charge coupled cell CCD.
The method and system of the measurement gamma curves of liquid crystal spatial light modulator that the present invention proposes, photoelectric sensor is utilized to receive the gray-scale value of image, after data normalization process, disposable generation gamma curve, relative to the mode of the reception output information of energy meter, eliminate the number of times at LCD space light modulator write gray level image, decrease the workload measuring gamma curve, in addition, relative to the energy value measured with energy meter, the data stability of the gray-scale value that quantizes received with photoelectric sensor is also higher.In addition, the present invention adds secondary display area to the image that photoelectric sensor receives, and eliminates the impact that image diffraction reads photoelectric sensor data, improves the accuracy that photoelectric sensor data reads further.
Embodiment
The principle that the present invention measures gamma curves of liquid crystal spatial light modulator is: on the one hand, and what gamma curve reflected is under different gray-scale value, and input light is by the change of energy after LCD space light modulator; On the other hand, the image that photoelectric sensor obtains, the different gray-scale values reaction of image be the change of energy, energy more high-gray level value is also larger, and the two is directly proportional.
As shown in Figure 1, one embodiment of the invention proposes a kind of method measuring gamma curves of liquid crystal spatial light modulator, comprising:
Step S1, writes image in LCD space light modulator, and image comprises main viewing area and is positioned at two secondary display area of both sides, main viewing area, and main viewing area comprises the first standard grayscale information, and secondary display area comprises the second standard grayscale information.
Described first standard grayscale information and described second standard grayscale information all comprise multiple standard grayscale value, the number of the standard grayscale value that the number of the standard grayscale value that described first standard grayscale information comprises comprises more than described second standard grayscale value information.The standard grayscale value of described image is included in the two-dimensional matrix of a 256*n, and often row gray-scale value increases progressively continuously with 0-255 order, and wherein, n is natural number.
In the present embodiment, image in write LCD space light modulator as shown in Figures 2 and 3, first standard grayscale packets of information of the main viewing area of this image is containing 256*256 gray-scale value, be included in the two-dimensional matrix of a 256*256, this every provisional capital of two dimensional gray matrix be comprise identical from 0 to 255 256 gray-scale values, the gray-scale value of any a line is all from left to right according to the order arrangement that the gray-scale value size on to be 0 (black rank) to gray-scale value by gray-scale value be 255 (white rank) increases progressively.Second standard grayscale information of two secondary display area of this image all comprises 256*51 gray-scale value, is included in the two-dimensional matrix of a 256*51.The described every provisional capital of two dimensional gray matrix being positioned at secondary display area on the left of main viewing area comprises 51 gray-scale values from 50 to 0, and namely the gray-scale value of a line is all from left to right according to the order arrangement that the gray-scale value size on to be 50 (GTGs) to gray-scale value by gray-scale value be 0 (black rank) is successively decreased arbitrarily.The described every provisional capital of two dimensional gray matrix being positioned at secondary display area on the right side of main viewing area comprises 51 gray-scale values from 255 to 205, and namely the gray-scale value of a line is all from left to right according to the order arrangement that the gray-scale value size of to be 255 (white rank) to gray-scale values by gray-scale value be 205 (GTGs) is successively decreased arbitrarily.
Wherein, according to the needs of practical operation, the two dimensional gray matrix of the main viewing area of described image also can be all from right to left according to the order arrangement that gray-scale value size increases progressively at the gray-scale value of any a line, accordingly, the two dimensional gray matrix of the secondary display area of described image is all from right to left according to the order arrangement that gray-scale value size is successively decreased at the gray-scale value of any a line.
As shown in Figure 2, this image contains the standard grayscale value measuring gamma curves of liquid crystal spatial light modulator, this standard grayscale value is exactly the gray-scale value by described two-dimensional matrix regular distribution, the described main viewing area of image containing the first standard grayscale information is evenly imaged on the pixel planes of LCD space light modulator, input light enters all pixels that LCD space light modulator illuminates LCD space light modulator, LCD space light modulator receives the first standard grayscale information of the write main viewing area of image, input light containing write image main viewing area first standard grayscale information becomes to export light through the modulation conversion of LCD space light modulator.
Step S2, LCD space light modulator is filtered the second standard grayscale information and the first standard grayscale information is converted to test half-tone information and outputs to photoelectric sensor.Described test half-tone information comprises multiple test gray-scale value, each test gray-scale value and the first standard grayscale value one_to_one corresponding.Described photoelectric sensor is charge coupled cell CCD.First standard grayscale information of described image becomes to export light and contains test half-tone information after the modulation conversion of LCD space light modulator, and the test half-tone information that the present embodiment obtains contains all data of drawing gamma curve.In the present embodiment, charge coupled cell CCD reads wherein any a line of write image when obtaining the test half-tone information of described image, as described in Figure 4, when reading standard grayscale value and being the gray areas of 0, the test gray-scale value received also is 0, entirely black background gray-scale value after denoising is 0, the corresponding test gray-scale value received of gray areas of each standard grayscale value, the difference reaction of this test gray-scale value and the standard grayscale value characteristic of LCD space light modulator self, collect the gamma curve that these data can draw LCD space light modulator.
Step S3, is normalized the test half-tone information that photoelectric sensor obtains, and utilizes normalization result to draw gamma curve.
When drawing gamma curve according to the test half-tone information received and known standard grayscale information, first each test gray-scale value in described test half-tone information is normalized, normalization is a kind of mode simplifying calculating, under guarantee does not affect the prerequisite of the implication of data own, calculating can be made to become simple and direct.
As shown in Figure 5, the step S3 utilizing normalization result to draw gamma curve comprises:
Step S31, determines the standard grayscale value corresponding with each test gray-scale value in described test half-tone information;
Step S32, by test gray-scale value divided by the standard grayscale value of correspondence, using its result as ordinate, sets up coordinate system using standard grayscale value as horizontal ordinate, draws gamma curve.
In the present embodiment, by the standard grayscale value of test gray-scale value divided by correspondence, the gray-scale value that standard grayscale value i.e. CCD can receive in theory, by test gray-scale value divided by after the standard grayscale value of correspondence, can obtain corresponding normalization result, these distribution of results are between 0-1.
In practice, not 256 all gray-scale values of read test gray-scale value, that is, test gray-scale value and the standard grayscale value of reception are not that pointwise is corresponding, therefore, also need the position of the standard grayscale value determining the test gray-scale value that correspondence receives.
As shown in Figure 6, determine that the step S31 of the standard grayscale value corresponding with test gray-scale value comprises:
Step S311, determines the maximal value X of the standard grayscale value writing LCD space light modulator;
Step S312, determines the number Y of the test gray-scale value that photoelectric sensor receives, and test gray-scale value to the number of the test gray-scale value of last non-zero that the number Y of test gray-scale value equals first non-zero that photoelectric sensor receives adds 1;
Step S313, calculates the spacing value Z between standard grayscale value according to X and Y, Z=X/ (Y-1);
Step S314, calculate the standard grayscale value An corresponding to test gray-scale value according to spacing value Z, An=Z*m, m are the integer being more than or equal to 0 and being less than Y.
In the present embodiment, the standard grayscale information of the corresponding actual grey received is obtained with charge coupled cell CCD, first the maximum gradation value X write in the standard grayscale information of LCD space light modulator is determined, in the present embodiment, this maximal value X is exactly the maximum gradation value 255 of write image, then the number of the test gray-scale value received is determined, the position of reading as shown in Figure 4, the number Y of test gray-scale value equal the test gray-scale value of first non-zero previous be that the gray-scale value of zero is to the number of the test gray-scale value of last non-zero, namely test gray-scale value to the number of the test gray-scale value of last non-zero of first non-zero adds 1, the interval 255/ (Y-1) of the standard grayscale value of corresponding test gray-scale value can be obtained according to the test gray-scale value number Y determined, the standard grayscale value then corresponding to test gray-scale value is ordered series of numbers 0, 255/ (Y-1), 2*255/ (Y-1), ..., (Y-2) * 255/ (Y-1), 255, such as, if the test gray-scale value read is 0, 0, 0, (0, 2, 40, 80, 120, 230), 0, 0, 0, 0, it is then the half-tone information of the test gray-scale value of the image output of write LCD space light modulator in bracket, therefore gray-scale value number Y=6 can be tested, the number of namely corresponding standard grayscale value is also 6, can obtain (6-1)=51, interval 255/ of the standard grayscale value of corresponding test gray-scale value thus, then corresponding test gray-scale value is 0, 2, 40, 80, 120, the standard grayscale value of 230 is 0, 51, 102, 153, 204, 255.
Special declaration be, principle can obtain 256 whole test gray-scale values with charge coupled cell CCD, it is more accurate that the test gray-scale value gathered obtains result more, therefore test gray-scale value number in the present embodiment to be exemplified as 6 and to be only concise description step S31, to understand, in reality is implemented, can get such as 16 according to different testing requirements, 86 grades more test gray-scale value number to determine corresponding more accurate standard grayscale value.
After collecting these data, by obtaining corresponding normalization result by testing the standard grayscale value of gray-scale value divided by correspondence, using the data after these normalization as ordinate, using the data of standard grayscale value as horizontal ordinate, set up coordinate system and just generate the gamma curve wanted required for the present invention.
As shown in Figure 7, one embodiment of the invention proposes a kind of system measuring gamma curves of liquid crystal spatial light modulator, comprise the light source, LCD space light modulator and the photoelectric sensor that sequentially arrange along light path, described light source output beam enters described photoelectric sensor through described LCD space light modulator, the test half-tone information that described photoelectric sensor exports for receiving LCD space light modulator.
In the present embodiment, system adopts charge coupled cell CCD 3 to receive the test half-tone information of described LCD space light modulator output, the beam expanding lens group 4 of expanded light beam diameter is had between the LCD space light modulator 2 of system and light source 1, the convex lens 5 of a convergent beam are provided with between charge coupled cell CCD 3 and LCD space light modulator 2, front polaroid 6 is provided with between the LCD space light modulator 2 of system and light source 1, front polaroid 6 is between light source 1 and beam expanding lens group 4, rear polarizer 9 is had between the charge coupled cell CCD 3 of system and LCD space light modulator 2, front half-wave plate 7 is had between LCD space light modulator 2 and front polaroid 6, front half-wave plate 7 is between beam expanding lens group 4 and LCD space light modulator 2, rear half-wave plate 8 is had between LCD space light modulator 2 and rear polarizer 9, wherein front polaroid 6 is placed at angle with rear polarizer 9, light source 1 can be sent light and be filtered into linearly polarized photon by front polaroid 6, play effect partially, rear polarizer 9 can control passing through through modulation linearity polarized light, play analyzing effect, an attenuator 11 is had after light source 1, an outer half-wave plate 10 is had after attenuator 11, outer half-wave plate 10 and attenuator 11 are between light source 1, attenuator 11 is kept to suitable light intensity for the light decay sent by light source 1, front half-wave plate 7, rear half-wave plate 8 and outer half-wave plate 10 are for controlling the polarization direction of light.
The system of the measurement gamma curves of liquid crystal spatial light modulator of the present embodiment is not limited to above-mentioned optics Control Component, can also according to different light path design and the common optical element of actual needs increase and decrease prism mirror etc.
The foregoing is only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize instructions of the present invention and accompanying drawing content to do equivalent structure or flow process conversion; or be directly or indirectly used in other relevant technical field, be all in like manner included in scope of patent protection of the present invention.