JP2015001674A - Light modulation method using spatial light modulator and device provided with spatial light modulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for attaining a desired modulation in each of pixel elements of a spatial light modulator.SOLUTION: A light modulation method using an LCOS 3 having a plurality of pixel elements independently modulating light, respectively is configured to: calculate a modulation pattern signal corresponding to a light modulation pattern to be attained by the LCOS 3 (S30); calculate a degree of influence showing an influence from a pixel element other than the pixel element out of the plurality of pixel elements on the basis of a modulation pixel signal of the plurality of pixel elements constituting the modulation pattern signal for each pixel element of the LCOS 3 (S40); calculate the modulation pixel signal of the pixel element corrected so that the influence from a pixel element other than the pixel element is cancelled out on the basis of the degree of influence calculated with respect to the pixel element for each pixel element of the LCOS 3 (S50); input the corrected modulation pattern signal composed of the corrected modulation pixel signal of the plurality of pixel elements to the LCOS 3 (S60); and modulate light by the LCOS 3 having the corrected modulation pattern signal input (S70).

Description

  The present invention relates to a light modulation method using a spatial light modulator and an apparatus including the spatial light modulator.

  Spatial Light Modulator (SLM) is an intensity modulation type spatial light modulator, LCOS (trademark) (Liquid Crystal On Silicon) that modulates the intensity of light represented by DMD (Digital Mirror Device). A phase modulation type spatial light modulator that modulates the phase of representative light is known. They are widely used in various fields.

  By the way, in these spatial light modulators, a plurality of pixel elements each independently modulating light are arranged. Each of the plurality of pixel elements has a voltage applied to surrounding pixel elements, etc. Affected by. For this reason, desired modulation may not be realized in each pixel element due to the influence from surrounding pixel elements.

  In Patent Document 1, in response to such a technical problem, the signal level is increased at a portion where the spatial frequency is high and the signal level is decreased at a portion where the spatial frequency is low, according to the spatial frequency of the pattern of each part forming the modulation pattern. An apparatus that corrects a deviation from a target modulation amount by changing in such a manner is disclosed.

JP 2005-135479 A

  In the device disclosed in Patent Document 1, the level of spatial frequency is determined based on the number of consecutive pixel elements with the same value (number of pixels), and the area where the pixel elements with the same value are continuous (hereinafter referred to as a continuous region). ) The signal level is determined every time. Therefore, in the apparatus disclosed in Patent Document 1, pixel elements at the edge portion of the continuous area (pixel elements adjacent to pixel elements outside the continuous area) and pixel elements at other parts (that is, pixel elements within the continuous area) And the adjacent pixel element) are corrected to the same signal level.

  However, the amount of deviation from the desired modulation amount is not the same for the pixel elements in the edge portion and the pixel elements in the other portions, and the pixel elements in the edge portion are usually larger. Therefore, it is difficult for the apparatus disclosed in Patent Document 1 to appropriately correct the deviation amount from the desired modulation amount.

  Based on the above situation, an object is to provide a technique for realizing desired modulation in each pixel element of a spatial light modulator.

  A first aspect of the present invention is a light modulation method using a spatial light modulator having a plurality of pixel elements each independently modulating light, and a modulation pattern for controlling the spatial light modulator A first signal calculating step of calculating a modulation pattern signal corresponding to a modulation pattern of light to be realized by the spatial light modulator, and for each pixel element of the spatial light modulator, the modulation pattern An influence degree calculating step for calculating an influence degree indicating an influence from a pixel element other than the pixel element of the plurality of pixel elements based on the modulated pixel signals of the plurality of pixel elements constituting the signal; and the space For each pixel element of the light modulator, based on the influence degree calculated for the pixel element, the modulation pixel of the pixel element corrected so that the influence from the pixel elements other than the pixel element is offset Trust A signal input step of inputting a corrected modulation pattern signal composed of corrected pixel signals of the plurality of pixel elements to the spatial light modulator, and the corrected modulation And a light modulation step of modulating light by the spatial light modulator to which a pattern signal is input.

  According to a second aspect of the present invention, in the light modulation method according to claim 1, the second signal calculation step increases as the absolute value of the degree of influence calculated for the pixel element increases. There is provided a light modulation method which is a step of calculating a corrected modulated pixel signal of the pixel element.

  According to a third aspect of the present invention, in the light modulation method according to claim 2, the influence calculation step includes, for each pixel element of the spatial light modulator, a value of the modulation pixel signal of the pixel element and A relative value calculation step of calculating a relative value obtained by comparing the value of the modulated pixel signal of a pixel element other than the pixel element for each pixel element other than the pixel element; and the pixel element and a pixel element other than the pixel element A weighting step of calculating a weighted relative value obtained by multiplying the relative value by a weighting coefficient determined based on a positional relationship for each pixel element other than the pixel element, and calculating for each pixel element other than the pixel element A sum total calculating step of calculating the weighted sum of the relative values as the degree of influence of the pixel element.

  According to a fourth aspect of the present invention, in the light modulation method according to claim 3, the relative value calculation step includes a value of a modulation pixel signal of the pixel element and a modulation pixel signal of a pixel element other than the pixel element. There is provided a light modulation method which is a step of calculating a difference between values as the relative value.

  According to a fifth aspect of the present invention, in the light modulation method according to any one of claims 2 to 4, the second signal calculation step is performed for each pixel element of the spatial light modulator. A correction coefficient determining step for determining a correction coefficient based on the degree of influence calculated for the pixel element; and the corrected value of the modulated pixel signal of the pixel element is the correction coefficient determined for the pixel element and the correction coefficient There is provided a light modulation method including a correction signal calculation step of calculating a corrected modulation pixel signal of the pixel element so as to be a value obtained by multiplying the value of the modulation pixel signal of the pixel element.

  A sixth aspect of the present invention provides the light modulation method according to claim 5, wherein the correction coefficient has a linear relationship with the degree of influence.

  According to a seventh aspect of the present invention, in the light modulation method according to any one of claims 1 to 6, the first signal calculation step is a step of calculating a computer generated hologram. Provide a method.

  An eighth aspect of the present invention includes a spatial light modulator having a plurality of pixel elements that independently modulate light, and a control device that controls the spatial light modulator, wherein the control device includes A modulation pattern signal for controlling the spatial light modulator, calculating a modulation pattern signal corresponding to a modulation pattern of light to be realized by the spatial light modulator, and for each pixel element of the spatial light modulator The spatial light is calculated based on the modulation pixel signal of the plurality of pixel elements included in the modulation pattern signal, and the degree of influence indicating the influence from pixel elements other than the pixel element among the plurality of pixel elements is calculated. For each pixel element of the modulator, the modulated pixel signal of the pixel element corrected so that the influence from the pixel elements other than the pixel element is canceled based on the influence degree calculated for the pixel element To calculate Inputting a corrected modulation pattern signal consisting corrected modulated pixel signals of the serial plurality of pixel elements in the spatial light modulator provides an apparatus configured to.

  ADVANTAGE OF THE INVENTION According to this invention, the technique for implement | achieving desired modulation in each pixel element of a spatial light modulator can be provided.

It is a figure which shows the structure of the microscope system which concerns on one Embodiment of this invention. FIG. 2 is a functional block diagram showing main functions of a computer included in the microscope system shown in FIG. 1. It is a flowchart of the whole light modulation process using the spatial light modulator performed with the microscope system shown in FIG. It is a flowchart of the process which calculates the influence degree shown in FIG. 4 is a flowchart of a process for calculating a corrected modulated pixel signal shown in FIG. 3. It is the figure which showed an example of the stimulus pattern input into the input device. It is a figure which shows an example of a modulation pattern signal. It is a figure which shows an example of the weighting coefficient allocated to the pixel element around a focused pixel element. It is a figure which shows another example of the weighting coefficient allocated to the pixel element around a focused pixel element. It is a figure which shows another example of the weighting coefficient allocated to the pixel element around the attention pixel element. It is a figure which shows an example of the influence degree of each pixel element calculated using the weighting coefficient illustrated by FIG. 8A. It is a figure which shows an example of the influence degree of each pixel element calculated using the weighting coefficient illustrated by FIG. 8B. It is a figure which shows the relationship between a correction coefficient and an influence degree. It is the figure which compared and showed the modulation pattern signal which consists of the modulation pixel signal before and behind correction | amendment.

  FIG. 1 is a diagram showing a configuration of a microscope system 100 according to an embodiment of the present invention. A microscope system 100 shown in FIG. 1 is an apparatus including a two-photon excitation microscope, a computer 70 that controls the two-photon excitation microscope, a monitor 80 connected to the computer 70, and an input device 90. It has a pattern stimulation function for stimulating the specimen 11 with light of the pattern and an image acquisition function for obtaining a scanned image of the specimen 11.

  As shown in FIG. 1, the two-photon excitation microscope that constitutes the microscope system 100 includes a laser light source 1, a beam expander 2, an LCOS 3 that is a phase modulation type spatial light modulator, a relay lens 4, and 0 A secondary light cut filter 5, a galvano mirror 6, a relay lens 7, a mirror 8, a dichroic mirror 9, an objective lens 10, a relay lens 12, and a photomultiplier tube (PMT) 13 are provided. ing.

  The LCOS 3 and the galvanometer mirror 6 are respectively disposed at positions optically conjugate with the pupil position of the objective lens 10. The PMT 13 is also disposed at a position optically conjugate with the pupil position of the objective lens 10. Furthermore, the 0th-order light cut filter 5 is disposed so as to be removable from the optical path. In the microscope system 100, pattern stimulation is performed with the 0th-order light cut filter 5 inserted into the optical path, and image acquisition is performed with the 0th-order light cut filter 5 removed from the optical path.

  The LCOS 3 includes a plurality of pixel elements that are controlled independently and modulate light, and are arranged in two dimensions. In the two-photon excitation microscope, the phase of the laser light is modulated by each pixel element of the LCOS 3 to perform, for example, pattern stimulation on the specimen 11 and correction of the aberration of the laser light at the condensing position.

The computer 70 is a control device including a storage unit 71 including a hard disk and a memory, and is connected to at least the laser light source 1, the LCOS 3, the galvanometer mirror 6, and the PMT 13 among the components of the two-photon excitation microscope. Yes. The computer 70 controls these components and receives and processes signals from these components.
FIG. 2 is a functional block diagram showing main functions of the computer 70 included in the microscope system 100 shown in FIG.

  As shown in FIG. 2, the computer 70 executes the control program stored in the storage unit 71, so that the light source control unit 72 that controls the light emission of the laser light source 1, the scanning position information of the galvanometer mirror 6, and the PMT 13. It functions as a scanned image acquisition unit 73 that generates an image based on the signal, and an SLM modulation control unit 74 that calculates a modulation pattern signal input to the LCOS 3 based on an input from the input device 90 in order to control the LCOS 3.

  When pattern stimulation is performed in the microscope system 100, the laser beam emitted from the laser light source 1 is adjusted in beam diameter by the beam expander 2 and enters the LCOS 3. The phase of the laser light incident on the LCOS 3 is modulated by the incident pixel element. This phase modulation is performed by the computer 70 calculating a modulation pattern signal based on the setting relating to illumination (here, stimulus) input by the user to the input device 90 and controlling the LCOS 3 according to the calculated modulation pattern signal. Is called. Thereafter, the laser light enters the mirror 8 via the relay lens 4, the galvano mirror 6, and the relay lens 7, but the 0th-order diffracted light generated by the LCOS 3 is cut by the 0th-order light cut filter 5 provided in the relay lens 4. Is done. The laser light is reflected by the mirror 8 in the optical axis direction of the objective lens 10, passes through the dichroic mirror 9 having the characteristics of transmitting the laser light and reflecting the fluorescence, and enters the objective lens 10. Then, the objective lens 10 irradiates the sample 11 with laser light, and pattern stimulation is performed according to the setting input to the input device 90.

  When image acquisition is performed with the microscope system 100, the zero-order light cut filter 5 is removed from the optical path. Then, the laser light emitted from the laser light source 1 is adjusted in the beam diameter by the beam expander 2 and enters the LCOS 3. The phase of the laser light incident on the LCOS 3 is modulated by the incident pixel element. This phase modulation is performed when the computer 70 calculates a modulation pattern signal based on the setting relating to illumination (here, aberration correction) input to the input device 90 by the user, and the LCOS 3 is controlled according to the calculated modulation pattern signal. Done. Thereafter, the laser light enters the mirror 8 through the relay lens 4, the galvano mirror 6, and the relay lens 7. The laser light is reflected by the mirror 8 in the optical axis direction of the objective lens 10, passes through the dichroic mirror 9 having the characteristics of transmitting the laser light and reflecting the fluorescence, and enters the objective lens 10. Since the laser beam is modulated by the LCOS 3 so that the aberration is appropriately corrected on the sample 11, the laser beam is condensed at one point on the sample 11 by the objective lens 10. Then, the specimen 11 is scanned two-dimensionally by the galvanometer mirror 6 disposed between the objective lens 10 and the LCOS 3 controlling the deflection direction of the laser light. The fluorescence generated from the specimen 11 by the irradiation of the laser light is reflected by the dichroic mirror 9 that enters through the objective lens 10 and enters the PMT 13 through the relay lens 12. The PMT 13 that has detected the fluorescence transmits an electrical signal generated by the detection to the computer 70. The computer 70 receives the electrical signal from the PMT 13 and generates an image of the specimen 11 from the received electrical signal and control information of the galvano mirror 6 indicating the scanning position.

  FIG. 3 is a flowchart of the entire light modulation process using the LCOS 3 performed in the microscope system 100. FIG. 4 is a flowchart of the process (step S40) for calculating the degree of influence shown in FIG. FIG. 5 is a flowchart of the process (step S50) for calculating the corrected modulated pixel signal shown in FIG. Hereinafter, the light modulation method performed using the LCOS 3 in the microscope system 100 will be described in detail with reference to the flowcharts shown in FIGS. Note that the processing shown in FIGS. 3 to 5 is performed by the computer 70 executing the control program stored in the storage unit 71.

  First, when a user inputs lighting settings using the input device 90, the computer 70 acquires the input lighting settings (step S10 in FIG. 3). Specifically, information such as a pattern of stimulation light (stimulation pattern) to be irradiated on the specimen 11, a laser wavelength, and a magnification of the objective lens 10 to be used, which is input to the input device 90 is acquired. FIG. 6 is a diagram illustrating an example of a stimulus pattern input to the input device 90, and illustrates an example in which a star-shaped pattern and a triangular pattern are formed on the specimen 11 at the same time. Such a stimulation pattern is designated by operating the input device 90 while looking at the GUI screen displayed on the monitor 80, for example.

  Next, the computer 70 calculates a light modulation pattern (hereinafter referred to as a target modulation pattern) to be realized by the LCOS 3 based on the input illumination setting (step S20 in FIG. 3). The target modulation pattern is a set of light modulation amounts to be performed by each pixel element of the spatial light modulator. In the microscope system 100, a set of light phase modulation amounts to be performed by each pixel element of the LCOS 3 It is. The target modulation pattern is calculated based on the stimulation pattern on the sample 11 acquired in step S10.

  When the target modulation pattern is calculated, the computer 70 calculates a modulation pattern signal S1 corresponding to the target modulation pattern (step S30 in FIG. 3). The modulation pattern signal is a signal for controlling the LCOS 3 and is a set of modulation pixel signals for controlling each pixel element. The modulation pattern signal S1 corresponding to the target modulation pattern is calculated from the target modulation pattern. FIG. 7 is an example of the modulation pattern signal calculated in step S30. Note that the modulation pattern signal S1 shown in FIG. 7 is a one-dimensional signal having only coordinate information in the X direction for the sake of simplicity.

  When the modulation pattern signal S1 is calculated, the computer 70, for each pixel element of the LCOS 3 based on the modulation pixel signals of the plurality of pixel elements of the LCOS 3 constituting the modulation pattern signal (that is, pays attention). The influence degree which shows the influence from pixel elements other than a pixel element is calculated (step S40 of FIG. 3). The influence degree is a value indicating the magnitude of the influence of surrounding pixel elements on the modulation amount in the pixel elements. More specifically, step S40 includes four processes as shown in FIG. 4, and these four processes are performed for each pixel element. Hereinafter, the pixel element focused on in the process performed for each pixel element is referred to as a focused pixel element.

  In step S40, first, the computer 70 determines a weighting coefficient to be assigned to pixel elements around the target pixel element (step S41 in FIG. 4). The weighting coefficient is determined based on the positional relationship between the target pixel element and pixel elements other than the target pixel element. Specifically, a smaller weighting coefficient is assigned to a pixel element farther from the target pixel element. FIGS. 8A to 8C show examples of weighting coefficients assigned to surrounding pixel elements. In FIG. 8A, a weighting coefficient of 1 is set for four pixel elements adjacent to the target pixel element on the side, a weighting coefficient of 0.7 is set for four pixel elements adjacent to the target pixel element at a point, An example of assigning 0 to a pixel element is shown. FIG. 8B shows an example in which a weighting factor of 1 is assigned to four pixel elements adjacent to the target pixel element on the side, and 0 is assigned to other pixel elements. FIG. 8C shows an example in which a weighting coefficient is assigned to a pixel element adjacent to an adjacent pixel element in addition to a pixel element adjacent to the target pixel element (adjacent pixel element). Which of these is used is set in advance in consideration of, for example, whether the shape of the stimulation pattern is simple or complex, or whether it takes time to calculate.

  When the assignment of the weighting coefficient is completed, the computer 70 compares the pixel element of interest with a pixel element other than the pixel element of interest and calculates a relative value (step S42 in FIG. 4). The relative value is a value indicating the magnitude of the difference calculated by comparing the value of the modulation pixel signal of the pixel element other than the target pixel element and the value of the modulation pixel signal of the target pixel element. Calculated for each pixel element. This relative value may be, for example, a difference between the values of the modulation pixel signals, or may be a ratio of the values of the modulation pixel signals.

  When the calculation of the relative value is completed, the computer 70 multiplies the relative value by a weighting coefficient to calculate a weighted relative value (step S43 in FIG. 4). The weighted relative value is a value calculated for each pixel element other than the target pixel element as in the case of the relative value, and is a value indicating the magnitude of the influence of each pixel element other than the target pixel element on the target pixel element. It is.

  When the calculation of the weighted relative value is completed, the computer 70 obtains the sum of the weighted relative values calculated for each pixel element other than the target pixel element, and uses the obtained result as the degree of influence (FIG. 4). Step S44).

  In the computer 70, the process from step S41 to step S44 is performed for each pixel element of LCOS3, whereby the degree of influence of each pixel element is calculated. 9A and 9B show the degree of influence of each pixel element calculated using the weighting coefficients exemplified in FIGS. 8A and 8B, respectively. Note that the relative values shown in FIGS. 9A and 9B are the difference between the values of the modulated pixel signals. In steps S42 and S43, an example is shown in which the relative value and the weighted relative value are calculated for each pixel element other than the target pixel element. However, the relative value of the pixel element having the weighting coefficient of 0 is calculated in step S44. In order not to affect the degree, only the relative value of the pixel element whose weighting coefficient is other than 0 and the weighted relative value may be calculated.

When the degree of influence for each pixel element of LCOS3 is calculated, the processing returns to FIG. A modulated pixel signal of the pixel element corrected so as to cancel the influence from the pixel element is calculated (step S50 in FIG. 3). Here, the larger the absolute value of the degree of influence calculated for that pixel element, the more the modulation pixel signal will fluctuate due to the influence from surrounding pixel elements, so a greatly corrected modulation pixel signal is calculated. To do.
More specifically, step S50 includes two processes as shown in FIG.

  First, for each pixel element, a correction coefficient is determined based on the degree of influence calculated for that pixel element (step S51 in FIG. 5). As described above, the influence degree is a value indicating the magnitude of the influence of surrounding pixel elements on the modulated pixel signal of each pixel element. On the other hand, the correction coefficient is a coefficient used for correcting the modulation pixel signal so as to cancel the influence indicated by the influence degree, and is uniquely determined for each influence degree. Since the correction coefficient is for canceling the influence indicated by the influence degree, the correction coefficient changes according to the influence degree, and typically has a linear relationship as shown in FIG.

  When the correction coefficient is determined, for each pixel element, based on the correction coefficient determined for the pixel element, the corrected modulated image signal of the pixel element is calculated (step S52 in FIG. 5). Specifically, the value of the corrected modulation pixel signal of the pixel element is a value obtained by multiplying the determined correction coefficient of the pixel element by the value of the modulation pixel signal before correction of the pixel element. Thus, the corrected modulated pixel signal of the pixel element is calculated.

  In the computer 70, the process of step S51 and step S52 is performed for each pixel element of LCOS3, thereby calculating a corrected modulation pattern signal composed of the corrected pixel signals of a plurality of pixel elements. FIG. 11 is a diagram illustrating a modulation pattern signal composed of modulated pixel signals before and after correction. The modulation pattern signal S1 indicates a modulation pattern signal before correction, and the modulation pattern signal S2 indicates a modulation pattern signal after correction. . As shown in FIG. 11, the corrected modulation pattern signal S2 is a signal whose edge portion is emphasized as a whole compared to the modulation pattern signal S1 before correction.

  When the calculation of the corrected modulation pattern signal is completed, the computer 70 inputs the corrected modulation pattern signal to the LCOS 3 (step S60 in FIG. 3), and the modulation pattern in which the LCOS 3 is corrected under the control of the computer 70. The light is modulated according to the signal (step S70 in FIG. 3).

  As described above, in the microscope system 100, the computer 70 not only calculates the modulation pattern signal from the light pattern to be irradiated on the specimen 11 (that is, calculates a computer generated hologram) but also based on the calculated modulation pattern signal. Then, the modulation pattern signal corrected so as to cancel the influence from surrounding pixel elements is calculated, and the corrected modulation pattern signal is input to the LCOS 3. For this reason, according to the microscope system 100, it is possible to realize desired modulation in each pixel element of the LCOS 3 even though each pixel element is influenced by surrounding pixel elements.

  In the microscope system 100, the computer 70 calculates the influence from surrounding pixel elements for each pixel element, and calculates a corrected signal for each pixel element. That is, a signal whose influence is corrected in the minimum unit in which modulation is performed is calculated. Further, the computer 70 compares the signal value of the pixel element of interest with the signal value of the surrounding pixel elements, and calculates the influence from the surrounding pixel elements. At this time, the influence is calculated in consideration of not only the presence / absence of a difference in signal values but also the magnitude of the difference. Further, by assigning a smaller weighting coefficient to a pixel element farther from the target pixel element, the influence is calculated in consideration of not only the adjacent pixel element but also the influence from pixel elements other than the adjacent pixel element.

  Therefore, a signal with a larger correction is calculated for a portion having a higher spatial frequency in the modulation pattern (that is, a portion having a large change in signal value per number of pixel elements). Thereby, since the signal of the pixel element of the edge part of a continuous area | region is correct | amended largely compared with the signal of the pixel element of a part other than that, the subject that the modulation | alteration of an edge part will become dull can be solved.

  As described above, according to the microscope system 100, for each pixel element, the influence of the surrounding pixel elements is appropriately evaluated, and the signal is corrected so as to cancel it. Can be realized.

  The above-described embodiment is a specific example for facilitating understanding of the invention, and the present invention is not limited to this embodiment. The light modulation method and apparatus according to this embodiment can be variously modified and changed without departing from the spirit of the present invention defined by the claims.

  Although an example in which light is modulated by LCOS3 which is a phase modulation type spatial light modulator has been shown, the present invention can also be applied to light modulation by an intensity modulation type spatial light modulator such as DMD.

  Moreover, although the example which modulates light by LCOS3 in order to perform pattern irritation | stimulation was shown, this invention is applicable also to modulation of the light for performing aberration correction instead of pattern irritation | stimulation.

  Furthermore, although the microscope system including the LCOS 3 has been exemplified, any device using a spatial light modulator may be used. For example, the present invention can be applied to a laser processing apparatus.

1 Laser light source 2 Beam expander 3 LCOS
4, 7, 12 Relay lens 5 0th-order light cut filter 6 Galvano mirror 8 Mirror 9 Dichroic mirror 10 Objective lens 11 Sample 13 PMT
70 Computer 71 Storage Unit 72 Light Source Control Unit 73 Scanned Image Acquisition Unit 74 SLM Modulation Control Unit 80 Monitor 90 Input Device 100 Microscope System S1, S2 Modulation Pattern Signal

Claims (8)

A light modulation method using a spatial light modulator having a plurality of pixel elements each independently modulating light,
A first signal calculating step for calculating a modulation pattern signal for controlling the spatial light modulator, the modulation pattern signal corresponding to a modulation pattern of light to be realized by the spatial light modulator;
For each pixel element of the spatial light modulator, based on the modulation pixel signal of the plurality of pixel elements constituting the modulation pattern signal, the influence from pixel elements other than the pixel element among the plurality of pixel elements is affected. An influence calculation step for calculating the influence shown,
For each pixel element of the spatial light modulator, based on the influence degree calculated for the pixel element, the pixel element corrected so that the influence from the pixel elements other than the pixel element is offset A second signal calculating step for calculating a modulated pixel signal;
A signal input step of inputting a corrected modulation pattern signal composed of corrected modulation pixel signals of the plurality of pixel elements to the spatial light modulator;
And a light modulation step of modulating light by the spatial light modulator to which the corrected modulation pattern signal is input. The light modulation method according to claim 1,
The second signal calculating step is a step of calculating a modulated pixel signal of the pixel element that is corrected to be larger as the absolute value of the influence calculated for the pixel element is larger. Light modulation method. The light modulation method according to claim 2.
In the influence calculation step, for each pixel element of the spatial light modulator,
A relative value calculation step of calculating a relative value comparing the value of the modulation pixel signal of the pixel element and the value of the modulation pixel signal of the pixel element other than the pixel element for each pixel element other than the pixel element;
Weighting that calculates a weighted relative value obtained by multiplying the relative value by a weighting coefficient determined based on a positional relationship between the pixel element and a pixel element other than the pixel element for each pixel element other than the pixel element Steps,
A light modulation method comprising: a sum total calculation step of calculating a sum of the weighted relative values calculated for each pixel element other than the pixel element as an influence degree of the pixel element. The light modulation method according to claim 3,
The relative value calculating step is a step of calculating a difference between a value of a modulated pixel signal of the pixel element and a value of a modulated pixel signal of a pixel element other than the pixel element as the relative value. Method. The light modulation method according to any one of claims 2 to 4,
In the second signal calculation step, for each pixel element of the spatial light modulator,
A correction coefficient determining step for determining a correction coefficient based on the degree of influence calculated for the pixel element;
The corrected pixel element of the pixel element corrected so that the corrected value of the modulated pixel signal of the pixel element is a value obtained by multiplying the determined correction coefficient of the pixel element by the value of the modulated pixel signal of the pixel element. And a correction signal calculation step of calculating a modulation pixel signal. The light modulation method according to claim 5,
The light modulation method, wherein the correction coefficient has a linear relationship with the influence degree. The light modulation method according to any one of claims 1 to 6,
The method for modulating light, wherein the first signal calculating step is a step of calculating a computer generated hologram. A spatial light modulator having a plurality of pixel elements each independently modulating light;
A controller for controlling the spatial light modulator,
The controller is
A modulation pattern signal for controlling the spatial light modulator, and calculating a modulation pattern signal corresponding to a modulation pattern of light to be realized by the spatial light modulator;
For each pixel element of the spatial light modulator, based on the modulation pixel signal of the plurality of pixel elements included in the modulation pattern signal, the influence from pixel elements other than the pixel element of the plurality of pixel elements is affected. Calculate the degree of impact
For each pixel element of the spatial light modulator, based on the influence degree calculated for the pixel element, the pixel element corrected so that the influence from the pixel elements other than the pixel element is offset Calculate the modulated pixel signal,
An apparatus configured to input a corrected modulation pattern signal composed of corrected pixel signals of the plurality of pixel elements to the spatial light modulator.

Images