Image generation apparatus and image generation method

A method for generating an image using a first light source, a second light source located a predetermined distance away from the first light source, an image sensor on which a translucent substance is disposed, and a mask located between the image sensor and the first and second light sources and having a light-transmitting portion that transmits light emitted from the first light source and light emitted from the second light source and a light-shielding portion that blocks light emitted from the first light source and light emitted from the second light source, the method comprising:

• (a) acquiring a first image of the substance by using the image sensor when the first light source is energized, where the first image has a plurality of first pixel regions;
• (b) acquiring a second image of the substance by using the image sensor when the second light source is energized, where the second image has a plurality of second pixel regions;
• (c) acquiring information regarding a focal plane located between the image sensor and the mask and having a plurality of focal points;
• (d) acquiring, for each of the first pixel regions, a ratio of first light including direct light that is emitted from the first light source, travels straight without being refracted and/or scattered, and is incident on the image sensor, and a ratio of second light including light other than the direct light that is emitted from the first light source and is incident on the image sensor;
• (e) acquiring, for each of the second pixel regions, a ratio of third light including direct light that is emitted from the second light source, travels straight without being refracted and/or scattered, and is incident on the image sensor, and a ratio of fourth light including light other than the direct light that is emitted from the second light source and is incident on the image sensor;
• (f) acquiring, by using the pixel values of the plurality of the first pixel regions of the first image, pixel values of the plurality of the second pixel regions of the second image, the ratio of the first light, the ratio of the second light, the ratio of the third light, and the ratio of the fourth light, a pixel value based on the first light and the third light for each of the plurality of focal points or a pixel value based on the second light and the fourth light for each of the plurality of focal points;
• and
• (g) generating a cross-sectional image of the substance on the focal plane by using the pixel values based on the first light and the third light for each of the plurality of focal points or the pixel values based on the second light and the fourth light for each of the plurality of focal points.

An image generation apparatus comprising:

• light sources including a 1st light source, . . . a jth light source, . . . , and an nth light source, where j and n are natural numbers and 1<j≤n;
• an image sensor having a translucent object placed thereon, the image sensor including a 1st pixel, . . . an ith pixel . . . , and an mth pixel, where i and m are natural numbers and 1<i≤m;
• a mask having a portion through which light emitted from the light sources transmits and a portion which blocks light emitted from the light sources;
• and
• a processing circuit,
• wherein, during the jth light source emitting light without the light sources except the jth light source emitting light, the processing circuit causes the image sensor to obtain a pixel value L(1j) of the 1st pixel, a pixel value L(ij) of the ith pixel, . . . , and a pixel value L(mj) of the mth pixel by changing j from 1 to n,
• wherein the processing circuit determines a pixel value L(i)max representing the largest value among the pixel values L(i1 ), . . . L(ij) . . . , L(in), αij=L(ij)/L(i)max, and βj=0.5 by changing j from 1 to n and changing i from 1 to m, and
• wherein the processing circuit obtains a direct light component Directi at a pixel position i in an in-focus image on the focal plane and a light component Globali other than the direct light component at the pixel position i by solving the following equation by using the least squares method:
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• wherein the processing circuit generates an image on a basis of Directi and Globali.