Image processing apparatus, image processing method, and three-dimensional shape measuring apparatus

Abstract

To provide an image processor, a method for processing an image, and a three-dimensional shape measuring device which can accurately acquire three-dimensional shape data of a measurement target object.SOLUTION: An information processor 100 acquires a plurality of images of a measurement target object Ob which an imaging device 10 imaged with different focal positions and corrects blurring of the acquired images on the basis of a point spread function for each focal position of the image formation optical system 14 of the imaging device 10. The image processor 100 calculates the evaluation value of the focus degree of each of a plurality of pixels after the blurring is corrected, and generates the three-dimensional shape data of the measurement target object Ob on the basis of the calculated evaluation degree of the focus degree for each pixel.SELECTED DRAWING: Figure 1

Claims

1. An image processing device that processes multiple images of a measurement target captured at different focal points, An image acquisition unit that acquires multiple images of the object to be measured, An image processing unit that processes the multiple images and corrects the blur of the images based on the point spread function for each focal position of the optical system of the imaging device that has captured the multiple images, A three-dimensional shape data generation unit calculates an evaluation value for the degree of focus for each pixel of the multiple images after blur correction, acquires height information for each pixel based on the calculated evaluation value for the degree of focus for each pixel, and generates three-dimensional shape data of the object to be measured based on the height information for each pixel. Equipped with an image processing device.

2. The image processing unit applies a frequency-domain restoration filter based on the point spreading function to the frequency-domain image obtained by Fourier transforming the image, corrects the frequency-domain image, and then performs an inverse Fourier transform on the corrected frequency-domain image to correct the blur of the image. The image processing apparatus according to claim 1.

3. The point spreading function is Fourier transformed to obtain the point spreading function in the frequency domain, and an inverse filter in the frequency domain is calculated from this point spreading function. The calculated inverse filter in the frequency domain is then set as the restoration filter in the frequency domain. The image processing apparatus according to claim 2.

4. A Wiener filter in the frequency domain is calculated from the point spreading function obtained by performing a Fourier transform on the point spreading function, and the calculated Wiener filter in the frequency domain is set as the restoration filter in the frequency domain. The image processing apparatus according to claim 2.

5. The Wiener filter is calculated by the following equation: PSF f *(oh x ,oh y ,oh z ) / {PSF f (oh x ,oh y ,oh z )PSF f *(oh x ,oh y ,oh z )+SN} however, PSF(x,y,z) is the voxel data of the point spread function. PSF f (ω x ,ω y ,ω z ) is a mapping obtained by the Fourier transform of PSF(x,y,z), PSF f *(ω x ,ω y ,ω z ) is PSF f (ω x ,ω y ,ω z The complex conjugate of ) SN is a constant. The image processing apparatus according to claim 4.

6. The constant SN is set experimentally. The image processing apparatus according to claim 5.

7. The image processing unit processes the voxel data of the object to be measured based on the voxel data of the point spreading function to correct the blurring of multiple images. The image processing apparatus according to any one of claims 1 to 6.

8. The image processing unit, when the size of the voxel data of the point spreading function is smaller than the size of the voxel data of the object to be measured, zero-padding the voxel data of the point spreading function to adjust it to the same size. The image processing apparatus according to claim 7.

9. The point spreading function is obtained by setting a bright spot on the optical axis of the optical system and taking an image by moving the imaging device relative to the bright spot. The image processing apparatus according to any one of claims 1 to 8.

10. The diameter of the bright spot is set to be less than or equal to the optical resolution of the imaging device via the optical system. The image processing apparatus according to claim 9.

11. The bright spot is composed of a pinhole light or a fluorescent bead. The image processing apparatus according to claim 9 or 10.

12. The image processing unit acquires temperature information when the object to be measured is imaged, and corrects the blur of the multiple images based on the point spread function corresponding to the acquired temperature. The image processing apparatus according to any one of claims 1 to 11.

13. Multiple images of the object to be measured are captured such that the maximum and minimum brightness values ​​of the object to be measured fall within the dynamic range that can be captured by the imaging device. The image processing apparatus according to any one of claims 1 to 12.

14. An imaging device that moves relative to an object to be measured, set on the optical axis, and captures multiple images with different focal positions, An image processing apparatus according to any one of claims 1 to 13, which processes a plurality of images of the object to be measured captured by the imaging device, A three-dimensional shape measuring device equipped with this device.

15. An image processing method for processing multiple images of a measurement target captured at different focal points, Multiple images of the object to be measured are acquired, Based on the point spread function for each focal position of the optical system of the imaging device that captured multiple images, the blur of the multiple images is corrected. For each of the multiple images after blur correction, an evaluation value for the degree of focus is calculated for each pixel, height information for each pixel is obtained based on the calculated evaluation value for the degree of focus for each pixel, and three-dimensional shape data of the object to be measured is generated based on the height information for each pixel. Image processing methods.

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