Optical system and method for composing color images from chromatically non-compensated optics

• US 6,590,612 B1
• Filed: 03/18/1999
• Issued: 07/08/2003
• Est. Priority Date: 03/18/1999
• Status: Expired due to Term

• Current Assignee: Cellavision AB
• Original Assignee: Cellavision AB
• Inventors: Sennmalm, Per, Fåhraeus, Christer, Rosenqvist, Anders, Almers, Martin, Elvin, Daniel
• Primary Examiner(s): Vu, Ngoc-Yen, VU, NGOC YEN T
• Application Number:
  US09/271,828
• Time in Patent Office: 1,573 Days
• Field of Search: H04/N.5232, H04/N.718, 348/79, 348/80, 348/335, 348/340, 348/345, 348/349, 348/351, 348/354-356, 382/254, 382/255, 382/260, 382/263
• US Class Current: 348/349
• CPC Class Codes: G02B 21/00 Microscopes
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals

Abstract

An image processing system for optical systems including microscopes which separately captures (grabs) different portions of the electromagnetic spectrum as emitted from an object as separate images. Each of the separate images are individually focused and then aligned with the other images to produce a composite image. In one embodiment, the different portions correspond to red, green, and blue and the composite image is displayed to the user on as a monitor without any need for an eyepiece.

Claims

1. An optical system comprising:

an objective which receives electromagnetic radiation from an object, modifies the electromagnetic radiation, and emits the modified electromagnetic radiation as an image of the object;

a focusing mechanism which controls the movement of the objective along at least one path to modify the image;

one or more cameras which detect separate images for each of a plurality of frequency bands of the modified electromagnetic radiation of the image emitted by the objective; and

an automatic focus controller which, in accordance with the detected images;

(1) provides control parameters to the focusing mechanism; and

(2) determines for each of the frequency bands, an optimal image which corresponds to an optimal focus of the objective for that frequency band.

2. The optical system of claim 1, wherein the automatic focus controller further comprises:

a filter calculator for receiving the detected images as image signals and for generating filtered image signals such that noise components of the image signals have been reduced, the noise components being reduced by increasing energy contributions from parts of the image signals which contribute a relatively larger proportion to image components than the noise components and by decreasing energy contributions from other parts of the image signals which contribute a relatively larger portion to the noise components than to the image components;

an energy calculator for receiving the filtered image signals and determining energy levels of the filtered image signals; and

a control calculator for receiving the energy levels and for generating the control parameters in accordance with the energy levels.

3. The optical system of claim 1, further comprising:

a registration controller which aligns a plurality of optimal images.

4. The optical system of claim 3, wherein the registration controller further comprises:

a transformer for receiving a first optimal image and a transformation, and for generating a transformed image, the transformation capable of translating, rotating, and/or magnifying the first optimal image;

a compositor for combining a second optimal image and the transformed image to generate a composite image;

an energy calculator for receiving the composite image and for determining an energy level of the composite image; and

a transformation generator for receiving the energy level and for generating the transformation in accordance with the energy level such that the transformation selected corresponds to a focus for the composite image.

5. The optical system of claim 1, further comprising:

a source of electromagnetic radiation capable of emitting electromagnetic radiation in different frequency bands and of selectively emitting electromagnetic radiation from only one of the frequency bands.

6. The optical system of claim 5, wherein the source further comprises:

a plurality of separate sources, each separate source corresponding to one or more of the different frequency bands.

7. The optical system of claim 1, wherein:

one or more of the frequency bands produce a response only from respective portions of the object.

8. The optical system of claim 1, wherein:

the objective lacks significant color compensation.

9. The optical system of claim 1, wherein:

one or more of the images are detected at different times.

10. The optical system of claim 1, wherein:

the objective is selected such that the optimal focus for each frequency band occurs at a different position along the path of the objective.

11. The optical system of claim 1, wherein:

the objective provides optimal focus positions which are monotonically related to the frequency bands.

12. The optical system of claim 1, wherein:

a single unidirectional movement of the objective along the path reveals the optimal focus for each of the frequency bands.

13. The optical system of claim 1, further comprising:

one or more image sharpening filters, each filter optimized for a particular frequency band.

14. The optical system of claim 1, wherein the camera comprises:

a single black and white camera.

15. The optical system of claim 1, wherein at least three of the frequency bands correspond to red, green, and blue color components of visible light.

16. The optical system of claim 1, further comprising:

a converter for transforming each n by 1 pixel of a composite image using a weight matrix to generate a respective 3 by 1 pixel for an RGB image, where n is the number of frequency bands.

17. A method for operating an optical system comprising the steps of:

illuminating an object with electromagnetic radiation from a source;

modifying electromagnetic radiation from the object through an objective to form an image of the object;

controlling the movement of the objective along at least one path to modify the image;

detecting separate images for each of a plurality of frequency bands of the electromagnetic radiation;

providing control parameters for controlling the movement of the objective; and

determining from the detected images for each of the frequency bands, an optimal image which corresponds to an optimal focus of the objective for that frequency band.

18. The method of claim 17, wherein the step of controlling the movement of the objective, further comprises the step of:

moving the objective only in one direction to reveal the optimal focus for each of the frequency bands.

19. The method of claim 17, further comprising the step of:

sharpening one or more of the optimal images using a filter optimized for the respective frequency band.

20. The method of claim 17, further comprising the step of:

aligning two or more of the optimal images with each other.