A method is provided for determining the distance between two optical boundary surfaces spaced apart from each other in a first direction. A first image is ascertained wherein the plane into which the pattern acquired coincides with a first of two optical boundary surfaces or has the smallest distance to the first optical boundary surface in a first direction. A position of the first image in the first direction is determined. A second image is ascertained wherein the plane into which the pattern acquired coincides with a second of two optical boundary surfaces or has the smallest distance to the second optical boundary surface in the first direction. The position of the second image in the first direction is determined. The distance is calculated by means of determined positions of the first and second image.

A method for performing microscopy-based imaging of samples comprises: loading a sample holder (100) onto a support (50) configured to receive the sample holder (100); moving the sample holder (100) in a first direction, from a starting position on a first strip of the sample holder (100), to move the sample holder (100) relative to an imaging line of a line camera (10), to capture an image of the first strip of the sample holder (100); monitoring a focal plane using an autofocus system (15) as the sample holder (100) is moved in the first direction; in response to a signal from the autofocus system (15), moving an objective lens (25) along the optical axis to adjust the focal plane; and moving the sample holder (100) in a second direction, to align the imaging line of the line camera (10) with a position on a second strip of the sample holder (100).

A focus detection unit to adjust a focal point of an image, of an object, formed by an optical system includes a first output section, a second output section, and a projection optical system. The first output section includes a first light modulation element configured to generate a first pattern image based on incident light and is configured to output the generated first pattern image. The second output section includes a second light modulation element configured to generate a second pattern image based on incident light and is configured to output the generated second pattern image. The projection optical system is configured to project the output first pattern image and the output second pattern image such that the output first pattern image and the output second pattern image have a predetermined positional relationship at an in-focus position of the optical system.

The disclosure features methods and systems that include positioning a surface of a coverslip overlying a sample relative to an object plane of a microscope system, projecting a two-dimensional pattern of light onto the surface, where a focal plane of the two-dimensional pattern at a position of the surface is rotated by an angle β relative to the object plane, obtaining a two-dimensional image of the pattern of light reflected from the surface using a detector that includes an imaging sensor oriented perpendicular to a direction of propagation of the reflected pattern of light at the sensor, analyzing the image to determine a line of best focus of the pattern within the image, determining an offset of the line of best focus from an expected position of the line of best focus within the image, and determining a position adjustment of the surface based on the offset.

A digital scanning apparatus is provided that includes imaging and focusing sensors and a processor to analyze the image data captured by the imaging and focusing sensors and adjust the focus of the scanning apparatus in real time during a scanning operation. The individual pixels of the imaging sensor are all in the same image plane with respect to the optical path of the digital scanning apparatus. The individual pixels of the focusing sensor are each in a different image plane with respect to the optical path, and one pixel of the focusing sensor is on the same image plane as the image sensor. The processor analyzes image data from the imaging sensor and the focusing sensor and determines a distance and direction to adjust the relative position of an objective lens and a stage of the digital scanning apparatus to achieve optimal focus during the scanning operation.

A system and a method for measuring the focus state of an optical instrument are described. The system and the method provide for forming an image of the exit pupil of the objective of the optical instrument. Where the image of the exit pupil is formed, one or more optical elements are placed, deviating at least part of the rays coming from the exit pupil, so that rays coming from different non-overlapping portions of the pupil follow separate optical paths. The rays coming from the two portions of the pupil are then focused, in order to obtain two bidimensional images. A computer determines the mutual distance between these two bidimensional images as a mutual rigid lateral displacement between the two and, based on this distance, determines the corresponding defocus of the optical instrument.

A device and a method for acquiring a microscopic image of a sample structure are described. An optic for imaging the sample structure and a reference structure is provided, as well as a drift sensing unit for sensing a drift of the sample structure relative to the optic on the basis of the imaged reference structure. The optic comprises a first sharpness plane for imaging the sample structure and at the same time a second sharpness plane, modifiable in location relative to the first sharpness plane, for imaging the reference structure.

A digital microscope having a pivoting stand, a method for calibrating said stand and a method for automatic focus tracking and image center tracking upon actuation of the pivoting stand. The pivoting stand includes an angle sensor for determining a current pivot angle of the pivot arm (07). The current pivot angle is processed in the control unit to execute automatic focus tracking and/or center tracking upon actuation of the pivot arm (07). Calibration is performed using two pivot angles, wherein deviating focus and image center positions are ascertained, and a pivot-angle-dependent function for focus and the image center position is ascertained therefrom.

A microscope system includes a microscope body, an XY stage mounted on the microscope body and including a stage configured to place a slide as an observation target and move in an X-axis direction and a Y-axis direction perpendicular to each other, and an XY two-dimensional scale plate fixed to the stage. The XY two-dimensional scale plate is provided with a first mark that provides axis information in the X-axis direction throughout a movable range of the stage in the Y-axis direction and a second mark that provides axis information in the Y-axis direction throughout a movable range of the stage in the X-axis direction, which are used to recognize X- and Y-coordinates of the stage.

A microscope includes a holder for holding a sample, an objective for imaging at least apart of a sample held by the holder, a detection module, a control unit for setting the focus position of the objective in a first direction for the recording by means of the detection module, and a focusing module for maintaining a set focus position of the objective. The focusing module includes the control unit, a second detector and first focusing optics with adjustable focal length. The focusing module is switchable into a focus-hold mode, wherein an intensity-modulated object is imaged into the sample via the first focusing optics and the objective, and an image of the imaged object is recorded by means of the second detector. The control unit holds the focus position of the objective on the set focus position, based upon the recording of the second detector.