DE202009003286U1 - Apparatus for capturing an image of an object - Google Patents

Abstract

Apparatus for capturing an image of an object (6, 66) having a detector (28) comprising a plurality of detector elements (32), an optical system (12) for imaging the article (6, 66) on the detector (28) and A light filter (30, 70) having a plurality of differently filtering filter areas (34, 58, 60, 62), characterized in that the light filter (30, 70) is arranged such that a plurality of filter areas (34, 58, 60, 62) differently filtered image areas of the image of the object (6, 66) are simultaneously imaged on the detector (28).

Description

The The application relates to a device for taking an image of an object with a detector comprising a plurality of detector elements, one optical system for imaging the object on the detector and a light filter with several differently filtering filter areas.

State of the art

to Recording color images is known to be a color camera with a color-sensitive detector to use. A color-sensitive detector is usually limited to three colors. When using a Bayer pattern, one pixel each consists of one blue, one red and two green sensitive detector cells, from whose signals all intermediate colors are put together. By The necessities Four detector cells per pixel is the resolution of such a color detector low.

To the Achieved a high image resolution with a high color resolution is a line spectrograph known. An item becomes line by line scanned, whereby the image of a line is spectrally fanned out, for example, by a prism, so that a three-dimensional image the line is created. In this way, line by line becomes a three-dimensional one Image is taken and saved and the individual images become assembled into a three-dimensional color image.

It is also known to move several color filters in succession in front of the detector and so on an object several pictures in different Record frequency ranges one after the other. The shots can too a hyperspectral image.

It is an object of the invention, a device for receiving a Specify an image of an object with the high-resolution color images can be included.

These The object is achieved by a device of the type mentioned, at the light filter according to the invention is arranged so that several different through the filter areas filtered image areas of the image of the object simultaneously be imaged the detector.

Of the Light filter can be a spectral filter or a polarizing filter be. It can be directly in front of the detector or directly on the detector be arranged. Conveniently, the light filter is arranged in an image plane of the optical system, where 1/10 of the focal length of the optical system on the light filter as Distance from the mathematical image plane is tolerable and as can still be viewed in the picture plane. The light filter can an edge filter, interference filter or absorber filter. The filter areas can spectrally different, so that the image areas spectral are filtered differently. They can take concrete forms, for example Stripes, a checkerboard pattern and / or a micropattern, in which the filter areas a length and / or width below 100 mycrometer. Conveniently, are the filter areas in their extension greater than two, in particular greater than ten detector elements or pixels. Also possible is a spatially continuous varying filter characteristics.

Of the Detector can be implemented as a chip be and is expediently sensitive in all spectral ranges of the filter areas. He can a CCD (Charge-Coupled Device) or a CMOS sensor (Complementary Metal Oxide Semiconductor). The detector elements are advantageously as two-dimensional grid arranged in the form of a matrix. The detector is expediently designed as a monochrome detector and is sensitive in the spectral range of the structured filter.

The Dimensions of the filter areas are advantageously on the dimensions the detector elements adapted, for example by a width and / or length a filter area is an integer multiple of a size of a the detector elements of the detector is, for example m × n detector elements. The light filter may be attached directly to the detector, for example directly on a detector chip, or directly on the sensitive surfaces of the Chip to be evaporated.

The Filter areas suitably correspond to a structure and / or Outline of the sample image or the sample or sample containers. she can be that big like regular structure sections the sample image and / or have their shape.

to explanation The apparatus will be described below, a method to their execution the device is advantageously capable of.

In this method, the filter areas are advantageously moved from one to the next photograph of the subject over a picture pattern of the picture, so that each point of the picture pattern is recorded in a plurality of light properties, in particular spectra. These values are expediently assigned to the point and can be displayed and / or stored. The image pattern can be the entire image or a section of the image. The movement is a relative movement whereby the filter areas can rest nen, z. B. relative to a detector housing, and the image pattern is moved, or vice versa.

at a multiple recording of each point in several light characteristics, For example, colors, can from the several shots a color image be assembled. By dividing the light filter in the filter areas is only one with a movement of the light filter small movement the size of one Sizing a single filter area is sufficient, so not the entire light filter away from the detector and a new light filter must be moved to the detector. Due to the low movement distance The movement can be done very fast.

To the Achieving a high light output, it is advantageous if signal contributions in the individual detector elements within a filter area, the during a movement of the sample image relative to the detector of a Sample area can be assigned, cumulated in a value become. Such cumulative values of a sample area of different Filter areas can to the overall light characteristic information of the sample area.

The Image pattern can be during the movement of the filter areas remain dormant to the detector, so that the filter areas are moved relative to the detector. Also possible is it, the picture above move the detector so that the filter areas are relative to the detector rest. The movement of the picture over The detector can be detected by means of a movement of the optical system or part of the optical system relative to the detector. One more way consists in moving the filter and the detector relative to the optical System, for example, resting relative to a camera body. Generally speaking, one or two of the three elements may look like Detector, light filter and optical system each resting on, for example a camera body whereas the remaining two or the remaining one are kept an element are movable relative to the other elements.

advantageously, The optical system is part of a microscope whose case is fixed Connected to a sample table on which the item is in shape a sample can be moved, for. On a moving tray, in particular with the aid of a motor drive and a position control by a control means.

advantageously, the object becomes relative to the optical system and light filter moved and the subject is in several shots each image by section taken, with the location of the filter areas in the image sections each unchanged is. The optical system can in this case in a housing, for example of the microscope, rest and the object and with it the light pattern of the object is passed by the optical system, wherein the image sections and with them the filter areas over the Hiking overall picture.

is For example, the object elongated, for example in the form of a series of samples, so can by a variety of taken in succession image areas of the entire object be, each pixel of the object in many colors or was recorded in each color or by each filter area. On This way can be very fast a color image of the entire subject can be recorded. On a Movement of the color filter relative to the optical system or to the detector can be dispensed with. As a device for taking pictures Of samples often over one Actuator for the controlled movement of the samples along the receiving device, For example, the microscope is guided, the recording device This makes it particularly easy to keep.

Conveniently, For example, the filter areas are designed as strips that are from one side of the image to the opposite Range and in their longitudinal direction are aligned perpendicular to the direction of movement. Also a stretching from one picture page to the opposite picture page is sufficient. This allows each pixel of the object especially easy about All filter areas of the light filter are guided.

advantageously, is the movement such that a pixel from one shot to the other next shot is moved by the width of a filter area. The width is always suitably several Pixel. A small overlap area, z. B. according to the double accuracy of the moving actuator, is useful here.

Around a very high resolution reach, in particular for image sections of particular interest, It is advantageous if the movement from an image capture to next Image capture is less than one image pixel. Due to the movement in the subpixel area can be a subpixel resolution be calculated.

The specification of the movement is advantageously predetermined by a control means, which in particular independently detects image areas of particular interest and triggers a subpixel movement. The movement can be performed in different modes, e.g. A subpixel mode, a filter area width mode in which the movement from one frame to the next is the width of a filter area, or a multi-pixel Mo where the movement is several pixels of the detector. It is also possible to control only two of the three described modes.

In an advantageous embodiment of the method, the light filter is an edge filter whose edge frequency in the spatial Course of the light filter perpendicular to the edge and in particular perpendicular varies to move. That way, through the controller the movement increment from one shot to the next shot the color resolution an overall picture from the recordings are controlled. The light filter is expediently connected to an actuator and a control means that is to control a movement of the light filter is used.

In addition, will suggested that the light filter two in the beam path of the figure comprises successively arranged edge filters whose edge frequency in the spatial Course of the edge filter in each case perpendicular to the edge - and in particular vertically to move - varies with mutually opposite frequency response. This can - with appropriate Arrangement of the edge filters to each other - a spatial transmission window be generated by a movement of the edge filter to each other both spatially as well as spectrally magnified and can be downsized. This can be a high variability in frequency and Space range of recorded images can be achieved.

A particularly good spectral adaptation of detector and light filter can be achieved if the detector several in the color sensitivity different, each in a color range sensitive detector areas and at least one filter area in front of each detector area is arranged. This is advantageously in its color range adapted to the color range of the detector, so that the color ranges of the light filter are different. The adaptation is advantageously carried out by the transmission of the filter area in the sensitivity range of the corresponding detector area and in a color range one of the other detector areas is not located.

The Different detector areas can be spatially directly be arranged side by side, for example in a contiguous Matrix of detector elements, or spatially separated be placed so that the optical system one or more Elements for directing the image of the object to a plurality of detector areas includes, for example, a dichroic mirror or the like. The detector areas are advantageously operated synchronously, so that an image of the object on the detector areas in several color channels is recorded simultaneously.

A further advantageous embodiment of the Method provides that the filter areas different transmission values and the transmission values to a recording characteristic of the detector are respectively adapted, in particular for achieving a uniform image exposure at an inconsistent spectral sensitivity of the detector elements. In this way, a particularly good image result can be achieved. The adjustment may be due to a different size of the filter areas respectively. Another possibility exists in the adaptation of a different frequency transmission width the filter areas to the detector. So can a frequency transmission width in a frequency range where the detector is less sensitive is to be bigger and in a frequency range where the detector is more sensitive, be smaller.

Besides that is it is possible the transmission strength, So a damping of the filter area to match the detector so that higher attenuation is selected in a frequency range where the detector is more sensitive than in other frequency ranges.

Also a high image quality can be achieved if the filter areas have different transmission values and an activation of the detector elements to a transmission value the shadowing filter area is adapted. So can one reinforcement raised, an integration time extended, or pixels merged, if a filter area has a high attenuation over one other filter area. It can thereby a uniform exposure of the picture in all frequency ranges. Is the transmission value a filter area particularly high, it is also possible only read every second pixel.

advantageously, follows the different control of the detector elements one Movement of the filter areas over the detector after. For example, if the light filter on the Detector moves, so this movement can be detected, allowing everyone Filter area can be assigned to the detector elements, the be covered by the area. The control of the detector elements can thereby pixel by pixel to the respective associated filter area be adjusted.

The Device comprises a control means, which advantageously is provided, one, several or all of the above method steps to control.

The invention is based on execution Examples explained in more detail that are shown in the drawings.

It demonstrate:

1 a schematic representation of a specimen-directed microscope with a camera with a light filter on a detector,

2 a beam path from a sample to three detectors,

3 - 6 a detector with a light filter in four different layers to a sample,

7 a diagram of an edge filter with a continuously moving edge in the filter surface,

8th a transmission diagram resulting from two successively arranged edge filters and

9 a sensitivity diagram of a detector.

1 shows a schematic representation of a z. B. executed as a microscope optical imaging system 2 pointing to one on a sample table 4 lying sample 6 is directed. The optical imaging system 2 includes a light source 8th , whose rays of light in a with a solid arrow 10 indicated beam path by means of an optical system 12 and a dichroic mirror 14 to the test 6 is directed. The optical system 12 closes a lens 16 with, with the help of an actuator 18 relative to a microscope housing 20 along the optical axis 22 the beam path for focusing the sample 6 is verifiable.

From the sample 6 reflected or scattered radiation is in a direction indicated by a dashed arrow beam through the dichroic mirror 14 and only indicated optical elements 24 of the optical system 12 in a camera 26 passed a detector 28 with a light filter 30 having. The detector 28 comprises a plurality of detector elements arranged in a two-dimensional matrix 32 , which are designed as CCD elements and mounted on a chip. The light filter 30 is a spectral filter with several spectrally different filter areas 34 also on the chip and in the beam path immediately in front of the detector elements 32 are arranged.

The sample table 4 and with him the rehearsal 6 is with the help of an actuator 36 perpendicular to the optical axis 22 of the lens 16 movable, as by arrows 38 is hinted, so that several shots of the sample 6 in different positions of the sample 6 to the microscope 2 can be made. The actuator 36 can by a control means 40 of the microscope 2 be controlled so that a trajectory of the sample 6 from recording to recording to a predetermined value or calculated by the control means. The control means 40 can at the same time control means 40 the camera 26 or an additional control means of the microscope 2 outside the camera 26 be.

By the control means 40 may alternatively or in addition to the actuator 36 an actuator 42 of the light filter 30 and / or an actuator 44 of the detector 28 be controlled so that the filter areas 34 and / or the detector elements 32 relative to the optical system 12 perpendicular to the optical axis 22 of the camera 26 incident beam path are controllably movable. This allows an image of an object of the sample 6 in one or more ways via light filters 30 and / or detector 28 hike.

An alternative embodiment of a detector 46 with several detector areas 48 . 50 . 52 is in 2 shown. The following description is essentially limited to the differences from the exemplary embodiment 1 which is referred to with regard to features and functions that remain the same. Substantially equal components are basically numbered with the same reference numerals and features not mentioned are taken over without being described again.

About two dichroic beam splitters 54 . 56 is from the sample 6 reflected radiation divided into three spectral regions on the detector areas 48 . 50 . 52 directed. The detector areas 48 . 50 . 52 are each sensitive or more sensitive in only one of the spectral ranges than in the other spectral ranges. In front of each detector area 48 . 50 . 52 is each a filter area 58 . 60 . 62 arranged, the filter areas 58 . 60 . 62 only one of the spectral regions are permeable or more permeable than in the other spectral regions. Their permeability is at the respective assigned detector area 48 . 50 . 52 spectrally adjusted. One or all of the filter areas 58 . 60 . 62 can in turn be divided into spectrally different filtering sub-areas, as in 2 is shown. By dividing into spectrally different sensitive detector areas 48 . 50 . 52 each with spectrally different filtering filter areas 58 . 60 . 62 a particularly high light output over a wide spectral range can be achieved.

In the 3 - 6 is each the image of a sample 6 represented, the 3 × 10 sample vessels, which can also represent sample surfaces, 64 having, Significant larger numbers are also conceivable, in each of which the same or different sample substance is contained. The sample vessels 64 are arranged in a rectangular matrix and on the sample table 4 attached. In the sample substance are objects to be examined 66 , The sample 6 shows a picture pattern in its entirety and in its objects.

The detector 28 and its 11x15 rectangular detector elements 32 are shown for clarity with dashed lines, whereas the light filter 30 with its 5 strip-shaped filter areas 34 are represented by solid lines. The strips of the filter areas 34 are arranged perpendicular to the direction of movement of the sample table by an arrow 38 is shown. To better distinguish the lines, the image of the sample is shown in phantom.

3 shows the detector 28 and the image of the sample 6 in a position to each other, in which a sample of the sample 6 is made, but not the first, as explained below. The photograph represents an image section with five image areas in which twelve sample vessels 64 complete with contents and three sample containers 64 only partially shown. Three sample containers each 64 be through a filter area 34 and thus imaged in its spectral range. Through a filter area 34 in each case one of five image areas of the image section is imaged. Each filter area 34 and each image area covers in this case perpendicular to the direction of movement of the sample 6 exactly three detector elements 32 More generally, exactly the same number of detector elements 32 ,

For a next shot will be the image of the sample 6 by the distance of the width of the filter areas 34 moved, with the width in the direction of movement of the sample 6 you can see. It will now be another image section of the sample 6 taken, this image section a different sample section and other items 66 covers. The location of the filter areas 34 in the image sections remains the same, but not relative to the sample sections and objects 66 , The second picture shows the re-imaged sample containers 64 in a different spectrum, that is, in a different color.

5 shows the sample 6 again by the width of the filter areas 34 offset, so that the now three times pictured sample vessels are shown in three different spectra. In this way, all areas of the sample 6 and all sample vessels 64 mapped at least as often as filter areas 34 are present, in the embodiment shown at least five times, so that each sample area is included in five spectra. From these five images, a five-color image can be assembled for each sample area. In order to image each sample area five times, the sample is taken in the first image 6 only through a filter area 34 recorded in the second shot through two filter areas 34 , and so on. 3 thus shows the fifth image of the sample 6 ,

The sample 6 is depicted in its entirety by the sample 6 in sections on the detector 28 and several partially overlapping images of the sample 6 and the objects 66 be made. At least as many images are made as different filter sections 34 available. From as many overlapping images as different filter sections 34 are present, each a multi-color image of the sample 6 or an object 66 generated, z. B. from the control means 40 ,

The recordings are evaluated by an evaluation, which is the control means 40 that can be with the detector 28 is technically connected. Here, for example, it is recognized that an object 68 is of particular importance and should be presented in a particularly high resolution. When this task is detected, the sample becomes 6 from one shot to the next only by less than a pixel length, that is, a length of a detector element 32 , moves, as in 6 compared to 5 is recognizable. From object to image, the object becomes subpixelwise over a boundary between two filter areas 34 emotional. From the recordings, a resolution can be achieved in the area that has been run over by the border, which lies in the subpixel area, so that the object 68 can be displayed particularly high resolution.

Alternatively to a movement of the sample 6 to the microscope 2 can the light filter 30 and / or the detector 28 relative to the sample 6 and for example the microscope housing 20 to be moved.

In another embodiment may charge the individual detector elements within a filter area be moved detector element with the image of the sample and only after one or more shifts are read. Or it can the charges that during the displacement of the sample image within a filter area associated with a sample position, associated with a pixel spectral value become. In this way, the charge generated by the light from the sample via a longer Time to be accumulated.

7 shows a double diagram in which the filter surface of a light filter 70 is shown in the x and y direction. The z direction is the direction of the op table axis 22 at the entrance to the camera 26 , In addition, the absorption A of the light filter 70 shown. The higher the transmission of the light filter 70 The lower the absorption A. In the hatched area, the absorption is ideally close to 100% and the light filter 70 not translucent. The light filter 70 is an edge filter with an edge 72 at a fixed wavelength λ. The wavelength λ is dependent on the position of the edge 72 in the x direction of the filter 70 , Further to the right in the filter is the wavelength λ of the edge 72 higher than further left. In the example shown, the change in the wavelength of the edge per distance light filter in the x direction is constant. Also other relations with linear or nonlinear change are conceivable. At the light filter 70 are very many or infinitely many spectrally different filtering filter areas very close or infinitely close to each other.

When using the light filter 70 instead of the light filter 30 in the 3 - 6 each sample area can be imaged as often as desired in different spectra, so that a spectral resolution of the overall image of the sample 6 from the moving distance of the sample 6 depends on admission to admission. In this way, the spectral resolution of the overall picture can be chosen freely.

Become two edge filters 74 . 76 arranged with an opposite edge course in a row, as in 8th is shown, so can a transmission window 78 both in its spatial extent Δx and in its spectral extent Δλ by a movement of the edge filters 74 . 76 be set against each other. Spectral ranges can be excluded and a spectral resolution can be set.

An adaptation of the light filter 30 to the detector 28 is in 9 shown. In 9 is a diagram of the sensitivity E of the detector 28 plotted over the wavelength λ of the registered light. The sensitivity E is dependent on the wavelength λ of the light and by a wavelength λ ₁ less than by a wavelength λ ₂ . To ensure a uniform exposure of the images of the sample 6 over the entire relevant spectral range is the transmissive at the wavelength λ ₁ filter area 34 of the light filter 30 in a larger wavelength range Δλ ₁ transmissive than the transmissive at the wavelength λ ₂ filter area 34 of the light filter 30 which is transmissive only in the smaller wavelength range Δλ ₂ .

Another way to achieve the most even exposure of the images of the sample 6 Over the entire relevant spectral range is an electronic adaptation of the detector elements 32 to the filter area in front of them 34 make. For a less transmissive filter area 34 can a range of this filter 34 associated detector element 32 be driven differently than a detector element 32 , which is a higher transmissive filter area 34 assigned. The different activation can be achieved by a different setting of the gain and / or the integration time of the detector elements 32 be achieved. Also a pixel binning, ie the merging of two or more pixels or detector elements 32 , is conceivable, as well as a subsampling, so a read only every n-th detector element 32 , with n = 1, 2, 3, ... The corresponding control can be provided by the control means 40 be made.

In a particularly advantageous embodiment, the electronic adaptation of the detector elements 32 a shift of the filter areas 34 in front of the detector elements 32 considered. This requires the position of light filter 30 to detector 28 be known, for. B. by position signals from one of the actuators 42 . 44 ,

2

microscope

4

sample table

6

sample

8th

light source

10

arrow

12

optical system

14

mirror

16

lens

18

actuator

20

microscope housing

22

optical axis

24

optical elements

26

camera

28

detector

30

light filter

32

detector element

34

filter area

36

actuator

38

arrow

40

control means

42

actuator

44

actuator

46

detector

48

detector region

50

detector region

52

detector region

54

mirror

56

mirror

58

filter area

60

filter area

62

filter area

64

sample vessel

66

object

68

object

70

light filter

72

edge

74

cut-off filter

76

cut-off filter

78

transmission window

A

absorption

e

sensitivity

λ

wavelength

Δλ

Wavelength range

Claims (2)

Device for taking a picture of an object ( 6 . 66 ) with a detector ( 28 ) comprising a plurality of detector elements ( 32 ), an optical system ( 12 ) for imaging the object ( 6 . 66 ) on the detector ( 28 ) and a light filter ( 30 . 70 ) with several differently filtering filter areas ( 34 . 58 . 60 . 62 ), characterized in that the light filter ( 30 . 70 ) is arranged so that several through the filter areas ( 34 . 58 . 60 . 62 ) differently filtered image areas of the image of the object ( 6 . 66 ) simultaneously to the detector ( 28 ). Apparatus according to claim 1, characterized by a control means which is provided to control a movement of the filter areas ( 34 ) from one to the next recording of the object ( 6 . 66 ) over an image pattern of the image so that each point of the image pattern is recorded in multiple light characteristics.