DE102012009975A1 - Opto-electronic rangefinder integrated camera, has pick-up modules comparing determined phase spacing with values for different phase spacings associated with microprocessor unit, and signal outputs provided in calibration chart - Google Patents

Abstract

The camera has a focusable retainer lens (2) and a visual observable display unit for representation of data and/or images. Electronic image pick-up modules (5, 6) are spaced from each other and aligned into a front surface of a housing (1) with optical axes on a common target point. The pick-up modules receive images of an objected space for determining phase spacing and compare the determined phase spacing with values for different phase spacings associated with a microprocessor unit (12) in the housing. Signal outputs of the image pick-up modules are provided in a calibration chart.

Description

The invention relates to a camera with an opto-electronic rangefinder, a focusable recording lens and a visually observable display unit for displaying data and / or images.

Digital cameras with these functional elements are known in different configurations. The distance measurement is usually performed through the taking lens via an autofocus sensor which controls the distance setting of the taking lens. The autofocus measurement works either by the contrast method via the image sensor or by the phase comparison method with pupil division via a separate AF module. With the contrast method commonly used with viewfinder cameras, the taking lens has to be moved across the focus area and iteratively approached the focus point. The process is relatively slow. The predominantly used in SLR cameras phase comparison method, however, directly indicates the direction of focus storage and allows by zeroing the phase faster automatic focus adjustment and focus tracking z. B. in continuous shooting or Aufnahmeschwenks.

The image area targeted for the distance measurement is usually displayed by image limitation within the image displayed on a display on the rear wall of the camera. However, there are also known cameras with a viewfinder in which the image to be recorded and the autofocus measuring range are displayed electronically.

Manually focusable rangefinder cameras are usually equipped with an optical rangefinder that is mechanically coupled to a manually operable focus ring of the taking lens. For distance measurement, two images are generated via separate viewfinder lenses, which are brought into a viewfinder image as mixed or sectional images by adjusting the recording lens to cover. The optical and mechanical structure of such rangefinder systems is very complex, especially in cameras with interchangeable recording lenses of different focal length, in which additionally different field-limiting frames must be reflected in the viewfinder beam path. To superimpose the images in the viewfinder view, at least the optical axis of one of the viewfinder objectives must be changed as a function of the adjustment of the focusing ring. The optical-mechanical adjustment of this system is difficult and dependent on the overall system of recording lens and rangefinder. The advantage is the possibility of image formation by individually selected sharpness settings and the accuracy of the distance measurement by triangulation, which is suitable only for a manual focus, as it does not provide electronically usable signals for an AF device.

The invention has for its object to combine the advantages of an opto-mechanical measuring viewfinder system with those of an opto-electronic distance measuring system for AF control, in addition, a reduction in manufacturing costs, the mechanical structure and the Justieraufwandes be possible should.

This object is achieved according to the invention in cameras with the features mentioned by the characterizing features of claim 1. Advantageous developments emerge from the features of the subclaims.

The arrangement of two spaced-apart electronic imaging modules allows the choice of the distance to create a suitable basis for the triangulation. The alignment of the optical axes of the image acquisition modules to a common target point avoids moving elements. By selecting the distance of the target point, the coverage of the image angle ranges detected by the two image acquisition modules can be influenced; in particular, an adaptation to the image angles of interchangeable recording lenses of different focal lengths or of zoom lenses can be achieved. The determination of the phase difference of the images taken by the image acquisition modules allows an indication of the measured distance relative to the distance of the target point. By test measurements with known object distances, a calibration table for the relationship between measured phase separation and object distance can be created and stored for evaluation by a microprocessor unit in the housing of the camera.

The rangefinder according to the invention can be constructed as a separate assembly and mechanically pre-adjusted outside the housing of the camera. A fine calibration of the image acquisition modules for phasing can be done by software. The calibration table for measured interpolation points of the distances can be interpolated for intermediate values of the distances by software calculation.

The recording lens may be associated with an integrated, the current focus setting of the recording lens-indicating sensor. The sensor can z. As well as the deflection of a known roller lever, which rests against a control cam of the recording lens measure. The Measurement signal of the sensor can be entered into the microprocessor unit as an additional signal.

The distance determined from the phase distance and the distance measured by the sensor can be displayed on the visually observable display unit. It is advantageous for the evaluation by the user if the targeted object area is displayed on the display unit and the difference between the two distance values is displayed as direction symbols in comparison to the distance according to phase adjustment. In addition, characteristics of the respective recording lens, frame limitation frame and / or exposure information can be displayed.

The recording lens may be connected to a manual or motorized actuator for zeroing the difference in distances displayed on the display unit. Both manually focusable and auto-focus lenses can be used on the camera.

In a manner known per se, an optical viewfinder with viewfinder view and viewfinder outlook for visual observation of the targeted object space can be present in the housing of the camera. The display unit can be arranged in the housing of the camera so that it is observable on the viewfinder.

About the viewfinder but can also be a purely electronic viewfinder with a bilddarstellenden display observable. Also, a combination viewfinder, which represents either a optical or an electronic image via a divider prism, can be used at this point. It is useful if the viewfinder view is dimmed. To cover the viewfinder outlook in particular a switchable opto-electronic device may be present, such. As a PN-LCD screen, a glass prism with electrically controllable liquid, an electrically controllable mirror, etc.

In the drawing, an embodiment of the subject invention is shown schematically and will be described below with reference to the figures. Showing:

1 a camera with the rangefinder and a combination viewfinder and

2 the influence of optical and geometrical parameters on the opto-electronic rangefinder.

In the 1 illustrated camera includes a housing 1 with recording lens 2 and viewfinder 3 , In the front of the case 1 and in the direction of the optical axis 4 the recording lens 2 are two electronic image acquisition modules 5 . 6 used spaced apart. The image acquisition modules 5 . 6 each consist of a measuring lens 7 . 8th and a downstream image capture sensor 9 . 10 , The image acquisition modules 5 . 6 are preferably on a common base plate 11 arranged. But they can also be separated from each other in corresponding openings in the front of the housing 1 be used.

The of the image acquisition modules 5 . 6 recorded electronic image signals become one in the housing 1 arranged microprocessor unit 12 for determining the phase spacing of the respective mutually assigned pixels supplied (arrows). The microprocessor unit 12 contains in a memory a calibration table for the object distance associated with a phase separation. About an unillustrated interface on the housing 1 The software can be used to operate the microprocessor unit 12 updated and / or expanded.

That to the case 1 scheduled recording lens 2 can be a manually focusable lens or a motorized lens. The manually focusable lens is provided in a conventional manner with a cam on which a roller lever 13 runs along. The roller lever 13 is provided with an electronic sensor, not shown, for determining its deflection. The focus distance of the taking lens 2 corresponding deflection signals are also the microprocessor unit 12 forwarded (arrow). Motor-focusable lenses contain an electronic scale to indicate the respective focus distance. These signals are also the microprocessor unit 12 forwarded (arrow).

The in the case 1 integrated viewfinder 3 contains a viewfinder 14 and a viewfinder outlook 15 , In between is a prism 16 with a splitter surface 17 , About the splitter surface 17 can be a display unit 18 to be watched. Before the viewfinder outlook 15 is a switchable opto-electronic component 19 arranged. Preferably, this is a PN-LCD for opaque cover of the viewfinder outlook 15 , Of course, a known per se mechanical lock can be provided at this point.

On the display unit 18 be from the microprocessor unit 12 and / or image and / or data information (thick arrow) generated by an image acquisition chip for visual observation. By covering the ambient light incident through the viewfinder view 15 can increase the visual perceptibility of the representations on the display unit 18 be improved.

In particular, the microprocessor unit determines 12 those from the image acquisition modules 5 . 6 and the sensor on the recording lens 2 derived different distance information and their difference. These can except an ad on the display unit 18 or a display, not shown, on the rear wall of the housing 1 also for autofocus adjustment of the taking lens 2 be used (arrow). In addition, characteristic data of the respective recording lenses 2 in the microprocessor unit 12 are entered, which generates matching frame boundaries and on the display unit 12 being represented.

The influences of the image angles of the measuring objectives 7 . 8th , the tilt angle of their optical axes and their distance from each other are in 2 shown.

2a) shows measuring lenses 7 . 8th with short focal length and thus a large image angle compared to measuring lenses 7 . 8th with a long focal length and thus a narrower angle of view. The measuring range for the distance measurement is indicated by the overlapping cross-hatching of the image angles. A larger coverage area results in a larger measurement range with a better focus detail in the image sensor. A narrower coverage area results in a better resolution of the targeted focus section and thus a more accurate measurement.

2 B) shows the influence of the tilt angle of the measuring lenses 7 . 8th to each other. The more the optical axes of the measuring lenses are inclined to each other, the larger the measuring range and the better and more accurate is the centric detection of the focusing area. In addition, the tilt angles of the two axes should be as equal as possible in order to ensure a more accurate distance overlap between the two axes to the target point. Possible differences due to an asymmetrical arrangement of the image acquisition modules 5 . 6 relative to the optical axis of the taking lens 2 can be compensated by software during the basic adjustment of the rangefinder.

2c) shows the influence of the distance of the two measuring lenses 7 . 8th to each other. The shorter the distance, the larger is the measuring range and the closer the camera begins to intersect the image angle. On the other hand, a further distance provides a larger measurement base with a larger image shift between the images of the image acquisition modules 5 . 6 and thus a more accurate evaluation of the phase separation.

The appropriate choice of influence parameters depends on the number and type of recording lenses to be considered 2 and can be optimized by the competent expert by simple experiments. In 2 is the near position by the beginning of the overlap area 20 given.

LIST OF REFERENCE NUMBERS

1

casing

2

Recording Lens

3

viewfinder

4

optical axis recording lens

5, 6

Image capture modules

7, 8

Measuring lenses

9, 10

Image acquisition sensors

11

baseplate

12

Microprocessor unit

13

roller lever

14

Eyepiece

15

Monocular

16

prism

17

splitter surface

18

Display Unit

19

switchable cover

20

Start of overlap area

Claims (8)

Camera with an opto-electronic rangefinder, a focusable recording lens and a visually observable display unit for displaying data and / or images, characterized in that as a distance meter two spaced apart and aligned with their optical axes to a common target point electronic image recording Modules ( 5 . 6 ) in the front surface of the housing ( 1 ) of the camera are used and for determining the phase separation of the image acquisition modules ( 5 . 6 ) recorded images of the object space and for comparison of the determined phase separation with the values stored in a calibration table for the distances assigned to the different phase spacings, a microprocessor unit ( 12 ) in the housing ( 1 ) and with the signal outputs of the image acquisition modules ( 5 . 6 ) connected is, A camera according to claim 1, characterized in that the lens a the current focus distance of the taking lens ( 2 ) indicative sensor associated with the microprocessor module ( 8th ) is connected to input the focus distance. Camera according to claim 2, characterized in that the microprocessor unit ( 12 ) with the visually observable display unit ( 18 ) is connected to represent the distance derived from the phase difference and the distance determined by the sensor. Camera according to claim 3, characterized in that on the display unit ( 12 ) from the microprocessor unit ( 12 ) determined difference between the derived from the phase difference and the sensor of the focusing unit of the recording lens ( 2 ) can be displayed relative to the distance derived from the phase separation. Camera according to claim 4, characterized in that the recording lens ( 2 ) with a manually or motor-operated adjusting device for zero adjustment of the display unit ( 18 ) displayed difference of the distances is connected. Camera according to claim 1, characterized in that an optical viewfinder ( 3 ) with viewfinder ( 14 ) and viewfinder view ( 15 ), an electronic viewfinder, an opto-electronic combination finder and / or a backplane display for visual observation of the object space is present. Camera according to claim 6, characterized in that the viewfinder outlook ( 15 ) is dimmable. Camera according to claim 7, characterized in that a switchable optoelectronic component ( 19 ) to cover the viewfinder view ( 15 ) is available.

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