The invention relates to a method or an apparatus according to claims 1 or 12. Here it is referred to image recorders for the recording of an object, that is, the image data of the object. Insofar the object is to be understood such that the object image represents the recording. In the description hereinafter it is also often referred to the object.
In photo cameras there are systems for automatically adjusting the focus (called auto-focus). Hereby, an image area selected in advance by the camera by is typically taken from the centre of the image. Various methods are applied to this image area. These methods may include the measurement of distances, if an auto-focus is desired. These methods may also include an automatic adjustment of aperture and/or illumination time (a so-called program automatic system). To this end, the brightness of the image area of interest is used and an evaluation and adjustment is performed. Alternatively to the selected centre measurement a spot measurement may be performed, if a small section is selected in the centre of the object image, from which the illumination information used for the adjustment of the camera is derived. Moreover, a plurality of positions may be used, which may be combined with the aforementioned spot measurement, either weighted or non-weighted.
The invention relates to an improved system that automatically adapts to the image information. It is not always ensured that the area of interest is located in the centre of the image. It is not always ensured that the spot measurement yields the correct illumination. A measurement with emphasis of the centre is in most cases not a satisfactory solution, since light and colour influences affect the adjustment of the image recorder, which may not be desired by the recording person (the user of the image recording device).
It is the object of the invention to provide a recording device with automatic adjustment that allows enhanced or improved application-specific adaptability.
The object is solved by a solution according to claims 1, 12 or 14. The invention extends the possibilities offered by an image recorder. Instead of static points or fields a measurement of dynamic fields is performed. The dynamic is determined by the image rather than by the camera (claim 14). The focus length, the aperture or the illumination or focus settings are dynamically controlled in such a manner that the image itself determines which position or which area of the image (object section) is used for the control of the camera. The adjustment of the camera is at least such that the recording of the object is affected. The focusing and aperture and illumination time are preferred aspects as well as the combination of focusing and at least one of the settings of aperture/illumination (claims 2, 3 and 4).
The image sections (fields or points) to be evaluated are selected such that prior to releasing the image recorder, or prior to starting the recording of a video recording device, a specific type of object type is pre-selected by the user (claim 1).
Such types of object types may represent faces (claim 10, claim 15). These should be represented in a focused manner and/or well-illuminated with respect to the object image.
Prior to the determination of the parameters for the adjustment of the recorded image there are performed the presetting of an object type (by the user) and the automatic evaluation of the system for obtaining those positions in the object image that correspond to the object type.
In addition to the position also the size, at least approximately, may be determined.
Thus, by means of the detection algorithm the selected object types are searched in the image, thereby affecting or altering the selection of the measurement points or measurement fields, which are used for the determination of parameters (claims 5, 6).
Several (identical) object types may also be present in the object image (claim 7); position data are then obtained for each section, which determines the position of the respective section within the (total) object image, or which is thus determined with respect to their positions (claim 11).
In case of a plurality of image sections of the object type (claim 7) the depth of focus may be optimised (claim 9).
A supporting co-control may be performed on the basis of selected non-movable (smaller) fields (claim 13). They are permanently selected in the object image (on the image sensor in the device).
Exemplary embodiments supplement and explain the invention.
a is a recording apparatus 100.
On the basis of the recording apparatus 100 of
The photo camera 100 of
To this end, motor drives may be provided to adjust the aperture position or the focus position of the lens 105. The (electronic) adjustment of the illumination time may be controlled by an electronic unit 68. The electronic unit may control a motion of the shutter (in the form of an iris aperture or a blade aperture), thereby also controlling the open time (illumination time) (mechanical shutter).
A recording of an object occurs, wherein the object is for example the image according to
For controlling, i.e., influencing the way of recording, first an object section is identified in the recording object image 1. This identification or localization is pre-defined with respect to its type, which is accomplished by selecting an object type via a user interface 9. For example, the object type may be a face that is defined by features or edge lines, such as a pattern or model according to DE-C 100 43 460 (Fraunhofer association); cf. the evaluation of edge information, the generation of a model according to
In a means 20 the position data PD is used to set image sections as object sections and to characterise the data in data processing fashion. Frames r1, r2, in which faces have been identified, are symbolically depicted in the respective more illustrative
From the object section that image information, at least a significant amount thereof, is used that resides within the section. From the image information a brightness value (in the form of a mean value) may be obtained, contrast information may be evaluated, or a focus setting may be aligned to this area 1a or 1b that is indicated by frames comparable to the frames r1, r2 of
The corresponding control means in the form of PD-based controller 68 are implemented in the individual components 30, 40, 50, which may act individually or in any combination to alter the camera setting.
The illustrative block circuit diagram of
It can be operated with one object section only. However, several object sections may be involved, which may commonly be used. For example, the object section 1a and the object section 1b that are placed before the image recorder so as to not have the same distance therefrom, may adjust, by selecting of a corresponding setting of the aperture, a depth of focus at which both object sections are still sufficiently focused within the region of the depth of focus. This is an example for an aperture setting 40 that would entail a corresponding automated illumination adjustment 30, 68 as is compatible with the environmental brightness.
Is a brightness adjustment to be performed at the same time, this can also be accomplished within the object section recognized, which in particular may readily be appreciated by the person skilled in this field in the case of sophisticated environmental conditions according to
The further exposure fields having reduced dimensions, in the following referred to as K2 and being arranged around the image perimeter, are evidently also inappropriate, after the sky, the snow and further bright items would have been measured for the illumination adjustment, whereas the illumination field r2 exactly extracts that area of the image that is substantially relevant for the illumination.
In particular, in the case of portable cameras and video cameras an altering of the described settings by automatically adapting to the object is advantageous. Frequently, the object is shifted away from the image centre, which in particular in
The area-like measurement fields r2, r1 of
If the person depicted in
For finding the object information, i.e., the position data, the entire image 1 may be searched. Hereby, also the information is obtained as to how many of the object types that are looked for, are present in the total image. If several object types are present, the user may select which one of these several object section he wishes to use, or he allows the employment of several section for controlling the camera setting.
In addition to an adjustment also a display 70 may be provided, which may inform about the number of object sections obtained as determining measurement areas r2, r1, if necessary may determine those object sections used for the controlling, or provides other control information that may be relevant to the user during the recording.
In
The focusing is performed substantially more precisely, as the person to be focused is not located in the centre of the image bur is slightly laterally offset with respect to a centre-based focusing.
If several persons are present in the image of
Hereby, it is again to be appreciated that the position of the object type in the image is not depending on the camera, but instead is determined by the image of the object, i.e., the object image. When the person is moving across the image, the measurement field r1 (or r2 or 1a or 1b) is also moving along with the person, even though the camera itself with its alignment and the remaining background remain unaltered.
In
Alternatively or additionally also the brightness of a face area may be used, which has previously been indicated as r2. This face area is determined by the position data PD, has been obtained by the search 10 may be used in the illumination adjustment.
In this manner, the illumination of the face may be enhanced. The bright/white background with its pronounced effect, which may be considered as difficult, is of reduced influence in the recorded image.
Number | Date | Country | Kind |
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103-05-851.6 | Feb 2003 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE04/00246 | 2/11/2004 | WO | 8/12/2005 |