The invention relates to an arrangement for the correction of the visual depiction of image information on a projection surface, such as a projection wall, comprising a processor, for the purpose of providing the image information, which is connected to a projector and a sensor unit for capturing image data, which can be captured by the processor and converted to correction data.
As is known, the settings for image information are changed by means of control elements provided on the projector, which is often disadvantageous during presentations.
To correct deterioration in color image displays on a projection surface, a solution is proposed, in EP 1 150 159, in which the image data stored on a computer and representing image information in a color space, are supplied to a projection device in the form of a video stream. This then generates corresponding optical signals and projects them onto a projection surface. Adjacent to the projector is a light metering device, which captures either the light emitted by the projector or the light reflected from the projection surface and supplies the metering data generated in this process to profile development software for the purpose of image correction.
A disadvantage of such arrangements is that, in addition to the projector, a device oriented to the projection surface must be installed, making the entire projection technology highly complex and cost-intensive. In addition, such solutions can only be used to precisely adjust or correct influences of the properties of the projection surface, such as those of a screen, or of light conditions at the projector location.
Based on the above, the object of the invention is to provide an arrangement for correction of the visual depiction of image information on a projection surface, with which, in a relatively simple manner and without additional technical equipment complexity, the image information depicted by a projector is, with regard to the light and color parameters, as well as the geometry on the projection surface, optimally adjustable for the viewer or correctable as a factor of changes specific to the surrounding environment.
According to the invention, this objective is solved by an arrangement of the type mentioned initially in that the sensor unit consists of a color sensor and/or a sensor for capturing geometric image data and is integrated into the projector.
Due to the direct integration of the sensor unit or sensor units for image data correction into the projector, there is no need to install additional measuring systems that are user-unfriendly.
Advantageously, the sensor unit is oriented in the direction of the projection beam path and/or in the direction of the light reflected by the project surface for the purpose of capturing metering light in this context. Here a spectrometer is provided for detecting the parameters of the true color depiction, brightness, and color of the projection wall, as well as brightness and ambient light.
The removal of the metering light for the sensor unit from directly within the projection beam path is a relatively simple embodiment of the arrangement according to the invention. However, the metering results are often insufficient because the conditions influencing the image data, in conjunction with the project surface (projection wall), as well as the illumination of the space are not measured. In this regard, it is more advantageous to derive the metering light for the sensor unit from the light reflected by the projection wall. Both possibilities are also conceivable.
This can be achieved by using an aspherical lens connected upstream from the sensor unit and located adjacent to the optic of the projection lens.
Another option is to feed the light reflected by the projection surface directly through the optic of the projection lens to the sensor unit. With this option, no additional optical elements would be required.
Another advantageous embodiment of the arrangement according to the invention consists in providing a sensor with two-dimensional, matrix-like detector elements for detection of the parameters of image sharpness and linear distortion. These could be CCD, CMOS or PDA detector elements, for example.
Through the projection of a template, such as a pattern provided with stripes, the image sharpness at the edges of the stripes can be determined using these detector elements, so that correction of the image data by means of a downstream process unit becomes possible.
In addition, trapeze corrections (keystone errors) based on the Scheimpflug principle or using microfine Fresnell lenses with image reversal can be performed through these detector elements. This is especially advantageous because such corrections by means of tilting projection surfaces can only be completed at a high cost.
The arrangement according to the invention is described in greater detail in the following.
A complete sensor unit 5 for detecting the light 6 reflected by the projection surface 3 is shown in
The light 6 reaches an entry gap 10 through a light entry window 8 and a lens 9. An imaging holographic grid 12 is provided to display the entry gap 10 on a detector unit 11, whose individual elements are arranged in matrix form (CCD, CMOS or PDA elements). To analyze the light 6 reflected by the projection surface 3, as well as to convert the values into correction settings of the projection beam path, the detector unit is connected to a processor 13.
Number | Date | Country | Kind |
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103 47 388.2 | Oct 2003 | DE | national |