Calibration camera device

Abstract

A calibration camera device for geometrical correction or color correction, including an optical lens part, an optical filter part which is provided in front of the optical lens part and to which at least three optical filters are attached, a filter switching part to select any one from among the optical filters and dispose the selected one optical filter at a photometric point, a near-infrared light cutting part which is provided in the rear of the optical lens part and to which a near-infrared light cutting filter is attached, a monochrome capturing part which is provided in the rear of the near-infrared light cutting part and includes a monochrome imaging element, an image storing part for storing a monochrome image which is captured by the monochrome capturing part, and a gain correction part for conducting sensitivity correction on the monochrome image.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a calibration camera device which can be used in geometrical correction in combination with color correction by itself and particularly to a calibration camera device which is preferably used in image quality control of an image displaying device. [0003] 2. Description of the Related Art [0004] Conventionally, an image displaying device has been proposed wherein a plurality of images are projected from the corresponding projectors and synthesized as one large image on one screen. At each projector, however, may occur geometrical distortion, color shading, luminance shading, difference in gamma characteristic, difference in white balance and the like. In this case, the differences in image quality between the projectors become conspicuous, thereby deteriorating the displaying quality of the image displaying device. In this point of view, an image displaying device is proposed wherein ...

AI Technical Summary

Benefits of technology

[0009] It is an object of the present invention to provide a not expensive calibration camera device with good operationality which is configured so that at least three optical filters are selectively used, thereby conducting the geometrical correction and color correction simultaneously by itself.

[0024] According to the invention of claim 1, since at least three optical filters are attached to the optical filter part which is provided in front of the optical lens part to which the lens is attached on the optical path and one appropriate optical filter is disposed at the photometric point on the optical path through the selection of the filter switching part, the monochrome image which is captured through the selected optical filter depends on the characteristics of the selected optical filter, the lens and the near-infrared light cutting filter which constitute an optical system. Therefore, the sensitivity correction is conducted on the monochrome image by the gain correction part. In the color correction, therefore, the correction data from the sensitivity correction on the monochrome image by the gain correction part is utilized as it is. In the geometrical correction, the correction data from the sensitivity correction on the monochrome image which is captured substantially without filters (e.g., correction data from the sensitivity correction on the monochrome image which is captured through a filter which is transparent over a visible light range or correction data from the sensitivity correction on the monochrome data which is captured without filters). As a result, both of the geometrical correction and the color correction can be conducted on only the calibration camera device of the present invention. In this point of view, the total cost and the operationality of the calibration camera device can be enhanced.

[0027] According to the invention of claim 4, since in the geometrical correction, the optical filter part is set transparent over a visible light range by the filter switching part (e.g., a transparent filter over the visible light range or a plate with an opening through which a light within the visible light range is passed may be used), the calibration can be conducted by utilizing the correction result at the time when the monochrome image data which is obtained without filters is corrected in sensitivity by the gain correction part. As a result, both of the geometrical correction and the color correction can be conducted on only the calibration camera device of the present invention. In this point of view, the total cost and the operationality of the calibration camera device can be enhanced.

[0028] According to the invention of claim 5, since the soft filmy optical filter made of a gelatine optical filter which is not expensive, the cost of the optical filters can be reduced, and thus, the total cost of the calibration camera device of the present invention can be reduced.

[0030] According to the invention of claim 7, since the filter switching part includes a slide photograph equipment with openings and the optical filters are attached to the openings, the number of the optical filters can be easily varied by varying the number of the openings.

Problems solved by technology

At each projector, however, may occur geometrical distortion, color shading, luminance shading, difference in gamma characteristic, difference in white balance and the like.

In this case, the differences in image quality between the projectors become conspicuous, thereby deteriorating the displaying quality of the image displaying device.

Since the color measuring device is expensive and is required to be set at every point if in the color correction, there are a plurality of photometric points, however, the cost in the color correction may be increased and the operationality in the color correction may be complicated.

Therefore, the total cost of the two dimensional color measuring device is increased because the parts cost is increased due to the use of the interference filter and the operationality becomes complicated due to the precise attachment of the optical filter in the capturing device.

Images