The present invention provides a system for illuminating an object with a special kind of structured light pattern, recording the shape of the reflected points of light by means of a camera, and, by a triangulation technique that does not depend on the fixed direction of the light source relative to the camera, reconstructing the 3D shape of the object through a computer using the data points collected from the reflection of the structured light pattern. The scanning system is portable and does not require data processing contemporaneous with the data collection. The portable system stores in the storage media several images of the objects with different illumination patterns. The data is subsequently processed, by a computer system which applies data processing routines, i.e., the model building algorithms which provide 3D surface generation. The data acquisition according to the present invention is simplified to acquiring of only two or, optionally, four images of the object, thereby significantly increasing the digitization speed over that of laser-based scanners. The light source projects both structured light and uniform illumination light from the same apparent source, and that allows for numerical normalization of the images.
A 3-dimensional image acquisition apparatus acquires images to be used for 3-dimensionally reconstructing an object by picking up the object by a camera twice or more in an image acquisition set including picking up at least once the object carrying a pattern projected onto it by a projection light source. The apparatus comprises a light projection information memory configured to store information on projection of light including information on the time for projecting light for the purpose of projecting the pattern in the image acquisition set, an image acquisition progress information memory configured to store information on the progress of image acquisition in the image acquisition set, and a controller configured to control the projection of light by the projection light source and the picking up by the camera on the basis of the stored information on projection of light and the stored information on the progress.
A 3D image acquisition apparatus comprises a pattern projection section which projects a pattern on an object to be measured, an imaging section which is disposed at a distance from the pattern projection section and images the object on which the pattern has been projected, and a depth calculation section which detects the projection pattern projected on the object on the basis of an image acquired by the imaging section, collates the detected pattern and the projected pattern, and calculates a depth of respective parts of the object on the basis of the correspondency of the collation. The projected pattern is stripes/matrix formed by alternately arranging areas with local maximum/minimum luminance values. Thus, stripes/matrix boundaries can be exactly extracted from the pattern projection image, and correct decoding is performed from the encoded projection image even where the object is not a white-based color one or a low-saturation color one.
Pattern projection apparatuses are placed on each other in a stack manner in a stripe pattern direction for projecting the same patterns. An image pickup apparatus (camera 1) is placed between the pattern projection apparatuses. The optical axes of the pattern projection apparatuses and the image pickup apparatus are aligned on the same plane parallel with the stripe pattern direction. On the plane, the principal points also become the same. An image of a stripe pattern is picked up directly by the image pickup apparatus without the intervention of a half mirror, etc., and is recoded. An image of the recoded stripe pattern is picked up by an image pickup apparatus (camera 2) and is decoded and the range of an object is measured by triangulation based on image correspondence points.
A method for filtering undesired light reflections in a structured light measurement system during the inspection of shiny metal prismatic objects having uncoated prismatic surfaces, such as turbine blades, using polarized light.
In order to reproduce a three-dimensional shape of an object accurately while maintaining measuring accuracy and high speed, in a three-dimensional measuring method of projecting a stripe pattern having colored stripes on the object and measuring the three-dimensional shape of the object based on stripe positions on the imaged image corresponding to the stripes on the stripe pattern, colors of the stripes on the stripe pattern are set according to a predetermined rule, and a plurality of stripes having a predetermined positional relationship are extracted from the image, and correspondence with stripes on the stripe pattern based on the color arrangement of the extracted plural stripes.
