Device for acquiring depth image, calibrating method and measuring method therefor

A depth image acquiring device, comprises:

• at least one projecting device, projecting a projection pattern to a measured object, wherein the at least one projecting device serves as a virtual image sensing device, and an original image of the projection pattern is taken as a virtual image;
• at least one image sensing device, receiving a focal length adjusting signal to adjust a focal length thereof, and sensing the projection pattern projected to the measured object to generate at least one real image;
• a mechanism device, coupled to the at least one image sensing device, and receives a lens adjusting signal to adjust a location and/or a convergence angle of the at least one image sensing device;
• a processing unit, coupled to the at least one projecting device, the at least one image sensing device and the mechanism device, providing the focal length adjusting signal and the lens adjusting signal to adjust the focal length, the location and/or the convergence angle of the at least one image sensing device, and performing a depth operation on the at least one real image and the virtual image to generate depth information,
• wherein the processing unit calibrates and obtains a three dimension (3D) measuring parameter set of the at least one image sensing device at a model focal length according to a plurality of image setting parameter sets corresponding to a model focal length and a plurality of predetermined node distances corresponding to each of the image sensing devices, and accordingly performs the depth operation.

A calibrating method of a depth image acquiring device, wherein the depth image acquiring device comprises at least one projecting device, at least one image sensing device and a mechanism device, the at least one projecting device projects a projection pattern to a measured object, wherein the at least one projecting device serves as a virtual image sensing device, the at least one image sensing device senses the projection pattern projected to the measured object to generate at least one real image, the mechanism device adjusts a location and/or a convergence angle of the at least one image sensing device, and the depth image acquiring device performs a depth operation on the at least one real image to generate depth information, the calibrating method of the depth image acquiring device comprising:

• respectively setting the at least one image sensing device to a model focal length;
• setting a plurality of node distances to serve as locations of a plurality of nodes;
• setting an image setting parameter set corresponding to each of the nodes;
• setting the at least one image sensing device to the respective focal length,
• setting a state of the at least one image sensing device according to the image setting parameter set of each of the nodes;
• and
• calibrating each of the nodes to obtain a 3D measuring parameter set of each of the nodes, wherein the 3D measuring parameter set is used to perform a 3D measuring calculation.

A measuring method of a depth image acquiring device, wherein the depth image acquiring device comprises at least one projecting device, at least one image sensing device and a mechanism device, the at least one projecting device projects a projection pattern to a measured object, wherein the at least one projecting device serves as a virtual image sensing device, the at least one image sensing device senses the projection pattern projected to the measured object to generate at least one real image, the mechanism device adjusts a location and/or a convergence angle of the at least one image sensing device, and the depth image acquiring device performs a depth operation on the at least one real image to generate depth information, the measuring method of the depth image acquiring device comprising:

• receiving a specific focal length and a specific measuring distance, wherein the at least one image sensing device is set to have a model focal length, a plurality of node distances corresponding to locations of a plurality of nodes, an image setting parameter set and a 3D measuring parameter set corresponding to each of the nodes;
• comparing the specified measuring distance with the corresponding node distances to calculate the image setting parameter set and the 3D measuring parameter set of the at least one image sensing device at the specified focal length;
• setting a state of the at least one image sensing device according to the image setting parameter set of the specified focal length, wherein the at least one image sensing device senses the projection pattern projected to the measured object to generate the at least one real image;
• calculating an image conversion equation according to the specified focal length and the at least one model focal length;
• and
• converting the at least one real image according to the image conversion equation, and performing calculation according to the 3D measuring parameter set of the specified focal length to generate the depth information.