Single-Lens 3D Camera Has Surgical Roots, Our Patent Search Finds
Canadian company ISee3D, formerly International Telepresence, is promising 3D from a single-lens camera, webcam or phone, thereby avoiding the cost and complexity of conventional twin-lens devices, and the time-consuming and expensive optical calibration needed to get good results from them. The newly promoted idea dates back to 1994 when International Telepresence filed patents on methods to get 3D images from a single-lens endoscope camera during minimally invasive “keyhole” surgery, our patent search has found.
"Our single-lens process streamlines the entire process,” Dwight Romanica, CEO at ISee3D, said in a statement. “By using our technology to drive a new 3D era, based on a single lens, we can enable universal adoption across numerous markets opening 3D up to health care, consumer electronics, science, and manufacturing.” Even the Hubble Space Telescope could be converted to 3D, the company claims.
The company’s patent filings reveal details, disclose other ideas under development and whet appetites for a practical demonstration of how well the system works in practice. International Telepresence, and inventors Anthony Greening and Thomas Mitchell, first filed for patents in April 1994 (US 5,828,487, US 6,151,164 and International WO/1995/028662), our search found. They described an ordinary endoscope (similar to a miniature telescope) that clamps to a video camera. Additionally, a small opaque leaf, on hinges, is fixed in the light path between the endoscope and camera, with electromagnets to flip the leaf from side to side, the patents say. In one position, the leaf blocks the left half of the light path and in the other position it blocks the right half, they say. This, says the patent, effectively shifts the perspective of the image path, from right to left, and so on, they say.
The electromagnets work very rapidly, in the half-millisecond gaps between normal video frames, the patents say. So the camera captures left and right perspective images on alternate frames, they say. These can then be displayed on a modern 3D TV and viewed with active shutter glasses that alternately blank the left and right eyes, they say. Sync signals stored with the captured images keep everything in step, they say.
In July 1995, the same inventors suggested in a new patent (International WO/1997/003378) putting a moveable lens in the image path, instead of an opaque leaf. This avoids the light loss caused by blanking alternate halves of the picture, it said The lens can either be slid rapidly from one side of the light path to the other, or twisted and turned, to switch the path between left and right perspective views, it said. Optical aberrations may be caused by the lens motion but can be corrected electronically by the camera or display, it said.
ISee3D says on its website that it won FDA approval for its medical system in 1995 and then started work on a consumer version, primarily for 3D video streaming. “That single strategic decision did not properly evaluate the inherent weaknesses with streaming video at that time,” ISee3D concedes now. “As a result of limited bandwidth in the late 90s and computer processor speeds that were one tenth of what they are today, the quality of image, speed of delivery and size of image was compromised … and resulted in a failed product launch.” Now, with far better broadband and faster processors available and with the mass market launch of 3D TV sets, ISee3D has changed its board of directors, recapitalized and “significantly cleaned up its operating base,” the company said.