AU2018100335A4

AU2018100335A4 - Simple Multi-Axis Positioner suitable for a camera mount.

Info

Publication number: AU2018100335A4
Application number: AU2018100335A
Authority: AU
Inventors: Herbert Nathan
Original assignee: Vesticam Pty Ltd
Current assignee: Vesticam Pty Ltd
Priority date: 2018-03-19
Filing date: 2018-03-19
Publication date: 2018-06-07
Anticipated expiration: 2026-03-19

Abstract

Abstract A sensor or active element mounted within a part that has a spherical form on the outside which may also have an illuminator / stimulator surrounding part or most of the sensor, this part sphere being located snugly inside a cylinder due to elastic deformation of the cylinder and / or sphere, where the spherical part is free to move in 3 rotational planes (roll, yaw and pitch), and simultaneously backwards and forwards along the cylinder axis to potentially provide a focus adjustment, all movements being made either by direct manipulation of a handle attached to the spherical part or by means of motorised screw threads. The cylinder being able to move along a track or in contact with a plane would provide the system with an additional 1 (left / right) or 2 (left / right, up / down) degrees of freedom. Thus a sensor / stimulator positioning system is described here capable of the full 6 degrees of freedom with a minimum of parts. Camera Focus Direction Fig 2 - Spherical camera inside cylinder

Description

Multi-Axis Positioner

Description

This invention is for an improved means for positioning a sensor / active element relative to a target. Whilst this description generally refers to a sensor being a camera, other forms are also included.

If the target varies in position relative to a fixed reference frame, the sensor e.g. a camera, needs to be moved in several different ways relative to that reference frame. An object in space has 6 degrees of freedom (ways of moving) - 3 rotational and 3 translational. For example a helicopter can move through space in 6 different ways, an airplane only 5 (not left / right) a wheel on a axle, only 1 way (rotation).

See Fig 5: 6 degrees of Freedom

This invention was originally developed for a head-mounted camera observing the eye on a goggles platform. The goggles housing can be exchanged for a variety of other housings designed for other applications, such as illumination under controlled conditions of skin (for melanoma photographs) or for ophthalmology.

Previous systems for obtaining an image of the eye have either used fixed optics - regardless of the individual variations of the eye position relative to the camera, or been overly complex with several adjustments.

The simple fixed systems suffer from several drawbacks - the eye occupies only a small part of the camera image (the eye position varies between individuals relative to the frame), which leads to loss of detail, the camera is unable to be positioned along the eyeball axis leading to distorted images and the image axis is often rotated relative to the horizontal, with no means for correction.

The alternative using complex positioning systems are awkward to use, heavy and expensive.

This invention allows the subject to have a frame on their head (for example a pair of goggles or a face mask) with a camera and illuminator to be positioned easily, accurately and robustly, at low cost along the optic axis of the eye. No training is needed, the manipulation being completely intuitive.

Due to the variety of the human face and eye position, obtaining a horizontally orientated (eye lid at the top, eye horizontal) image of the eye in the centre of the camera field of view and getting it in focus, close to the optic axis of the eyeball, requires at least 5 degrees of freedom for the camera relative to the frame which is positioned on the user’s face. Moving the goggles frame itself, slightly up and down, can provide the required 6 degree of freedom if the cylinder is allowed only a sliding movement along guide rail(s) relative to the reference frame.

This invention allows a user to very easily position a camera manually by allowing the camera to be moved in all 6 degrees of freedom in a simple, robust, low-cost configuration. Adding motors and a re-design of the moving parts, can also allow similar movement flexibility by means of motors. Simple part changes can allow the camera movement to be constrained to having fewer degrees of freedom if required. A spherical camera mounting is fitted snugly inside a cylinder, which allows the part sphere to have all 3 rotational movements, (roll, yaw and pitch) relative to the cylinder. Being spherically shaped, it can also move along the cylinder axis (forwards and backwards), whilst still retaining the 3 rotational degrees of freedom at every position along the cylinder axis. Therefore, moving the part sphere along the cylinder axis provides the focus or similar function. Only part of a sphere is required in order to have a limited range of movement.

The part sphere should be slightly larger than the cylinder diameter in order to be a snug fit that will permit the spherical housing to remain wherever it is positioned. To this end, the design of the cylinder and / or the sphere, must allow for a small amount of elastic deformation. The part sphere may or may not be more firmly clamped by mechanical or magnetic force after it is finally positioned. The spherical camera mount can have a handle for direct manual manipulation or be connected to a series of motors for electrical positioning.

The cylinder itself can be constrained when fixed to the frame i.e. slide along a linear track (left / right) or be confined to a plane by a clamping screw or magnetic force (left / right and up / down), giving one and 2 additional degrees of freedom respectively. One or two motors can be provided to move the cylinder in one or two orthogonal directions as required.

An additional advantage of this system is its inherent symmetry. If the cylinder track is horizontal (for example in the goggles format to accommodate variations in the interpupillary distance), the cylinder can be swapped from the left eye to the right eye with the main adjustment being to rotate the camera in the cylinder 180 ° to get the orientation correct (so as to keep the eyelid at the top of the camera image regardless of whether one is looking at the left or right eye).

Whilst we describe here a single version of the head-mounted goggles, there are several different embodiments of this invention.

Instead of a camera, other optical instruments may be enclosed in a spherical container for example, for use in ophthalmology.

Another example is a colorimeter that includes the ability to change the angle of reflected light entering the sensor. A further example is an illuminator for microscopy that is enclosed within the spherical container, changing the illumination of the object under investigation, for optimum effect.

The spherical housing can include illuminators (IR LEDs, White light LEDs or Full RGB LEDs) mounted around the camera lens, providing uniform or non-uniform illumination regardless of the camera orientation.

Whilst plastic may be a preferred material for the part sphere and cylinder, the parts may be made of metal or other suitable materials - for example to improve thermal / electrical conduction.

Drawings

Fig 1 Shows the patent as applied to a possible camera design 1. Manual stick for manipulating pitch, yaw, rotation and focus 2. Spherical camera housing

3. Illuminating components (IR, white / colour LED 4. Camera Lens

Fig 2 Shows the sphere inside the cylinder (4 degrees of freedom) 5. Cylinder diameter slightly smaller than sphere diameter to allow a snug fit 6. Camera assemble as shown in fig 1

Fig 3 Shows movement of cylinder along guide rail (additional 1 degree of freedom) 7. Reference plane 8. Guide track on reference frame - x direction 9. Component on cylinder that follows guide track

Not shown, similar arrangement whereby cylinder is free to move over plane in both X and Y without guide track

Fig 4 Shows further adjustments possible (additional 2 degrees of freedom) 7. Reference frame 10. Cylinder base - clamped onto reference frame Fig 5 shows the degrees of freedom of a single object 6 degrees of Freedom - Image courtesy of Wikipedia

Claims

1. A spherical shaped housing that may contain a camera or other sensors and integrated illuminators, with the spherical housing having a handle either for direct manual manipulation or movement by motors driving threaded rods.

2. The spherical housing being a friction fit inside a cylinder so as to be gripped firmly but allow manual movement of the sphere, where the design of the cylinder and / or sphere includes features that allow elastic deformation of the cylinder and or sphere, so as to keep the sphere in place during movement of the cylinder.

3. As in 2 above but with an option to clamp the cylinder (mechanically or magnetically) to securely hold the sphere in its correct position.

4. The cylinder having a form so that it can slide either along single or multiple guided rail(s) that could pass through an axis of symmetry that intersects the cylinder axis (‘left / right’ movement), or allow both ‘left / right’ and ‘up / down’ movement, and in both cases, be clamped in its final position by mechanical or magnetic means against the reference frame.

5. Whilst the detailed example given here is for a camera, the combination of a sphere fitting snugly inside a cylinder, where the cylinder can move either linearly or in a plane is suitable for a wide variety of positioning applications requiring 4 or 5 or 6 degrees of freedom such as pointing a laser, optimising the position of an optical receiver, positioning of a probe or sensor or electrode either manually or by means of motors.