Method, system and processing software for distance measurement using speckle patterns

1. A distance measurement system, comprising:

a plurality of reference planes;

a light source module, provided a light beam having a speckle pattern to the reference planes and an object, so that a plurality of images having the speckle pattern are shown on the reference planes and a surface of the object respectively, wherein the speckle pattern has a plurality of speckles;

an image capture device, capturing the images having the speckle pattern on each reference plane to generate a plurality of reference image information, and capturing the image having the speckle pattern on the surface of the object to generate an object image information; and

a processing module, coupled to the image capture device so as to compare brightness relationship between each of the speckles and the other speckles rounding the each of the speckles to constitute a brightness information of each of speckles, compute the position of each of the speckles on each of the reference image information based on the brightness information, and compare the position of each of the speckles on the object image information with the position of each of the speckles on each of the reference image information to obtain a plurality of similarity scores;

wherein when the highest similarity score is less than a threshold value, the processing module ignores the distance measurement result, and

when the highest similarity score is greater than or equal to the threshold value, the processing module computes the position of the object according to the position of corresponding reference plane with the highest similarity score.

2. The distance measurement system of claim 1 , wherein the light source module comprises a planar light source module.

3. The distance measurement system of claim 1 , wherein the light source module comprises:

a laser light, providing a laser light beam; and

a light diffusing element, placed in a transmission path of the light beam to perform the light beam having the speckle pattern.

4. The distance measurement system of claim 3 , wherein the light diffusing element comprising a diffusion sheet, a piece of ground glass or a diffraction element.

5. The distance measurement system of claim 1 , wherein the image capture device comprising a video camera or a charge-coupled device.

6. The distance measurement system of claim 1 , wherein the reference planes are parallel with each other in a viewable region, and are perpendicular to an optical axis of the light source module.

7. The distance measurement system of claim 1 , wherein the distances between each of reference planes and next reference planes are the same.

8. A distance measurement method, comprising:

projecting a light beam having a speckle pattern to a plurality of reference planes and an object, so that a plurality of images having the speckle pattern are shown on the reference planes and a surface of the object, wherein the speckle pattern has a plurality of speckles;

capturing the images having the speckle pattern on each of the reference planes so as to generate a plurality of reference image information;

capturing the image having the speckle pattern on the surface of the object to generate an object image information;

comparing brightness relationship between each of the speckles and the other speckles rounding the each of the speckles to constitute a brightness information of each of speckles;

computing the position of each of the speckles on each of the reference image information based on the brightness information;

comparing the position of each of the speckles on the object image information with the position of each of the speckles on each of the reference image information to obtain a plurality of similarity scores;

determining whether or not the highest similarity score is greater than or equal to a threshold value;

ignoring the distance measurement result, when the highest similarity score is less than the threshold value; and

computing the position of the object according to the position of corresponding reference plane with the highest similarity score, when the highest similarity score is greater than or equal to the threshold value.

9. A non-transitory storage media, having a processing software suitable for a distance measurement system for analyzing a position of an object, wherein the processing software at least performs the following steps:

receiving a plurality of reference image information derived from a plurality of images shown on a plurality of reference planes by reflecting a light beam having a speckle pattern, wherein the speckle pattern having a plurality of speckles;

receiving an object image information derived from an image shown on a surface of an object by reflecting light beam having the speckle pattern;

computing brightness relationship among each of the speckles and the other speckles to constitute a brightness information of each of speckles;

computing the position of each of the speckles on each of the reference image information based on the brightness information;

comparing the position of each of the speckles on the object image information with the position of each of the speckles on each of the reference image information to obtain a plurality of similarity scores;

determining whether or not the highest similarity score is greater than or equal to a threshold value;

ignoring the distance measurement result, when the highest similarity score is less than the threshold value; and

computing the position of the object according to the position of corresponding reference plane having the highest similarity score, when the highest similarity score is greater than or equal to the threshold value.