Determining dimension of target object in an image using reference object

1. A method for determining separation between two regions in an image captured by a camera, the method comprising:

identifying a digital picture captured by a camera of a mobile phone, wherein the digital picture includes an image of a user's body part and an image of the mobile phone;

identifying a location of a first digital marker placed by the user on the digital picture;

identifying a boundary of the body part image using the location of the first digital marker;

computing a first distance between the identified boundary of the body part image and another boundary of the body part image;

computing a second distance between boundaries of the mobile phone image;

identifying a known physical dimension of the mobile phone;

determining a scaling factor using the known physical dimension of the mobile phone and the second distance;

determining a physical dimension of the user's body part by applying the scaling factor to the first distance.

2. The method of claim 1 , wherein the method comprises:

identifying a position coordinate of an initial location of the first digital marker placed by the user on the digital picture;

identifying a location of an estimated end point of one section of the body part image

identifying a position coordinate of the location of the estimated end point;

determining a difference between the position coordinate of the initial location of the first digital marker and the position coordinate of the location of the estimated end point; and

after determining that the difference exceeds a permitted difference, instructing the user to move the first digital marker from the initial location,

wherein the location of the first digital marker is identified after the user moves the first digital marker from the initial location.

3. The method of claim 1 , wherein the method comprises:

identifying a location of a second digital marker placed by the user on the digital picture; and

identifying the other boundary of the body part image using the location of the second digital marker.

4. The method of claim 3 , wherein the method comprises:

identifying a position coordinate of the location of the first digital marker;

identifying a position coordinate of an initial location of the second digital marker placed by the user on the digital picture;

determining a difference between the position coordinate of the location of the first digital marker and the position coordinate of the initial location of the second digital marker; and

after determining that the difference exceeds a permitted difference, instructing the user to move the second digital marker from the initial location,

wherein the location of the second digital marker is identified after the user moves the second digital marker from the initial location.

5. The method of claim 1 , wherein the method comprises:

identifying an initial digital picture captured by the camera of the mobile phone, wherein the initial digital picture includes an initial image of a user's body part and an initial image of the mobile phone;

identifying a central feature of the initial body part image;

identifying a first outer feature of the initial body part image;

identifying a second outer feature of the initial body part image;

determining a first distance between the central feature and the first outer feature;

determining a second distance between the central feature and the second outer feature;

determining a difference between the first distance and the second distance;

after determining that the difference exceeds a permitted difference, instructing the user actuate the camera to capture the digital picture that includes the body part image and the mobile phone image.

6. The method of claim 1 , wherein the boundary of the body part image is identified using the location of the first digital marker by:

determining a first region of interest that includes the location of the first digital marker; and

identifying, within the first region of interest, a boundary between background pixels and foreground pixels,

wherein the identified boundary of the body part image is the identified boundary between background pixels and foreground pixels.

7. The method of claim 6 , wherein the first region of interest includes the location of the first digital marker and a predefined number of pixels around one or more pixels designated by the first digital marker.

8. The method of claim 6 , wherein the method comprises:

determining the other boundary of the body part image by detecting a difference between foreground pixels and background pixels.

9. The method of claim 3 , wherein the method comprises:

determining a first region of interest that includes the location of the first digital marker;

identifying a first boundary between background pixels and foreground pixels within the first region of interest,

wherein the identified boundary of the body part image is the first boundary;

determining a second region of interest that includes the location of the second digital marker; and

identifying a second boundary between background pixels and foreground pixels within the second region of interest,

wherein the identified other boundary of the body part image is the second boundary.

10. The method of claim 1 , wherein the method comprises:

providing instructions on a screen of the mobile device,

wherein the instructions instruct the user to place the first set of digital markers on the opposite boundaries of the body part image, and to place the second set of digital markers on the opposite boundaries of the mobile device image; and

displaying the digital picture, the first set of markers, and the second set of markers on the screen of the mobile device.

11. One or more non-transitory processor-readable media embodying program instructions that, when executed by one or more processors, cause the one or more processors to perform the method of claim 1 .