CLIAMS:1. A method for estimating calories expended by a user, the method comprising:
identifying, by a processor (110), a step-based activity being performed by the user, wherein the identifying is based on raw data received from an accelerometer of a mobile device (104) carried by the user;
evaluating, by the processor (110), a stride length for each detected step in the step-based activity, wherein the evaluation is based on a step frequency, a type of activity, and a height of the user;
determining, by the processor (110), an average speed of the user, based on a distance covered by the user, wherein the distance covered by the user is obtained by adding the stride length of the user for each detected step; and
computing, by the processor (110), calories expended by the user while performing the step-based activity, wherein the computation is based on a weight of the user and a metabolic equivalent (MET) value corresponding to the average speed of the user.

2. The method as claimed in claim 1, wherein the identifying comprising analyzing the raw data by employing a window based technique to identify the step-based activity being performed by the user.

3. The method as claimed in claim 2, wherein the window based technique comprises:
classifying the raw data in a plurality of windows of pre-defined time period;
removing noise from the raw data captured in each of the plurality of windows to prevent false detections of steps; and
detecting total number of steps completed by the user in each of the plurality of windows.

4. The method as claimed in claim 3, wherein the evaluating comprising determining a step frequency of the user for each window, based on the detected steps.

5. The method as claimed in claim 1, wherein the height is provided by the user for evaluating the stride length.

6. The method as claimed in claim 1, wherein the MET value is obtained by comparing the average speed of the user with the MET values pertaining to various step-based activities.

7. The method as claimed in claim 1 further comprising displaying, by the processor (110), information pertaining to at least the distance traveled and calories consumed by the user on the mobile device (104).

8. A calorie estimation system (102) comprising:
a processor (110);
an activity detection module (120), executable by the processor (110), to
receive raw data captured by an accelerometer of a mobile device (110) when a user is performing a step-based activity;
analyze the raw data by employing a window based technique to identify a step frequency of the user;
based on the step frequency, determine a step-based activity being performed by the person;
an estimation module (122), executable by the processor (110), to
determine a distance covered by the user, wherein the distance is determined by a stride length of the user;
based on the distance, evaluate an average speed of the user; and
compute calories expended by the user based on the average speed of the user and a weight of the user.

9. The calorie estimation system (102) as claimed in claim 8, wherein the estimation module (122) further determines the stride length of the user for each complete step based on a step frequency, a type of activity, and a height of the user.
10. The calorie estimation system (102) as claimed in claim 8, wherein the estimation module (122) identifies an MET value corresponding to the average speed of the user for the detected step-based activity from a plurality of MET values.

11. The calorie estimation system (102) as claimed in claim 10, wherein the estimation module (122) employs the MET value corresponding to the average speed of the user for computation of the calories expended by the user.

12. The calorie estimation system (102) as claimed in claim 8, wherein the user inputs the weight for computation of the calories expended while performing the step-based activity.

13. A non-transitory computer-readable medium having embodied thereon a computer program for executing a method for estimating calories expended by a user, the method comprising:
identifying, by a processor (110), a step-based activity being performed by the user, wherein the identifying is based on raw data received by an accelerometer of a mobile device (104) carried by the user;
evaluating, by the processor (110), a stride length for each detected step in the step-based activity, wherein the evaluation is based on a step frequency, a type of activity, and a height of the user;
determining, by the processor (110), an average speed of the user, based on a distance covered by the user, wherein the distance covered by the user is obtained by adding the stride length of the user for each detected step; and
computing, by the processor (110), calories expended by the user while performing the step-based activity, wherein the computation is based on a weight of the user and a metabolic equivalent (MET) value corresponding to the average speed of the user.
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