For computing calories, we have proposed an auto-calibration
approach in [8] which makes use of the distance between the user
and food to calibrate the food dimensions. It further makes use
of mobile sensors like accelerometer and magnetic field sensor
to compute the distance between the food object and the person
capturing the image. This computed distance is used to calibrate
the dimensions, without using the user’s thumb discussed earlier.
The distance value acts like a reference for calculating the block
dimension which is further picked from the database in the cloud.
The block dimensions themselves are used to calculate the area
of the food portion, based on which the volume, hence mass, and
finally the calorie value of the food portion is calculated.