Smile, Texas schoolchildren. You’re on calorie camera. That’s the idea behind a $2 million project being unveiled Wednesday in the lunchroom of a San Antonio elementary school, where high-tech cameras installed in the cafeteria will begin photographing what foods children pile onto their trays — and later capture what they don’t finish eating. Digital imaging analysis of the snapshots will then calculate how many calories each student scarfed down. Local health officials said the program, funded by a U.S. Department of Agriculture grant, is the first of its kind in a U.S. school, and will be so precise that the...