i think you understood the problem.
The response time of the sensors is very low (< 5 microseconds), if iam scanning the sensor one by one, and using a single ADC to convert to digital, all the 19 sensors will take time in the order of milli seconds. But the response time of the sensor is very low, and if the person is moving his hand, and if by any chance i am scanning some other sensor, by the time i come and scan this sensor, i will be registering a lower value than that was applied...
This will affect all the readings and this error cannot be corrected because it is random.... so what to do? you have any better ideas?