Peace! I want ask about the number of bits shoud I use in an fixed_point number to obtein the good precision, precision of distance eclidean. some detail: I want to determine an vector of foor element VECT[MOY1,MOY2,MOY3,MOY4], each element is the moyen of one quart of matrix of (64*64), the matrix' element value varies (0-255)'''it's pixel valor''' --> the result of division (MOY1=SUM/Nbits) has 8 bits in the integer part; Question: how many bits of fractional part shout I use to get the good result (result of euclidean distance between two vector VECT1[MOY11,MOY12,MOY13,MOY14] and VECT[MOY21,MOY22,MOY23,MOY24]).. thank you....peace:
Abdallah wrote: > about the number of bits shoud I use in an fixed_point number > to obtein the good precision You have to define the precision. Independed if you use fixed point or integer number format. The number of bits depends on your dynamic range: http://en.wikipedia.org/wiki/Dynamic_range Roughly: NoBs = SNR / 6 eg.: 16 Bit = 96 dB / 6 Duke
Why would you consider to be the DR at 16 Bits not to be 96dB but 96dB/6?
You wanted a GOOD precission in the result, right? then divide it by 6 :-)
Markus Wagner wrote: > Why would you consider to be the DR at 16 Bits not to be 96dB but > 96dB/6? Read carefully: number of bits * 6 dB = dynamic range