Team 9 / LineScan

Moved to Team 9.

Fork of LineScan by Nicholas Gan

LineScan.cpp@7:7d3b6edd783e, 2015-03-31 (annotated)

Committer:
ikrase
Date:
Tue Mar 31 23:34:18 2015 +0000
Revision:
7:7d3b6edd783e
Parent:
6:984ccef5ca19
Child:
8:b9ec2f3e12b6
Test version with all telemetry commented out

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ng3600 0:2d546112b0b8 1 /*
ng3600 0:2d546112b0b8 2 AnalogIn cam1(CAM1_IN);
ng3600 0:2d546112b0b8 3 DigitalOut camSi(CAM_SI);
ikrase 1:f10ec868cd71 4 DigitalOut camClk(CAM_CLK); // Definining camera pins. These are actually defined in Main...
ng3600 0:2d546112b0b8 5 */
ng3600 0:2d546112b0b8 6 #include "LineScan.h"
ng3600 0:2d546112b0b8 7
ng3600 3:f31986cb68fd 8 #define MEAN_REF 15000 //ideal difference we should see
ng3600 3:f31986cb68fd 9 #define CAM_CTRL_GAIN 0.001 //should be small
ng3600 3:f31986cb68fd 10
ng3600 0:2d546112b0b8 11 uint16_t read1Bit(AnalogIn cam, DigitalOut *camClk){
ng3600 0:2d546112b0b8 12 uint16_t pixel;
ng3600 0:2d546112b0b8 13
ng3600 0:2d546112b0b8 14 //read pixel n
ng3600 0:2d546112b0b8 15 pixel = cam.read_u16();
ng3600 0:2d546112b0b8 16
ng3600 0:2d546112b0b8 17 //clock pulse for next pixel n + 1
ng3600 0:2d546112b0b8 18 *camClk = 1;
ikrase 1:f10ec868cd71 19 *camClk = 0; // Apparently there is no need for any delay. It may be desireable to flatten this, or perhaps the compiler does it.
ng3600 0:2d546112b0b8 20
ng3600 0:2d546112b0b8 21 return pixel; //return result as an uint16_t (16 bit integer)
ng3600 0:2d546112b0b8 22 }
ng3600 0:2d546112b0b8 23
ng3600 0:2d546112b0b8 24 void startRead(DigitalOut *camSi, DigitalOut *camClk){
ng3600 0:2d546112b0b8 25 //pulse first clock cycle and start integral pin
ng3600 0:2d546112b0b8 26 *camSi = 1;
ng3600 0:2d546112b0b8 27 *camClk = 1;
ng3600 0:2d546112b0b8 28 *camSi = 0;
ng3600 0:2d546112b0b8 29 *camClk = 0;
ng3600 0:2d546112b0b8 30 }
ng3600 0:2d546112b0b8 31
ng3600 3:f31986cb68fd 32 int processFn(uint16_t *array, int arraySz, int* exposure){
ng3600 2:6a87b2348245 33 int avg[NUM_PIX];
ng3600 2:6a87b2348245 34 int diff[NUM_PIX];
ng3600 2:6a87b2348245 35 int highest = 0;
ng3600 2:6a87b2348245 36 int lowest = 0;
ng3600 2:6a87b2348245 37 int h_idx = NUM_PIX/2;
ng3600 2:6a87b2348245 38 int l_idx = NUM_PIX/2;
ng3600 0:2d546112b0b8 39
ng3600 3:f31986cb68fd 40 //for AGC
ng3600 3:f31986cb68fd 41 float exposureChange;
ng3600 3:f31986cb68fd 42
ng3600 3:f31986cb68fd 43 //Just finds line center, does not track crossings (needs this feature)
ng3600 2:6a87b2348245 44 if(array){
ng3600 2:6a87b2348245 45 avg[0] = array[0];
ng3600 2:6a87b2348245 46 diff[0] = 0;
ng3600 2:6a87b2348245 47
ng3600 2:6a87b2348245 48 for(int i = 1; i < NUM_PIX; i++){
ng3600 3:f31986cb68fd 49 avg[i] = array[i - 1]/2 + array[i]/2; //smoothing
ng3600 3:f31986cb68fd 50 diff[i] = avg[i - 1] - avg[i]; //differential
ng3600 2:6a87b2348245 51
ng3600 2:6a87b2348245 52 if(diff[i] > highest){
ng3600 2:6a87b2348245 53 highest = diff[i];
ng3600 2:6a87b2348245 54 h_idx = i;
ng3600 2:6a87b2348245 55 }
ng3600 2:6a87b2348245 56 else if(diff[i] < lowest){
ng3600 2:6a87b2348245 57 lowest = diff[i];
ng3600 2:6a87b2348245 58 l_idx = i;
ng3600 2:6a87b2348245 59 }
ng3600 2:6a87b2348245 60 }
ng3600 3:f31986cb68fd 61 exposureChange = ((float)(MEAN_REF - highest)) * CAM_CTRL_GAIN; //AGC, simple proportional controller
ng3600 3:f31986cb68fd 62 *exposure += (int)exposureChange;
ng3600 3:f31986cb68fd 63 if(*exposure <= 0)
ng3600 3:f31986cb68fd 64 *exposure = 1;
ng3600 3:f31986cb68fd 65 else if(*exposure > 40)
ng3600 3:f31986cb68fd 66 *exposure = 40;
ng3600 0:2d546112b0b8 67 }
ng3600 0:2d546112b0b8 68
ng3600 2:6a87b2348245 69 return (h_idx + l_idx)/2;
ng3600 0:2d546112b0b8 70 }
ng3600 0:2d546112b0b8 71
ng3600 3:f31986cb68fd 72 //call after integration time is done, returns index of array line is expected to be at and new exposure time
ikrase 7:7d3b6edd783e 73 int getLinePos(AnalogIn cam, DigitalOut *camSi, DigitalOut *camClk, int *exposure){ // telemetry::NumericArray<uint16_t, 128> &tele_linescan){
ng3600 3:f31986cb68fd 74 uint16_t lineAry[NUM_PIX];
ng3600 0:2d546112b0b8 75 int position;
ng3600 0:2d546112b0b8 76
ng3600 0:2d546112b0b8 77 //read
ng3600 0:2d546112b0b8 78 startRead(camSi, camClk);
ng3600 0:2d546112b0b8 79 for(int i = 0; i < NUM_PIX; i++){
ng3600 0:2d546112b0b8 80 lineAry[i] = read1Bit(cam, camClk);
ikrase 7:7d3b6edd783e 81 //tele_linescan[i] = lineAry[i];
ng3600 0:2d546112b0b8 82 }
ng3600 0:2d546112b0b8 83
ng3600 0:2d546112b0b8 84 //process line scan data
ng3600 3:f31986cb68fd 85 position = processFn(lineAry, NUM_PIX, exposure);
ng3600 0:2d546112b0b8 86
ng3600 0:2d546112b0b8 87 return position;
ng3600 0:2d546112b0b8 88 }
ng3600 0:2d546112b0b8 89
ng3600 0:2d546112b0b8 90 /*
ng3600 0:2d546112b0b8 91 sample call (handler thread):
ng3600 0:2d546112b0b8 92
ng3600 0:2d546112b0b8 93 while(1){
ng3600 3:f31986cb68fd 94 linePos = getLinePos(cameraIn1, si, clk, &exposureTime); //volatile linePos, replace with steering angle and read 2 cameras?
ng3600 3:f31986cb68fd 95 Thread::wait(exposureTime); //sleep for 14 us
ng3600 0:2d546112b0b8 96 }
ng3600 2:6a87b2348245 97 */