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work in progress
Dependencies: FastAnalogIn FastIO USBDevice mbed FastPWM SimpleDMA
Fork of Pinscape_Controller by
ccdSensor.h@38:697e10d8fb80, 2015-12-16 (annotated)
- Committer:
- mkalkbrenner
- Date:
- Wed Dec 16 15:37:59 2015 +0000
- Revision:
- 38:697e10d8fb80
- Parent:
- 25:e22b88bd783a
fixed default configuration for extension boards
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
mjr | 17:ab3cec0c8bf4 | 1 | // CCD plunger sensor |
mjr | 17:ab3cec0c8bf4 | 2 | // |
mjr | 17:ab3cec0c8bf4 | 3 | // This file implements our generic plunger sensor interface for the |
mjr | 17:ab3cec0c8bf4 | 4 | // TAOS TSL1410R CCD array sensor. |
mjr | 17:ab3cec0c8bf4 | 5 | |
mjr | 17:ab3cec0c8bf4 | 6 | |
mjr | 17:ab3cec0c8bf4 | 7 | |
mjr | 25:e22b88bd783a | 8 | // Number of pixels we read from the CCD on each frame. Use the |
mjr | 25:e22b88bd783a | 9 | // sample size from config.h. |
mjr | 25:e22b88bd783a | 10 | const int npix = CCD_NPIXELS_SAMPLED; |
mjr | 17:ab3cec0c8bf4 | 11 | |
mjr | 25:e22b88bd783a | 12 | // PlungerSensor interface implementation for the CCD |
mjr | 17:ab3cec0c8bf4 | 13 | class PlungerSensor |
mjr | 17:ab3cec0c8bf4 | 14 | { |
mjr | 17:ab3cec0c8bf4 | 15 | public: |
mjr | 17:ab3cec0c8bf4 | 16 | PlungerSensor() : ccd(CCD_SO_PIN) |
mjr | 17:ab3cec0c8bf4 | 17 | { |
mjr | 17:ab3cec0c8bf4 | 18 | } |
mjr | 17:ab3cec0c8bf4 | 19 | |
mjr | 17:ab3cec0c8bf4 | 20 | // initialize |
mjr | 17:ab3cec0c8bf4 | 21 | void init() |
mjr | 17:ab3cec0c8bf4 | 22 | { |
mjr | 17:ab3cec0c8bf4 | 23 | // flush any random power-on values from the CCD's integration |
mjr | 17:ab3cec0c8bf4 | 24 | // capacitors, and start the first integration cycle |
mjr | 17:ab3cec0c8bf4 | 25 | ccd.clear(); |
mjr | 17:ab3cec0c8bf4 | 26 | } |
mjr | 17:ab3cec0c8bf4 | 27 | |
mjr | 17:ab3cec0c8bf4 | 28 | // Perform a low-res scan of the sensor. |
mjr | 17:ab3cec0c8bf4 | 29 | int lowResScan() |
mjr | 17:ab3cec0c8bf4 | 30 | { |
mjr | 17:ab3cec0c8bf4 | 31 | |
mjr | 17:ab3cec0c8bf4 | 32 | // read the pixels at low resolution |
mjr | 17:ab3cec0c8bf4 | 33 | const int nlpix = 32; |
mjr | 17:ab3cec0c8bf4 | 34 | uint16_t pix[nlpix]; |
mjr | 17:ab3cec0c8bf4 | 35 | ccd.read(pix, nlpix); |
mjr | 17:ab3cec0c8bf4 | 36 | |
mjr | 17:ab3cec0c8bf4 | 37 | // determine which end is brighter |
mjr | 17:ab3cec0c8bf4 | 38 | uint16_t p1 = pix[0]; |
mjr | 17:ab3cec0c8bf4 | 39 | uint16_t p2 = pix[nlpix-1]; |
mjr | 17:ab3cec0c8bf4 | 40 | int si = 1, di = 1; |
mjr | 17:ab3cec0c8bf4 | 41 | if (p1 < p2) |
mjr | 17:ab3cec0c8bf4 | 42 | si = nlpix, di = -1; |
mjr | 17:ab3cec0c8bf4 | 43 | |
mjr | 17:ab3cec0c8bf4 | 44 | // figure the shadow edge threshold - just use the midpoint |
mjr | 17:ab3cec0c8bf4 | 45 | // of the levels at the bright and dark ends |
mjr | 17:ab3cec0c8bf4 | 46 | uint16_t shadow = uint16_t((long(p1) + long(p2))/2); |
mjr | 17:ab3cec0c8bf4 | 47 | |
mjr | 17:ab3cec0c8bf4 | 48 | // find the current tip position |
mjr | 17:ab3cec0c8bf4 | 49 | for (int n = 0 ; n < nlpix ; ++n, si += di) |
mjr | 17:ab3cec0c8bf4 | 50 | { |
mjr | 17:ab3cec0c8bf4 | 51 | // check to see if we found the shadow |
mjr | 17:ab3cec0c8bf4 | 52 | if (pix[si] <= shadow) |
mjr | 17:ab3cec0c8bf4 | 53 | { |
mjr | 17:ab3cec0c8bf4 | 54 | // got it - normalize it to normal 'npix' resolution and |
mjr | 17:ab3cec0c8bf4 | 55 | // return the result |
mjr | 17:ab3cec0c8bf4 | 56 | return n*npix/nlpix; |
mjr | 17:ab3cec0c8bf4 | 57 | } |
mjr | 17:ab3cec0c8bf4 | 58 | } |
mjr | 17:ab3cec0c8bf4 | 59 | |
mjr | 17:ab3cec0c8bf4 | 60 | // didn't find a shadow - assume the whole array is in shadow (so |
mjr | 17:ab3cec0c8bf4 | 61 | // the edge is at the zero pixel point) |
mjr | 17:ab3cec0c8bf4 | 62 | return 0; |
mjr | 17:ab3cec0c8bf4 | 63 | } |
mjr | 17:ab3cec0c8bf4 | 64 | |
mjr | 17:ab3cec0c8bf4 | 65 | // Perform a high-res scan of the sensor. |
mjr | 17:ab3cec0c8bf4 | 66 | bool highResScan(int &pos) |
mjr | 17:ab3cec0c8bf4 | 67 | { |
mjr | 17:ab3cec0c8bf4 | 68 | // read the array |
mjr | 18:5e890ebd0023 | 69 | ccd.read(pix, npix); |
mjr | 17:ab3cec0c8bf4 | 70 | |
mjr | 18:5e890ebd0023 | 71 | // get the brightness at each end of the sensor |
mjr | 18:5e890ebd0023 | 72 | long b1 = pix[0]; |
mjr | 18:5e890ebd0023 | 73 | long b2 = pix[npix-1]; |
mjr | 17:ab3cec0c8bf4 | 74 | |
mjr | 17:ab3cec0c8bf4 | 75 | // Work from the bright end to the dark end. VP interprets the |
mjr | 17:ab3cec0c8bf4 | 76 | // Z axis value as the amount the plunger is pulled: zero is the |
mjr | 17:ab3cec0c8bf4 | 77 | // rest position, and the axis maximum is fully pulled. So we |
mjr | 17:ab3cec0c8bf4 | 78 | // essentially want to report how much of the sensor is lit, |
mjr | 17:ab3cec0c8bf4 | 79 | // since this increases as the plunger is pulled back. |
mjr | 18:5e890ebd0023 | 80 | int si = 0, di = 1; |
mjr | 18:5e890ebd0023 | 81 | long hi = b1; |
mjr | 18:5e890ebd0023 | 82 | if (b1 < b2) |
mjr | 18:5e890ebd0023 | 83 | si = npix - 1, di = -1, hi = b2; |
mjr | 17:ab3cec0c8bf4 | 84 | |
mjr | 17:ab3cec0c8bf4 | 85 | // Figure the shadow threshold. In practice, the portion of the |
mjr | 17:ab3cec0c8bf4 | 86 | // sensor that's not in shadow has all pixels consistently near |
mjr | 17:ab3cec0c8bf4 | 87 | // saturation; the first drop in brightness is pretty reliably the |
mjr | 17:ab3cec0c8bf4 | 88 | // start of the shadow. So set the threshold level to be closer |
mjr | 17:ab3cec0c8bf4 | 89 | // to the bright end's brightness level, so that we detect the leading |
mjr | 17:ab3cec0c8bf4 | 90 | // edge if the shadow isn't perfectly sharp. Use the point 1/3 of |
mjr | 17:ab3cec0c8bf4 | 91 | // the way down from the high top the low side, so: |
mjr | 17:ab3cec0c8bf4 | 92 | // |
mjr | 17:ab3cec0c8bf4 | 93 | // threshold = lo + (hi - lo)*2/3 |
mjr | 17:ab3cec0c8bf4 | 94 | // = lo + hi*2/3 - lo*2/3 |
mjr | 17:ab3cec0c8bf4 | 95 | // = lo - lo*2/3 + hi*2/3 |
mjr | 17:ab3cec0c8bf4 | 96 | // = lo*1/3 + hi*2/3 |
mjr | 17:ab3cec0c8bf4 | 97 | // = (lo + hi*2)/3 |
mjr | 17:ab3cec0c8bf4 | 98 | // |
mjr | 18:5e890ebd0023 | 99 | // Now, 'lo' is always one of b1 or b2, and 'hi' is the other |
mjr | 18:5e890ebd0023 | 100 | // one, so we can rewrite this as: |
mjr | 18:5e890ebd0023 | 101 | long midpt = (b1 + b2 + hi)/3; |
mjr | 17:ab3cec0c8bf4 | 102 | |
mjr | 17:ab3cec0c8bf4 | 103 | // If we have enough contrast, proceed with the scan. |
mjr | 17:ab3cec0c8bf4 | 104 | // |
mjr | 17:ab3cec0c8bf4 | 105 | // If the bright end and dark end don't differ by enough, skip this |
mjr | 17:ab3cec0c8bf4 | 106 | // reading entirely. Either we have an overexposed or underexposed frame, |
mjr | 17:ab3cec0c8bf4 | 107 | // or the sensor is misaligned and is either fully in or out of shadow |
mjr | 17:ab3cec0c8bf4 | 108 | // (it's supposed to be mounted such that the edge of the shadow always |
mjr | 17:ab3cec0c8bf4 | 109 | // falls within the sensor, for any possible plunger position). |
mjr | 18:5e890ebd0023 | 110 | if (labs(b1 - b2) > 0x1000) |
mjr | 17:ab3cec0c8bf4 | 111 | { |
mjr | 17:ab3cec0c8bf4 | 112 | uint16_t *pixp = pix + si; |
mjr | 18:5e890ebd0023 | 113 | for (int n = 0 ; n < npix ; ++n, pixp += di) |
mjr | 17:ab3cec0c8bf4 | 114 | { |
mjr | 17:ab3cec0c8bf4 | 115 | // if we've crossed the midpoint, report this position |
mjr | 18:5e890ebd0023 | 116 | if (long(*pixp) < midpt) |
mjr | 17:ab3cec0c8bf4 | 117 | { |
mjr | 17:ab3cec0c8bf4 | 118 | // note the new position |
mjr | 17:ab3cec0c8bf4 | 119 | pos = n; |
mjr | 17:ab3cec0c8bf4 | 120 | return true; |
mjr | 17:ab3cec0c8bf4 | 121 | } |
mjr | 17:ab3cec0c8bf4 | 122 | } |
mjr | 17:ab3cec0c8bf4 | 123 | } |
mjr | 17:ab3cec0c8bf4 | 124 | |
mjr | 17:ab3cec0c8bf4 | 125 | // we didn't find a shadow - return no reading |
mjr | 17:ab3cec0c8bf4 | 126 | return false; |
mjr | 17:ab3cec0c8bf4 | 127 | } |
mjr | 17:ab3cec0c8bf4 | 128 | |
mjr | 17:ab3cec0c8bf4 | 129 | // send an exposure report to the joystick interface |
mjr | 17:ab3cec0c8bf4 | 130 | void sendExposureReport(USBJoystick &js) |
mjr | 17:ab3cec0c8bf4 | 131 | { |
mjr | 17:ab3cec0c8bf4 | 132 | // send reports for all pixels |
mjr | 17:ab3cec0c8bf4 | 133 | int idx = 0; |
mjr | 17:ab3cec0c8bf4 | 134 | while (idx < npix) |
mjr | 18:5e890ebd0023 | 135 | { |
mjr | 17:ab3cec0c8bf4 | 136 | js.updateExposure(idx, npix, pix); |
mjr | 18:5e890ebd0023 | 137 | wait_ms(1); |
mjr | 18:5e890ebd0023 | 138 | } |
mjr | 17:ab3cec0c8bf4 | 139 | |
mjr | 17:ab3cec0c8bf4 | 140 | // The pixel dump requires many USB reports, since each report |
mjr | 17:ab3cec0c8bf4 | 141 | // can only send a few pixel values. An integration cycle has |
mjr | 17:ab3cec0c8bf4 | 142 | // been running all this time, since each read starts a new |
mjr | 17:ab3cec0c8bf4 | 143 | // cycle. Our timing is longer than usual on this round, so |
mjr | 17:ab3cec0c8bf4 | 144 | // the integration won't be comparable to a normal cycle. Throw |
mjr | 17:ab3cec0c8bf4 | 145 | // this one away by doing a read now, and throwing it away - that |
mjr | 17:ab3cec0c8bf4 | 146 | // will get the timing of the *next* cycle roughly back to normal. |
mjr | 17:ab3cec0c8bf4 | 147 | ccd.read(pix, npix); |
mjr | 17:ab3cec0c8bf4 | 148 | } |
mjr | 17:ab3cec0c8bf4 | 149 | |
mjr | 17:ab3cec0c8bf4 | 150 | private: |
mjr | 17:ab3cec0c8bf4 | 151 | // pixel buffer |
mjr | 17:ab3cec0c8bf4 | 152 | uint16_t pix[npix]; |
mjr | 17:ab3cec0c8bf4 | 153 | |
mjr | 17:ab3cec0c8bf4 | 154 | // the low-level interface to the CCD hardware |
mjr | 17:ab3cec0c8bf4 | 155 | TSL1410R<CCD_SI_PIN, CCD_CLOCK_PIN> ccd; |
mjr | 17:ab3cec0c8bf4 | 156 | }; |