An I/O controller for virtual pinball machines: accelerometer nudge sensing, analog plunger input, button input encoding, LedWiz compatible output controls, and more.

Dependencies:   mbed FastIO FastPWM USBDevice

Fork of Pinscape_Controller by Mike R


This is Version 2 of the Pinscape Controller, an I/O controller for virtual pinball machines. (You can find the old version 1 software here.) Pinscape is software for the KL25Z that turns the board into a full-featured I/O controller for virtual pinball, with support for accelerometer-based nudging, a real plunger, button inputs, and feedback device control.

In case you haven't heard of the concept before, a "virtual pinball machine" is basically a video pinball simulator that's built into a real pinball machine body. A TV monitor goes in place of the pinball playfield, and a second TV goes in the backbox to serve as the "backglass" display. A third smaller monitor can serve as the "DMD" (the Dot Matrix Display used for scoring on newer machines), or you can even install a real pinball plasma DMD. A computer is hidden inside the cabinet, running pinball emulation software that displays a life-sized playfield on the main TV. The cabinet has all of the usual buttons, too, so it not only looks like the real thing, but plays like it too. That's a picture of my own machine to the right. On the outside, it's built exactly like a real arcade pinball machine, with the same overall dimensions and all of the standard pinball cabinet hardware.

A few small companies build and sell complete, finished virtual pinball machines, but I think it's more fun as a DIY project. If you have some basic wood-working skills and know your way around PCs, you can build one from scratch. The computer part is just an ordinary Windows PC, and all of the pinball emulation can be built out of free, open-source software. In that spirit, the Pinscape Controller is an open-source software/hardware project that offers a no-compromises, all-in-one control center for all of the unique input/output needs of a virtual pinball cabinet. If you've been thinking about building one of these, but you're not sure how to connect a plunger, flipper buttons, lights, nudge sensor, and whatever else you can think of, this project might be just what you're looking for.

You can find much more information about DIY Pin Cab building in general in the Virtual Cabinet Forum on Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.


  • Pinscape Release Builds: This page has download links for all of the Pinscape software. To get started, install and run the Pinscape Config Tool on your Windows computer. It will lead you through the steps for installing the Pinscape firmware on the KL25Z.
  • Config Tool Source Code. The complete C# source code for the config tool. You don't need this to run the tool, but it's available if you want to customize anything or see how it works inside.


The new Version 2 Build Guide is now complete! This new version aims to be a complete guide to building a virtual pinball machine, including not only the Pinscape elements but all of the basics, from sourcing parts to building all of the hardware.

You can also refer to the original Hardware Build Guide (PDF), but that's out of date now, since it refers to the old version 1 software, which was rather different (especially when it comes to configuration).

System Requirements

The new config tool requires a fairly up-to-date Microsoft .NET installation. If you use Windows Update to keep your system current, you should be fine. A modern version of Internet Explorer (IE) is required, even if you don't use it as your main browser, because the config tool uses some system components that Microsoft packages into the IE install set. I test with IE11, so that's known to work. IE8 doesn't work. IE9 and 10 are unknown at this point.

The Windows requirements are only for the config tool. The firmware doesn't care about anything on the Windows side, so if you can make do without the config tool, you can use almost any Windows setup.

Main Features

Plunger: The Pinscape Controller started out as a "mechanical plunger" controller: a device for attaching a real pinball plunger to the video game software so that you could launch the ball the natural way. This is still, of course, a central feature of the project. The software supports several types of sensors: a high-resolution optical sensor (which works by essentially taking pictures of the plunger as it moves); a slide potentionmeter (which determines the position via the changing electrical resistance in the pot); a quadrature sensor (which counts bars printed on a special guide rail that it moves along); and an IR distance sensor (which determines the position by sending pulses of light at the plunger and measuring the round-trip travel time). The Build Guide explains how to set up each type of sensor.

Nudging: The KL25Z (the little microcontroller that the software runs on) has a built-in accelerometer. The Pinscape software uses it to sense when you nudge the cabinet, and feeds the acceleration data to the pinball software on the PC. This turns physical nudges into virtual English on the ball. The accelerometer is quite sensitive and accurate, so we can measure the difference between little bumps and hard shoves, and everything in between. The result is natural and immersive.

Buttons: You can wire real pinball buttons to the KL25Z, and the software will translate the buttons into PC input. You have the option to map each button to a keyboard key or joystick button. You can wire up your flipper buttons, Magna Save buttons, Start button, coin slots, operator buttons, and whatever else you need.

Feedback devices: You can also attach "feedback devices" to the KL25Z. Feedback devices are things that create tactile, sound, and lighting effects in sync with the game action. The most popular PC pinball emulators know how to address a wide variety of these devices, and know how to match them to on-screen action in each virtual table. You just need an I/O controller that translates commands from the PC into electrical signals that turn the devices on and off. The Pinscape Controller can do that for you.

Expansion Boards

There are two main ways to run the Pinscape Controller: standalone, or using the "expansion boards".

In the basic standalone setup, you just need the KL25Z, plus whatever buttons, sensors, and feedback devices you want to attach to it. This mode lets you take advantage of everything the software can do, but for some features, you'll have to build some ad hoc external circuitry to interface external devices with the KL25Z. The Build Guide has detailed plans for exactly what you need to build.

The other option is the Pinscape Expansion Boards. The expansion boards are a companion project, which is also totally free and open-source, that provides Printed Circuit Board (PCB) layouts that are designed specifically to work with the Pinscape software. The PCB designs are in the widely used EAGLE format, which many PCB manufacturers can turn directly into physical boards for you. The expansion boards organize all of the external connections more neatly than on the standalone KL25Z, and they add all of the interface circuitry needed for all of the advanced software functions. The big thing they bring to the table is lots of high-power outputs. The boards provide a modular system that lets you add boards to add more outputs. If you opt for the basic core setup, you'll have enough outputs for all of the toys in a really well-equipped cabinet. If your ambitions go beyond merely well-equipped and run to the ridiculously extravagant, just add an extra board or two. The modular design also means that you can add to the system over time.

Expansion Board project page

Update notes

If you have a Pinscape V1 setup already installed, you should be able to switch to the new version pretty seamlessly. There are just a couple of things to be aware of.

First, the "configuration" procedure is completely different in the new version. Way better and way easier, but it's not what you're used to from V1. In V1, you had to edit the project source code and compile your own custom version of the program. No more! With V2, you simply install the standard, pre-compiled .bin file, and select options using the Pinscape Config Tool on Windows.

Second, if you're using the TSL1410R optical sensor for your plunger, there's a chance you'll need to boost your light source's brightness a little bit. The "shutter speed" is faster in this version, which means that it doesn't spend as much time collecting light per frame as before. The software actually does "auto exposure" adaptation on every frame, so the increased shutter speed really shouldn't bother it, but it does require a certain minimum level of contrast, which requires a certain minimal level of lighting. Check the plunger viewer in the setup tool if you have any problems; if the image looks totally dark, try increasing the light level to see if that helps.

New Features

V2 has numerous new features. Here are some of the highlights...

Dynamic configuration: as explained above, configuration is now handled through the Config Tool on Windows. It's no longer necessary to edit the source code or compile your own modified binary.

Improved plunger sensing: the software now reads the TSL1410R optical sensor about 15x faster than it did before. This allows reading the sensor at full resolution (400dpi), about 400 times per second. The faster frame rate makes a big difference in how accurately we can read the plunger position during the fast motion of a release, which allows for more precise position sensing and faster response. The differences aren't dramatic, since the sensing was already pretty good even with the slower V1 scan rate, but you might notice a little better precision in tricky skill shots.

Keyboard keys: button inputs can now be mapped to keyboard keys. The joystick button option is still available as well, of course. Keyboard keys have the advantage of being closer to universal for PC pinball software: some pinball software can be set up to take joystick input, but nearly all PC pinball emulators can take keyboard input, and nearly all of them use the same key mappings.

Local shift button: one physical button can be designed as the local shift button. This works like a Shift button on a keyboard, but with cabinet buttons. It allows each physical button on the cabinet to have two PC keys assigned, one normal and one shifted. Hold down the local shift button, then press another key, and the other key's shifted key mapping is sent to the PC. The shift button can have a regular key mapping of its own as well, so it can do double duty. The shift feature lets you access more functions without cluttering your cabinet with extra buttons. It's especially nice for less frequently used functions like adjusting the volume or activating night mode.

Night mode: the output controller has a new "night mode" option, which lets you turn off all of your noisy devices with a single button, switch, or PC command. You can designate individual ports as noisy or not. Night mode only disables the noisemakers, so you still get the benefit of your flashers, button lights, and other quiet devices. This lets you play late into the night without disturbing your housemates or neighbors.

Gamma correction: you can designate individual output ports for gamma correction. This adjusts the intensity level of an output to make it match the way the human eye perceives brightness, so that fades and color mixes look more natural in lighting devices. You can apply this to individual ports, so that it only affects ports that actually have lights of some kind attached.

IR Remote Control: the controller software can transmit and/or receive IR remote control commands if you attach appropriate parts (an IR LED to send, an IR sensor chip to receive). This can be used to turn on your TV(s) when the system powers on, if they don't turn on automatically, and for any other functions you can think of requiring IR send/receive capabilities. You can assign IR commands to cabinet buttons, so that pressing a button on your cabinet sends a remote control command from the attached IR LED, and you can have the controller generate virtual key presses on your PC in response to received IR commands. If you have the IR sensor attached, the system can use it to learn commands from your existing remotes.

Yet more USB fixes: I've been gradually finding and fixing USB bugs in the mbed library for months now. This version has all of the fixes of the last couple of releases, of course, plus some new ones. It also has a new "last resort" feature, since there always seems to be "just one more" USB bug. The last resort is that you can tell the device to automatically reboot itself if it loses the USB connection and can't restore it within a given time limit.

More Downloads

  • Custom VP builds: I created modified versions of Visual Pinball 9.9 and Physmod5 that you might want to use in combination with this controller. The modified versions have special handling for plunger calibration specific to the Pinscape Controller, as well as some enhancements to the nudge physics. If you're not using the plunger, you might still want it for the nudge improvements. The modified version also works with any other input controller, so you can get the enhanced nudging effects even if you're using a different plunger/nudge kit. The big change in the modified versions is a "filter" for accelerometer input that's designed to make the response to cabinet nudges more realistic. It also makes the response more subdued than in the standard VP, so it's not to everyone's taste. The downloads include both the updated executables and the source code changes, in case you want to merge the changes into your own custom version(s).

    Note! These features are now standard in the official VP releases, so you don't need my custom builds if you're using 9.9.1 or later and/or VP 10. I don't think there's any reason to use my versions instead of the latest official ones, and in fact I'd encourage you to use the official releases since they're more up to date, but I'm leaving my builds available just in case. In the official versions, look for the checkbox "Enable Nudge Filter" in the Keys preferences dialog. My custom versions don't include that checkbox; they just enable the filter unconditionally.
  • Output circuit shopping list: This is a saved shopping cart at with the parts needed to build one copy of the high-power output circuit for the LedWiz emulator feature, for use with the standalone KL25Z (that is, without the expansion boards). The quantities in the cart are for one output channel, so if you want N outputs, simply multiply the quantities by the N, with one exception: you only need one ULN2803 transistor array chip for each eight output circuits. If you're using the expansion boards, you won't need any of this, since the boards provide their own high-power outputs.
  • Cary Owens' optical sensor housing: A 3D-printable design for a housing/mounting bracket for the optical plunger sensor, designed by Cary Owens. This makes it easy to mount the sensor.
  • Lemming77's potentiometer mounting bracket and shooter rod connecter: Sketchup designs for 3D-printable parts for mounting a slide potentiometer as the plunger sensor. These were designed for a particular slide potentiometer that used to be available from an seller but is no longer listed. You can probably use this design as a starting point for other similar devices; just check the dimensions before committing the design to plastic.

Copyright and License

The Pinscape firmware is copyright 2014, 2021 by Michael J Roberts. It's released under an MIT open-source license. See License.

Warning to VirtuaPin Kit Owners

This software isn't designed as a replacement for the VirtuaPin plunger kit's firmware. If you bought the VirtuaPin kit, I recommend that you don't install this software. The VirtuaPin kit uses the same KL25Z microcontroller that Pinscape uses, but the rest of its hardware is different and incompatible. In particular, the Pinscape firmware doesn't include support for the IR proximity sensor used in the VirtuaPin plunger kit, so you won't be able to use your plunger device with the Pinscape firmware. In addition, the VirtuaPin setup uses a different set of GPIO pins for the button inputs from the Pinscape defaults, so if you do install the Pinscape firmware, you'll have to go into the Config Tool and reassign all of the buttons to match the VirtuaPin wiring.

Sat Apr 18 19:08:55 2020 +0000
TCD1103 DMA setup time padding to fix sporadic missed first pixel in transfer; fix TV ON so that the TV ON IR commands don't have to be grouped in the IR command first slots

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 82:4f6209cb5c33 1 // Plunger sensor type for bar-code based absolute position encoders.
mjr 82:4f6209cb5c33 2 // This type of sensor uses an optical sensor that moves with the plunger
mjr 82:4f6209cb5c33 3 // along a guide rail with printed bar codes along its length that encode
mjr 82:4f6209cb5c33 4 // the absolute position at each point. We figure the plunger position
mjr 82:4f6209cb5c33 5 // by reading the bar code and decoding it into a position figure.
mjr 82:4f6209cb5c33 6 //
mjr 82:4f6209cb5c33 7 // The bar code has to be encoded in a specific format that we recognize.
mjr 87:8d35c74403af 8 // We use a reflected Gray code, optically encoded in black/white pixel
mjr 87:8d35c74403af 9 // patterns. Each bit is represented by a fixed-width area. Half the
mjr 87:8d35c74403af 10 // pixels in every bit are white, and half are black. A '0' bit is
mjr 87:8d35c74403af 11 // represented by black pixels in the left half and white pixels in the
mjr 87:8d35c74403af 12 // right half, and a '1' bit is white on the left and black on the right.
mjr 87:8d35c74403af 13 // To read a bit, we identify the set of pixels covering the bit's fixed
mjr 87:8d35c74403af 14 // area in the code, then we see if the left or right half is brighter.
mjr 87:8d35c74403af 15 //
mjr 87:8d35c74403af 16 // (This optical encoding scheme is based on Manchester coding, which is
mjr 87:8d35c74403af 17 // normally used in the context of serial protocols, but translates to
mjr 87:8d35c74403af 18 // bar codes straightforwardly. Replace the serial protocol's time
mjr 87:8d35c74403af 19 // dimension with the spatial dimension across the bar, and replace the
mjr 87:8d35c74403af 20 // high/low wire voltage levels with white/black pixels.)
mjr 82:4f6209cb5c33 21 //
mjr 86:e30a1f60f783 22 // Gray codes are ideal for this type of application. Gray codes are
mjr 86:e30a1f60f783 23 // defined such that each code point differs in exactly one bit from each
mjr 86:e30a1f60f783 24 // adjacent code point. This provides natural error correction when used
mjr 86:e30a1f60f783 25 // as a position scale, since any single-bit error will yield a code point
mjr 86:e30a1f60f783 26 // reading that's only one spot off from the true position. So a bit read
mjr 86:e30a1f60f783 27 // error acts like a reduction in precision. Likewise, any time the sensor
mjr 86:e30a1f60f783 28 // is halfway between two code points, only one bit will be ambiguous, so
mjr 86:e30a1f60f783 29 // the reading will come out as one of points on either side of the true
mjr 86:e30a1f60f783 30 // position. Finally, motion blur will have the same effect, of creating
mjr 86:e30a1f60f783 31 // ambiguity in the least significant bits, and thus giving us a reading
mjr 87:8d35c74403af 32 // that's correct to as many bits as we can make out.
mjr 82:4f6209cb5c33 33 //
mjr 87:8d35c74403af 34 // The half-and-half optical coding also has good properties for our
mjr 87:8d35c74403af 35 // purposes. The fixed-width bit regions require essentially no CPU work
mjr 87:8d35c74403af 36 // to find the bits, which is good because we're using a fairly slow CPU.
mjr 87:8d35c74403af 37 // The half white/half black coding of each pixel makes every pixel
mjr 87:8d35c74403af 38 // self-relative in terms of brightness, so we don't need to figure the
mjr 87:8d35c74403af 39 // black and white thresholds globally for the whole image. That makes
mjr 87:8d35c74403af 40 // the physical device engineering and installation easier because the
mjr 87:8d35c74403af 41 // software can tolerate a fairly wide range of lighting conditions.
mjr 82:4f6209cb5c33 42 //
mjr 82:4f6209cb5c33 43
mjr 82:4f6209cb5c33 44 #ifndef _BARCODESENSOR_H_
mjr 82:4f6209cb5c33 45 #define _BARCODESENSOR_H_
mjr 82:4f6209cb5c33 46
mjr 82:4f6209cb5c33 47 #include "plunger.h"
mjr 87:8d35c74403af 48
mjr 87:8d35c74403af 49 // Gray code to binary mapping for our special coding. This is a custom
mjr 87:8d35c74403af 50 // 7-bit code, minimum run length 6, 110 positions populated. The minimum
mjr 87:8d35c74403af 51 // run length is the minimum number of consecutive code points where each
mjr 87:8d35c74403af 52 // bit must remain fixed. For out optical coding, this defines the smallest
mjr 87:8d35c74403af 53 // "island" size for a black or white bar horizontally. Small features are
mjr 87:8d35c74403af 54 // prone to light scattering that makes them appear gray on the sensor.
mjr 87:8d35c74403af 55 // Larger features are less subject to scatter, making them easier to
mjr 87:8d35c74403af 56 // distinguish by brightness level.
mjr 87:8d35c74403af 57 static const uint8_t grayToBin[] = {
mjr 87:8d35c74403af 58 0, 1, 83, 2, 71, 100, 84, 3, 69, 102, 82, 128, 70, 101, 57, 4, // 0-15
mjr 87:8d35c74403af 59 35, 50, 36, 37, 86, 87, 85, 128, 34, 103, 21, 104, 128, 128, 20, 5, // 16-31
mjr 87:8d35c74403af 60 11, 128, 24, 25, 98, 99, 97, 40, 68, 67, 81, 80, 55, 54, 56, 41, // 32-47
mjr 87:8d35c74403af 61 10, 51, 23, 38, 128, 52, 128, 39, 9, 66, 22, 128, 8, 53, 7, 6, // 48-63
mjr 87:8d35c74403af 62 47, 14, 60, 128, 72, 15, 59, 16, 46, 91, 93, 92, 45, 128, 58, 17, // 64-79
mjr 87:8d35c74403af 63 48, 49, 61, 62, 73, 88, 74, 75, 33, 90, 106, 105, 32, 89, 19, 18, // 80-95
mjr 87:8d35c74403af 64 12, 13, 95, 26, 128, 28, 96, 27, 128, 128, 94, 79, 44, 29, 43, 42, // 96-111
mjr 87:8d35c74403af 65 128, 64, 128, 63, 110, 128, 109, 76, 128, 65, 107, 78, 31, 30, 108, 77 // 112-127
mjr 87:8d35c74403af 66 };
mjr 87:8d35c74403af 67
mjr 87:8d35c74403af 68
mjr 87:8d35c74403af 69 // Auto-exposure counter
mjr 87:8d35c74403af 70 class BarCodeExposureCounter
mjr 87:8d35c74403af 71 {
mjr 87:8d35c74403af 72 public:
mjr 87:8d35c74403af 73 BarCodeExposureCounter()
mjr 87:8d35c74403af 74 {
mjr 87:8d35c74403af 75 nDark = 0;
mjr 87:8d35c74403af 76 nBright = 0;
mjr 87:8d35c74403af 77 nZero = 0;
mjr 87:8d35c74403af 78 nSat = 0;
mjr 87:8d35c74403af 79 }
mjr 87:8d35c74403af 80
mjr 87:8d35c74403af 81 inline void count(int pix)
mjr 87:8d35c74403af 82 {
mjr 87:8d35c74403af 83 if (pix <= 2)
mjr 87:8d35c74403af 84 ++nZero;
mjr 87:8d35c74403af 85 else if (pix < 12)
mjr 87:8d35c74403af 86 ++nDark;
mjr 87:8d35c74403af 87 else if (pix >= 253)
mjr 87:8d35c74403af 88 ++nSat;
mjr 87:8d35c74403af 89 else if (pix > 200)
mjr 87:8d35c74403af 90 ++nBright;
mjr 87:8d35c74403af 91 }
mjr 87:8d35c74403af 92
mjr 87:8d35c74403af 93 int nDark; // dark pixels
mjr 87:8d35c74403af 94 int nBright; // bright pixels
mjr 87:8d35c74403af 95 int nZero; // pixels at zero brightness
mjr 87:8d35c74403af 96 int nSat; // pixels at full saturation
mjr 87:8d35c74403af 97 };
mjr 87:8d35c74403af 98
mjr 82:4f6209cb5c33 99
mjr 82:4f6209cb5c33 100 // Base class for bar-code sensors
mjr 86:e30a1f60f783 101 //
mjr 86:e30a1f60f783 102 // This is a template class with template parameters for the bar
mjr 86:e30a1f60f783 103 // code pixel structure. The bar code layout is fixed for a given
mjr 86:e30a1f60f783 104 // sensor type. We can assume fixed pixel sizes because we don't
mjr 86:e30a1f60f783 105 // have to process arbitrary images. We only have to read scales
mjr 86:e30a1f60f783 106 // specially prepared for this application, so we can count on them
mjr 86:e30a1f60f783 107 // being printed at an exact size relative to the sensor pixels.
mjr 86:e30a1f60f783 108 //
mjr 86:e30a1f60f783 109 // nBits = Number of bits in the code
mjr 86:e30a1f60f783 110 //
mjr 86:e30a1f60f783 111 // leftBarWidth = Width in pixels of delimiting left bar. The code is
mjr 86:e30a1f60f783 112 // delimited by a black bar on the "left" end, nearest pixel 0. This
mjr 86:e30a1f60f783 113 // gives the pixel width of the bar.
mjr 86:e30a1f60f783 114 //
mjr 86:e30a1f60f783 115 // leftBarMaxOfs = Maximum offset of the delimiting bar from the left
mjr 86:e30a1f60f783 116 // edge of the sensor (pixel 0), in pixels
mjr 86:e30a1f60f783 117 //
mjr 86:e30a1f60f783 118 // bitWidth = Width of each bit in pixels. This is the width of the
mjr 86:e30a1f60f783 119 // full bit, including both "half bits" - it's the full white/black or
mjr 86:e30a1f60f783 120 // black/white pattern area.
mjr 86:e30a1f60f783 121
mjr 87:8d35c74403af 122 struct BarCodeProcessResult
mjr 87:8d35c74403af 123 {
mjr 87:8d35c74403af 124 int pixofs;
mjr 87:8d35c74403af 125 int raw;
mjr 87:8d35c74403af 126 int mask;
mjr 87:8d35c74403af 127 };
mjr 87:8d35c74403af 128
mjr 86:e30a1f60f783 129 template <int nBits, int leftBarWidth, int leftBarMaxOfs, int bitWidth>
mjr 87:8d35c74403af 130 class PlungerSensorBarCode: public PlungerSensorImage<BarCodeProcessResult>
mjr 82:4f6209cb5c33 131 {
mjr 82:4f6209cb5c33 132 public:
mjr 104:6e06e0f4b476 133 PlungerSensorBarCode(PlungerSensorImageInterface &sensor, int npix)
mjr 87:8d35c74403af 134 : PlungerSensorImage(sensor, npix, (1 << nBits) - 1)
mjr 87:8d35c74403af 135 {
mjr 87:8d35c74403af 136 startOfs = 0;
mjr 87:8d35c74403af 137 }
mjr 87:8d35c74403af 138
mjr 87:8d35c74403af 139 // process a configuration change
mjr 87:8d35c74403af 140 virtual void onConfigChange(int varno, Config &cfg)
mjr 87:8d35c74403af 141 {
mjr 87:8d35c74403af 142 // check for bar-code variables
mjr 87:8d35c74403af 143 switch (varno)
mjr 87:8d35c74403af 144 {
mjr 87:8d35c74403af 145 case 20:
mjr 87:8d35c74403af 146 // bar code offset
mjr 87:8d35c74403af 147 startOfs = cfg.plunger.barCode.startPix;
mjr 87:8d35c74403af 148 break;
mjr 87:8d35c74403af 149 }
mjr 87:8d35c74403af 150
mjr 87:8d35c74403af 151 // do the generic work
mjr 87:8d35c74403af 152 PlungerSensorImage::onConfigChange(varno, cfg);
mjr 87:8d35c74403af 153 }
mjr 87:8d35c74403af 154
mjr 87:8d35c74403af 155 protected:
mjr 86:e30a1f60f783 156 // process the image
mjr 87:8d35c74403af 157 virtual bool process(const uint8_t *pix, int npix, int &pos, BarCodeProcessResult &res)
mjr 82:4f6209cb5c33 158 {
mjr 87:8d35c74403af 159 // adjust auto-exposure
mjr 87:8d35c74403af 160 adjustExposure(pix, npix);
mjr 87:8d35c74403af 161
mjr 87:8d35c74403af 162 // clear the result descriptor
mjr 87:8d35c74403af 163 res.pixofs = 0;
mjr 87:8d35c74403af 164 res.raw = 0;
mjr 87:8d35c74403af 165 res.mask = 0;
mjr 87:8d35c74403af 166
mjr 86:e30a1f60f783 167 #if 0 // $$$
mjr 86:e30a1f60f783 168
mjr 86:e30a1f60f783 169 // scan from the left edge until we find the fixed '0' start bit
mjr 86:e30a1f60f783 170 for (int i = 0 ; i < leftBarMaxOfs ; ++i, ++pix)
mjr 86:e30a1f60f783 171 {
mjr 86:e30a1f60f783 172 // check for the '0' bit
mjr 86:e30a1f60f783 173 if (readBit8(pix) == 0)
mjr 86:e30a1f60f783 174 {
mjr 86:e30a1f60f783 175 // got it - skip the start bit
mjr 86:e30a1f60f783 176 pix += bitWidth;
mjr 86:e30a1f60f783 177
mjr 86:e30a1f60f783 178 // read the gray code bits
mjr 86:e30a1f60f783 179 int gray = 0;
mjr 86:e30a1f60f783 180 for (int j = 0 ; j < nBits ; ++j, pix += bitWidth)
mjr 86:e30a1f60f783 181 {
mjr 86:e30a1f60f783 182 // read the bit; return failure if we can't decode a bit
mjr 86:e30a1f60f783 183 int bit = readBit8(pix);
mjr 86:e30a1f60f783 184 if (bit < 0)
mjr 86:e30a1f60f783 185 return false;
mjr 86:e30a1f60f783 186
mjr 86:e30a1f60f783 187 // shift it into the code
mjr 86:e30a1f60f783 188 gray = (gray << 1) | bit;
mjr 86:e30a1f60f783 189 }
mjr 86:e30a1f60f783 190 }
mjr 86:e30a1f60f783 191
mjr 86:e30a1f60f783 192 // convert the gray code to binary
mjr 86:e30a1f60f783 193 int bin = grayToBin(gray);
mjr 86:e30a1f60f783 194
mjr 86:e30a1f60f783 195 // compute the parity of the binary value
mjr 86:e30a1f60f783 196 int parity = 0;
mjr 86:e30a1f60f783 197 for (int j = 0 ; j < nBits ; ++j)
mjr 86:e30a1f60f783 198 parity ^= bin >> j;
mjr 86:e30a1f60f783 199
mjr 86:e30a1f60f783 200 // figure the bit required for odd parity
mjr 86:e30a1f60f783 201 int odd = (parity & 0x01) ^ 0x01;
mjr 86:e30a1f60f783 202
mjr 86:e30a1f60f783 203 // read the check bit
mjr 86:e30a1f60f783 204 int bit = readBit8(pix);
mjr 86:e30a1f60f783 205 if (pix < 0)
mjr 86:e30a1f60f783 206 return false;
mjr 86:e30a1f60f783 207
mjr 86:e30a1f60f783 208 // check that it matches the expected parity
mjr 86:e30a1f60f783 209 if (bit != odd)
mjr 86:e30a1f60f783 210 return false;
mjr 86:e30a1f60f783 211
mjr 86:e30a1f60f783 212 // success
mjr 86:e30a1f60f783 213 pos = bin;
mjr 86:e30a1f60f783 214 return true;
mjr 86:e30a1f60f783 215 }
mjr 86:e30a1f60f783 216
mjr 86:e30a1f60f783 217 // no code found
mjr 82:4f6209cb5c33 218 return false;
mjr 86:e30a1f60f783 219
mjr 86:e30a1f60f783 220 #else
mjr 86:e30a1f60f783 221 int barStart = leftBarMaxOfs/2;
mjr 86:e30a1f60f783 222 if (leftBarWidth != 0) // $$$
mjr 86:e30a1f60f783 223 {
mjr 86:e30a1f60f783 224 // Find the black bar on the left side (nearest pixel 0) that
mjr 86:e30a1f60f783 225 // delimits the start of the bar code. To find it, first figure
mjr 86:e30a1f60f783 226 // the average brightness over the left margin up to the maximum
mjr 86:e30a1f60f783 227 // allowable offset, then look for the bar by finding the first
mjr 86:e30a1f60f783 228 // bar-width run of pixels that are darker than the average.
mjr 86:e30a1f60f783 229 int lsum = 0;
mjr 86:e30a1f60f783 230 for (int x = 1 ; x <= leftBarMaxOfs ; ++x)
mjr 86:e30a1f60f783 231 lsum += pix[x];
mjr 86:e30a1f60f783 232 int lavg = lsum / leftBarMaxOfs;
mjr 86:e30a1f60f783 233
mjr 86:e30a1f60f783 234 // now find the first dark edge
mjr 86:e30a1f60f783 235 for (int x = 0 ; x < leftBarMaxOfs ; ++x)
mjr 86:e30a1f60f783 236 {
mjr 86:e30a1f60f783 237 // if this pixel is dark, and one of the next two is dark,
mjr 86:e30a1f60f783 238 // take it as the edge
mjr 86:e30a1f60f783 239 if (pix[x] < lavg && (pix[x+1] < lavg || pix[x+2] < lavg))
mjr 86:e30a1f60f783 240 {
mjr 86:e30a1f60f783 241 // move past the delimier
mjr 86:e30a1f60f783 242 barStart = x + leftBarWidth;
mjr 86:e30a1f60f783 243 break;
mjr 86:e30a1f60f783 244 }
mjr 86:e30a1f60f783 245 }
mjr 86:e30a1f60f783 246 }
mjr 86:e30a1f60f783 247 else
mjr 86:e30a1f60f783 248 {
mjr 87:8d35c74403af 249 // start at the fixed pixel offset
mjr 87:8d35c74403af 250 barStart = startOfs;
mjr 86:e30a1f60f783 251 }
mjr 86:e30a1f60f783 252
mjr 87:8d35c74403af 253 // Start with zero in the barcode and success mask. The mask
mjr 87:8d35c74403af 254 // indicates which bits we were able to read successfully: a
mjr 87:8d35c74403af 255 // '1' bit in the mask indicates that the corresponding bit
mjr 87:8d35c74403af 256 // position in 'barcode' was successfully read, a '0' bit means
mjr 87:8d35c74403af 257 // that the image was too fuzzy to read.
mjr 87:8d35c74403af 258 int barcode = 0, mask = 0;
mjr 87:8d35c74403af 259
mjr 86:e30a1f60f783 260 // Scan the bits
mjr 86:e30a1f60f783 261 for (int bit = 0, x0 = barStart; bit < nBits ; ++bit, x0 += bitWidth)
mjr 86:e30a1f60f783 262 {
mjr 87:8d35c74403af 263 #if 0
mjr 87:8d35c74403af 264 // Figure the extent of this bit. The last bit is double
mjr 87:8d35c74403af 265 // the width of the other bits, to give us a better chance
mjr 87:8d35c74403af 266 // of making out the small features of the last bit.
mjr 87:8d35c74403af 267 int w = bitWidth;
mjr 87:8d35c74403af 268 if (bit == nBits - 1) w *= 2;
mjr 87:8d35c74403af 269 #else
mjr 87:8d35c74403af 270 // width of the bit
mjr 87:8d35c74403af 271 const int w = bitWidth;
mjr 87:8d35c74403af 272 #endif
mjr 87:8d35c74403af 273
mjr 87:8d35c74403af 274 // figure the bit's internal pixel layout
mjr 87:8d35c74403af 275 int halfBitWidth = w / 2;
mjr 87:8d35c74403af 276 int x1 = x0 + halfBitWidth; // midpoint
mjr 87:8d35c74403af 277 int x2 = x0 + w; // right edge
mjr 87:8d35c74403af 278
mjr 87:8d35c74403af 279 // make sure we didn't go out of bounds
mjr 86:e30a1f60f783 280 if (x1 > npix) x1 = npix;
mjr 86:e30a1f60f783 281 if (x2 > npix) x2 = npix;
mjr 86:e30a1f60f783 282
mjr 87:8d35c74403af 283 #if 0
mjr 86:e30a1f60f783 284 // get the average of the pixels over the bit
mjr 86:e30a1f60f783 285 int sum = 0;
mjr 86:e30a1f60f783 286 for (int x = x0 ; x < x2 ; ++x)
mjr 86:e30a1f60f783 287 sum += pix[x];
mjr 87:8d35c74403af 288 int avg = sum / w;
mjr 86:e30a1f60f783 289 // Scan the left and right sections. Classify each
mjr 86:e30a1f60f783 290 // section according to whether the majority of its
mjr 86:e30a1f60f783 291 // pixels are above or below the local average.
mjr 86:e30a1f60f783 292 int lsum = 0, rsum = 0;
mjr 86:e30a1f60f783 293 for (int x = x0 + 1 ; x < x1 - 1 ; ++x)
mjr 86:e30a1f60f783 294 lsum += (pix[x] < avg ? 0 : 1);
mjr 86:e30a1f60f783 295 for (int x = x1 + 1 ; x < x2 - 1 ; ++x)
mjr 86:e30a1f60f783 296 rsum += (pix[x] < avg ? 0 : 1);
mjr 87:8d35c74403af 297 #else
mjr 87:8d35c74403af 298 // Sum the pixel readings in each half-bit. Ignore
mjr 87:8d35c74403af 299 // the first and last bit of each section, since these
mjr 87:8d35c74403af 300 // could be contaminated with scattered light from the
mjr 87:8d35c74403af 301 // adjacent half-bit. On the right half, hew to the
mjr 87:8d35c74403af 302 // right side if the overall pixel width is odd.
mjr 87:8d35c74403af 303 int lsum = 0, rsum = 0;
mjr 87:8d35c74403af 304 for (int x = x0 + 1 ; x < x1 - 1 ; ++x)
mjr 87:8d35c74403af 305 lsum += pix[x];
mjr 87:8d35c74403af 306 for (int x = x2 - halfBitWidth + 1 ; x < x2 - 1 ; ++x)
mjr 87:8d35c74403af 307 rsum += pix[x];
mjr 87:8d35c74403af 308 #endif
mjr 86:e30a1f60f783 309
mjr 87:8d35c74403af 310 // shift a zero bit into the code and success mask
mjr 87:8d35c74403af 311 barcode <<= 1;
mjr 87:8d35c74403af 312 mask <<= 1;
mjr 86:e30a1f60f783 313
mjr 87:8d35c74403af 314 // Brightness difference required per pixel. Higher values
mjr 87:8d35c74403af 315 // require greater contrast to make a reading, which reduces
mjr 87:8d35c74403af 316 // spurious readings at the cost of reducing the overall
mjr 87:8d35c74403af 317 // success rate. The right level depends on the quality of
mjr 87:8d35c74403af 318 // the optical system. Setting this to zero makes us maximally
mjr 87:8d35c74403af 319 // tolerant of low-contrast images, allowing for the simplest
mjr 87:8d35c74403af 320 // optical system. Our simple optical system suffers from
mjr 87:8d35c74403af 321 // poor focus, which in turn causes poor contrast in small
mjr 87:8d35c74403af 322 // features.
mjr 87:8d35c74403af 323 const int minDelta = 2;
mjr 87:8d35c74403af 324
mjr 87:8d35c74403af 325 // see if we could tell the difference in brightness
mjr 87:8d35c74403af 326 int delta = lsum - rsum;
mjr 87:8d35c74403af 327 if (delta < 0) delta = -delta;
mjr 87:8d35c74403af 328 if (delta > minDelta * w/2)
mjr 87:8d35c74403af 329 {
mjr 87:8d35c74403af 330 // got it - black/white = 0, white/black = 1
mjr 87:8d35c74403af 331 if (lsum > rsum) barcode |= 1;
mjr 87:8d35c74403af 332 mask |= 1;
mjr 87:8d35c74403af 333 }
mjr 86:e30a1f60f783 334 }
mjr 86:e30a1f60f783 335
mjr 86:e30a1f60f783 336 // decode the Gray code value to binary
mjr 87:8d35c74403af 337 pos = grayToBin[barcode];
mjr 86:e30a1f60f783 338
mjr 87:8d35c74403af 339 // set the results descriptor structure
mjr 87:8d35c74403af 340 res.pixofs = barStart;
mjr 87:8d35c74403af 341 res.raw = barcode;
mjr 87:8d35c74403af 342 res.mask = mask;
mjr 87:8d35c74403af 343
mjr 87:8d35c74403af 344 // return success if we decoded all bits, and the Gray-to-binary
mjr 87:8d35c74403af 345 // mapping was populated
mjr 87:8d35c74403af 346 return pos != (1 << nBits) && mask == ((1 << nBits) - 1);
mjr 86:e30a1f60f783 347 #endif
mjr 86:e30a1f60f783 348 }
mjr 86:e30a1f60f783 349
mjr 86:e30a1f60f783 350 // read a bar starting at the given pixel
mjr 86:e30a1f60f783 351 int readBit8(const uint8_t *pix)
mjr 86:e30a1f60f783 352 {
mjr 86:e30a1f60f783 353 // pull out the pixels for the bar
mjr 86:e30a1f60f783 354 uint8_t s[8];
mjr 86:e30a1f60f783 355 memcpy(s, pix, 8);
mjr 86:e30a1f60f783 356
mjr 86:e30a1f60f783 357 // sort them in brightness order (using an 8-element network sort)
mjr 86:e30a1f60f783 358 #define SWAP(a, b) if (s[a] > s[b]) { uint8_t tmp = s[a]; s[a] = s[b]; s[b] = tmp; }
mjr 86:e30a1f60f783 359 SWAP(0, 1);
mjr 86:e30a1f60f783 360 SWAP(2, 3);
mjr 86:e30a1f60f783 361 SWAP(0, 2);
mjr 86:e30a1f60f783 362 SWAP(1, 3);
mjr 86:e30a1f60f783 363 SWAP(1, 2);
mjr 86:e30a1f60f783 364 SWAP(4, 5);
mjr 86:e30a1f60f783 365 SWAP(6, 7);
mjr 86:e30a1f60f783 366 SWAP(4, 6);
mjr 86:e30a1f60f783 367 SWAP(5, 7);
mjr 86:e30a1f60f783 368 SWAP(5, 6);
mjr 86:e30a1f60f783 369 SWAP(0, 4);
mjr 86:e30a1f60f783 370 SWAP(1, 5);
mjr 86:e30a1f60f783 371 SWAP(1, 4);
mjr 86:e30a1f60f783 372 SWAP(2, 6);
mjr 86:e30a1f60f783 373 SWAP(3, 7);
mjr 86:e30a1f60f783 374 SWAP(3, 6);
mjr 86:e30a1f60f783 375 SWAP(2, 4);
mjr 86:e30a1f60f783 376 SWAP(3, 5);
mjr 86:e30a1f60f783 377 SWAP(3, 4);
mjr 86:e30a1f60f783 378 #undef SWAP
mjr 86:e30a1f60f783 379
mjr 86:e30a1f60f783 380 // figure the median brightness
mjr 86:e30a1f60f783 381 int median = (int(s[3]) + s[4] + 1) / 2;
mjr 86:e30a1f60f783 382
mjr 86:e30a1f60f783 383 // count pixels below the median on each side
mjr 86:e30a1f60f783 384 int ldark = 0, rdark = 0;
mjr 86:e30a1f60f783 385 for (int i = 0 ; i < 3 ; ++i)
mjr 86:e30a1f60f783 386 {
mjr 86:e30a1f60f783 387 if (pix[i] < median)
mjr 86:e30a1f60f783 388 ldark++;
mjr 86:e30a1f60f783 389 }
mjr 86:e30a1f60f783 390 for (int i = 4 ; i < 8 ; ++i)
mjr 86:e30a1f60f783 391 {
mjr 86:e30a1f60f783 392 if (pix[i] < median)
mjr 86:e30a1f60f783 393 rdark++;
mjr 86:e30a1f60f783 394 }
mjr 86:e30a1f60f783 395
mjr 86:e30a1f60f783 396 // we need >=3 dark + >=3 light or vice versa
mjr 86:e30a1f60f783 397 if (ldark >= 3 && rdark <= 1)
mjr 86:e30a1f60f783 398 {
mjr 86:e30a1f60f783 399 // dark + light = '0' bit
mjr 86:e30a1f60f783 400 return 0;
mjr 86:e30a1f60f783 401 }
mjr 86:e30a1f60f783 402 if (ldark <= 1 && rdark >= 3)
mjr 86:e30a1f60f783 403 {
mjr 86:e30a1f60f783 404 // light + dark = '1' bit
mjr 86:e30a1f60f783 405 return 1;
mjr 86:e30a1f60f783 406 }
mjr 86:e30a1f60f783 407 else
mjr 86:e30a1f60f783 408 {
mjr 86:e30a1f60f783 409 // ambiguous bit
mjr 86:e30a1f60f783 410 return -1;
mjr 86:e30a1f60f783 411 }
mjr 86:e30a1f60f783 412 }
mjr 86:e30a1f60f783 413
mjr 86:e30a1f60f783 414 // bar code sensor orientation is fixed
mjr 86:e30a1f60f783 415 virtual int getOrientation() const { return 1; }
mjr 86:e30a1f60f783 416
mjr 87:8d35c74403af 417 // send extra status report headers
mjr 87:8d35c74403af 418 virtual void extraStatusHeaders(USBJoystick &js, BarCodeProcessResult &res)
mjr 87:8d35c74403af 419 {
mjr 87:8d35c74403af 420 // Send the bar code status report. We use coding type 1 (Gray code,
mjr 87:8d35c74403af 421 // Manchester pixel coding).
mjr 87:8d35c74403af 422 js.sendPlungerStatusBarcode(nBits, 1, res.pixofs, bitWidth, res.raw, res.mask);
mjr 87:8d35c74403af 423 }
mjr 87:8d35c74403af 424
mjr 82:4f6209cb5c33 425 // adjust the exposure
mjr 82:4f6209cb5c33 426 void adjustExposure(const uint8_t *pix, int npix)
mjr 82:4f6209cb5c33 427 {
mjr 86:e30a1f60f783 428 #if 1
mjr 86:e30a1f60f783 429 // The Manchester code has a nice property for auto exposure
mjr 86:e30a1f60f783 430 // control: each bit area has equal numbers of white and black
mjr 86:e30a1f60f783 431 // pixels. So we know exactly how the overall population of
mjr 86:e30a1f60f783 432 // pixels has to look: the bit area will be 50% black and 50%
mjr 86:e30a1f60f783 433 // white, and the margins will be all white. For maximum
mjr 86:e30a1f60f783 434 // contrast, target an exposure level where the black pixels
mjr 87:8d35c74403af 435 // are all below a certain brightness level and the white
mjr 86:e30a1f60f783 436 // pixels are all above. Start by figuring the number of
mjr 86:e30a1f60f783 437 // pixels above and below.
mjr 87:8d35c74403af 438 const int medianTarget = 160;
mjr 87:8d35c74403af 439 int nBelow = 0;
mjr 86:e30a1f60f783 440 for (int i = 0 ; i < npix ; ++i)
mjr 86:e30a1f60f783 441 {
mjr 87:8d35c74403af 442 if (pix[i] < medianTarget)
mjr 87:8d35c74403af 443 ++nBelow;
mjr 86:e30a1f60f783 444 }
mjr 86:e30a1f60f783 445
mjr 87:8d35c74403af 446 // Figure the desired number of black pixels: the left bar is
mjr 86:e30a1f60f783 447 // all black pixels, and 50% of each bit is black pixels.
mjr 87:8d35c74403af 448 int targetBelow = leftBarWidth + (nBits * bitWidth)/2;
mjr 86:e30a1f60f783 449
mjr 86:e30a1f60f783 450 // Increase exposure time if too many pixels are below the
mjr 86:e30a1f60f783 451 // halfway point; decrease it if too many pixels are above.
mjr 87:8d35c74403af 452 int d = nBelow - targetBelow;
mjr 86:e30a1f60f783 453 if (d > 5 || d < -5)
mjr 86:e30a1f60f783 454 {
mjr 86:e30a1f60f783 455 axcTime += d;
mjr 86:e30a1f60f783 456 }
mjr 86:e30a1f60f783 457
mjr 86:e30a1f60f783 458
mjr 86:e30a1f60f783 459 #elif 0 //$$$
mjr 86:e30a1f60f783 460 // Count exposure levels of pixels in the left and right margins
mjr 86:e30a1f60f783 461 BarCodeExposureCounter counter;
mjr 86:e30a1f60f783 462 for (int i = 0 ; i < leftBarMaxOfs/2 ; ++i)
mjr 86:e30a1f60f783 463 {
mjr 86:e30a1f60f783 464 // count the pixels at the left and right margins
mjr 86:e30a1f60f783 465 counter.count(pix[i]);
mjr 86:e30a1f60f783 466 counter.count(pix[npix - i - 1]);
mjr 86:e30a1f60f783 467 }
mjr 86:e30a1f60f783 468
mjr 86:e30a1f60f783 469 // The margin is all white, so try to get all of these pixels
mjr 86:e30a1f60f783 470 // in the bright range, but not saturated. That should give us
mjr 86:e30a1f60f783 471 // the best overall contrast throughout the image.
mjr 86:e30a1f60f783 472 if (counter.nSat > 0)
mjr 86:e30a1f60f783 473 {
mjr 86:e30a1f60f783 474 // overexposed - reduce exposure time
mjr 86:e30a1f60f783 475 if (axcTime > 5)
mjr 86:e30a1f60f783 476 axcTime -= 5;
mjr 86:e30a1f60f783 477 else
mjr 86:e30a1f60f783 478 axcTime = 0;
mjr 86:e30a1f60f783 479 }
mjr 86:e30a1f60f783 480 else if (counter.nBright < leftBarMaxOfs)
mjr 86:e30a1f60f783 481 {
mjr 86:e30a1f60f783 482 // they're not all in the bright range - increase exposure time
mjr 86:e30a1f60f783 483 axcTime += 5;
mjr 86:e30a1f60f783 484 }
mjr 86:e30a1f60f783 485
mjr 86:e30a1f60f783 486 #else // $$$
mjr 82:4f6209cb5c33 487 // Count the number of pixels near total darkness and
mjr 82:4f6209cb5c33 488 // total saturation
mjr 86:e30a1f60f783 489 int nZero = 0, nDark = 0, nBri = 0, nSat = 0;
mjr 82:4f6209cb5c33 490 for (int i = 0 ; i < npix ; ++i)
mjr 82:4f6209cb5c33 491 {
mjr 82:4f6209cb5c33 492 int pi = pix[i];
mjr 86:e30a1f60f783 493 if (pi <= 2)
mjr 86:e30a1f60f783 494 ++nZero;
mjr 86:e30a1f60f783 495 else if (pi < 12)
mjr 82:4f6209cb5c33 496 ++nDark;
mjr 86:e30a1f60f783 497 else if (pi >= 254)
mjr 82:4f6209cb5c33 498 ++nSat;
mjr 86:e30a1f60f783 499 else if (pi > 242)
mjr 86:e30a1f60f783 500 ++nBri;
mjr 82:4f6209cb5c33 501 }
mjr 82:4f6209cb5c33 502
mjr 82:4f6209cb5c33 503 // If more than 30% of pixels are near total darkness, increase
mjr 82:4f6209cb5c33 504 // the exposure time. If more than 30% are near total saturation,
mjr 82:4f6209cb5c33 505 // decrease the exposure time.
mjr 86:e30a1f60f783 506 int pct5 = uint32_t(npix * 3277) >> 16;
mjr 82:4f6209cb5c33 507 int pct30 = uint32_t(npix * 19661) >> 16;
mjr 82:4f6209cb5c33 508 int pct50 = uint32_t(npix) >> 1;
mjr 86:e30a1f60f783 509 if (nSat == 0)
mjr 86:e30a1f60f783 510 {
mjr 86:e30a1f60f783 511 // no saturated pixels - increase exposure time
mjr 86:e30a1f60f783 512 axcTime += 5;
mjr 86:e30a1f60f783 513 }
mjr 86:e30a1f60f783 514 else if (nSat > pct5)
mjr 86:e30a1f60f783 515 {
mjr 86:e30a1f60f783 516 if (axcTime > 5)
mjr 86:e30a1f60f783 517 axcTime -= 5;
mjr 86:e30a1f60f783 518 else
mjr 86:e30a1f60f783 519 axcTime = 0;
mjr 86:e30a1f60f783 520 }
mjr 86:e30a1f60f783 521 else if (nZero == 0)
mjr 86:e30a1f60f783 522 {
mjr 86:e30a1f60f783 523 // no totally dark pixels - decrease exposure time
mjr 86:e30a1f60f783 524 if (axcTime > 5)
mjr 86:e30a1f60f783 525 axcTime -= 5;
mjr 86:e30a1f60f783 526 else
mjr 86:e30a1f60f783 527 axcTime = 0;
mjr 86:e30a1f60f783 528 }
mjr 86:e30a1f60f783 529 else if (nZero > pct5)
mjr 86:e30a1f60f783 530 {
mjr 86:e30a1f60f783 531 axcTime += 5;
mjr 86:e30a1f60f783 532 }
mjr 86:e30a1f60f783 533 else if (nZero > pct30 || (nDark > pct50 && nSat < pct30))
mjr 82:4f6209cb5c33 534 {
mjr 82:4f6209cb5c33 535 // very dark - increase exposure time a lot
mjr 82:4f6209cb5c33 536 if (axcTime < 450)
mjr 82:4f6209cb5c33 537 axcTime += 50;
mjr 82:4f6209cb5c33 538 }
mjr 82:4f6209cb5c33 539 else if (nDark > pct30 && nSat < pct30)
mjr 82:4f6209cb5c33 540 {
mjr 82:4f6209cb5c33 541 // dark - increase exposure time a bit
mjr 82:4f6209cb5c33 542 if (axcTime < 490)
mjr 82:4f6209cb5c33 543 axcTime += 10;
mjr 82:4f6209cb5c33 544 }
mjr 86:e30a1f60f783 545 else if (nSat > pct30 || (nBri > pct50 && nDark < pct30))
mjr 82:4f6209cb5c33 546 {
mjr 82:4f6209cb5c33 547 // very overexposed - decrease exposure time a lot
mjr 82:4f6209cb5c33 548 if (axcTime > 50)
mjr 82:4f6209cb5c33 549 axcTime -= 50;
mjr 82:4f6209cb5c33 550 else
mjr 82:4f6209cb5c33 551 axcTime = 0;
mjr 82:4f6209cb5c33 552 }
mjr 86:e30a1f60f783 553 else if (nBri > pct30 && nDark < pct30)
mjr 82:4f6209cb5c33 554 {
mjr 82:4f6209cb5c33 555 // overexposed - decrease exposure time a little
mjr 82:4f6209cb5c33 556 if (axcTime > 10)
mjr 82:4f6209cb5c33 557 axcTime -= 10;
mjr 82:4f6209cb5c33 558 else
mjr 82:4f6209cb5c33 559 axcTime = 0;
mjr 82:4f6209cb5c33 560 }
mjr 86:e30a1f60f783 561 #endif
mjr 86:e30a1f60f783 562
mjr 100:1ff35c07217c 563 // don't allow the exposure time to go below 0 or over 2.5ms
mjr 86:e30a1f60f783 564 if (int(axcTime) < 0)
mjr 86:e30a1f60f783 565 axcTime = 0;
mjr 86:e30a1f60f783 566 if (axcTime > 2500)
mjr 86:e30a1f60f783 567 axcTime = 2500;
mjr 82:4f6209cb5c33 568 }
mjr 82:4f6209cb5c33 569
mjr 87:8d35c74403af 570 #if 0
mjr 87:8d35c74403af 571 // convert a reflected Gray code value (up to 16 bits) to binary
mjr 87:8d35c74403af 572 static inline int grayToBin(int grayval)
mjr 82:4f6209cb5c33 573 {
mjr 87:8d35c74403af 574 int temp = grayval ^ (grayval >> 8);
mjr 87:8d35c74403af 575 temp ^= (temp >> 4);
mjr 87:8d35c74403af 576 temp ^= (temp >> 2);
mjr 87:8d35c74403af 577 temp ^= (temp >> 1);
mjr 87:8d35c74403af 578 return temp;
mjr 82:4f6209cb5c33 579 }
mjr 87:8d35c74403af 580 #endif
mjr 87:8d35c74403af 581
mjr 87:8d35c74403af 582 // bar code starting pixel offset
mjr 87:8d35c74403af 583 int startOfs;
mjr 82:4f6209cb5c33 584 };
mjr 82:4f6209cb5c33 585
mjr 82:4f6209cb5c33 586 #endif