SC1ModCam Class Reference

Control an SC1-modified pwc-compatible webcam. More...

#include <SC1ModCam.hpp>

List of all members.

Public Types
enum	ERRCODE { ERR_OK = 0, ERR_ERROR, ERR_WARN, ERR_FATAL }
Public Member Functions
	SC1ModCam (string devname="/dev/video", int parport=0x378)
	Initialize the class.
	~SC1ModCam ()
	Free memory and close the device.
unsigned long	set_exposure (unsigned long msecs)
	Set exposure time in milliseconds.
unsigned long	get_exposure (void)
	Get exposure time in milliseconds.
unsigned long	set_multiplier (unsigned int m)
	Set number of frames to drop.
unsigned long	get_multiplier (void)
	Get number of frames that will be dropped.
unsigned int	set_fps (unsigned int fps)
	Set frames-per-second for camera.
unsigned int	get_fps (void)
	Get number of frames per second.
bool	set_resolution (int width, int height)
	Set capture resolution of camera.
void	get_resolution (int *width, int *height)
	Get capture resolution from camera.
void *	get_buffer (void)
	Get pointer to buffer containing image.
size_t	get_buffer_size (void)
	Get size of buffer in bytes.
bool	take_photo ()
	Take exposure (synchronously).
enum ERRCODE	error (string *msg=NULL)
	Get error code and descriptive string.
Protected Member Functions
void	_set_error (string error, enum ERRCODE code=ERR_ERROR)
void	_unset_error (void)
bool	_sync_settings (void)
	Synchronizes camera settings with local values.
bool	_setup_camera (void)
	Sets up all hardcoded settings and calls _sync_settings().
bool	_open_shutter ()
	Set pin 2 on the parport low, starting the exposure.
bool	_close_shutter ()
	Set pin 2 on the parport high, stopping the exposure.
void	_usleep (unsigned long usecs)
	Sleep for the specifed number of microseconds.
Protected Attributes
string	_error_string
enum ERRCODE	_error_code
void *	_buffer
int	_multiplier
int	_fps
int	_image_width
int	_image_height
int	_devfd
Static Protected Attributes
const float	_bytes_per_pixel = 1.5

---

Detailed Description

Control an SC1-modified pwc-compatible webcam.

This class allows you to control a pwc-compatible camera that has been modified according to the SC1 Modifiction:

http://pmdo.com/SC1.htm

This class has been tested with a Philips ToUcam PRO II (PCVC840K) but should work with any camera supported by the pwc driver:

http://www.smcc.demon.nl/webcam/

Examples:

lexp.cpp.

---

Constructor & Destructor Documentation

SC1ModCam::SC1ModCam (  string  devname = "/dev/video", int  parport = 0x378 )

Initialize the class. This calls various other functions to set defaults: FPS = 5 Multiplier = 8 Resolution = 640x480 Parameters: devname  Name of webcam's video4linux device parport  Numerical address of parallel port connected to the webcam

---

Member Function Documentation

bool SC1ModCam::_close_shutter (  void   )  [protected]

Set pin 2 on the parport high, stopping the exposure. Currently, this function always returns true. Returns: false if an error occurred, true otherwise

bool SC1ModCam::_open_shutter (  void   )  [protected]

Set pin 2 on the parport low, starting the exposure. Currently, this function always returns true. Returns: false if an error occurred, true otherwise

bool SC1ModCam::_setup_camera (  void   )  [protected]

Sets up all hardcoded settings and calls _sync_settings(). Returns: false if an error occurred, true otherwise See also: _sync_settings()

bool SC1ModCam::_sync_settings (  void   )  [protected]

Synchronizes camera settings with local values. Used in the constructor to set all the default values in the camera. Returns: false if an error occurred, true otherwise

void SC1ModCam::_usleep (  unsigned long  usecs  )  [protected]

Sleep for the specifed number of microseconds. The system call nanosleep(2) is used in this implementation. Parameters: usecs  Number of microseconds to sleep

enum SC1ModCam::ERRCODE SC1ModCam::error (  string *  msg = NULL  )

Get error code and descriptive string. If msg is null or not specified, only the error code is returned. Parameters: msg  Pointer to string to set to error string Returns: Error code Examples: lexp.cpp.

void * SC1ModCam::get_buffer (  void   )

Get pointer to buffer containing image. It only makes sense to call this function after calling take_photo(). If you call this function before take_photo, you will receive a null pointer. Warning: The pointer returned by this function is only valid while the object still exists! Returns: Pointer to image in YUV420P format (1.5 bytes per pixel) Examples: lexp.cpp.

size_t SC1ModCam::get_buffer_size (  void   )

Get size of buffer in bytes. Use this to avoid reading an incomplete image. Examples: lexp.cpp.

void SC1ModCam::get_resolution (  int *  width, int *  height )

Get capture resolution from camera. This function assumes that the internal variables reflect reality. In proper operation, this should be fine. Parameters: width  Pointer to value to set to image width height  Pointer to value to set to image height

unsigned long SC1ModCam::set_exposure (  unsigned long  msecs  )

Set exposure time in milliseconds. The actual exposure time may be shorter than the specified exposure time by as much as (1/FPS). A warning will be generated if the exposure time is set to less than 1 second. Exposure times this short have been known to result in corrupted frames. Warning: Changing the FPS after calling this function will change the exposure time but won't trigger a warning! Parameters: msecs  exposure time in miilliseconds Returns: Actual exposure time in milliseconds

unsigned int SC1ModCam::set_fps (  unsigned int  fps  )

Set frames-per-second for camera. The FPS will be set in the class and on the camera itself. If the camera does not support the given FPS value, an error of type ERR_WARN will be set and the current value will be returned. Parameters: fps  Number of frames per second. Acceptable values depend on the specific camera in use, but 5 is the default. Returns: Actual FPS set in camera - will be different from parameter if there was an error. See also: http://www.smcc.demon.nl/webcam/ Examples: lexp.cpp.

unsigned long SC1ModCam::set_multiplier (  unsigned int  mult  )

Set number of frames to drop. The long exposure is taken by grabbing a bunch of frames and throwing most of them away. This function sets approximately how many frames get dropped. Parameters: mult  Number of frames to drop Returns: Time, in milliseconds, of exposure Examples: lexp.cpp.

bool SC1ModCam::set_resolution (  int  width, int  height )

Set capture resolution of camera. Parameters: width  Width in pixels height  Height in pixels Returns: Success (true) or failure (false) Examples: lexp.cpp.

bool SC1ModCam::take_photo (  void   )

Take exposure (synchronously). This function takes the long exposure synchronously, meaning it blocks the calling function for the entire length of the exposure. Returns: false if an error occurred, true otherwise. Examples: lexp.cpp.

---

The documentation for this class was generated from the following files:

• SC1ModCam.hpp
• SC1ModCam.cpp

---