float ColorCalibrator::findCorrectExposure()
{
Log::get() << Log::MESSAGE << "ColorCalibrator::" << __FUNCTION__ << " - Finding correct exposure time" << Log::endl;
Values res;
while (true)
{
_gcamera->getAttribute("shutterspeed", res);
int status = _gcamera->capture();
if (false == status)
{
Log::get() << Log::WARNING << "ColorCalibrator::" << __FUNCTION__ << " - There was an issue during capture." << Log::endl;
return 0.f;
}
_gcamera->update();
ImageBuffer img = _gcamera->get();
ImageBufferSpec spec = _gcamera->getSpec();
// Exposure is found from a centered area, covering 4% of the frame
int roiSize = spec.width / 5;
unsigned long total = roiSize * roiSize;
unsigned long sum = 0;
uint8_t* pixel = reinterpret_cast<uint8_t*>(img.data());
for (int y = spec.height / 2 - roiSize / 2; y < spec.height / 2 + roiSize / 2; ++y)
for (int x = spec.width / 2 - roiSize / 2; x < spec.width / 2 + roiSize / 2; ++x)
{
sum += (unsigned long)(255.f * (0.2126 * pixel[(x + y * spec.width) * 3]
+ 0.7152 * pixel[(x + y * spec.width) * 3 + 1]
+ 0.0722 * pixel[(x + y * spec.width) * 3 + 2]));
}
float meanValue = (float)sum / (float)total;
Log::get() << Log::MESSAGE << "ColorCalibrator::" << __FUNCTION__ << " - Mean value over all channels: " << meanValue << Log::endl;
if (meanValue < 100.f)
{
float speed = res[0].asFloat() * std::max(1.5f, 100.f / meanValue);
_gcamera->setAttribute("shutterspeed", {speed});
}
else if (meanValue > 160.f)
{
float speed = res[0].asFloat() / std::max(1.5f, 160.f / meanValue);
_gcamera->setAttribute("shutterspeed", {speed});
}
else
{
break;
}
}
if (res.size() == 0)
return 0.f;
else
return res[0].asFloat();
}
ImageTGA::ImageTGA (const ImageBuffer &ibuff)
: _header (NULL)
{
const GLubyte *colormap = NULL;
const GLubyte *data_ptr;
try
{
_name = ibuff.filename ();
data_ptr = ibuff.data ();
_standardCoordSystem = true;
// Read TGA header
_header = reinterpret_cast<const TGA_Header *>(data_ptr);
data_ptr += sizeof (TGA_Header) + _header->id_lenght;
// Get image information
getTextureInfo ();
// Memory allocation for pixel data
_pixels = new GLubyte[_width * _height * _components];
// Read color map, if present
if (_header->colormap_type)
{
// NOTE: color map is stored in BGR
colormap = data_ptr;
data_ptr += _header->cm_length * (_header->cm_size >> 3);
}
// Decode image data
switch (_header->image_type)
{
case 0:
// No data
break;
case 1:
// Uncompressed 8 bits color index
readTGA8bits (data_ptr, colormap);
break;
case 2:
// Uncompressed 16-24-32 bits
switch (_header->pixel_depth)
{
case 16:
readTGA16bits (data_ptr);
break;
case 24:
readTGA24bits (data_ptr);
break;
case 32:
readTGA32bits (data_ptr);
break;
}
break;
case 3:
// Uncompressed 8 or 16 bits grayscale
if (_header->pixel_depth == 8)
readTGAgray8bits (data_ptr);
else // 16 bits
readTGAgray16bits (data_ptr);
break;
case 9:
// RLE compressed 8 bits color index
readTGA8bitsRLE (data_ptr, colormap);
break;
case 10:
// RLE compressed 16-24-32 bits
switch (_header->pixel_depth)
{
case 16:
readTGA16bitsRLE (data_ptr);
break;
case 24:
readTGA24bitsRLE (data_ptr);
break;
case 32:
readTGA32bitsRLE (data_ptr);
break;
}
break;
case 11:
// RLE compressed 8 or 16 bits grayscale
if (_header->pixel_depth == 8)
readTGAgray8bitsRLE (data_ptr);
else // 16 bits
readTGAgray16bitsRLE (data_ptr);
break;
default:
// Image type is not correct, free memory and quit
throw ImageException ("Unknown TGA image type", _name);
}
}