[Elphel-support] Re1: get image and histogram for the command line

[Andrey Filippov]

You may find example of reading histograms in
http://elphel.cvs.sourceforge.net/viewvc/elphel/elphel353-8.0/packages/web/353/php_top/diag_utils.php?view=markup(lines
425 and below)

It is available in the camera as
http://camera_ip/diag_utils.php (linked from the main page)

Andrey


On Wed, Mar 23, 2011 at 10:40 AM, Andrey Filippov <
support-list at support.elphel.com> wrote:

> Sebastien, Sebastian
>
> 1) Monochrome images - you may set monochrome mode (selection list in camvc
> or COLOR=0 in parsedit.pho or just from the PHP script.
> It will still appear as "color JPEG", but color components will be zeroed
> completely so compressed nicely.
> 2) "Raw" - I would still recommend using JPEG with quality=100%. The
> compression error will be less than 1 count, but you'll get the normal fps -
> real raw data from the camera is made fro debugging mostly, it requires each
> pixel to be read from the FPGA by software - in compressed mode data is
> transferred to the system memory over DMA
> 3) Using camvc.php to control the camera - yes, it is possible but I would
> recommend using custom php script (you may use snapfull.php as an example)
> 4) Histograms - you may use PHP code to read histogram arrays from the
> camera, there is support in the PHP extension:
>
> http://elphel.cvs.sourceforge.net/viewvc/elphel/elphel353-8.0/apps/php-5.2.9/ext/elphel/elphel_php.c?view=markup:
>
> 1245 /**  1246 * @brief return histograms for selected frame (absolute
> frame number) as a plain integer array  1247 * some derivative histograms
> may be calculated if they do not exist yet  1248 * (raw FPGA data should
> be read from IRQ/tasklet - no attemt to re-read FPGA here)  1249 * @param
> frame - absolute frame number  1250 * @param needed - bitmask specifying
> what tables to include in the output array, each group is in the order
> r(0),g(1),gb(2),b(3)  1251 * - bits 0..3 - raw histograms from the FPGA
> (only if they are already in the cache)  1252 * - bits 4..7 - cumulative
> histograms (sum of raw ones) - normally called from applications  1253 * -
> bits 8..11 - calculate percentiles (reverse cumulative histograms) -
> normally called from applications  1254 * @return NULL - error, otherwise
> a string with (struct histogram_stuct_t)  1255 *  1256 */  1257
>  1258 PHP_FUNCTION(elphel_histogram_get)  1259 {  1260 struct
> histogram_stuct_t * frame_histogram_structure;  1261 long frame=-1;  1262
> long needed=0xfff;  1263 long index;  1264 int i;  1265 if (
> zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|ll", &needed, &frame)
> == FAILURE) {  1266 php_error_docref(NULL TSRMLS_CC, E_ERROR, "Wrong
> index");  1267 RETURN_NULL ();  1268 }
> (all php functions are listed in the beginning of the file)
>
> For each function format is specified in a line like
> if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|ll", &needed, &
> frame) == FAILURE) {
>
> "|ll" means that there are no required parameters (nothing before "|"), so
> you can call
> $histogram=elphel_histogram_get();
>
> and two optional long parameters that will be assigned to "needed" and
> "frame" variables
>
> Note, there is no automatic conversion of the parameter types, they should
> be numbers, not string. You may ensure that the strings are converted by
> adding 0 to them, i.e
> $numeric_value=$_GET('url_value')+0;
> to convert url parameter (...&url_value=1234&..) to integer value 1234
>
> Andrey
>
>
>
>
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