[GST gvawatermark] Add inclusive/exclusive label filtering

walidbarakat · walidbarakat · commit e2fc774c259e · 2026-02-18T12:08:33.000+01:00
Implement object label filtering functionality that allows users
to control which detected objects are highlighted with watermark
based on their classification labels.

- Add include-labels and exclude-labels parameters to displ-cfg
- Support colon-delimited label specification (e.g., "person:car:bicycle")
- Precedence logic where inclusion filters above exclusion filters
- Add parseFilterConfig utility function for label parsing
- Update documentation with filtering parameter usage examples

Signed-off-by: Walid &lt;walid.aly@intel.com&gt;
diff --git a/docs/source/_images/roi-exclude-car.png b/docs/source/_images/roi-exclude-car.png
diff --git a/docs/source/_images/roi-include-car.png b/docs/source/_images/roi-include-car.png
diff --git a/docs/source/elements/gvawatermark.md b/docs/source/elements/gvawatermark.md
@@ -144,18 +144,35 @@ Controls the size of text labels displayed on detected objects.
 
 *The default triplex font provides good readability*
 
-### FPS Display
+### Label Filtering
 
-**Average FPS Display (`displ-avgfps=true`)**
-![Show FPS](../_images/show-avg-fps.png)
+You can selectively show or hide detected objects based on their labels using filtering parameters:
 
-*Displays average FPS counter when `gvafpscounter` element is present in pipeline*
+**Include Labels (`show-roi=person:car:truck`)**
+- Only objects with labels "person", "car", or "truck" will be displayed
+- All other detected objects will be hidden
+- Useful for focusing on specific object types
+
+e.g `displ-cfg=show-labels=true,show-roi=car`
+![Car label included](../_images/roi-include-car.png)
+
+**Exclude Labels (`hide-roi=bottle:cup:laptop`)**
+- Objects with labels "bottle", "cup", or "laptop" will be hidden
+- All other detected objects will be displayed
+- Useful for removing distracting or irrelevant objects from the display
+
+e.g `displ-cfg=show-labels=true,hide-roi=car`
+![Car label excluded](../_images/roi-exclude-car.png)
+
+**Filter Priority**
+- If both `show-roi` and `hide-roi` are specified, `show-roi` takes precedence
+- Empty lists mean no filtering is applied
 
 ### Configuration Examples
 
 ```bash
 # Minimal labels with smaller font
-displ-cfg=show-labels=false
+displ-cfg=show-labels=true,show-roi=false
 
 # Large text with background
 displ-cfg=font-scale=2.0,draw-txt-bg=true
@@ -165,4 +182,21 @@ displ-cfg=color-idx=0,thickness=1,font-type=simplex
 
 # Complete custom styling
 displ-cfg=font-scale=1.5,thickness=3,color-idx=2,font-type=complex,draw-txt-bg=true
+
+# Show only specific object types
+displ-cfg=show-labels=true,show-roi=person:car:truck
+
+# Hide specific object types
+displ-cfg=show-labels=true,hide-roi=bottle:cup:laptop
+
+# Combine filtering with styling
+displ-cfg=show-labels=true,show-roi=person:car,font-scale=1.2,color-idx=1
 ```
+
+### FPS Display
+
+**Average FPS Display (`displ-avgfps=true`)**
+![Show FPS](../_images/show-avg-fps.png)
+
+*Displays average FPS counter when `gvafpscounter` element is present in pipeline*
+
diff --git a/src/monolithic/gst/elements/gvawatermark/gstgvawatermarkimpl.cpp b/src/monolithic/gst/elements/gvawatermark/gstgvawatermarkimpl.cpp
@@ -40,6 +40,7 @@
 
 #include <array>
 #include <exception>
+#include <optional>
 #include <string>
 #include <typeinfo>
 #if !defined(ENABLE_VAAPI) || defined(_WIN32)
@@ -146,6 +147,8 @@ struct Impl {
                                             const GVA::Rect<double> &rectangle, std::vector<render::Prim> &prims) const;
     void find_gvafpscounter_element();
     void parse_displ_config();
+    inline bool is_ROI_filtered_out(const std::string &label) const;
+
     std::unique_ptr<Renderer> createRenderer(std::shared_ptr<ColorConverter> converter);
 
     std::unique_ptr<Renderer> createGPURenderer(dlstreamer::ImageFormat format,
@@ -192,6 +195,8 @@ struct Impl {
         uint thickness = DEFAULT_THICKNESS;
         int font_type = cv::FONT_HERSHEY_TRIPLEX;
         double font_scale = DEFAULT_TEXT_SCALE;
+        std::optional<std::unordered_set<std::string>> include_labels_filter;
+        std::optional<std::unordered_set<std::string>> exclude_labels_filter;
     } _displCfg;
 };
 
@@ -899,54 +904,62 @@ bool Impl::render_va(cv::Mat *buffer) {
     return true;
 }
 
-void Impl::preparePrimsForRoi(GVA::RegionOfInterest &roi, std::vector<render::Prim> &prims) const {
-    size_t color_index = roi.label_id();
+inline bool Impl::is_ROI_filtered_out(const std::string &label) const {
+    return _displCfg.include_labels_filter.has_value()
+               ? (_displCfg.include_labels_filter->count(label) == 0)
+               : (_displCfg.exclude_labels_filter.has_value() && _displCfg.exclude_labels_filter->count(label) != 0);
+}
 
-    auto rect_u32 = roi.rect();
-    GVA::Rect<double> rect = {safe_convert<double>(rect_u32.x), safe_convert<double>(rect_u32.y),
-                              safe_convert<double>(rect_u32.w), safe_convert<double>(rect_u32.h)};
+void Impl::preparePrimsForRoi(GVA::RegionOfInterest &roi, std::vector<render::Prim> &prims) const {
+    if (!is_ROI_filtered_out(roi.label())) {
+        size_t color_index = roi.label_id();
 
-    clip_rect(rect.x, rect.y, rect.w, rect.h, _vinfo);
+        auto rect_u32 = roi.rect();
+        GVA::Rect<double> rect = {safe_convert<double>(rect_u32.x), safe_convert<double>(rect_u32.y),
+                                  safe_convert<double>(rect_u32.w), safe_convert<double>(rect_u32.h)};
 
-    std::ostringstream text;
-    const int object_id = roi.object_id();
-    if (object_id > 0) {
-        text << object_id << ": ";
-        color_index = object_id;
-    }
+        clip_rect(rect.x, rect.y, rect.w, rect.h, _vinfo);
 
-    if (roi.label().size() > 1) {
-        appendStr(text, roi.label());
-        text << int(roi.confidence() * 100) << "%";
-    }
+        std::ostringstream text;
+        const int object_id = roi.object_id();
+        if (object_id > 0) {
+            text << object_id << ": ";
+            color_index = object_id;
+        }
 
-    // Prepare primitives for tensors
-    for (auto &tensor : roi.tensors()) {
-        preparePrimsForTensor(tensor, rect, prims, color_index);
-        if (!tensor.is_detection()) {
-            appendStr(text, tensor.label());
+        if (roi.label().size() > 1) {
+            appendStr(text, roi.label());
+            text << int(roi.confidence() * 100) << "%";
         }
-    }
 
-    // set color
-    Color color = indexToColor(color_index);
-    if (_displCfg.color_idx != DEFAULT_COLOR_IDX)
-        color = _default_color;
-
-    // put rectangle
-    cv::Rect bbox_rect(rect.x, rect.y, rect.w, rect.h);
-    if (!_obb)
-        prims.emplace_back(render::Rect(bbox_rect, color, _displCfg.thickness, roi.rotation()));
-
-    // put text
-    if (_displCfg.show_labels)
-        if (text.str().size() != 0) {
-            cv::Point2f pos(rect.x, rect.y - 5.f);
-            if (pos.y < 0)
-                pos.y = rect.y + 30.f;
-            prims.emplace_back(render::Text(text.str(), pos, _displCfg.font_type, _displCfg.font_scale, color));
+        // Prepare primitives for tensors
+        for (auto &tensor : roi.tensors()) {
+            preparePrimsForTensor(tensor, rect, prims, color_index);
+            if (!tensor.is_detection()) {
+                appendStr(text, tensor.label());
+            }
         }
 
+        // set color
+        Color color = indexToColor(color_index);
+        if (_displCfg.color_idx != DEFAULT_COLOR_IDX)
+            color = _default_color;
+
+        // put rectangle
+        cv::Rect bbox_rect(rect.x, rect.y, rect.w, rect.h);
+        if (!_obb)
+            prims.emplace_back(render::Rect(bbox_rect, color, _displCfg.thickness, roi.rotation()));
+
+        // put text
+        if (_displCfg.show_labels)
+            if (text.str().size() != 0) {
+                cv::Point2f pos(rect.x, rect.y - 5.f);
+                if (pos.y < 0)
+                    pos.y = rect.y + 30.f;
+                prims.emplace_back(render::Text(text.str(), pos, _displCfg.font_type, _displCfg.font_scale, color));
+            }
+    }
+
     // put avg-fps from gvafpscounter element
     if (_displ_avgfps) {
         std::ostringstream fpstext;
@@ -1195,6 +1208,21 @@ void Impl::parse_displ_config() {
                 _displCfg.draw_text_background = (iter->second != "false");
                 cfg.erase(iter);
             }
+            if (iter = cfg.find("show-roi"); iter != cfg.end()) {
+                _displCfg.include_labels_filter = std::unordered_set<std::string>();
+                Utils::parseFilterConfig(iter->second, *_displCfg.include_labels_filter);
+                cfg.erase(iter);
+            }
+            if (iter = cfg.find("hide-roi"); iter != cfg.end()) {
+                if (_displCfg.include_labels_filter.has_value() && !(_displCfg.include_labels_filter->empty())) {
+                    GST_WARNING("[gvawatermarkimpl] Both 'show-roi' and 'hide-roi' parameters are set, "
+                                "'hide-roi' will be ignored.");
+                } else {
+                    _displCfg.exclude_labels_filter = std::unordered_set<std::string>();
+                    Utils::parseFilterConfig(iter->second, *_displCfg.exclude_labels_filter);
+                }
+                cfg.erase(iter);
+            }
         }
         if (iter = cfg.find("thickness"); iter != cfg.end()) {
             _displCfg.thickness = std::stoi(iter->second);
diff --git a/src/monolithic/gst/elements/gvawatermark/gstgvawatermarkimpl.h b/src/monolithic/gst/elements/gvawatermark/gstgvawatermarkimpl.h
@@ -82,8 +82,14 @@ enum { PROP_0, PROP_DEVICE, PROP_OBB, PROP_DISPL_AVGFPS, PROP_DISPL_CFG };
     "script_simplex, script_complex), default triplex\n"                                                               \
     "\t\t\tdraw-txt-bg=<bool> enable or disable displaying text labels background, by enabling it the text color "     \
     "is set to white, default false\n"                                                                                 \
+    "\t\t\tshow-roi=<string> colon-separated list of labels to include (only these objects will be shown), "           \
+    "default empty\n"                                                                                                  \
+    "\t\t\thide-roi=<string> colon-separated list of labels to exclude (these objects will be hidden), default "       \
+    "empty\n"                                                                                                          \
     "\t\t\te.g.: displ-cfg=show-labels=false\n"                                                                        \
-    "\t\t\te.g.: displ-cfg=font-scale=0.5,thickness=3,color-idx=2,font-type=simplex"
+    "\t\t\te.g.: displ-cfg=font-scale=0.5,thickness=3,color-idx=2,font-type=simplex\n"                                 \
+    "\t\t\te.g.: displ-cfg=show-labels=true,show-roi=person:car:truck\n"                                               \
+    "\t\t\te.g.: displ-cfg=show-labels=true,hide-roi=bottle:cup"
 
 G_END_DECLS
 
diff --git a/src/utils/utils.cpp b/src/utils/utils.cpp
@@ -46,6 +46,15 @@ std::vector<std::string> splitString(const std::string &input, char delimiter) {
     return tokens;
 }
 
+void parseFilterConfig(const std::string &config_str, std::unordered_set<std::string> &filtered_set, char delimiter) {
+    auto labels = splitString(config_str, delimiter);
+    for (const auto &label : labels) {
+        if (filtered_set.count(label) == 0) {
+            filtered_set.insert(label);
+        }
+    }
+}
+
 std::map<std::string, std::string> stringToMap(const std::string &s, char rec_delim /*= ','*/,
                                                char kv_delim /*= '='*/) {
     std::string key, val;
diff --git a/src/utils/utils.h b/src/utils/utils.h
@@ -16,6 +16,7 @@
 #include <set>
 #include <sstream>
 #include <string>
+#include <unordered_set>
 #include <vector>
 
 #ifdef _MSC_VER
@@ -55,6 +56,17 @@ std::string join(Iter begin, Iter end, char delimiter = ',') {
     return result.str();
 }
 
+/**
+ * Parses a label filter configuration string in the format `label1:label2:label3:...`.
+ * Labels values are added to the output set for filtering.
+ *
+ * @param config_str The configuration string to parse (e.g., "person:car:bike").
+ * @param filtered_set Output set that will contain only the relevant labels.
+ * @param delimiter The delimiter used to separate label entries (default is ':').
+ */
+void parseFilterConfig(const std::string &config_str, std::unordered_set<std::string> &filtered_set,
+                       char delimiter = ':');
+
 /**
  * Converts string in format `key1=val1,key2=val2,...` to key/value pairs.
  *
