Updated code

README.md

@@ -1,4 +1,4 @@
-# TinyML-CAM - Image Recognition System that Runs at 80 FPS in 1 Kb of RAM
+## TinyML-CAM - Image Recognition System that Runs at 80 FPS in 1 Kb of RAM
 
 ### Image Recognition Demo - ESP32
 ESP32 classifying Raspberry Pi Pico, Portenta H7, Wio Terminal from image frames
@@ -17,6 +17,6 @@ Following can be observed from the video:
 
 ### Code
 
-- [ipynb]-TinyML-CAM-full-code-with-markdown.ipynb
-- [h]-HOG-plus-RandomForest-classifier.h
-- [ino]-arduino-ESP32-code.ino - upload to
+- [[ipynb]-TinyML-CAM-full-code-with-markdown.ipynb](https://github.com/bharathsudharsan/TinyML-CAM/blob/main/%5Bipynb%5D-TinyML-CAM-full-code-with-markdown.ipynb)
+- [[h]-HOG-plus-RandomForest-classifier.h](https://github.com/bharathsudharsan/TinyML-CAM/blob/main/%5Bh%5D-HOG-plus-RandomForest-classifier.h)
+- [[ino]-arduino-ESP32-code.ino](https://github.com/bharathsudharsan/TinyML-CAM/blob/main/%5Bino%5D-arduino-ESP32-code.ino) - upload to

[h]-HogPipeline.h

@@ -0,0 +1,220 @@
+#ifndef UUID5853197456
+#define UUID5853197456
+
+
+    #ifndef UUID5853199664
+#define UUID5853199664
+
+/**
+  * HOG(block_size=8, bins=9, cell_size=3)
+ */
+class HOG {
+    public:
+
+        /**
+         * Transform input image
+         */
+         template<typename T, typename U>
+        bool transform(T *input, U *output) {
+            
+    uint16_t f = 0;
+    uint16_t block = 0;
+    float hog[135] = {0};
+
+    // compute gradients
+    for (uint16_t blockY = 0; blockY < 3; blockY++) {
+        const uint16_t blockOffsetY = blockY * 320;
+
+        for (uint16_t blockX = 0; blockX < 5; blockX++) {
+            const uint16_t blockOffsetX = blockX * 8;
+            float hist[9] = {0};
+
+            for (uint16_t _y = 1; _y < 7; _y += 1) {
+                const uint16_t rowOffset = blockOffsetY + _y * 40 + blockOffsetX;
+                const uint16_t rowOffsetBefore = rowOffset - 40;
+                const uint16_t rowOffsetAfter = rowOffset + 40;
+
+                for (uint16_t _x = 1; _x < 7; _x += 1) {
+                    const uint16_t offset = rowOffset + _x;
+                    const uint16_t offsetBefore = rowOffsetBefore + _x;
+                    const uint16_t offsetAfter = rowOffsetAfter + _x;
+                    const float gy = input[offsetAfter] - input[offsetBefore];
+                    const float gx = input[offset + 1] - input[offset - 1];
+                    const float g = sqrt(gy * gy + gx * gx);
+                    uint8_t angle = abs(this->arctan(gy, gx) * 180 / 3.141592653589793f / 20);
+
+                    if (angle >= 8) angle = 8;
+                    hist[angle] += g;
+                }
+            }
+
+            for (uint16_t i = 0; i < 9; i++)
+                hog[f++] = hist[i];
+
+            block += 1;
+
+            // end of cell, normalize
+            if ((block % 3) == 0) {
+                const uint16_t offset = (block - 3) * 9;
+                float maxGradient = 0.0001;
+
+                for (uint16_t i = 0; i < 27; i++) {
+                    const float h = hog[offset + i];
+
+                    if (h > maxGradient)
+                        maxGradient = h;
+                }
+
+                for (uint16_t i = 0; i < 27; i++) {
+                    hog[offset + i] /= maxGradient;
+                }
+
+                maxGradient = 0.0001;
+            }
+        }
+    }
+
+
+    // copy over
+    for (uint16_t i = 0; i < 135; i++)
+        output[i] = hog[i];
+
+
+            return true;
+        }
+
+    protected:
+        
+
+    /**
+     * optional atan2 approximation for faster calculation
+     */
+    float arctan(float y, float x) {
+        
+            float r = 0;
+
+            if (abs(y) < 0.00000001)
+                return 0;
+            else if (abs(x) < 0.00000001)
+                return 3.14159274 * (y > 0 ? 1 : -1);
+            else {
+                float a = min(abs(x), abs(y)) / max(abs(x), abs(y));
+                float s = a * a;
+                r = ((-0.0464964749 * s + 0.15931422) * s - 0.327622764) * s * a + a;
+
+                if (abs(y) > abs(x))
+                r = 1.57079637 - r;
+            }
+
+            if (x < 0)
+                r = 3.14159274 - r;
+            if (y < 0)
+                r = -r;
+
+            return r;
+        
+    }
+
+
+};
+
+
+
+#endif
+
+
+/**
+  * ImagePipeline: HogPipeline
+ * ---------
+ *  - Resize(from=((160, 120)), to=(40, 30), pixformat=gray)
+ *  > HOG(block_size=8, bins=9, cell_size=3)
+ */
+class HogPipeline {
+    public:
+        static const size_t NUM_INPUTS = 1200;
+        static const size_t NUM_OUTPUTS = 135;
+        static const size_t WORKING_SIZE = 135;
+        float features[135];
+
+        /**
+         * Extract features from input image
+         */
+        template<typename T>
+        bool transform(T *input) {
+            time_t start = micros();
+            ok = true;
+
+            preprocess(input);
+
+            
+                
+                    ok = ok && hog.transform(input, features);
+                
+            
+
+            latency = micros() - start;
+
+            return ok;
+        }
+
+        /**
+         * Debug output feature vector
+         */
+        template<typename PrinterInterface>
+        void debugTo(PrinterInterface &printer, uint8_t precision=5) {
+            printer.print(features[0], precision);
+
+            for (uint16_t i = 1; i < 135; i++) {
+                printer.print(", ");
+                printer.print(features[i], precision);
+            }
+
+            printer.print('\n');
+        }
+
+        /**
+ * Get latency in micros
+ */
+uint32_t latencyInMicros() {
+    return latency;
+}
+
+/**
+ * Get latency in millis
+ */
+uint16_t latencyInMillis() {
+    return latency / 1000;
+}
+
+    protected:
+        bool ok;
+        time_t latency;
+        
+            HOG hog;
+        
+
+        template<typename T>
+        void preprocess(T *input) {
+            
+                
+    // grayscale rescaling
+    const float dy = 4.0f;
+    const float dx = 4.0f;
+
+    for (uint16_t y = 0; y < 30; y++) {
+        const size_t sourceOffset = round(y * dy) * 160;
+        const size_t destOffset = y * 40;
+
+        for (uint16_t x = 0; x < 40; x++)
+            input[destOffset + x] = input[sourceOffset + ((uint16_t) (x * dx))];
+    }
+
+            
+        }
+};
+
+
+static HogPipeline hog;
+
+
+#endif